drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/gpio/consumer.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/pm_domain.h>
  24 #include <linux/property.h>
  25 #include <linux/export.h>
  26 #include <linux/sched/rt.h>
  27 #include <uapi/linux/sched/types.h>
  28 #include <linux/delay.h>
  29 #include <linux/kthread.h>
  30 #include <linux/ioport.h>
  31 #include <linux/acpi.h>
  32 #include <linux/highmem.h>
  33 #include <linux/idr.h>
  34 #include <linux/platform_data/x86/apple.h>
  35 #include <linux/ptp_clock_kernel.h>
  36 #include <linux/percpu.h>
  37
  38 #define CREATE_TRACE_POINTS
  39 #include <trace/events/spi.h>
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  41 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  42
  43 #include "internals.h"
  44
  45 static DEFINE_IDR(spi_master_idr);
  46
  47 static void spidev_release(struct device *dev)
  48 {
  49         struct spi_device       *spi = to_spi_device(dev);
  50
  51         spi_controller_put(spi->controller);
  52         kfree(spi->driver_override);
  53         free_percpu(spi->pcpu_statistics);
  54         kfree(spi);
  55 }
  56
  57 static ssize_t
  58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  59 {
  60         const struct spi_device *spi = to_spi_device(dev);
  61         int len;
  62
  63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  64         if (len != -ENODEV)
  65                 return len;
  66
  67         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  68 }
  69 static DEVICE_ATTR_RO(modalias);
  70
  71 static ssize_t driver_override_store(struct device *dev,
  72                                      struct device_attribute *a,
  73                                      const char *buf, size_t count)
  74 {
  75         struct spi_device *spi = to_spi_device(dev);
  76         int ret;
  77
  78         ret = driver_set_override(dev, &spi->driver_override, buf, count);
  79         if (ret)
  80                 return ret;
  81
  82         return count;
  83 }
  84
  85 static ssize_t driver_override_show(struct device *dev,
  86                                     struct device_attribute *a, char *buf)
  87 {
  88         const struct spi_device *spi = to_spi_device(dev);
  89         ssize_t len;
  90
  91         device_lock(dev);
  92         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
  93         device_unlock(dev);
  94         return len;
  95 }
  96 static DEVICE_ATTR_RW(driver_override);
  97
  98 static struct spi_statistics *spi_alloc_pcpu_stats(struct device *dev)
  99 {
 100         struct spi_statistics __percpu *pcpu_stats;
 101
 102         if (dev)
 103                 pcpu_stats = devm_alloc_percpu(dev, struct spi_statistics);
 104         else
 105                 pcpu_stats = alloc_percpu_gfp(struct spi_statistics, GFP_KERNEL);
 106
 107         if (pcpu_stats) {
 108                 int cpu;
 109
 110                 for_each_possible_cpu(cpu) {
 111                         struct spi_statistics *stat;
 112
 113                         stat = per_cpu_ptr(pcpu_stats, cpu);
 114                         u64_stats_init(&stat->syncp);
 115                 }
 116         }
 117         return pcpu_stats;
 118 }
 119
 120 #define spi_pcpu_stats_totalize(ret, in, field)                         \
 121 do {                                                                    \
 122         int i;                                                          \
 123         ret = 0;                                                        \
 124         for_each_possible_cpu(i) {                                      \
 125                 const struct spi_statistics *pcpu_stats;                \
 126                 u64 inc;                                                \
 127                 unsigned int start;                                     \
 128                 pcpu_stats = per_cpu_ptr(in, i);                        \
 129                 do {                                                    \
 130                         start = u64_stats_fetch_begin_irq(              \
 131                                         &pcpu_stats->syncp);            \
 132                         inc = u64_stats_read(&pcpu_stats->field);       \
 133                 } while (u64_stats_fetch_retry_irq(                     \
 134                                         &pcpu_stats->syncp, start));    \
 135                 ret += inc;                                             \
 136         }                                                               \
 137 } while (0)
 138
 139 #define SPI_STATISTICS_ATTRS(field, file)                               \
 140 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 141                                              struct device_attribute *attr, \
 142                                              char *buf)                 \
 143 {                                                                       \
 144         struct spi_controller *ctlr = container_of(dev,                 \
 145                                          struct spi_controller, dev);   \
 146         return spi_statistics_##field##_show(ctlr->pcpu_statistics, buf); \
 147 }                                                                       \
 148 static struct device_attribute dev_attr_spi_controller_##field = {      \
 149         .attr = { .name = file, .mode = 0444 },                         \
 150         .show = spi_controller_##field##_show,                          \
 151 };                                                                      \
 152 static ssize_t spi_device_##field##_show(struct device *dev,            \
 153                                          struct device_attribute *attr, \
 154                                         char *buf)                      \
 155 {                                                                       \
 156         struct spi_device *spi = to_spi_device(dev);                    \
 157         return spi_statistics_##field##_show(spi->pcpu_statistics, buf); \
 158 }                                                                       \
 159 static struct device_attribute dev_attr_spi_device_##field = {          \
 160         .attr = { .name = file, .mode = 0444 },                         \
 161         .show = spi_device_##field##_show,                              \
 162 }
 163
 164 #define SPI_STATISTICS_SHOW_NAME(name, file, field)                     \
 165 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 166                                             char *buf)                  \
 167 {                                                                       \
 168         ssize_t len;                                                    \
 169         u64 val;                                                        \
 170         spi_pcpu_stats_totalize(val, stat, field);                      \
 171         len = sysfs_emit(buf, "%llu\n", val);                           \
 172         return len;                                                     \
 173 }                                                                       \
 174 SPI_STATISTICS_ATTRS(name, file)
 175
 176 #define SPI_STATISTICS_SHOW(field)                                      \
 177         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 178                                  field)
 179
 180 SPI_STATISTICS_SHOW(messages);
 181 SPI_STATISTICS_SHOW(transfers);
 182 SPI_STATISTICS_SHOW(errors);
 183 SPI_STATISTICS_SHOW(timedout);
 184
 185 SPI_STATISTICS_SHOW(spi_sync);
 186 SPI_STATISTICS_SHOW(spi_sync_immediate);
 187 SPI_STATISTICS_SHOW(spi_async);
 188
 189 SPI_STATISTICS_SHOW(bytes);
 190 SPI_STATISTICS_SHOW(bytes_rx);
 191 SPI_STATISTICS_SHOW(bytes_tx);
 192
 193 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 194         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 195                                  "transfer_bytes_histo_" number,        \
 196                                  transfer_bytes_histo[index])
 197 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 198 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 199 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 200 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 201 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 202 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 203 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 204 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 205 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 206 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 207 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 208 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 209 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 210 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 211 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 212 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 213 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 214
 215 SPI_STATISTICS_SHOW(transfers_split_maxsize);
 216
 217 static struct attribute *spi_dev_attrs[] = {
 218         &dev_attr_modalias.attr,
 219         &dev_attr_driver_override.attr,
 220         NULL,
 221 };
 222
 223 static const struct attribute_group spi_dev_group = {
 224         .attrs  = spi_dev_attrs,
 225 };
 226
 227 static struct attribute *spi_device_statistics_attrs[] = {
 228         &dev_attr_spi_device_messages.attr,
 229         &dev_attr_spi_device_transfers.attr,
 230         &dev_attr_spi_device_errors.attr,
 231         &dev_attr_spi_device_timedout.attr,
 232         &dev_attr_spi_device_spi_sync.attr,
 233         &dev_attr_spi_device_spi_sync_immediate.attr,
 234         &dev_attr_spi_device_spi_async.attr,
 235         &dev_attr_spi_device_bytes.attr,
 236         &dev_attr_spi_device_bytes_rx.attr,
 237         &dev_attr_spi_device_bytes_tx.attr,
 238         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 239         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 240         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 241         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 242         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 243         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 244         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 245         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 246         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 247         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 248         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 249         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 250         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 251         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 252         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 253         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 254         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 255         &dev_attr_spi_device_transfers_split_maxsize.attr,
 256         NULL,
 257 };
 258
 259 static const struct attribute_group spi_device_statistics_group = {
 260         .name  = "statistics",
 261         .attrs  = spi_device_statistics_attrs,
 262 };
 263
 264 static const struct attribute_group *spi_dev_groups[] = {
 265         &spi_dev_group,
 266         &spi_device_statistics_group,
 267         NULL,
 268 };
 269
 270 static struct attribute *spi_controller_statistics_attrs[] = {
 271         &dev_attr_spi_controller_messages.attr,
 272         &dev_attr_spi_controller_transfers.attr,
 273         &dev_attr_spi_controller_errors.attr,
 274         &dev_attr_spi_controller_timedout.attr,
 275         &dev_attr_spi_controller_spi_sync.attr,
 276         &dev_attr_spi_controller_spi_sync_immediate.attr,
 277         &dev_attr_spi_controller_spi_async.attr,
 278         &dev_attr_spi_controller_bytes.attr,
 279         &dev_attr_spi_controller_bytes_rx.attr,
 280         &dev_attr_spi_controller_bytes_tx.attr,
 281         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 282         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 283         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 284         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 285         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 286         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 287         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 288         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 289         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 290         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 291         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 292         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 293         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 294         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 295         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 296         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 297         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 298         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 299         NULL,
 300 };
 301
 302 static const struct attribute_group spi_controller_statistics_group = {
 303         .name  = "statistics",
 304         .attrs  = spi_controller_statistics_attrs,
 305 };
 306
 307 static const struct attribute_group *spi_master_groups[] = {
 308         &spi_controller_statistics_group,
 309         NULL,
 310 };
 311
 312 static void spi_statistics_add_transfer_stats(struct spi_statistics *pcpu_stats,
 313                                               struct spi_transfer *xfer,
 314                                               struct spi_controller *ctlr)
 315 {
 316         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 317         struct spi_statistics *stats;
 318
 319         if (l2len < 0)
 320                 l2len = 0;
 321
 322         get_cpu();
 323         stats = this_cpu_ptr(pcpu_stats);
 324         u64_stats_update_begin(&stats->syncp);
 325
 326         u64_stats_inc(&stats->transfers);
 327         u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
 328
 329         u64_stats_add(&stats->bytes, xfer->len);
 330         if ((xfer->tx_buf) &&
 331             (xfer->tx_buf != ctlr->dummy_tx))
 332                 u64_stats_add(&stats->bytes_tx, xfer->len);
 333         if ((xfer->rx_buf) &&
 334             (xfer->rx_buf != ctlr->dummy_rx))
 335                 u64_stats_add(&stats->bytes_rx, xfer->len);
 336
 337         u64_stats_update_end(&stats->syncp);
 338         put_cpu();
 339 }
 340
 341 /*
 342  * modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 343  * and the sysfs version makes coldplug work too.
 344  */
 345 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
 346 {
 347         while (id->name[0]) {
 348                 if (!strcmp(name, id->name))
 349                         return id;
 350                 id++;
 351         }
 352         return NULL;
 353 }
 354
 355 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 356 {
 357         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 358
 359         return spi_match_id(sdrv->id_table, sdev->modalias);
 360 }
 361 EXPORT_SYMBOL_GPL(spi_get_device_id);
 362
 363 static int spi_match_device(struct device *dev, struct device_driver *drv)
 364 {
 365         const struct spi_device *spi = to_spi_device(dev);
 366         const struct spi_driver *sdrv = to_spi_driver(drv);
 367
 368         /* Check override first, and if set, only use the named driver */
 369         if (spi->driver_override)
 370                 return strcmp(spi->driver_override, drv->name) == 0;
 371
 372         /* Attempt an OF style match */
 373         if (of_driver_match_device(dev, drv))
 374                 return 1;
 375
 376         /* Then try ACPI */
 377         if (acpi_driver_match_device(dev, drv))
 378                 return 1;
 379
 380         if (sdrv->id_table)
 381                 return !!spi_match_id(sdrv->id_table, spi->modalias);
 382
 383         return strcmp(spi->modalias, drv->name) == 0;
 384 }
 385
 386 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 387 {
 388         const struct spi_device         *spi = to_spi_device(dev);
 389         int rc;
 390
 391         rc = acpi_device_uevent_modalias(dev, env);
 392         if (rc != -ENODEV)
 393                 return rc;
 394
 395         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 396 }
 397
 398 static int spi_probe(struct device *dev)
 399 {
 400         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 401         struct spi_device               *spi = to_spi_device(dev);
 402         int ret;
 403
 404         ret = of_clk_set_defaults(dev->of_node, false);
 405         if (ret)
 406                 return ret;
 407
 408         if (dev->of_node) {
 409                 spi->irq = of_irq_get(dev->of_node, 0);
 410                 if (spi->irq == -EPROBE_DEFER)
 411                         return -EPROBE_DEFER;
 412                 if (spi->irq < 0)
 413                         spi->irq = 0;
 414         }
 415
 416         ret = dev_pm_domain_attach(dev, true);
 417         if (ret)
 418                 return ret;
 419
 420         if (sdrv->probe) {
 421                 ret = sdrv->probe(spi);
 422                 if (ret)
 423                         dev_pm_domain_detach(dev, true);
 424         }
 425
 426         return ret;
 427 }
 428
 429 static void spi_remove(struct device *dev)
 430 {
 431         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 432
 433         if (sdrv->remove)
 434                 sdrv->remove(to_spi_device(dev));
 435
 436         dev_pm_domain_detach(dev, true);
 437 }
 438
 439 static void spi_shutdown(struct device *dev)
 440 {
 441         if (dev->driver) {
 442                 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
 443
 444                 if (sdrv->shutdown)
 445                         sdrv->shutdown(to_spi_device(dev));
 446         }
 447 }
 448
 449 struct bus_type spi_bus_type = {
 450         .name           = "spi",
 451         .dev_groups     = spi_dev_groups,
 452         .match          = spi_match_device,
 453         .uevent         = spi_uevent,
 454         .probe          = spi_probe,
 455         .remove         = spi_remove,
 456         .shutdown       = spi_shutdown,
 457 };
 458 EXPORT_SYMBOL_GPL(spi_bus_type);
 459
 460 /**
 461  * __spi_register_driver - register a SPI driver
 462  * @owner: owner module of the driver to register
 463  * @sdrv: the driver to register
 464  * Context: can sleep
 465  *
 466  * Return: zero on success, else a negative error code.
 467  */
 468 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 469 {
 470         sdrv->driver.owner = owner;
 471         sdrv->driver.bus = &spi_bus_type;
 472
 473         /*
 474          * For Really Good Reasons we use spi: modaliases not of:
 475          * modaliases for DT so module autoloading won't work if we
 476          * don't have a spi_device_id as well as a compatible string.
 477          */
 478         if (sdrv->driver.of_match_table) {
 479                 const struct of_device_id *of_id;
 480
 481                 for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
 482                      of_id++) {
 483                         const char *of_name;
 484
 485                         /* Strip off any vendor prefix */
 486                         of_name = strnchr(of_id->compatible,
 487                                           sizeof(of_id->compatible), ',');
 488                         if (of_name)
 489                                 of_name++;
 490                         else
 491                                 of_name = of_id->compatible;
 492
 493                         if (sdrv->id_table) {
 494                                 const struct spi_device_id *spi_id;
 495
 496                                 spi_id = spi_match_id(sdrv->id_table, of_name);
 497                                 if (spi_id)
 498                                         continue;
 499                         } else {
 500                                 if (strcmp(sdrv->driver.name, of_name) == 0)
 501                                         continue;
 502                         }
 503
 504                         pr_warn("SPI driver %s has no spi_device_id for %s\n",
 505                                 sdrv->driver.name, of_id->compatible);
 506                 }
 507         }
 508
 509         return driver_register(&sdrv->driver);
 510 }
 511 EXPORT_SYMBOL_GPL(__spi_register_driver);
 512
 513 /*-------------------------------------------------------------------------*/
 514
 515 /*
 516  * SPI devices should normally not be created by SPI device drivers; that
 517  * would make them board-specific.  Similarly with SPI controller drivers.
 518  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 519  * with other readonly (flashable) information about mainboard devices.
 520  */
 521
 522 struct boardinfo {
 523         struct list_head        list;
 524         struct spi_board_info   board_info;
 525 };
 526
 527 static LIST_HEAD(board_list);
 528 static LIST_HEAD(spi_controller_list);
 529
 530 /*
 531  * Used to protect add/del operation for board_info list and
 532  * spi_controller list, and their matching process also used
 533  * to protect object of type struct idr.
 534  */
 535 static DEFINE_MUTEX(board_lock);
 536
 537 /**
 538  * spi_alloc_device - Allocate a new SPI device
 539  * @ctlr: Controller to which device is connected
 540  * Context: can sleep
 541  *
 542  * Allows a driver to allocate and initialize a spi_device without
 543  * registering it immediately.  This allows a driver to directly
 544  * fill the spi_device with device parameters before calling
 545  * spi_add_device() on it.
 546  *
 547  * Caller is responsible to call spi_add_device() on the returned
 548  * spi_device structure to add it to the SPI controller.  If the caller
 549  * needs to discard the spi_device without adding it, then it should
 550  * call spi_dev_put() on it.
 551  *
 552  * Return: a pointer to the new device, or NULL.
 553  */
 554 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 555 {
 556         struct spi_device       *spi;
 557
 558         if (!spi_controller_get(ctlr))
 559                 return NULL;
 560
 561         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 562         if (!spi) {
 563                 spi_controller_put(ctlr);
 564                 return NULL;
 565         }
 566
 567         spi->pcpu_statistics = spi_alloc_pcpu_stats(NULL);
 568         if (!spi->pcpu_statistics) {
 569                 kfree(spi);
 570                 spi_controller_put(ctlr);
 571                 return NULL;
 572         }
 573
 574         spi->master = spi->controller = ctlr;
 575         spi->dev.parent = &ctlr->dev;
 576         spi->dev.bus = &spi_bus_type;
 577         spi->dev.release = spidev_release;
 578         spi->mode = ctlr->buswidth_override_bits;
 579
 580         device_initialize(&spi->dev);
 581         return spi;
 582 }
 583 EXPORT_SYMBOL_GPL(spi_alloc_device);
 584
 585 static void spi_dev_set_name(struct spi_device *spi)
 586 {
 587         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 588
 589         if (adev) {
 590                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 591                 return;
 592         }
 593
 594         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 595                      spi->chip_select);
 596 }
 597
 598 static int spi_dev_check(struct device *dev, void *data)
 599 {
 600         struct spi_device *spi = to_spi_device(dev);
 601         struct spi_device *new_spi = data;
 602
 603         if (spi->controller == new_spi->controller &&
 604             spi->chip_select == new_spi->chip_select)
 605                 return -EBUSY;
 606         return 0;
 607 }
 608
 609 static void spi_cleanup(struct spi_device *spi)
 610 {
 611         if (spi->controller->cleanup)
 612                 spi->controller->cleanup(spi);
 613 }
 614
 615 static int __spi_add_device(struct spi_device *spi)
 616 {
 617         struct spi_controller *ctlr = spi->controller;
 618         struct device *dev = ctlr->dev.parent;
 619         int status;
 620
 621         /*
 622          * We need to make sure there's no other device with this
 623          * chipselect **BEFORE** we call setup(), else we'll trash
 624          * its configuration.
 625          */
 626         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 627         if (status) {
 628                 dev_err(dev, "chipselect %d already in use\n",
 629                                 spi->chip_select);
 630                 return status;
 631         }
 632
 633         /* Controller may unregister concurrently */
 634         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 635             !device_is_registered(&ctlr->dev)) {
 636                 return -ENODEV;
 637         }
 638
 639         if (ctlr->cs_gpiods)
 640                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 641
 642         /*
 643          * Drivers may modify this initial i/o setup, but will
 644          * normally rely on the device being setup.  Devices
 645          * using SPI_CS_HIGH can't coexist well otherwise...
 646          */
 647         status = spi_setup(spi);
 648         if (status < 0) {
 649                 dev_err(dev, "can't setup %s, status %d\n",
 650                                 dev_name(&spi->dev), status);
 651                 return status;
 652         }
 653
 654         /* Device may be bound to an active driver when this returns */
 655         status = device_add(&spi->dev);
 656         if (status < 0) {
 657                 dev_err(dev, "can't add %s, status %d\n",
 658                                 dev_name(&spi->dev), status);
 659                 spi_cleanup(spi);
 660         } else {
 661                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 662         }
 663
 664         return status;
 665 }
 666
 667 /**
 668  * spi_add_device - Add spi_device allocated with spi_alloc_device
 669  * @spi: spi_device to register
 670  *
 671  * Companion function to spi_alloc_device.  Devices allocated with
 672  * spi_alloc_device can be added onto the spi bus with this function.
 673  *
 674  * Return: 0 on success; negative errno on failure
 675  */
 676 int spi_add_device(struct spi_device *spi)
 677 {
 678         struct spi_controller *ctlr = spi->controller;
 679         struct device *dev = ctlr->dev.parent;
 680         int status;
 681
 682         /* Chipselects are numbered 0..max; validate. */
 683         if (spi->chip_select >= ctlr->num_chipselect) {
 684                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 685                         ctlr->num_chipselect);
 686                 return -EINVAL;
 687         }
 688
 689         /* Set the bus ID string */
 690         spi_dev_set_name(spi);
 691
 692         mutex_lock(&ctlr->add_lock);
 693         status = __spi_add_device(spi);
 694         mutex_unlock(&ctlr->add_lock);
 695         return status;
 696 }
 697 EXPORT_SYMBOL_GPL(spi_add_device);
 698
 699 static int spi_add_device_locked(struct spi_device *spi)
 700 {
 701         struct spi_controller *ctlr = spi->controller;
 702         struct device *dev = ctlr->dev.parent;
 703
 704         /* Chipselects are numbered 0..max; validate. */
 705         if (spi->chip_select >= ctlr->num_chipselect) {
 706                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 707                         ctlr->num_chipselect);
 708                 return -EINVAL;
 709         }
 710
 711         /* Set the bus ID string */
 712         spi_dev_set_name(spi);
 713
 714         WARN_ON(!mutex_is_locked(&ctlr->add_lock));
 715         return __spi_add_device(spi);
 716 }
 717
 718 /**
 719  * spi_new_device - instantiate one new SPI device
 720  * @ctlr: Controller to which device is connected
 721  * @chip: Describes the SPI device
 722  * Context: can sleep
 723  *
 724  * On typical mainboards, this is purely internal; and it's not needed
 725  * after board init creates the hard-wired devices.  Some development
 726  * platforms may not be able to use spi_register_board_info though, and
 727  * this is exported so that for example a USB or parport based adapter
 728  * driver could add devices (which it would learn about out-of-band).
 729  *
 730  * Return: the new device, or NULL.
 731  */
 732 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 733                                   struct spi_board_info *chip)
 734 {
 735         struct spi_device       *proxy;
 736         int                     status;
 737
 738         /*
 739          * NOTE:  caller did any chip->bus_num checks necessary.
 740          *
 741          * Also, unless we change the return value convention to use
 742          * error-or-pointer (not NULL-or-pointer), troubleshootability
 743          * suggests syslogged diagnostics are best here (ugh).
 744          */
 745
 746         proxy = spi_alloc_device(ctlr);
 747         if (!proxy)
 748                 return NULL;
 749
 750         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 751
 752         proxy->chip_select = chip->chip_select;
 753         proxy->max_speed_hz = chip->max_speed_hz;
 754         proxy->mode = chip->mode;
 755         proxy->irq = chip->irq;
 756         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 757         proxy->dev.platform_data = (void *) chip->platform_data;
 758         proxy->controller_data = chip->controller_data;
 759         proxy->controller_state = NULL;
 760
 761         if (chip->swnode) {
 762                 status = device_add_software_node(&proxy->dev, chip->swnode);
 763                 if (status) {
 764                         dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
 765                                 chip->modalias, status);
 766                         goto err_dev_put;
 767                 }
 768         }
 769
 770         status = spi_add_device(proxy);
 771         if (status < 0)
 772                 goto err_dev_put;
 773
 774         return proxy;
 775
 776 err_dev_put:
 777         device_remove_software_node(&proxy->dev);
 778         spi_dev_put(proxy);
 779         return NULL;
 780 }
 781 EXPORT_SYMBOL_GPL(spi_new_device);
 782
 783 /**
 784  * spi_unregister_device - unregister a single SPI device
 785  * @spi: spi_device to unregister
 786  *
 787  * Start making the passed SPI device vanish. Normally this would be handled
 788  * by spi_unregister_controller().
 789  */
 790 void spi_unregister_device(struct spi_device *spi)
 791 {
 792         if (!spi)
 793                 return;
 794
 795         if (spi->dev.of_node) {
 796                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 797                 of_node_put(spi->dev.of_node);
 798         }
 799         if (ACPI_COMPANION(&spi->dev))
 800                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 801         device_remove_software_node(&spi->dev);
 802         device_del(&spi->dev);
 803         spi_cleanup(spi);
 804         put_device(&spi->dev);
 805 }
 806 EXPORT_SYMBOL_GPL(spi_unregister_device);
 807
 808 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 809                                               struct spi_board_info *bi)
 810 {
 811         struct spi_device *dev;
 812
 813         if (ctlr->bus_num != bi->bus_num)
 814                 return;
 815
 816         dev = spi_new_device(ctlr, bi);
 817         if (!dev)
 818                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 819                         bi->modalias);
 820 }
 821
 822 /**
 823  * spi_register_board_info - register SPI devices for a given board
 824  * @info: array of chip descriptors
 825  * @n: how many descriptors are provided
 826  * Context: can sleep
 827  *
 828  * Board-specific early init code calls this (probably during arch_initcall)
 829  * with segments of the SPI device table.  Any device nodes are created later,
 830  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 831  * this table of devices forever, so that reloading a controller driver will
 832  * not make Linux forget about these hard-wired devices.
 833  *
 834  * Other code can also call this, e.g. a particular add-on board might provide
 835  * SPI devices through its expansion connector, so code initializing that board
 836  * would naturally declare its SPI devices.
 837  *
 838  * The board info passed can safely be __initdata ... but be careful of
 839  * any embedded pointers (platform_data, etc), they're copied as-is.
 840  *
 841  * Return: zero on success, else a negative error code.
 842  */
 843 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 844 {
 845         struct boardinfo *bi;
 846         int i;
 847
 848         if (!n)
 849                 return 0;
 850
 851         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 852         if (!bi)
 853                 return -ENOMEM;
 854
 855         for (i = 0; i < n; i++, bi++, info++) {
 856                 struct spi_controller *ctlr;
 857
 858                 memcpy(&bi->board_info, info, sizeof(*info));
 859
 860                 mutex_lock(&board_lock);
 861                 list_add_tail(&bi->list, &board_list);
 862                 list_for_each_entry(ctlr, &spi_controller_list, list)
 863                         spi_match_controller_to_boardinfo(ctlr,
 864                                                           &bi->board_info);
 865                 mutex_unlock(&board_lock);
 866         }
 867
 868         return 0;
 869 }
 870
 871 /*-------------------------------------------------------------------------*/
 872
 873 /* Core methods for SPI resource management */
 874
 875 /**
 876  * spi_res_alloc - allocate a spi resource that is life-cycle managed
 877  *                 during the processing of a spi_message while using
 878  *                 spi_transfer_one
 879  * @spi:     the spi device for which we allocate memory
 880  * @release: the release code to execute for this resource
 881  * @size:    size to alloc and return
 882  * @gfp:     GFP allocation flags
 883  *
 884  * Return: the pointer to the allocated data
 885  *
 886  * This may get enhanced in the future to allocate from a memory pool
 887  * of the @spi_device or @spi_controller to avoid repeated allocations.
 888  */
 889 static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
 890                            size_t size, gfp_t gfp)
 891 {
 892         struct spi_res *sres;
 893
 894         sres = kzalloc(sizeof(*sres) + size, gfp);
 895         if (!sres)
 896                 return NULL;
 897
 898         INIT_LIST_HEAD(&sres->entry);
 899         sres->release = release;
 900
 901         return sres->data;
 902 }
 903
 904 /**
 905  * spi_res_free - free an spi resource
 906  * @res: pointer to the custom data of a resource
 907  */
 908 static void spi_res_free(void *res)
 909 {
 910         struct spi_res *sres = container_of(res, struct spi_res, data);
 911
 912         if (!res)
 913                 return;
 914
 915         WARN_ON(!list_empty(&sres->entry));
 916         kfree(sres);
 917 }
 918
 919 /**
 920  * spi_res_add - add a spi_res to the spi_message
 921  * @message: the spi message
 922  * @res:     the spi_resource
 923  */
 924 static void spi_res_add(struct spi_message *message, void *res)
 925 {
 926         struct spi_res *sres = container_of(res, struct spi_res, data);
 927
 928         WARN_ON(!list_empty(&sres->entry));
 929         list_add_tail(&sres->entry, &message->resources);
 930 }
 931
 932 /**
 933  * spi_res_release - release all spi resources for this message
 934  * @ctlr:  the @spi_controller
 935  * @message: the @spi_message
 936  */
 937 static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
 938 {
 939         struct spi_res *res, *tmp;
 940
 941         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
 942                 if (res->release)
 943                         res->release(ctlr, message, res->data);
 944
 945                 list_del(&res->entry);
 946
 947                 kfree(res);
 948         }
 949 }
 950
 951 /*-------------------------------------------------------------------------*/
 952
 953 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 954 {
 955         bool activate = enable;
 956
 957         /*
 958          * Avoid calling into the driver (or doing delays) if the chip select
 959          * isn't actually changing from the last time this was called.
 960          */
 961         if (!force && ((enable && spi->controller->last_cs == spi->chip_select) ||
 962                                 (!enable && spi->controller->last_cs != spi->chip_select)) &&
 963             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 964                 return;
 965
 966         trace_spi_set_cs(spi, activate);
 967
 968         spi->controller->last_cs = enable ? spi->chip_select : -1;
 969         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 970
 971         if ((spi->cs_gpiod || !spi->controller->set_cs_timing) && !activate) {
 972                 spi_delay_exec(&spi->cs_hold, NULL);
 973         }
 974
 975         if (spi->mode & SPI_CS_HIGH)
 976                 enable = !enable;
 977
 978         if (spi->cs_gpiod) {
 979                 if (!(spi->mode & SPI_NO_CS)) {
 980                         /*
 981                          * Historically ACPI has no means of the GPIO polarity and
 982                          * thus the SPISerialBus() resource defines it on the per-chip
 983                          * basis. In order to avoid a chain of negations, the GPIO
 984                          * polarity is considered being Active High. Even for the cases
 985                          * when _DSD() is involved (in the updated versions of ACPI)
 986                          * the GPIO CS polarity must be defined Active High to avoid
 987                          * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
 988                          * into account.
 989                          */
 990                         if (has_acpi_companion(&spi->dev))
 991                                 gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
 992                         else
 993                                 /* Polarity handled by GPIO library */
 994                                 gpiod_set_value_cansleep(spi->cs_gpiod, activate);
 995                 }
 996                 /* Some SPI masters need both GPIO CS & slave_select */
 997                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 998                     spi->controller->set_cs)
 999                         spi->controller->set_cs(spi, !enable);
1000         } else if (spi->controller->set_cs) {
1001                 spi->controller->set_cs(spi, !enable);
1002         }
1003
1004         if (spi->cs_gpiod || !spi->controller->set_cs_timing) {
1005                 if (activate)
1006                         spi_delay_exec(&spi->cs_setup, NULL);
1007                 else
1008                         spi_delay_exec(&spi->cs_inactive, NULL);
1009         }
1010 }
1011
1012 #ifdef CONFIG_HAS_DMA
1013 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
1014                 struct sg_table *sgt, void *buf, size_t len,
1015                 enum dma_data_direction dir)
1016 {
1017         const bool vmalloced_buf = is_vmalloc_addr(buf);
1018         unsigned int max_seg_size = dma_get_max_seg_size(dev);
1019 #ifdef CONFIG_HIGHMEM
1020         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
1021                                 (unsigned long)buf < (PKMAP_BASE +
1022                                         (LAST_PKMAP * PAGE_SIZE)));
1023 #else
1024         const bool kmap_buf = false;
1025 #endif
1026         int desc_len;
1027         int sgs;
1028         struct page *vm_page;
1029         struct scatterlist *sg;
1030         void *sg_buf;
1031         size_t min;
1032         int i, ret;
1033
1034         if (vmalloced_buf || kmap_buf) {
1035                 desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
1036                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
1037         } else if (virt_addr_valid(buf)) {
1038                 desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
1039                 sgs = DIV_ROUND_UP(len, desc_len);
1040         } else {
1041                 return -EINVAL;
1042         }
1043
1044         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
1045         if (ret != 0)
1046                 return ret;
1047
1048         sg = &sgt->sgl[0];
1049         for (i = 0; i < sgs; i++) {
1050
1051                 if (vmalloced_buf || kmap_buf) {
1052                         /*
1053                          * Next scatterlist entry size is the minimum between
1054                          * the desc_len and the remaining buffer length that
1055                          * fits in a page.
1056                          */
1057                         min = min_t(size_t, desc_len,
1058                                     min_t(size_t, len,
1059                                           PAGE_SIZE - offset_in_page(buf)));
1060                         if (vmalloced_buf)
1061                                 vm_page = vmalloc_to_page(buf);
1062                         else
1063                                 vm_page = kmap_to_page(buf);
1064                         if (!vm_page) {
1065                                 sg_free_table(sgt);
1066                                 return -ENOMEM;
1067                         }
1068                         sg_set_page(sg, vm_page,
1069                                     min, offset_in_page(buf));
1070                 } else {
1071                         min = min_t(size_t, len, desc_len);
1072                         sg_buf = buf;
1073                         sg_set_buf(sg, sg_buf, min);
1074                 }
1075
1076                 buf += min;
1077                 len -= min;
1078                 sg = sg_next(sg);
1079         }
1080
1081         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
1082         if (!ret)
1083                 ret = -ENOMEM;
1084         if (ret < 0) {
1085                 sg_free_table(sgt);
1086                 return ret;
1087         }
1088
1089         sgt->nents = ret;
1090
1091         return 0;
1092 }
1093
1094 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
1095                    struct sg_table *sgt, enum dma_data_direction dir)
1096 {
1097         if (sgt->orig_nents) {
1098                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
1099                 sg_free_table(sgt);
1100         }
1101 }
1102
1103 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1104 {
1105         struct device *tx_dev, *rx_dev;
1106         struct spi_transfer *xfer;
1107         int ret;
1108
1109         if (!ctlr->can_dma)
1110                 return 0;
1111
1112         if (ctlr->dma_tx)
1113                 tx_dev = ctlr->dma_tx->device->dev;
1114         else if (ctlr->dma_map_dev)
1115                 tx_dev = ctlr->dma_map_dev;
1116         else
1117                 tx_dev = ctlr->dev.parent;
1118
1119         if (ctlr->dma_rx)
1120                 rx_dev = ctlr->dma_rx->device->dev;
1121         else if (ctlr->dma_map_dev)
1122                 rx_dev = ctlr->dma_map_dev;
1123         else
1124                 rx_dev = ctlr->dev.parent;
1125
1126         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1127                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1128                         continue;
1129
1130                 if (xfer->tx_buf != NULL) {
1131                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
1132                                           (void *)xfer->tx_buf, xfer->len,
1133                                           DMA_TO_DEVICE);
1134                         if (ret != 0)
1135                                 return ret;
1136                 }
1137
1138                 if (xfer->rx_buf != NULL) {
1139                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
1140                                           xfer->rx_buf, xfer->len,
1141                                           DMA_FROM_DEVICE);
1142                         if (ret != 0) {
1143                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
1144                                               DMA_TO_DEVICE);
1145                                 return ret;
1146                         }
1147                 }
1148         }
1149
1150         ctlr->cur_msg_mapped = true;
1151
1152         return 0;
1153 }
1154
1155 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1156 {
1157         struct spi_transfer *xfer;
1158         struct device *tx_dev, *rx_dev;
1159
1160         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1161                 return 0;
1162
1163         if (ctlr->dma_tx)
1164                 tx_dev = ctlr->dma_tx->device->dev;
1165         else if (ctlr->dma_map_dev)
1166                 tx_dev = ctlr->dma_map_dev;
1167         else
1168                 tx_dev = ctlr->dev.parent;
1169
1170         if (ctlr->dma_rx)
1171                 rx_dev = ctlr->dma_rx->device->dev;
1172         else if (ctlr->dma_map_dev)
1173                 rx_dev = ctlr->dma_map_dev;
1174         else
1175                 rx_dev = ctlr->dev.parent;
1176
1177         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1178                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1179                         continue;
1180
1181                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1182                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1183         }
1184
1185         ctlr->cur_msg_mapped = false;
1186
1187         return 0;
1188 }
1189 #else /* !CONFIG_HAS_DMA */
1190 static inline int __spi_map_msg(struct spi_controller *ctlr,
1191                                 struct spi_message *msg)
1192 {
1193         return 0;
1194 }
1195
1196 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1197                                   struct spi_message *msg)
1198 {
1199         return 0;
1200 }
1201 #endif /* !CONFIG_HAS_DMA */
1202
1203 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1204                                 struct spi_message *msg)
1205 {
1206         struct spi_transfer *xfer;
1207
1208         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1209                 /*
1210                  * Restore the original value of tx_buf or rx_buf if they are
1211                  * NULL.
1212                  */
1213                 if (xfer->tx_buf == ctlr->dummy_tx)
1214                         xfer->tx_buf = NULL;
1215                 if (xfer->rx_buf == ctlr->dummy_rx)
1216                         xfer->rx_buf = NULL;
1217         }
1218
1219         return __spi_unmap_msg(ctlr, msg);
1220 }
1221
1222 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1223 {
1224         struct spi_transfer *xfer;
1225         void *tmp;
1226         unsigned int max_tx, max_rx;
1227
1228         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1229                 && !(msg->spi->mode & SPI_3WIRE)) {
1230                 max_tx = 0;
1231                 max_rx = 0;
1232
1233                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1234                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1235                             !xfer->tx_buf)
1236                                 max_tx = max(xfer->len, max_tx);
1237                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1238                             !xfer->rx_buf)
1239                                 max_rx = max(xfer->len, max_rx);
1240                 }
1241
1242                 if (max_tx) {
1243                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1244                                        GFP_KERNEL | GFP_DMA | __GFP_ZERO);
1245                         if (!tmp)
1246                                 return -ENOMEM;
1247                         ctlr->dummy_tx = tmp;
1248                 }
1249
1250                 if (max_rx) {
1251                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1252                                        GFP_KERNEL | GFP_DMA);
1253                         if (!tmp)
1254                                 return -ENOMEM;
1255                         ctlr->dummy_rx = tmp;
1256                 }
1257
1258                 if (max_tx || max_rx) {
1259                         list_for_each_entry(xfer, &msg->transfers,
1260                                             transfer_list) {
1261                                 if (!xfer->len)
1262                                         continue;
1263                                 if (!xfer->tx_buf)
1264                                         xfer->tx_buf = ctlr->dummy_tx;
1265                                 if (!xfer->rx_buf)
1266                                         xfer->rx_buf = ctlr->dummy_rx;
1267                         }
1268                 }
1269         }
1270
1271         return __spi_map_msg(ctlr, msg);
1272 }
1273
1274 static int spi_transfer_wait(struct spi_controller *ctlr,
1275                              struct spi_message *msg,
1276                              struct spi_transfer *xfer)
1277 {
1278         struct spi_statistics *statm = ctlr->pcpu_statistics;
1279         struct spi_statistics *stats = msg->spi->pcpu_statistics;
1280         u32 speed_hz = xfer->speed_hz;
1281         unsigned long long ms;
1282
1283         if (spi_controller_is_slave(ctlr)) {
1284                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1285                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1286                         return -EINTR;
1287                 }
1288         } else {
1289                 if (!speed_hz)
1290                         speed_hz = 100000;
1291
1292                 /*
1293                  * For each byte we wait for 8 cycles of the SPI clock.
1294                  * Since speed is defined in Hz and we want milliseconds,
1295                  * use respective multiplier, but before the division,
1296                  * otherwise we may get 0 for short transfers.
1297                  */
1298                 ms = 8LL * MSEC_PER_SEC * xfer->len;
1299                 do_div(ms, speed_hz);
1300
1301                 /*
1302                  * Increase it twice and add 200 ms tolerance, use
1303                  * predefined maximum in case of overflow.
1304                  */
1305                 ms += ms + 200;
1306                 if (ms > UINT_MAX)
1307                         ms = UINT_MAX;
1308
1309                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1310                                                  msecs_to_jiffies(ms));
1311
1312                 if (ms == 0) {
1313                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1314                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1315                         dev_err(&msg->spi->dev,
1316                                 "SPI transfer timed out\n");
1317                         return -ETIMEDOUT;
1318                 }
1319         }
1320
1321         return 0;
1322 }
1323
1324 static void _spi_transfer_delay_ns(u32 ns)
1325 {
1326         if (!ns)
1327                 return;
1328         if (ns <= NSEC_PER_USEC) {
1329                 ndelay(ns);
1330         } else {
1331                 u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1332
1333                 if (us <= 10)
1334                         udelay(us);
1335                 else
1336                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1337         }
1338 }
1339
1340 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1341 {
1342         u32 delay = _delay->value;
1343         u32 unit = _delay->unit;
1344         u32 hz;
1345
1346         if (!delay)
1347                 return 0;
1348
1349         switch (unit) {
1350         case SPI_DELAY_UNIT_USECS:
1351                 delay *= NSEC_PER_USEC;
1352                 break;
1353         case SPI_DELAY_UNIT_NSECS:
1354                 /* Nothing to do here */
1355                 break;
1356         case SPI_DELAY_UNIT_SCK:
1357                 /* Clock cycles need to be obtained from spi_transfer */
1358                 if (!xfer)
1359                         return -EINVAL;
1360                 /*
1361                  * If there is unknown effective speed, approximate it
1362                  * by underestimating with half of the requested hz.
1363                  */
1364                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1365                 if (!hz)
1366                         return -EINVAL;
1367
1368                 /* Convert delay to nanoseconds */
1369                 delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1370                 break;
1371         default:
1372                 return -EINVAL;
1373         }
1374
1375         return delay;
1376 }
1377 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1378
1379 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1380 {
1381         int delay;
1382
1383         might_sleep();
1384
1385         if (!_delay)
1386                 return -EINVAL;
1387
1388         delay = spi_delay_to_ns(_delay, xfer);
1389         if (delay < 0)
1390                 return delay;
1391
1392         _spi_transfer_delay_ns(delay);
1393
1394         return 0;
1395 }
1396 EXPORT_SYMBOL_GPL(spi_delay_exec);
1397
1398 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1399                                           struct spi_transfer *xfer)
1400 {
1401         u32 default_delay_ns = 10 * NSEC_PER_USEC;
1402         u32 delay = xfer->cs_change_delay.value;
1403         u32 unit = xfer->cs_change_delay.unit;
1404         int ret;
1405
1406         /* Return early on "fast" mode - for everything but USECS */
1407         if (!delay) {
1408                 if (unit == SPI_DELAY_UNIT_USECS)
1409                         _spi_transfer_delay_ns(default_delay_ns);
1410                 return;
1411         }
1412
1413         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1414         if (ret) {
1415                 dev_err_once(&msg->spi->dev,
1416                              "Use of unsupported delay unit %i, using default of %luus\n",
1417                              unit, default_delay_ns / NSEC_PER_USEC);
1418                 _spi_transfer_delay_ns(default_delay_ns);
1419         }
1420 }
1421
1422 /*
1423  * spi_transfer_one_message - Default implementation of transfer_one_message()
1424  *
1425  * This is a standard implementation of transfer_one_message() for
1426  * drivers which implement a transfer_one() operation.  It provides
1427  * standard handling of delays and chip select management.
1428  */
1429 static int spi_transfer_one_message(struct spi_controller *ctlr,
1430                                     struct spi_message *msg)
1431 {
1432         struct spi_transfer *xfer;
1433         bool keep_cs = false;
1434         int ret = 0;
1435         struct spi_statistics *statm = ctlr->pcpu_statistics;
1436         struct spi_statistics *stats = msg->spi->pcpu_statistics;
1437
1438         spi_set_cs(msg->spi, true, false);
1439
1440         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1441         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1442
1443         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1444                 trace_spi_transfer_start(msg, xfer);
1445
1446                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1447                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1448
1449                 if (!ctlr->ptp_sts_supported) {
1450                         xfer->ptp_sts_word_pre = 0;
1451                         ptp_read_system_prets(xfer->ptp_sts);
1452                 }
1453
1454                 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1455                         reinit_completion(&ctlr->xfer_completion);
1456
1457 fallback_pio:
1458                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1459                         if (ret < 0) {
1460                                 if (ctlr->cur_msg_mapped &&
1461                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1462                                         __spi_unmap_msg(ctlr, msg);
1463                                         ctlr->fallback = true;
1464                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1465                                         goto fallback_pio;
1466                                 }
1467
1468                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1469                                                                errors);
1470                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1471                                                                errors);
1472                                 dev_err(&msg->spi->dev,
1473                                         "SPI transfer failed: %d\n", ret);
1474                                 goto out;
1475                         }
1476
1477                         if (ret > 0) {
1478                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1479                                 if (ret < 0)
1480                                         msg->status = ret;
1481                         }
1482                 } else {
1483                         if (xfer->len)
1484                                 dev_err(&msg->spi->dev,
1485                                         "Bufferless transfer has length %u\n",
1486                                         xfer->len);
1487                 }
1488
1489                 if (!ctlr->ptp_sts_supported) {
1490                         ptp_read_system_postts(xfer->ptp_sts);
1491                         xfer->ptp_sts_word_post = xfer->len;
1492                 }
1493
1494                 trace_spi_transfer_stop(msg, xfer);
1495
1496                 if (msg->status != -EINPROGRESS)
1497                         goto out;
1498
1499                 spi_transfer_delay_exec(xfer);
1500
1501                 if (xfer->cs_change) {
1502                         if (list_is_last(&xfer->transfer_list,
1503                                          &msg->transfers)) {
1504                                 keep_cs = true;
1505                         } else {
1506                                 spi_set_cs(msg->spi, false, false);
1507                                 _spi_transfer_cs_change_delay(msg, xfer);
1508                                 spi_set_cs(msg->spi, true, false);
1509                         }
1510                 }
1511
1512                 msg->actual_length += xfer->len;
1513         }
1514
1515 out:
1516         if (ret != 0 || !keep_cs)
1517                 spi_set_cs(msg->spi, false, false);
1518
1519         if (msg->status == -EINPROGRESS)
1520                 msg->status = ret;
1521
1522         if (msg->status && ctlr->handle_err)
1523                 ctlr->handle_err(ctlr, msg);
1524
1525         spi_finalize_current_message(ctlr);
1526
1527         return ret;
1528 }
1529
1530 /**
1531  * spi_finalize_current_transfer - report completion of a transfer
1532  * @ctlr: the controller reporting completion
1533  *
1534  * Called by SPI drivers using the core transfer_one_message()
1535  * implementation to notify it that the current interrupt driven
1536  * transfer has finished and the next one may be scheduled.
1537  */
1538 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1539 {
1540         complete(&ctlr->xfer_completion);
1541 }
1542 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1543
1544 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1545 {
1546         if (ctlr->auto_runtime_pm) {
1547                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1548                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1549         }
1550 }
1551
1552 static int __spi_pump_transfer_message(struct spi_controller *ctlr,
1553                 struct spi_message *msg, bool was_busy)
1554 {
1555         struct spi_transfer *xfer;
1556         int ret;
1557
1558         if (!was_busy && ctlr->auto_runtime_pm) {
1559                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1560                 if (ret < 0) {
1561                         pm_runtime_put_noidle(ctlr->dev.parent);
1562                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1563                                 ret);
1564                         return ret;
1565                 }
1566         }
1567
1568         if (!was_busy)
1569                 trace_spi_controller_busy(ctlr);
1570
1571         if (!was_busy && ctlr->prepare_transfer_hardware) {
1572                 ret = ctlr->prepare_transfer_hardware(ctlr);
1573                 if (ret) {
1574                         dev_err(&ctlr->dev,
1575                                 "failed to prepare transfer hardware: %d\n",
1576                                 ret);
1577
1578                         if (ctlr->auto_runtime_pm)
1579                                 pm_runtime_put(ctlr->dev.parent);
1580
1581                         msg->status = ret;
1582                         spi_finalize_current_message(ctlr);
1583
1584                         return ret;
1585                 }
1586         }
1587
1588         trace_spi_message_start(msg);
1589
1590         if (ctlr->prepare_message) {
1591                 ret = ctlr->prepare_message(ctlr, msg);
1592                 if (ret) {
1593                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1594                                 ret);
1595                         msg->status = ret;
1596                         spi_finalize_current_message(ctlr);
1597                         return ret;
1598                 }
1599                 msg->prepared = true;
1600         }
1601
1602         ret = spi_map_msg(ctlr, msg);
1603         if (ret) {
1604                 msg->status = ret;
1605                 spi_finalize_current_message(ctlr);
1606                 return ret;
1607         }
1608
1609         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1610                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1611                         xfer->ptp_sts_word_pre = 0;
1612                         ptp_read_system_prets(xfer->ptp_sts);
1613                 }
1614         }
1615
1616         /*
1617          * Drivers implementation of transfer_one_message() must arrange for
1618          * spi_finalize_current_message() to get called. Most drivers will do
1619          * this in the calling context, but some don't. For those cases, a
1620          * completion is used to guarantee that this function does not return
1621          * until spi_finalize_current_message() is done accessing
1622          * ctlr->cur_msg.
1623          * Use of the following two flags enable to opportunistically skip the
1624          * use of the completion since its use involves expensive spin locks.
1625          * In case of a race with the context that calls
1626          * spi_finalize_current_message() the completion will always be used,
1627          * due to strict ordering of these flags using barriers.
1628          */
1629         WRITE_ONCE(ctlr->cur_msg_incomplete, true);
1630         WRITE_ONCE(ctlr->cur_msg_need_completion, false);
1631         reinit_completion(&ctlr->cur_msg_completion);
1632         smp_wmb(); /* Make these available to spi_finalize_current_message() */
1633
1634         ret = ctlr->transfer_one_message(ctlr, msg);
1635         if (ret) {
1636                 dev_err(&ctlr->dev,
1637                         "failed to transfer one message from queue\n");
1638                 return ret;
1639         }
1640
1641         WRITE_ONCE(ctlr->cur_msg_need_completion, true);
1642         smp_mb(); /* See spi_finalize_current_message()... */
1643         if (READ_ONCE(ctlr->cur_msg_incomplete))
1644                 wait_for_completion(&ctlr->cur_msg_completion);
1645
1646         return 0;
1647 }
1648
1649 /**
1650  * __spi_pump_messages - function which processes spi message queue
1651  * @ctlr: controller to process queue for
1652  * @in_kthread: true if we are in the context of the message pump thread
1653  *
1654  * This function checks if there is any spi message in the queue that
1655  * needs processing and if so call out to the driver to initialize hardware
1656  * and transfer each message.
1657  *
1658  * Note that it is called both from the kthread itself and also from
1659  * inside spi_sync(); the queue extraction handling at the top of the
1660  * function should deal with this safely.
1661  */
1662 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1663 {
1664         struct spi_message *msg;
1665         bool was_busy = false;
1666         unsigned long flags;
1667         int ret;
1668
1669         /* Take the IO mutex */
1670         mutex_lock(&ctlr->io_mutex);
1671
1672         /* Lock queue */
1673         spin_lock_irqsave(&ctlr->queue_lock, flags);
1674
1675         /* Make sure we are not already running a message */
1676         if (ctlr->cur_msg)
1677                 goto out_unlock;
1678
1679         /* Check if the queue is idle */
1680         if (list_empty(&ctlr->queue) || !ctlr->running) {
1681                 if (!ctlr->busy)
1682                         goto out_unlock;
1683
1684                 /* Defer any non-atomic teardown to the thread */
1685                 if (!in_kthread) {
1686                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1687                             !ctlr->unprepare_transfer_hardware) {
1688                                 spi_idle_runtime_pm(ctlr);
1689                                 ctlr->busy = false;
1690                                 ctlr->queue_empty = true;
1691                                 trace_spi_controller_idle(ctlr);
1692                         } else {
1693                                 kthread_queue_work(ctlr->kworker,
1694                                                    &ctlr->pump_messages);
1695                         }
1696                         goto out_unlock;
1697                 }
1698
1699                 ctlr->busy = false;
1700                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1701
1702                 kfree(ctlr->dummy_rx);
1703                 ctlr->dummy_rx = NULL;
1704                 kfree(ctlr->dummy_tx);
1705                 ctlr->dummy_tx = NULL;
1706                 if (ctlr->unprepare_transfer_hardware &&
1707                     ctlr->unprepare_transfer_hardware(ctlr))
1708                         dev_err(&ctlr->dev,
1709                                 "failed to unprepare transfer hardware\n");
1710                 spi_idle_runtime_pm(ctlr);
1711                 trace_spi_controller_idle(ctlr);
1712
1713                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1714                 ctlr->queue_empty = true;
1715                 goto out_unlock;
1716         }
1717
1718         /* Extract head of queue */
1719         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1720         ctlr->cur_msg = msg;
1721
1722         list_del_init(&msg->queue);
1723         if (ctlr->busy)
1724                 was_busy = true;
1725         else
1726                 ctlr->busy = true;
1727         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1728
1729         ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
1730         if (!ret)
1731                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1732
1733         ctlr->cur_msg = NULL;
1734         ctlr->fallback = false;
1735
1736         mutex_unlock(&ctlr->io_mutex);
1737
1738         /* Prod the scheduler in case transfer_one() was busy waiting */
1739         if (!ret)
1740                 cond_resched();
1741         return;
1742
1743 out_unlock:
1744         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1745         mutex_unlock(&ctlr->io_mutex);
1746 }
1747
1748 /**
1749  * spi_pump_messages - kthread work function which processes spi message queue
1750  * @work: pointer to kthread work struct contained in the controller struct
1751  */
1752 static void spi_pump_messages(struct kthread_work *work)
1753 {
1754         struct spi_controller *ctlr =
1755                 container_of(work, struct spi_controller, pump_messages);
1756
1757         __spi_pump_messages(ctlr, true);
1758 }
1759
1760 /**
1761  * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
1762  * @ctlr: Pointer to the spi_controller structure of the driver
1763  * @xfer: Pointer to the transfer being timestamped
1764  * @progress: How many words (not bytes) have been transferred so far
1765  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1766  *            transfer, for less jitter in time measurement. Only compatible
1767  *            with PIO drivers. If true, must follow up with
1768  *            spi_take_timestamp_post or otherwise system will crash.
1769  *            WARNING: for fully predictable results, the CPU frequency must
1770  *            also be under control (governor).
1771  *
1772  * This is a helper for drivers to collect the beginning of the TX timestamp
1773  * for the requested byte from the SPI transfer. The frequency with which this
1774  * function must be called (once per word, once for the whole transfer, once
1775  * per batch of words etc) is arbitrary as long as the @tx buffer offset is
1776  * greater than or equal to the requested byte at the time of the call. The
1777  * timestamp is only taken once, at the first such call. It is assumed that
1778  * the driver advances its @tx buffer pointer monotonically.
1779  */
1780 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1781                             struct spi_transfer *xfer,
1782                             size_t progress, bool irqs_off)
1783 {
1784         if (!xfer->ptp_sts)
1785                 return;
1786
1787         if (xfer->timestamped)
1788                 return;
1789
1790         if (progress > xfer->ptp_sts_word_pre)
1791                 return;
1792
1793         /* Capture the resolution of the timestamp */
1794         xfer->ptp_sts_word_pre = progress;
1795
1796         if (irqs_off) {
1797                 local_irq_save(ctlr->irq_flags);
1798                 preempt_disable();
1799         }
1800
1801         ptp_read_system_prets(xfer->ptp_sts);
1802 }
1803 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1804
1805 /**
1806  * spi_take_timestamp_post - helper to collect the end of the TX timestamp
1807  * @ctlr: Pointer to the spi_controller structure of the driver
1808  * @xfer: Pointer to the transfer being timestamped
1809  * @progress: How many words (not bytes) have been transferred so far
1810  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1811  *
1812  * This is a helper for drivers to collect the end of the TX timestamp for
1813  * the requested byte from the SPI transfer. Can be called with an arbitrary
1814  * frequency: only the first call where @tx exceeds or is equal to the
1815  * requested word will be timestamped.
1816  */
1817 void spi_take_timestamp_post(struct spi_controller *ctlr,
1818                              struct spi_transfer *xfer,
1819                              size_t progress, bool irqs_off)
1820 {
1821         if (!xfer->ptp_sts)
1822                 return;
1823
1824         if (xfer->timestamped)
1825                 return;
1826
1827         if (progress < xfer->ptp_sts_word_post)
1828                 return;
1829
1830         ptp_read_system_postts(xfer->ptp_sts);
1831
1832         if (irqs_off) {
1833                 local_irq_restore(ctlr->irq_flags);
1834                 preempt_enable();
1835         }
1836
1837         /* Capture the resolution of the timestamp */
1838         xfer->ptp_sts_word_post = progress;
1839
1840         xfer->timestamped = true;
1841 }
1842 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1843
1844 /**
1845  * spi_set_thread_rt - set the controller to pump at realtime priority
1846  * @ctlr: controller to boost priority of
1847  *
1848  * This can be called because the controller requested realtime priority
1849  * (by setting the ->rt value before calling spi_register_controller()) or
1850  * because a device on the bus said that its transfers needed realtime
1851  * priority.
1852  *
1853  * NOTE: at the moment if any device on a bus says it needs realtime then
1854  * the thread will be at realtime priority for all transfers on that
1855  * controller.  If this eventually becomes a problem we may see if we can
1856  * find a way to boost the priority only temporarily during relevant
1857  * transfers.
1858  */
1859 static void spi_set_thread_rt(struct spi_controller *ctlr)
1860 {
1861         dev_info(&ctlr->dev,
1862                 "will run message pump with realtime priority\n");
1863         sched_set_fifo(ctlr->kworker->task);
1864 }
1865
1866 static int spi_init_queue(struct spi_controller *ctlr)
1867 {
1868         ctlr->running = false;
1869         ctlr->busy = false;
1870         ctlr->queue_empty = true;
1871
1872         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1873         if (IS_ERR(ctlr->kworker)) {
1874                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1875                 return PTR_ERR(ctlr->kworker);
1876         }
1877
1878         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1879
1880         /*
1881          * Controller config will indicate if this controller should run the
1882          * message pump with high (realtime) priority to reduce the transfer
1883          * latency on the bus by minimising the delay between a transfer
1884          * request and the scheduling of the message pump thread. Without this
1885          * setting the message pump thread will remain at default priority.
1886          */
1887         if (ctlr->rt)
1888                 spi_set_thread_rt(ctlr);
1889
1890         return 0;
1891 }
1892
1893 /**
1894  * spi_get_next_queued_message() - called by driver to check for queued
1895  * messages
1896  * @ctlr: the controller to check for queued messages
1897  *
1898  * If there are more messages in the queue, the next message is returned from
1899  * this call.
1900  *
1901  * Return: the next message in the queue, else NULL if the queue is empty.
1902  */
1903 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1904 {
1905         struct spi_message *next;
1906         unsigned long flags;
1907
1908         /* Get a pointer to the next message, if any */
1909         spin_lock_irqsave(&ctlr->queue_lock, flags);
1910         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1911                                         queue);
1912         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1913
1914         return next;
1915 }
1916 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1917
1918 /**
1919  * spi_finalize_current_message() - the current message is complete
1920  * @ctlr: the controller to return the message to
1921  *
1922  * Called by the driver to notify the core that the message in the front of the
1923  * queue is complete and can be removed from the queue.
1924  */
1925 void spi_finalize_current_message(struct spi_controller *ctlr)
1926 {
1927         struct spi_transfer *xfer;
1928         struct spi_message *mesg;
1929         int ret;
1930
1931         mesg = ctlr->cur_msg;
1932
1933         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1934                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1935                         ptp_read_system_postts(xfer->ptp_sts);
1936                         xfer->ptp_sts_word_post = xfer->len;
1937                 }
1938         }
1939
1940         if (unlikely(ctlr->ptp_sts_supported))
1941                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1942                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1943
1944         spi_unmap_msg(ctlr, mesg);
1945
1946         /*
1947          * In the prepare_messages callback the SPI bus has the opportunity
1948          * to split a transfer to smaller chunks.
1949          *
1950          * Release the split transfers here since spi_map_msg() is done on
1951          * the split transfers.
1952          */
1953         spi_res_release(ctlr, mesg);
1954
1955         if (mesg->prepared && ctlr->unprepare_message) {
1956                 ret = ctlr->unprepare_message(ctlr, mesg);
1957                 if (ret) {
1958                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1959                                 ret);
1960                 }
1961         }
1962
1963         mesg->prepared = false;
1964
1965         WRITE_ONCE(ctlr->cur_msg_incomplete, false);
1966         smp_mb(); /* See __spi_pump_transfer_message()... */
1967         if (READ_ONCE(ctlr->cur_msg_need_completion))
1968                 complete(&ctlr->cur_msg_completion);
1969
1970         trace_spi_message_done(mesg);
1971
1972         mesg->state = NULL;
1973         if (mesg->complete)
1974                 mesg->complete(mesg->context);
1975 }
1976 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1977
1978 static int spi_start_queue(struct spi_controller *ctlr)
1979 {
1980         unsigned long flags;
1981
1982         spin_lock_irqsave(&ctlr->queue_lock, flags);
1983
1984         if (ctlr->running || ctlr->busy) {
1985                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1986                 return -EBUSY;
1987         }
1988
1989         ctlr->running = true;
1990         ctlr->cur_msg = NULL;
1991         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1992
1993         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1994
1995         return 0;
1996 }
1997
1998 static int spi_stop_queue(struct spi_controller *ctlr)
1999 {
2000         unsigned long flags;
2001         unsigned limit = 500;
2002         int ret = 0;
2003
2004         spin_lock_irqsave(&ctlr->queue_lock, flags);
2005
2006         /*
2007          * This is a bit lame, but is optimized for the common execution path.
2008          * A wait_queue on the ctlr->busy could be used, but then the common
2009          * execution path (pump_messages) would be required to call wake_up or
2010          * friends on every SPI message. Do this instead.
2011          */
2012         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
2013                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2014                 usleep_range(10000, 11000);
2015                 spin_lock_irqsave(&ctlr->queue_lock, flags);
2016         }
2017
2018         if (!list_empty(&ctlr->queue) || ctlr->busy)
2019                 ret = -EBUSY;
2020         else
2021                 ctlr->running = false;
2022
2023         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2024
2025         if (ret) {
2026                 dev_warn(&ctlr->dev, "could not stop message queue\n");
2027                 return ret;
2028         }
2029         return ret;
2030 }
2031
2032 static int spi_destroy_queue(struct spi_controller *ctlr)
2033 {
2034         int ret;
2035
2036         ret = spi_stop_queue(ctlr);
2037
2038         /*
2039          * kthread_flush_worker will block until all work is done.
2040          * If the reason that stop_queue timed out is that the work will never
2041          * finish, then it does no good to call flush/stop thread, so
2042          * return anyway.
2043          */
2044         if (ret) {
2045                 dev_err(&ctlr->dev, "problem destroying queue\n");
2046                 return ret;
2047         }
2048
2049         kthread_destroy_worker(ctlr->kworker);
2050
2051         return 0;
2052 }
2053
2054 static int __spi_queued_transfer(struct spi_device *spi,
2055                                  struct spi_message *msg,
2056                                  bool need_pump)
2057 {
2058         struct spi_controller *ctlr = spi->controller;
2059         unsigned long flags;
2060
2061         spin_lock_irqsave(&ctlr->queue_lock, flags);
2062
2063         if (!ctlr->running) {
2064                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2065                 return -ESHUTDOWN;
2066         }
2067         msg->actual_length = 0;
2068         msg->status = -EINPROGRESS;
2069
2070         list_add_tail(&msg->queue, &ctlr->queue);
2071         ctlr->queue_empty = false;
2072         if (!ctlr->busy && need_pump)
2073                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2074
2075         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2076         return 0;
2077 }
2078
2079 /**
2080  * spi_queued_transfer - transfer function for queued transfers
2081  * @spi: spi device which is requesting transfer
2082  * @msg: spi message which is to handled is queued to driver queue
2083  *
2084  * Return: zero on success, else a negative error code.
2085  */
2086 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
2087 {
2088         return __spi_queued_transfer(spi, msg, true);
2089 }
2090
2091 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
2092 {
2093         int ret;
2094
2095         ctlr->transfer = spi_queued_transfer;
2096         if (!ctlr->transfer_one_message)
2097                 ctlr->transfer_one_message = spi_transfer_one_message;
2098
2099         /* Initialize and start queue */
2100         ret = spi_init_queue(ctlr);
2101         if (ret) {
2102                 dev_err(&ctlr->dev, "problem initializing queue\n");
2103                 goto err_init_queue;
2104         }
2105         ctlr->queued = true;
2106         ret = spi_start_queue(ctlr);
2107         if (ret) {
2108                 dev_err(&ctlr->dev, "problem starting queue\n");
2109                 goto err_start_queue;
2110         }
2111
2112         return 0;
2113
2114 err_start_queue:
2115         spi_destroy_queue(ctlr);
2116 err_init_queue:
2117         return ret;
2118 }
2119
2120 /**
2121  * spi_flush_queue - Send all pending messages in the queue from the callers'
2122  *                   context
2123  * @ctlr: controller to process queue for
2124  *
2125  * This should be used when one wants to ensure all pending messages have been
2126  * sent before doing something. Is used by the spi-mem code to make sure SPI
2127  * memory operations do not preempt regular SPI transfers that have been queued
2128  * before the spi-mem operation.
2129  */
2130 void spi_flush_queue(struct spi_controller *ctlr)
2131 {
2132         if (ctlr->transfer == spi_queued_transfer)
2133                 __spi_pump_messages(ctlr, false);
2134 }
2135
2136 /*-------------------------------------------------------------------------*/
2137
2138 #if defined(CONFIG_OF)
2139 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
2140                            struct device_node *nc)
2141 {
2142         u32 value;
2143         int rc;
2144
2145         /* Mode (clock phase/polarity/etc.) */
2146         if (of_property_read_bool(nc, "spi-cpha"))
2147                 spi->mode |= SPI_CPHA;
2148         if (of_property_read_bool(nc, "spi-cpol"))
2149                 spi->mode |= SPI_CPOL;
2150         if (of_property_read_bool(nc, "spi-3wire"))
2151                 spi->mode |= SPI_3WIRE;
2152         if (of_property_read_bool(nc, "spi-lsb-first"))
2153                 spi->mode |= SPI_LSB_FIRST;
2154         if (of_property_read_bool(nc, "spi-cs-high"))
2155                 spi->mode |= SPI_CS_HIGH;
2156
2157         /* Device DUAL/QUAD mode */
2158         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2159                 switch (value) {
2160                 case 0:
2161                         spi->mode |= SPI_NO_TX;
2162                         break;
2163                 case 1:
2164                         break;
2165                 case 2:
2166                         spi->mode |= SPI_TX_DUAL;
2167                         break;
2168                 case 4:
2169                         spi->mode |= SPI_TX_QUAD;
2170                         break;
2171                 case 8:
2172                         spi->mode |= SPI_TX_OCTAL;
2173                         break;
2174                 default:
2175                         dev_warn(&ctlr->dev,
2176                                 "spi-tx-bus-width %d not supported\n",
2177                                 value);
2178                         break;
2179                 }
2180         }
2181
2182         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2183                 switch (value) {
2184                 case 0:
2185                         spi->mode |= SPI_NO_RX;
2186                         break;
2187                 case 1:
2188                         break;
2189                 case 2:
2190                         spi->mode |= SPI_RX_DUAL;
2191                         break;
2192                 case 4:
2193                         spi->mode |= SPI_RX_QUAD;
2194                         break;
2195                 case 8:
2196                         spi->mode |= SPI_RX_OCTAL;
2197                         break;
2198                 default:
2199                         dev_warn(&ctlr->dev,
2200                                 "spi-rx-bus-width %d not supported\n",
2201                                 value);
2202                         break;
2203                 }
2204         }
2205
2206         if (spi_controller_is_slave(ctlr)) {
2207                 if (!of_node_name_eq(nc, "slave")) {
2208                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2209                                 nc);
2210                         return -EINVAL;
2211                 }
2212                 return 0;
2213         }
2214
2215         /* Device address */
2216         rc = of_property_read_u32(nc, "reg", &value);
2217         if (rc) {
2218                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2219                         nc, rc);
2220                 return rc;
2221         }
2222         spi->chip_select = value;
2223
2224         /* Device speed */
2225         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2226                 spi->max_speed_hz = value;
2227
2228         return 0;
2229 }
2230
2231 static struct spi_device *
2232 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2233 {
2234         struct spi_device *spi;
2235         int rc;
2236
2237         /* Alloc an spi_device */
2238         spi = spi_alloc_device(ctlr);
2239         if (!spi) {
2240                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2241                 rc = -ENOMEM;
2242                 goto err_out;
2243         }
2244
2245         /* Select device driver */
2246         rc = of_modalias_node(nc, spi->modalias,
2247                                 sizeof(spi->modalias));
2248         if (rc < 0) {
2249                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2250                 goto err_out;
2251         }
2252
2253         rc = of_spi_parse_dt(ctlr, spi, nc);
2254         if (rc)
2255                 goto err_out;
2256
2257         /* Store a pointer to the node in the device structure */
2258         of_node_get(nc);
2259         spi->dev.of_node = nc;
2260         spi->dev.fwnode = of_fwnode_handle(nc);
2261
2262         /* Register the new device */
2263         rc = spi_add_device(spi);
2264         if (rc) {
2265                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2266                 goto err_of_node_put;
2267         }
2268
2269         return spi;
2270
2271 err_of_node_put:
2272         of_node_put(nc);
2273 err_out:
2274         spi_dev_put(spi);
2275         return ERR_PTR(rc);
2276 }
2277
2278 /**
2279  * of_register_spi_devices() - Register child devices onto the SPI bus
2280  * @ctlr:       Pointer to spi_controller device
2281  *
2282  * Registers an spi_device for each child node of controller node which
2283  * represents a valid SPI slave.
2284  */
2285 static void of_register_spi_devices(struct spi_controller *ctlr)
2286 {
2287         struct spi_device *spi;
2288         struct device_node *nc;
2289
2290         if (!ctlr->dev.of_node)
2291                 return;
2292
2293         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2294                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2295                         continue;
2296                 spi = of_register_spi_device(ctlr, nc);
2297                 if (IS_ERR(spi)) {
2298                         dev_warn(&ctlr->dev,
2299                                  "Failed to create SPI device for %pOF\n", nc);
2300                         of_node_clear_flag(nc, OF_POPULATED);
2301                 }
2302         }
2303 }
2304 #else
2305 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2306 #endif
2307
2308 /**
2309  * spi_new_ancillary_device() - Register ancillary SPI device
2310  * @spi:         Pointer to the main SPI device registering the ancillary device
2311  * @chip_select: Chip Select of the ancillary device
2312  *
2313  * Register an ancillary SPI device; for example some chips have a chip-select
2314  * for normal device usage and another one for setup/firmware upload.
2315  *
2316  * This may only be called from main SPI device's probe routine.
2317  *
2318  * Return: 0 on success; negative errno on failure
2319  */
2320 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2321                                              u8 chip_select)
2322 {
2323         struct spi_device *ancillary;
2324         int rc = 0;
2325
2326         /* Alloc an spi_device */
2327         ancillary = spi_alloc_device(spi->controller);
2328         if (!ancillary) {
2329                 rc = -ENOMEM;
2330                 goto err_out;
2331         }
2332
2333         strlcpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2334
2335         /* Use provided chip-select for ancillary device */
2336         ancillary->chip_select = chip_select;
2337
2338         /* Take over SPI mode/speed from SPI main device */
2339         ancillary->max_speed_hz = spi->max_speed_hz;
2340         ancillary->mode = spi->mode;
2341
2342         /* Register the new device */
2343         rc = spi_add_device_locked(ancillary);
2344         if (rc) {
2345                 dev_err(&spi->dev, "failed to register ancillary device\n");
2346                 goto err_out;
2347         }
2348
2349         return ancillary;
2350
2351 err_out:
2352         spi_dev_put(ancillary);
2353         return ERR_PTR(rc);
2354 }
2355 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2356
2357 #ifdef CONFIG_ACPI
2358 struct acpi_spi_lookup {
2359         struct spi_controller   *ctlr;
2360         u32                     max_speed_hz;
2361         u32                     mode;
2362         int                     irq;
2363         u8                      bits_per_word;
2364         u8                      chip_select;
2365         int                     n;
2366         int                     index;
2367 };
2368
2369 static int acpi_spi_count(struct acpi_resource *ares, void *data)
2370 {
2371         struct acpi_resource_spi_serialbus *sb;
2372         int *count = data;
2373
2374         if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
2375                 return 1;
2376
2377         sb = &ares->data.spi_serial_bus;
2378         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
2379                 return 1;
2380
2381         *count = *count + 1;
2382
2383         return 1;
2384 }
2385
2386 /**
2387  * acpi_spi_count_resources - Count the number of SpiSerialBus resources
2388  * @adev:       ACPI device
2389  *
2390  * Returns the number of SpiSerialBus resources in the ACPI-device's
2391  * resource-list; or a negative error code.
2392  */
2393 int acpi_spi_count_resources(struct acpi_device *adev)
2394 {
2395         LIST_HEAD(r);
2396         int count = 0;
2397         int ret;
2398
2399         ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
2400         if (ret < 0)
2401                 return ret;
2402
2403         acpi_dev_free_resource_list(&r);
2404
2405         return count;
2406 }
2407 EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
2408
2409 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2410                                             struct acpi_spi_lookup *lookup)
2411 {
2412         const union acpi_object *obj;
2413
2414         if (!x86_apple_machine)
2415                 return;
2416
2417         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2418             && obj->buffer.length >= 4)
2419                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2420
2421         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2422             && obj->buffer.length == 8)
2423                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2424
2425         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2426             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2427                 lookup->mode |= SPI_LSB_FIRST;
2428
2429         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2430             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2431                 lookup->mode |= SPI_CPOL;
2432
2433         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2434             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2435                 lookup->mode |= SPI_CPHA;
2436 }
2437
2438 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
2439
2440 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2441 {
2442         struct acpi_spi_lookup *lookup = data;
2443         struct spi_controller *ctlr = lookup->ctlr;
2444
2445         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2446                 struct acpi_resource_spi_serialbus *sb;
2447                 acpi_handle parent_handle;
2448                 acpi_status status;
2449
2450                 sb = &ares->data.spi_serial_bus;
2451                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2452
2453                         if (lookup->index != -1 && lookup->n++ != lookup->index)
2454                                 return 1;
2455
2456                         status = acpi_get_handle(NULL,
2457                                                  sb->resource_source.string_ptr,
2458                                                  &parent_handle);
2459
2460                         if (ACPI_FAILURE(status))
2461                                 return -ENODEV;
2462
2463                         if (ctlr) {
2464                                 if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2465                                         return -ENODEV;
2466                         } else {
2467                                 struct acpi_device *adev;
2468
2469                                 adev = acpi_fetch_acpi_dev(parent_handle);
2470                                 if (!adev)
2471                                         return -ENODEV;
2472
2473                                 ctlr = acpi_spi_find_controller_by_adev(adev);
2474                                 if (!ctlr)
2475                                         return -EPROBE_DEFER;
2476
2477                                 lookup->ctlr = ctlr;
2478                         }
2479
2480                         /*
2481                          * ACPI DeviceSelection numbering is handled by the
2482                          * host controller driver in Windows and can vary
2483                          * from driver to driver. In Linux we always expect
2484                          * 0 .. max - 1 so we need to ask the driver to
2485                          * translate between the two schemes.
2486                          */
2487                         if (ctlr->fw_translate_cs) {
2488                                 int cs = ctlr->fw_translate_cs(ctlr,
2489                                                 sb->device_selection);
2490                                 if (cs < 0)
2491                                         return cs;
2492                                 lookup->chip_select = cs;
2493                         } else {
2494                                 lookup->chip_select = sb->device_selection;
2495                         }
2496
2497                         lookup->max_speed_hz = sb->connection_speed;
2498                         lookup->bits_per_word = sb->data_bit_length;
2499
2500                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2501                                 lookup->mode |= SPI_CPHA;
2502                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2503                                 lookup->mode |= SPI_CPOL;
2504                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2505                                 lookup->mode |= SPI_CS_HIGH;
2506                 }
2507         } else if (lookup->irq < 0) {
2508                 struct resource r;
2509
2510                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2511                         lookup->irq = r.start;
2512         }
2513
2514         /* Always tell the ACPI core to skip this resource */
2515         return 1;
2516 }
2517
2518 /**
2519  * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
2520  * @ctlr: controller to which the spi device belongs
2521  * @adev: ACPI Device for the spi device
2522  * @index: Index of the spi resource inside the ACPI Node
2523  *
2524  * This should be used to allocate a new spi device from and ACPI Node.
2525  * The caller is responsible for calling spi_add_device to register the spi device.
2526  *
2527  * If ctlr is set to NULL, the Controller for the spi device will be looked up
2528  * using the resource.
2529  * If index is set to -1, index is not used.
2530  * Note: If index is -1, ctlr must be set.
2531  *
2532  * Return: a pointer to the new device, or ERR_PTR on error.
2533  */
2534 struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
2535                                          struct acpi_device *adev,
2536                                          int index)
2537 {
2538         acpi_handle parent_handle = NULL;
2539         struct list_head resource_list;
2540         struct acpi_spi_lookup lookup = {};
2541         struct spi_device *spi;
2542         int ret;
2543
2544         if (!ctlr && index == -1)
2545                 return ERR_PTR(-EINVAL);
2546
2547         lookup.ctlr             = ctlr;
2548         lookup.irq              = -1;
2549         lookup.index            = index;
2550         lookup.n                = 0;
2551
2552         INIT_LIST_HEAD(&resource_list);
2553         ret = acpi_dev_get_resources(adev, &resource_list,
2554                                      acpi_spi_add_resource, &lookup);
2555         acpi_dev_free_resource_list(&resource_list);
2556
2557         if (ret < 0)
2558                 /* Found SPI in _CRS but it points to another controller */
2559                 return ERR_PTR(ret);
2560
2561         if (!lookup.max_speed_hz &&
2562             ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2563             ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
2564                 /* Apple does not use _CRS but nested devices for SPI slaves */
2565                 acpi_spi_parse_apple_properties(adev, &lookup);
2566         }
2567
2568         if (!lookup.max_speed_hz)
2569                 return ERR_PTR(-ENODEV);
2570
2571         spi = spi_alloc_device(lookup.ctlr);
2572         if (!spi) {
2573                 dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
2574                         dev_name(&adev->dev));
2575                 return ERR_PTR(-ENOMEM);
2576         }
2577
2578         ACPI_COMPANION_SET(&spi->dev, adev);
2579         spi->max_speed_hz       = lookup.max_speed_hz;
2580         spi->mode               |= lookup.mode;
2581         spi->irq                = lookup.irq;
2582         spi->bits_per_word      = lookup.bits_per_word;
2583         spi->chip_select        = lookup.chip_select;
2584
2585         return spi;
2586 }
2587 EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
2588
2589 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2590                                             struct acpi_device *adev)
2591 {
2592         struct spi_device *spi;
2593
2594         if (acpi_bus_get_status(adev) || !adev->status.present ||
2595             acpi_device_enumerated(adev))
2596                 return AE_OK;
2597
2598         spi = acpi_spi_device_alloc(ctlr, adev, -1);
2599         if (IS_ERR(spi)) {
2600                 if (PTR_ERR(spi) == -ENOMEM)
2601                         return AE_NO_MEMORY;
2602                 else
2603                         return AE_OK;
2604         }
2605
2606         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2607                           sizeof(spi->modalias));
2608
2609         if (spi->irq < 0)
2610                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2611
2612         acpi_device_set_enumerated(adev);
2613
2614         adev->power.flags.ignore_parent = true;
2615         if (spi_add_device(spi)) {
2616                 adev->power.flags.ignore_parent = false;
2617                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2618                         dev_name(&adev->dev));
2619                 spi_dev_put(spi);
2620         }
2621
2622         return AE_OK;
2623 }
2624
2625 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2626                                        void *data, void **return_value)
2627 {
2628         struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
2629         struct spi_controller *ctlr = data;
2630
2631         if (!adev)
2632                 return AE_OK;
2633
2634         return acpi_register_spi_device(ctlr, adev);
2635 }
2636
2637 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2638
2639 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2640 {
2641         acpi_status status;
2642         acpi_handle handle;
2643
2644         handle = ACPI_HANDLE(ctlr->dev.parent);
2645         if (!handle)
2646                 return;
2647
2648         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2649                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2650                                      acpi_spi_add_device, NULL, ctlr, NULL);
2651         if (ACPI_FAILURE(status))
2652                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2653 }
2654 #else
2655 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2656 #endif /* CONFIG_ACPI */
2657
2658 static void spi_controller_release(struct device *dev)
2659 {
2660         struct spi_controller *ctlr;
2661
2662         ctlr = container_of(dev, struct spi_controller, dev);
2663         kfree(ctlr);
2664 }
2665
2666 static struct class spi_master_class = {
2667         .name           = "spi_master",
2668         .owner          = THIS_MODULE,
2669         .dev_release    = spi_controller_release,
2670         .dev_groups     = spi_master_groups,
2671 };
2672
2673 #ifdef CONFIG_SPI_SLAVE
2674 /**
2675  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2676  *                   controller
2677  * @spi: device used for the current transfer
2678  */
2679 int spi_slave_abort(struct spi_device *spi)
2680 {
2681         struct spi_controller *ctlr = spi->controller;
2682
2683         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2684                 return ctlr->slave_abort(ctlr);
2685
2686         return -ENOTSUPP;
2687 }
2688 EXPORT_SYMBOL_GPL(spi_slave_abort);
2689
2690 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2691                           char *buf)
2692 {
2693         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2694                                                    dev);
2695         struct device *child;
2696
2697         child = device_find_any_child(&ctlr->dev);
2698         return sprintf(buf, "%s\n",
2699                        child ? to_spi_device(child)->modalias : NULL);
2700 }
2701
2702 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2703                            const char *buf, size_t count)
2704 {
2705         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2706                                                    dev);
2707         struct spi_device *spi;
2708         struct device *child;
2709         char name[32];
2710         int rc;
2711
2712         rc = sscanf(buf, "%31s", name);
2713         if (rc != 1 || !name[0])
2714                 return -EINVAL;
2715
2716         child = device_find_any_child(&ctlr->dev);
2717         if (child) {
2718                 /* Remove registered slave */
2719                 device_unregister(child);
2720                 put_device(child);
2721         }
2722
2723         if (strcmp(name, "(null)")) {
2724                 /* Register new slave */
2725                 spi = spi_alloc_device(ctlr);
2726                 if (!spi)
2727                         return -ENOMEM;
2728
2729                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2730
2731                 rc = spi_add_device(spi);
2732                 if (rc) {
2733                         spi_dev_put(spi);
2734                         return rc;
2735                 }
2736         }
2737
2738         return count;
2739 }
2740
2741 static DEVICE_ATTR_RW(slave);
2742
2743 static struct attribute *spi_slave_attrs[] = {
2744         &dev_attr_slave.attr,
2745         NULL,
2746 };
2747
2748 static const struct attribute_group spi_slave_group = {
2749         .attrs = spi_slave_attrs,
2750 };
2751
2752 static const struct attribute_group *spi_slave_groups[] = {
2753         &spi_controller_statistics_group,
2754         &spi_slave_group,
2755         NULL,
2756 };
2757
2758 static struct class spi_slave_class = {
2759         .name           = "spi_slave",
2760         .owner          = THIS_MODULE,
2761         .dev_release    = spi_controller_release,
2762         .dev_groups     = spi_slave_groups,
2763 };
2764 #else
2765 extern struct class spi_slave_class;    /* dummy */
2766 #endif
2767
2768 /**
2769  * __spi_alloc_controller - allocate an SPI master or slave controller
2770  * @dev: the controller, possibly using the platform_bus
2771  * @size: how much zeroed driver-private data to allocate; the pointer to this
2772  *      memory is in the driver_data field of the returned device, accessible
2773  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2774  *      drivers granting DMA access to portions of their private data need to
2775  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2776  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2777  *      slave (true) controller
2778  * Context: can sleep
2779  *
2780  * This call is used only by SPI controller drivers, which are the
2781  * only ones directly touching chip registers.  It's how they allocate
2782  * an spi_controller structure, prior to calling spi_register_controller().
2783  *
2784  * This must be called from context that can sleep.
2785  *
2786  * The caller is responsible for assigning the bus number and initializing the
2787  * controller's methods before calling spi_register_controller(); and (after
2788  * errors adding the device) calling spi_controller_put() to prevent a memory
2789  * leak.
2790  *
2791  * Return: the SPI controller structure on success, else NULL.
2792  */
2793 struct spi_controller *__spi_alloc_controller(struct device *dev,
2794                                               unsigned int size, bool slave)
2795 {
2796         struct spi_controller   *ctlr;
2797         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2798
2799         if (!dev)
2800                 return NULL;
2801
2802         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2803         if (!ctlr)
2804                 return NULL;
2805
2806         device_initialize(&ctlr->dev);
2807         INIT_LIST_HEAD(&ctlr->queue);
2808         spin_lock_init(&ctlr->queue_lock);
2809         spin_lock_init(&ctlr->bus_lock_spinlock);
2810         mutex_init(&ctlr->bus_lock_mutex);
2811         mutex_init(&ctlr->io_mutex);
2812         mutex_init(&ctlr->add_lock);
2813         ctlr->bus_num = -1;
2814         ctlr->num_chipselect = 1;
2815         ctlr->slave = slave;
2816         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2817                 ctlr->dev.class = &spi_slave_class;
2818         else
2819                 ctlr->dev.class = &spi_master_class;
2820         ctlr->dev.parent = dev;
2821         pm_suspend_ignore_children(&ctlr->dev, true);
2822         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2823
2824         return ctlr;
2825 }
2826 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2827
2828 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2829 {
2830         spi_controller_put(*(struct spi_controller **)ctlr);
2831 }
2832
2833 /**
2834  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2835  * @dev: physical device of SPI controller
2836  * @size: how much zeroed driver-private data to allocate
2837  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2838  * Context: can sleep
2839  *
2840  * Allocate an SPI controller and automatically release a reference on it
2841  * when @dev is unbound from its driver.  Drivers are thus relieved from
2842  * having to call spi_controller_put().
2843  *
2844  * The arguments to this function are identical to __spi_alloc_controller().
2845  *
2846  * Return: the SPI controller structure on success, else NULL.
2847  */
2848 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2849                                                    unsigned int size,
2850                                                    bool slave)
2851 {
2852         struct spi_controller **ptr, *ctlr;
2853
2854         ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2855                            GFP_KERNEL);
2856         if (!ptr)
2857                 return NULL;
2858
2859         ctlr = __spi_alloc_controller(dev, size, slave);
2860         if (ctlr) {
2861                 ctlr->devm_allocated = true;
2862                 *ptr = ctlr;
2863                 devres_add(dev, ptr);
2864         } else {
2865                 devres_free(ptr);
2866         }
2867
2868         return ctlr;
2869 }
2870 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2871
2872 /**
2873  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2874  * @ctlr: The SPI master to grab GPIO descriptors for
2875  */
2876 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2877 {
2878         int nb, i;
2879         struct gpio_desc **cs;
2880         struct device *dev = &ctlr->dev;
2881         unsigned long native_cs_mask = 0;
2882         unsigned int num_cs_gpios = 0;
2883
2884         nb = gpiod_count(dev, "cs");
2885         if (nb < 0) {
2886                 /* No GPIOs at all is fine, else return the error */
2887                 if (nb == -ENOENT)
2888                         return 0;
2889                 return nb;
2890         }
2891
2892         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2893
2894         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2895                           GFP_KERNEL);
2896         if (!cs)
2897                 return -ENOMEM;
2898         ctlr->cs_gpiods = cs;
2899
2900         for (i = 0; i < nb; i++) {
2901                 /*
2902                  * Most chipselects are active low, the inverted
2903                  * semantics are handled by special quirks in gpiolib,
2904                  * so initializing them GPIOD_OUT_LOW here means
2905                  * "unasserted", in most cases this will drive the physical
2906                  * line high.
2907                  */
2908                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2909                                                       GPIOD_OUT_LOW);
2910                 if (IS_ERR(cs[i]))
2911                         return PTR_ERR(cs[i]);
2912
2913                 if (cs[i]) {
2914                         /*
2915                          * If we find a CS GPIO, name it after the device and
2916                          * chip select line.
2917                          */
2918                         char *gpioname;
2919
2920                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2921                                                   dev_name(dev), i);
2922                         if (!gpioname)
2923                                 return -ENOMEM;
2924                         gpiod_set_consumer_name(cs[i], gpioname);
2925                         num_cs_gpios++;
2926                         continue;
2927                 }
2928
2929                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2930                         dev_err(dev, "Invalid native chip select %d\n", i);
2931                         return -EINVAL;
2932                 }
2933                 native_cs_mask |= BIT(i);
2934         }
2935
2936         ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
2937
2938         if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
2939             ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
2940                 dev_err(dev, "No unused native chip select available\n");
2941                 return -EINVAL;
2942         }
2943
2944         return 0;
2945 }
2946
2947 static int spi_controller_check_ops(struct spi_controller *ctlr)
2948 {
2949         /*
2950          * The controller may implement only the high-level SPI-memory like
2951          * operations if it does not support regular SPI transfers, and this is
2952          * valid use case.
2953          * If ->mem_ops is NULL, we request that at least one of the
2954          * ->transfer_xxx() method be implemented.
2955          */
2956         if (ctlr->mem_ops) {
2957                 if (!ctlr->mem_ops->exec_op)
2958                         return -EINVAL;
2959         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2960                    !ctlr->transfer_one_message) {
2961                 return -EINVAL;
2962         }
2963
2964         return 0;
2965 }
2966
2967 /**
2968  * spi_register_controller - register SPI master or slave controller
2969  * @ctlr: initialized master, originally from spi_alloc_master() or
2970  *      spi_alloc_slave()
2971  * Context: can sleep
2972  *
2973  * SPI controllers connect to their drivers using some non-SPI bus,
2974  * such as the platform bus.  The final stage of probe() in that code
2975  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2976  *
2977  * SPI controllers use board specific (often SOC specific) bus numbers,
2978  * and board-specific addressing for SPI devices combines those numbers
2979  * with chip select numbers.  Since SPI does not directly support dynamic
2980  * device identification, boards need configuration tables telling which
2981  * chip is at which address.
2982  *
2983  * This must be called from context that can sleep.  It returns zero on
2984  * success, else a negative error code (dropping the controller's refcount).
2985  * After a successful return, the caller is responsible for calling
2986  * spi_unregister_controller().
2987  *
2988  * Return: zero on success, else a negative error code.
2989  */
2990 int spi_register_controller(struct spi_controller *ctlr)
2991 {
2992         struct device           *dev = ctlr->dev.parent;
2993         struct boardinfo        *bi;
2994         int                     status;
2995         int                     id, first_dynamic;
2996
2997         if (!dev)
2998                 return -ENODEV;
2999
3000         /*
3001          * Make sure all necessary hooks are implemented before registering
3002          * the SPI controller.
3003          */
3004         status = spi_controller_check_ops(ctlr);
3005         if (status)
3006                 return status;
3007
3008         if (ctlr->bus_num >= 0) {
3009                 /* Devices with a fixed bus num must check-in with the num */
3010                 mutex_lock(&board_lock);
3011                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
3012                         ctlr->bus_num + 1, GFP_KERNEL);
3013                 mutex_unlock(&board_lock);
3014                 if (WARN(id < 0, "couldn't get idr"))
3015                         return id == -ENOSPC ? -EBUSY : id;
3016                 ctlr->bus_num = id;
3017         } else if (ctlr->dev.of_node) {
3018                 /* Allocate dynamic bus number using Linux idr */
3019                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
3020                 if (id >= 0) {
3021                         ctlr->bus_num = id;
3022                         mutex_lock(&board_lock);
3023                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
3024                                        ctlr->bus_num + 1, GFP_KERNEL);
3025                         mutex_unlock(&board_lock);
3026                         if (WARN(id < 0, "couldn't get idr"))
3027                                 return id == -ENOSPC ? -EBUSY : id;
3028                 }
3029         }
3030         if (ctlr->bus_num < 0) {
3031                 first_dynamic = of_alias_get_highest_id("spi");
3032                 if (first_dynamic < 0)
3033                         first_dynamic = 0;
3034                 else
3035                         first_dynamic++;
3036
3037                 mutex_lock(&board_lock);
3038                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
3039                                0, GFP_KERNEL);
3040                 mutex_unlock(&board_lock);
3041                 if (WARN(id < 0, "couldn't get idr"))
3042                         return id;
3043                 ctlr->bus_num = id;
3044         }
3045         ctlr->bus_lock_flag = 0;
3046         init_completion(&ctlr->xfer_completion);
3047         init_completion(&ctlr->cur_msg_completion);
3048         if (!ctlr->max_dma_len)
3049                 ctlr->max_dma_len = INT_MAX;
3050
3051         /*
3052          * Register the device, then userspace will see it.
3053          * Registration fails if the bus ID is in use.
3054          */
3055         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
3056
3057         if (!spi_controller_is_slave(ctlr) && ctlr->use_gpio_descriptors) {
3058                 status = spi_get_gpio_descs(ctlr);
3059                 if (status)
3060                         goto free_bus_id;
3061                 /*
3062                  * A controller using GPIO descriptors always
3063                  * supports SPI_CS_HIGH if need be.
3064                  */
3065                 ctlr->mode_bits |= SPI_CS_HIGH;
3066         }
3067
3068         /*
3069          * Even if it's just one always-selected device, there must
3070          * be at least one chipselect.
3071          */
3072         if (!ctlr->num_chipselect) {
3073                 status = -EINVAL;
3074                 goto free_bus_id;
3075         }
3076
3077         /* Setting last_cs to -1 means no chip selected */
3078         ctlr->last_cs = -1;
3079
3080         status = device_add(&ctlr->dev);
3081         if (status < 0)
3082                 goto free_bus_id;
3083         dev_dbg(dev, "registered %s %s\n",
3084                         spi_controller_is_slave(ctlr) ? "slave" : "master",
3085                         dev_name(&ctlr->dev));
3086
3087         /*
3088          * If we're using a queued driver, start the queue. Note that we don't
3089          * need the queueing logic if the driver is only supporting high-level
3090          * memory operations.
3091          */
3092         if (ctlr->transfer) {
3093                 dev_info(dev, "controller is unqueued, this is deprecated\n");
3094         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
3095                 status = spi_controller_initialize_queue(ctlr);
3096                 if (status) {
3097                         device_del(&ctlr->dev);
3098                         goto free_bus_id;
3099                 }
3100         }
3101         /* Add statistics */
3102         ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev);
3103         if (!ctlr->pcpu_statistics) {
3104                 dev_err(dev, "Error allocating per-cpu statistics\n");
3105                 status = -ENOMEM;
3106                 goto destroy_queue;
3107         }
3108
3109         mutex_lock(&board_lock);
3110         list_add_tail(&ctlr->list, &spi_controller_list);
3111         list_for_each_entry(bi, &board_list, list)
3112                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
3113         mutex_unlock(&board_lock);
3114
3115         /* Register devices from the device tree and ACPI */
3116         of_register_spi_devices(ctlr);
3117         acpi_register_spi_devices(ctlr);
3118         return status;
3119
3120 destroy_queue:
3121         spi_destroy_queue(ctlr);
3122 free_bus_id:
3123         mutex_lock(&board_lock);
3124         idr_remove(&spi_master_idr, ctlr->bus_num);
3125         mutex_unlock(&board_lock);
3126         return status;
3127 }
3128 EXPORT_SYMBOL_GPL(spi_register_controller);
3129
3130 static void devm_spi_unregister(struct device *dev, void *res)
3131 {
3132         spi_unregister_controller(*(struct spi_controller **)res);
3133 }
3134
3135 /**
3136  * devm_spi_register_controller - register managed SPI master or slave
3137  *      controller
3138  * @dev:    device managing SPI controller
3139  * @ctlr: initialized controller, originally from spi_alloc_master() or
3140  *      spi_alloc_slave()
3141  * Context: can sleep
3142  *
3143  * Register a SPI device as with spi_register_controller() which will
3144  * automatically be unregistered and freed.
3145  *
3146  * Return: zero on success, else a negative error code.
3147  */
3148 int devm_spi_register_controller(struct device *dev,
3149                                  struct spi_controller *ctlr)
3150 {
3151         struct spi_controller **ptr;
3152         int ret;
3153
3154         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
3155         if (!ptr)
3156                 return -ENOMEM;
3157
3158         ret = spi_register_controller(ctlr);
3159         if (!ret) {
3160                 *ptr = ctlr;
3161                 devres_add(dev, ptr);
3162         } else {
3163                 devres_free(ptr);
3164         }
3165
3166         return ret;
3167 }
3168 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
3169
3170 static int __unregister(struct device *dev, void *null)
3171 {
3172         spi_unregister_device(to_spi_device(dev));
3173         return 0;
3174 }
3175
3176 /**
3177  * spi_unregister_controller - unregister SPI master or slave controller
3178  * @ctlr: the controller being unregistered
3179  * Context: can sleep
3180  *
3181  * This call is used only by SPI controller drivers, which are the
3182  * only ones directly touching chip registers.
3183  *
3184  * This must be called from context that can sleep.
3185  *
3186  * Note that this function also drops a reference to the controller.
3187  */
3188 void spi_unregister_controller(struct spi_controller *ctlr)
3189 {
3190         struct spi_controller *found;
3191         int id = ctlr->bus_num;
3192
3193         /* Prevent addition of new devices, unregister existing ones */
3194         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3195                 mutex_lock(&ctlr->add_lock);
3196
3197         device_for_each_child(&ctlr->dev, NULL, __unregister);
3198
3199         /* First make sure that this controller was ever added */
3200         mutex_lock(&board_lock);
3201         found = idr_find(&spi_master_idr, id);
3202         mutex_unlock(&board_lock);
3203         if (ctlr->queued) {
3204                 if (spi_destroy_queue(ctlr))
3205                         dev_err(&ctlr->dev, "queue remove failed\n");
3206         }
3207         mutex_lock(&board_lock);
3208         list_del(&ctlr->list);
3209         mutex_unlock(&board_lock);
3210
3211         device_del(&ctlr->dev);
3212
3213         /* Free bus id */
3214         mutex_lock(&board_lock);
3215         if (found == ctlr)
3216                 idr_remove(&spi_master_idr, id);
3217         mutex_unlock(&board_lock);
3218
3219         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3220                 mutex_unlock(&ctlr->add_lock);
3221
3222         /* Release the last reference on the controller if its driver
3223          * has not yet been converted to devm_spi_alloc_master/slave().
3224          */
3225         if (!ctlr->devm_allocated)
3226                 put_device(&ctlr->dev);
3227 }
3228 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3229
3230 int spi_controller_suspend(struct spi_controller *ctlr)
3231 {
3232         int ret;
3233
3234         /* Basically no-ops for non-queued controllers */
3235         if (!ctlr->queued)
3236                 return 0;
3237
3238         ret = spi_stop_queue(ctlr);
3239         if (ret)
3240                 dev_err(&ctlr->dev, "queue stop failed\n");
3241
3242         return ret;
3243 }
3244 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3245
3246 int spi_controller_resume(struct spi_controller *ctlr)
3247 {
3248         int ret;
3249
3250         if (!ctlr->queued)
3251                 return 0;
3252
3253         ret = spi_start_queue(ctlr);
3254         if (ret)
3255                 dev_err(&ctlr->dev, "queue restart failed\n");
3256
3257         return ret;
3258 }
3259 EXPORT_SYMBOL_GPL(spi_controller_resume);
3260
3261 /*-------------------------------------------------------------------------*/
3262
3263 /* Core methods for spi_message alterations */
3264
3265 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3266                                             struct spi_message *msg,
3267                                             void *res)
3268 {
3269         struct spi_replaced_transfers *rxfer = res;
3270         size_t i;
3271
3272         /* Call extra callback if requested */
3273         if (rxfer->release)
3274                 rxfer->release(ctlr, msg, res);
3275
3276         /* Insert replaced transfers back into the message */
3277         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3278
3279         /* Remove the formerly inserted entries */
3280         for (i = 0; i < rxfer->inserted; i++)
3281                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3282 }
3283
3284 /**
3285  * spi_replace_transfers - replace transfers with several transfers
3286  *                         and register change with spi_message.resources
3287  * @msg:           the spi_message we work upon
3288  * @xfer_first:    the first spi_transfer we want to replace
3289  * @remove:        number of transfers to remove
3290  * @insert:        the number of transfers we want to insert instead
3291  * @release:       extra release code necessary in some circumstances
3292  * @extradatasize: extra data to allocate (with alignment guarantees
3293  *                 of struct @spi_transfer)
3294  * @gfp:           gfp flags
3295  *
3296  * Returns: pointer to @spi_replaced_transfers,
3297  *          PTR_ERR(...) in case of errors.
3298  */
3299 static struct spi_replaced_transfers *spi_replace_transfers(
3300         struct spi_message *msg,
3301         struct spi_transfer *xfer_first,
3302         size_t remove,
3303         size_t insert,
3304         spi_replaced_release_t release,
3305         size_t extradatasize,
3306         gfp_t gfp)
3307 {
3308         struct spi_replaced_transfers *rxfer;
3309         struct spi_transfer *xfer;
3310         size_t i;
3311
3312         /* Allocate the structure using spi_res */
3313         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3314                               struct_size(rxfer, inserted_transfers, insert)
3315                               + extradatasize,
3316                               gfp);
3317         if (!rxfer)
3318                 return ERR_PTR(-ENOMEM);
3319
3320         /* The release code to invoke before running the generic release */
3321         rxfer->release = release;
3322
3323         /* Assign extradata */
3324         if (extradatasize)
3325                 rxfer->extradata =
3326                         &rxfer->inserted_transfers[insert];
3327
3328         /* Init the replaced_transfers list */
3329         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3330
3331         /*
3332          * Assign the list_entry after which we should reinsert
3333          * the @replaced_transfers - it may be spi_message.messages!
3334          */
3335         rxfer->replaced_after = xfer_first->transfer_list.prev;
3336
3337         /* Remove the requested number of transfers */
3338         for (i = 0; i < remove; i++) {
3339                 /*
3340                  * If the entry after replaced_after it is msg->transfers
3341                  * then we have been requested to remove more transfers
3342                  * than are in the list.
3343                  */
3344                 if (rxfer->replaced_after->next == &msg->transfers) {
3345                         dev_err(&msg->spi->dev,
3346                                 "requested to remove more spi_transfers than are available\n");
3347                         /* Insert replaced transfers back into the message */
3348                         list_splice(&rxfer->replaced_transfers,
3349                                     rxfer->replaced_after);
3350
3351                         /* Free the spi_replace_transfer structure... */
3352                         spi_res_free(rxfer);
3353
3354                         /* ...and return with an error */
3355                         return ERR_PTR(-EINVAL);
3356                 }
3357
3358                 /*
3359                  * Remove the entry after replaced_after from list of
3360                  * transfers and add it to list of replaced_transfers.
3361                  */
3362                 list_move_tail(rxfer->replaced_after->next,
3363                                &rxfer->replaced_transfers);
3364         }
3365
3366         /*
3367          * Create copy of the given xfer with identical settings
3368          * based on the first transfer to get removed.
3369          */
3370         for (i = 0; i < insert; i++) {
3371                 /* We need to run in reverse order */
3372                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3373
3374                 /* Copy all spi_transfer data */
3375                 memcpy(xfer, xfer_first, sizeof(*xfer));
3376
3377                 /* Add to list */
3378                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3379
3380                 /* Clear cs_change and delay for all but the last */
3381                 if (i) {
3382                         xfer->cs_change = false;
3383                         xfer->delay.value = 0;
3384                 }
3385         }
3386
3387         /* Set up inserted... */
3388         rxfer->inserted = insert;
3389
3390         /* ...and register it with spi_res/spi_message */
3391         spi_res_add(msg, rxfer);
3392
3393         return rxfer;
3394 }
3395
3396 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3397                                         struct spi_message *msg,
3398                                         struct spi_transfer **xferp,
3399                                         size_t maxsize,
3400                                         gfp_t gfp)
3401 {
3402         struct spi_transfer *xfer = *xferp, *xfers;
3403         struct spi_replaced_transfers *srt;
3404         size_t offset;
3405         size_t count, i;
3406
3407         /* Calculate how many we have to replace */
3408         count = DIV_ROUND_UP(xfer->len, maxsize);
3409
3410         /* Create replacement */
3411         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3412         if (IS_ERR(srt))
3413                 return PTR_ERR(srt);
3414         xfers = srt->inserted_transfers;
3415
3416         /*
3417          * Now handle each of those newly inserted spi_transfers.
3418          * Note that the replacements spi_transfers all are preset
3419          * to the same values as *xferp, so tx_buf, rx_buf and len
3420          * are all identical (as well as most others)
3421          * so we just have to fix up len and the pointers.
3422          *
3423          * This also includes support for the depreciated
3424          * spi_message.is_dma_mapped interface.
3425          */
3426
3427         /*
3428          * The first transfer just needs the length modified, so we
3429          * run it outside the loop.
3430          */
3431         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3432
3433         /* All the others need rx_buf/tx_buf also set */
3434         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3435                 /* Update rx_buf, tx_buf and dma */
3436                 if (xfers[i].rx_buf)
3437                         xfers[i].rx_buf += offset;
3438                 if (xfers[i].rx_dma)
3439                         xfers[i].rx_dma += offset;
3440                 if (xfers[i].tx_buf)
3441                         xfers[i].tx_buf += offset;
3442                 if (xfers[i].tx_dma)
3443                         xfers[i].tx_dma += offset;
3444
3445                 /* Update length */
3446                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3447         }
3448
3449         /*
3450          * We set up xferp to the last entry we have inserted,
3451          * so that we skip those already split transfers.
3452          */
3453         *xferp = &xfers[count - 1];
3454
3455         /* Increment statistics counters */
3456         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics,
3457                                        transfers_split_maxsize);
3458         SPI_STATISTICS_INCREMENT_FIELD(msg->spi->pcpu_statistics,
3459                                        transfers_split_maxsize);
3460
3461         return 0;
3462 }
3463
3464 /**
3465  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3466  *                               when an individual transfer exceeds a
3467  *                               certain size
3468  * @ctlr:    the @spi_controller for this transfer
3469  * @msg:   the @spi_message to transform
3470  * @maxsize:  the maximum when to apply this
3471  * @gfp: GFP allocation flags
3472  *
3473  * Return: status of transformation
3474  */
3475 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3476                                 struct spi_message *msg,
3477                                 size_t maxsize,
3478                                 gfp_t gfp)
3479 {
3480         struct spi_transfer *xfer;
3481         int ret;
3482
3483         /*
3484          * Iterate over the transfer_list,
3485          * but note that xfer is advanced to the last transfer inserted
3486          * to avoid checking sizes again unnecessarily (also xfer does
3487          * potentially belong to a different list by the time the
3488          * replacement has happened).
3489          */
3490         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3491                 if (xfer->len > maxsize) {
3492                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3493                                                            maxsize, gfp);
3494                         if (ret)
3495                                 return ret;
3496                 }
3497         }
3498
3499         return 0;
3500 }
3501 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3502
3503 /*-------------------------------------------------------------------------*/
3504
3505 /* Core methods for SPI controller protocol drivers.  Some of the
3506  * other core methods are currently defined as inline functions.
3507  */
3508
3509 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3510                                         u8 bits_per_word)
3511 {
3512         if (ctlr->bits_per_word_mask) {
3513                 /* Only 32 bits fit in the mask */
3514                 if (bits_per_word > 32)
3515                         return -EINVAL;
3516                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3517                         return -EINVAL;
3518         }
3519
3520         return 0;
3521 }
3522
3523 /**
3524  * spi_setup - setup SPI mode and clock rate
3525  * @spi: the device whose settings are being modified
3526  * Context: can sleep, and no requests are queued to the device
3527  *
3528  * SPI protocol drivers may need to update the transfer mode if the
3529  * device doesn't work with its default.  They may likewise need
3530  * to update clock rates or word sizes from initial values.  This function
3531  * changes those settings, and must be called from a context that can sleep.
3532  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3533  * effect the next time the device is selected and data is transferred to
3534  * or from it.  When this function returns, the spi device is deselected.
3535  *
3536  * Note that this call will fail if the protocol driver specifies an option
3537  * that the underlying controller or its driver does not support.  For
3538  * example, not all hardware supports wire transfers using nine bit words,
3539  * LSB-first wire encoding, or active-high chipselects.
3540  *
3541  * Return: zero on success, else a negative error code.
3542  */
3543 int spi_setup(struct spi_device *spi)
3544 {
3545         unsigned        bad_bits, ugly_bits;
3546         int             status = 0;
3547
3548         /*
3549          * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3550          * are set at the same time.
3551          */
3552         if ((hweight_long(spi->mode &
3553                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3554             (hweight_long(spi->mode &
3555                 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3556                 dev_err(&spi->dev,
3557                 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3558                 return -EINVAL;
3559         }
3560         /* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
3561         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3562                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3563                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3564                 return -EINVAL;
3565         /*
3566          * Help drivers fail *cleanly* when they need options
3567          * that aren't supported with their current controller.
3568          * SPI_CS_WORD has a fallback software implementation,
3569          * so it is ignored here.
3570          */
3571         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3572                                  SPI_NO_TX | SPI_NO_RX);
3573         ugly_bits = bad_bits &
3574                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3575                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3576         if (ugly_bits) {
3577                 dev_warn(&spi->dev,
3578                          "setup: ignoring unsupported mode bits %x\n",
3579                          ugly_bits);
3580                 spi->mode &= ~ugly_bits;
3581                 bad_bits &= ~ugly_bits;
3582         }
3583         if (bad_bits) {
3584                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3585                         bad_bits);
3586                 return -EINVAL;
3587         }
3588
3589         if (!spi->bits_per_word) {
3590                 spi->bits_per_word = 8;
3591         } else {
3592                 /*
3593                  * Some controllers may not support the default 8 bits-per-word
3594                  * so only perform the check when this is explicitly provided.
3595                  */
3596                 status = __spi_validate_bits_per_word(spi->controller,
3597                                                       spi->bits_per_word);
3598                 if (status)
3599                         return status;
3600         }
3601
3602         if (spi->controller->max_speed_hz &&
3603             (!spi->max_speed_hz ||
3604              spi->max_speed_hz > spi->controller->max_speed_hz))
3605                 spi->max_speed_hz = spi->controller->max_speed_hz;
3606
3607         mutex_lock(&spi->controller->io_mutex);
3608
3609         if (spi->controller->setup) {
3610                 status = spi->controller->setup(spi);
3611                 if (status) {
3612                         mutex_unlock(&spi->controller->io_mutex);
3613                         dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3614                                 status);
3615                         return status;
3616                 }
3617         }
3618
3619         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3620                 status = pm_runtime_resume_and_get(spi->controller->dev.parent);
3621                 if (status < 0) {
3622                         mutex_unlock(&spi->controller->io_mutex);
3623                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3624                                 status);
3625                         return status;
3626                 }
3627
3628                 /*
3629                  * We do not want to return positive value from pm_runtime_get,
3630                  * there are many instances of devices calling spi_setup() and
3631                  * checking for a non-zero return value instead of a negative
3632                  * return value.
3633                  */
3634                 status = 0;
3635
3636                 spi_set_cs(spi, false, true);
3637                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3638                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3639         } else {
3640                 spi_set_cs(spi, false, true);
3641         }
3642
3643         mutex_unlock(&spi->controller->io_mutex);
3644
3645         if (spi->rt && !spi->controller->rt) {
3646                 spi->controller->rt = true;
3647                 spi_set_thread_rt(spi->controller);
3648         }
3649
3650         trace_spi_setup(spi, status);
3651
3652         dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3653                         spi->mode & SPI_MODE_X_MASK,
3654                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3655                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3656                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3657                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3658                         spi->bits_per_word, spi->max_speed_hz,
3659                         status);
3660
3661         return status;
3662 }
3663 EXPORT_SYMBOL_GPL(spi_setup);
3664
3665 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3666                                        struct spi_device *spi)
3667 {
3668         int delay1, delay2;
3669
3670         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3671         if (delay1 < 0)
3672                 return delay1;
3673
3674         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3675         if (delay2 < 0)
3676                 return delay2;
3677
3678         if (delay1 < delay2)
3679                 memcpy(&xfer->word_delay, &spi->word_delay,
3680                        sizeof(xfer->word_delay));
3681
3682         return 0;
3683 }
3684
3685 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3686 {
3687         struct spi_controller *ctlr = spi->controller;
3688         struct spi_transfer *xfer;
3689         int w_size;
3690
3691         if (list_empty(&message->transfers))
3692                 return -EINVAL;
3693
3694         /*
3695          * If an SPI controller does not support toggling the CS line on each
3696          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3697          * for the CS line, we can emulate the CS-per-word hardware function by
3698          * splitting transfers into one-word transfers and ensuring that
3699          * cs_change is set for each transfer.
3700          */
3701         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3702                                           spi->cs_gpiod)) {
3703                 size_t maxsize;
3704                 int ret;
3705
3706                 maxsize = (spi->bits_per_word + 7) / 8;
3707
3708                 /* spi_split_transfers_maxsize() requires message->spi */
3709                 message->spi = spi;
3710
3711                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3712                                                   GFP_KERNEL);
3713                 if (ret)
3714                         return ret;
3715
3716                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3717                         /* Don't change cs_change on the last entry in the list */
3718                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3719                                 break;
3720                         xfer->cs_change = 1;
3721                 }
3722         }
3723
3724         /*
3725          * Half-duplex links include original MicroWire, and ones with
3726          * only one data pin like SPI_3WIRE (switches direction) or where
3727          * either MOSI or MISO is missing.  They can also be caused by
3728          * software limitations.
3729          */
3730         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3731             (spi->mode & SPI_3WIRE)) {
3732                 unsigned flags = ctlr->flags;
3733
3734                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3735                         if (xfer->rx_buf && xfer->tx_buf)
3736                                 return -EINVAL;
3737                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3738                                 return -EINVAL;
3739                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3740                                 return -EINVAL;
3741                 }
3742         }
3743
3744         /*
3745          * Set transfer bits_per_word and max speed as spi device default if
3746          * it is not set for this transfer.
3747          * Set transfer tx_nbits and rx_nbits as single transfer default
3748          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3749          * Ensure transfer word_delay is at least as long as that required by
3750          * device itself.
3751          */
3752         message->frame_length = 0;
3753         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3754                 xfer->effective_speed_hz = 0;
3755                 message->frame_length += xfer->len;
3756                 if (!xfer->bits_per_word)
3757                         xfer->bits_per_word = spi->bits_per_word;
3758
3759                 if (!xfer->speed_hz)
3760                         xfer->speed_hz = spi->max_speed_hz;
3761
3762                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3763                         xfer->speed_hz = ctlr->max_speed_hz;
3764
3765                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3766                         return -EINVAL;
3767
3768                 /*
3769                  * SPI transfer length should be multiple of SPI word size
3770                  * where SPI word size should be power-of-two multiple.
3771                  */
3772                 if (xfer->bits_per_word <= 8)
3773                         w_size = 1;
3774                 else if (xfer->bits_per_word <= 16)
3775                         w_size = 2;
3776                 else
3777                         w_size = 4;
3778
3779                 /* No partial transfers accepted */
3780                 if (xfer->len % w_size)
3781                         return -EINVAL;
3782
3783                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3784                     xfer->speed_hz < ctlr->min_speed_hz)
3785                         return -EINVAL;
3786
3787                 if (xfer->tx_buf && !xfer->tx_nbits)
3788                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3789                 if (xfer->rx_buf && !xfer->rx_nbits)
3790                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3791                 /*
3792                  * Check transfer tx/rx_nbits:
3793                  * 1. check the value matches one of single, dual and quad
3794                  * 2. check tx/rx_nbits match the mode in spi_device
3795                  */
3796                 if (xfer->tx_buf) {
3797                         if (spi->mode & SPI_NO_TX)
3798                                 return -EINVAL;
3799                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3800                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3801                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3802                                 return -EINVAL;
3803                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3804                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3805                                 return -EINVAL;
3806                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3807                                 !(spi->mode & SPI_TX_QUAD))
3808                                 return -EINVAL;
3809                 }
3810                 /* Check transfer rx_nbits */
3811                 if (xfer->rx_buf) {
3812                         if (spi->mode & SPI_NO_RX)
3813                                 return -EINVAL;
3814                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3815                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3816                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3817                                 return -EINVAL;
3818                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3819                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3820                                 return -EINVAL;
3821                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3822                                 !(spi->mode & SPI_RX_QUAD))
3823                                 return -EINVAL;
3824                 }
3825
3826                 if (_spi_xfer_word_delay_update(xfer, spi))
3827                         return -EINVAL;
3828         }
3829
3830         message->status = -EINPROGRESS;
3831
3832         return 0;
3833 }
3834
3835 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3836 {
3837         struct spi_controller *ctlr = spi->controller;
3838         struct spi_transfer *xfer;
3839
3840         /*
3841          * Some controllers do not support doing regular SPI transfers. Return
3842          * ENOTSUPP when this is the case.
3843          */
3844         if (!ctlr->transfer)
3845                 return -ENOTSUPP;
3846
3847         message->spi = spi;
3848
3849         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_async);
3850         SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_async);
3851
3852         trace_spi_message_submit(message);
3853
3854         if (!ctlr->ptp_sts_supported) {
3855                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3856                         xfer->ptp_sts_word_pre = 0;
3857                         ptp_read_system_prets(xfer->ptp_sts);
3858                 }
3859         }
3860
3861         return ctlr->transfer(spi, message);
3862 }
3863
3864 /**
3865  * spi_async - asynchronous SPI transfer
3866  * @spi: device with which data will be exchanged
3867  * @message: describes the data transfers, including completion callback
3868  * Context: any (irqs may be blocked, etc)
3869  *
3870  * This call may be used in_irq and other contexts which can't sleep,
3871  * as well as from task contexts which can sleep.
3872  *
3873  * The completion callback is invoked in a context which can't sleep.
3874  * Before that invocation, the value of message->status is undefined.
3875  * When the callback is issued, message->status holds either zero (to
3876  * indicate complete success) or a negative error code.  After that
3877  * callback returns, the driver which issued the transfer request may
3878  * deallocate the associated memory; it's no longer in use by any SPI
3879  * core or controller driver code.
3880  *
3881  * Note that although all messages to a spi_device are handled in
3882  * FIFO order, messages may go to different devices in other orders.
3883  * Some device might be higher priority, or have various "hard" access
3884  * time requirements, for example.
3885  *
3886  * On detection of any fault during the transfer, processing of
3887  * the entire message is aborted, and the device is deselected.
3888  * Until returning from the associated message completion callback,
3889  * no other spi_message queued to that device will be processed.
3890  * (This rule applies equally to all the synchronous transfer calls,
3891  * which are wrappers around this core asynchronous primitive.)
3892  *
3893  * Return: zero on success, else a negative error code.
3894  */
3895 int spi_async(struct spi_device *spi, struct spi_message *message)
3896 {
3897         struct spi_controller *ctlr = spi->controller;
3898         int ret;
3899         unsigned long flags;
3900
3901         ret = __spi_validate(spi, message);
3902         if (ret != 0)
3903                 return ret;
3904
3905         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3906
3907         if (ctlr->bus_lock_flag)
3908                 ret = -EBUSY;
3909         else
3910                 ret = __spi_async(spi, message);
3911
3912         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3913
3914         return ret;
3915 }
3916 EXPORT_SYMBOL_GPL(spi_async);
3917
3918 /**
3919  * spi_async_locked - version of spi_async with exclusive bus usage
3920  * @spi: device with which data will be exchanged
3921  * @message: describes the data transfers, including completion callback
3922  * Context: any (irqs may be blocked, etc)
3923  *
3924  * This call may be used in_irq and other contexts which can't sleep,
3925  * as well as from task contexts which can sleep.
3926  *
3927  * The completion callback is invoked in a context which can't sleep.
3928  * Before that invocation, the value of message->status is undefined.
3929  * When the callback is issued, message->status holds either zero (to
3930  * indicate complete success) or a negative error code.  After that
3931  * callback returns, the driver which issued the transfer request may
3932  * deallocate the associated memory; it's no longer in use by any SPI
3933  * core or controller driver code.
3934  *
3935  * Note that although all messages to a spi_device are handled in
3936  * FIFO order, messages may go to different devices in other orders.
3937  * Some device might be higher priority, or have various "hard" access
3938  * time requirements, for example.
3939  *
3940  * On detection of any fault during the transfer, processing of
3941  * the entire message is aborted, and the device is deselected.
3942  * Until returning from the associated message completion callback,
3943  * no other spi_message queued to that device will be processed.
3944  * (This rule applies equally to all the synchronous transfer calls,
3945  * which are wrappers around this core asynchronous primitive.)
3946  *
3947  * Return: zero on success, else a negative error code.
3948  */
3949 static int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3950 {
3951         struct spi_controller *ctlr = spi->controller;
3952         int ret;
3953         unsigned long flags;
3954
3955         ret = __spi_validate(spi, message);
3956         if (ret != 0)
3957                 return ret;
3958
3959         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3960
3961         ret = __spi_async(spi, message);
3962
3963         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3964
3965         return ret;
3966
3967 }
3968
3969 static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg)
3970 {
3971         bool was_busy;
3972         int ret;
3973
3974         mutex_lock(&ctlr->io_mutex);
3975
3976         was_busy = ctlr->busy;
3977
3978         ctlr->cur_msg = msg;
3979         ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
3980         if (ret)
3981                 goto out;
3982
3983         ctlr->cur_msg = NULL;
3984         ctlr->fallback = false;
3985
3986         if (!was_busy) {
3987                 kfree(ctlr->dummy_rx);
3988                 ctlr->dummy_rx = NULL;
3989                 kfree(ctlr->dummy_tx);
3990                 ctlr->dummy_tx = NULL;
3991                 if (ctlr->unprepare_transfer_hardware &&
3992                     ctlr->unprepare_transfer_hardware(ctlr))
3993                         dev_err(&ctlr->dev,
3994                                 "failed to unprepare transfer hardware\n");
3995                 spi_idle_runtime_pm(ctlr);
3996         }
3997
3998 out:
3999         mutex_unlock(&ctlr->io_mutex);
4000 }
4001
4002 /*-------------------------------------------------------------------------*/
4003
4004 /*
4005  * Utility methods for SPI protocol drivers, layered on
4006  * top of the core.  Some other utility methods are defined as
4007  * inline functions.
4008  */
4009
4010 static void spi_complete(void *arg)
4011 {
4012         complete(arg);
4013 }
4014
4015 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
4016 {
4017         DECLARE_COMPLETION_ONSTACK(done);
4018         int status;
4019         struct spi_controller *ctlr = spi->controller;
4020
4021         status = __spi_validate(spi, message);
4022         if (status != 0)
4023                 return status;
4024
4025         message->spi = spi;
4026
4027         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync);
4028         SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync);
4029
4030         /*
4031          * Checking queue_empty here only guarantees async/sync message
4032          * ordering when coming from the same context. It does not need to
4033          * guard against reentrancy from a different context. The io_mutex
4034          * will catch those cases.
4035          */
4036         if (READ_ONCE(ctlr->queue_empty)) {
4037                 message->actual_length = 0;
4038                 message->status = -EINPROGRESS;
4039
4040                 trace_spi_message_submit(message);
4041
4042                 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync_immediate);
4043                 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync_immediate);
4044
4045                 __spi_transfer_message_noqueue(ctlr, message);
4046
4047                 return message->status;
4048         }
4049
4050         /*
4051          * There are messages in the async queue that could have originated
4052          * from the same context, so we need to preserve ordering.
4053          * Therefor we send the message to the async queue and wait until they
4054          * are completed.
4055          */
4056         message->complete = spi_complete;
4057         message->context = &done;
4058         status = spi_async_locked(spi, message);
4059         if (status == 0) {
4060                 wait_for_completion(&done);
4061                 status = message->status;
4062         }
4063         message->context = NULL;
4064
4065         return status;
4066 }
4067
4068 /**
4069  * spi_sync - blocking/synchronous SPI data transfers
4070  * @spi: device with which data will be exchanged
4071  * @message: describes the data transfers
4072  * Context: can sleep
4073  *
4074  * This call may only be used from a context that may sleep.  The sleep
4075  * is non-interruptible, and has no timeout.  Low-overhead controller
4076  * drivers may DMA directly into and out of the message buffers.
4077  *
4078  * Note that the SPI device's chip select is active during the message,
4079  * and then is normally disabled between messages.  Drivers for some
4080  * frequently-used devices may want to minimize costs of selecting a chip,
4081  * by leaving it selected in anticipation that the next message will go
4082  * to the same chip.  (That may increase power usage.)
4083  *
4084  * Also, the caller is guaranteeing that the memory associated with the
4085  * message will not be freed before this call returns.
4086  *
4087  * Return: zero on success, else a negative error code.
4088  */
4089 int spi_sync(struct spi_device *spi, struct spi_message *message)
4090 {
4091         int ret;
4092
4093         mutex_lock(&spi->controller->bus_lock_mutex);
4094         ret = __spi_sync(spi, message);
4095         mutex_unlock(&spi->controller->bus_lock_mutex);
4096
4097         return ret;
4098 }
4099 EXPORT_SYMBOL_GPL(spi_sync);
4100
4101 /**
4102  * spi_sync_locked - version of spi_sync with exclusive bus usage
4103  * @spi: device with which data will be exchanged
4104  * @message: describes the data transfers
4105  * Context: can sleep
4106  *
4107  * This call may only be used from a context that may sleep.  The sleep
4108  * is non-interruptible, and has no timeout.  Low-overhead controller
4109  * drivers may DMA directly into and out of the message buffers.
4110  *
4111  * This call should be used by drivers that require exclusive access to the
4112  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
4113  * be released by a spi_bus_unlock call when the exclusive access is over.
4114  *
4115  * Return: zero on success, else a negative error code.
4116  */
4117 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
4118 {
4119         return __spi_sync(spi, message);
4120 }
4121 EXPORT_SYMBOL_GPL(spi_sync_locked);
4122
4123 /**
4124  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
4125  * @ctlr: SPI bus master that should be locked for exclusive bus access
4126  * Context: can sleep
4127  *
4128  * This call may only be used from a context that may sleep.  The sleep
4129  * is non-interruptible, and has no timeout.
4130  *
4131  * This call should be used by drivers that require exclusive access to the
4132  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
4133  * exclusive access is over. Data transfer must be done by spi_sync_locked
4134  * and spi_async_locked calls when the SPI bus lock is held.
4135  *
4136  * Return: always zero.
4137  */
4138 int spi_bus_lock(struct spi_controller *ctlr)
4139 {
4140         unsigned long flags;
4141
4142         mutex_lock(&ctlr->bus_lock_mutex);
4143
4144         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4145         ctlr->bus_lock_flag = 1;
4146         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4147
4148         /* Mutex remains locked until spi_bus_unlock() is called */
4149
4150         return 0;
4151 }
4152 EXPORT_SYMBOL_GPL(spi_bus_lock);
4153
4154 /**
4155  * spi_bus_unlock - release the lock for exclusive SPI bus usage
4156  * @ctlr: SPI bus master that was locked for exclusive bus access
4157  * Context: can sleep
4158  *
4159  * This call may only be used from a context that may sleep.  The sleep
4160  * is non-interruptible, and has no timeout.
4161  *
4162  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4163  * call.
4164  *
4165  * Return: always zero.
4166  */
4167 int spi_bus_unlock(struct spi_controller *ctlr)
4168 {
4169         ctlr->bus_lock_flag = 0;
4170
4171         mutex_unlock(&ctlr->bus_lock_mutex);
4172
4173         return 0;
4174 }
4175 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4176
4177 /* Portable code must never pass more than 32 bytes */
4178 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
4179
4180 static u8       *buf;
4181
4182 /**
4183  * spi_write_then_read - SPI synchronous write followed by read
4184  * @spi: device with which data will be exchanged
4185  * @txbuf: data to be written (need not be dma-safe)
4186  * @n_tx: size of txbuf, in bytes
4187  * @rxbuf: buffer into which data will be read (need not be dma-safe)
4188  * @n_rx: size of rxbuf, in bytes
4189  * Context: can sleep
4190  *
4191  * This performs a half duplex MicroWire style transaction with the
4192  * device, sending txbuf and then reading rxbuf.  The return value
4193  * is zero for success, else a negative errno status code.
4194  * This call may only be used from a context that may sleep.
4195  *
4196  * Parameters to this routine are always copied using a small buffer.
4197  * Performance-sensitive or bulk transfer code should instead use
4198  * spi_{async,sync}() calls with dma-safe buffers.
4199  *
4200  * Return: zero on success, else a negative error code.
4201  */
4202 int spi_write_then_read(struct spi_device *spi,
4203                 const void *txbuf, unsigned n_tx,
4204                 void *rxbuf, unsigned n_rx)
4205 {
4206         static DEFINE_MUTEX(lock);
4207
4208         int                     status;
4209         struct spi_message      message;
4210         struct spi_transfer     x[2];
4211         u8                      *local_buf;
4212
4213         /*
4214          * Use preallocated DMA-safe buffer if we can. We can't avoid
4215          * copying here, (as a pure convenience thing), but we can
4216          * keep heap costs out of the hot path unless someone else is
4217          * using the pre-allocated buffer or the transfer is too large.
4218          */
4219         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4220                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4221                                     GFP_KERNEL | GFP_DMA);
4222                 if (!local_buf)
4223                         return -ENOMEM;
4224         } else {
4225                 local_buf = buf;
4226         }
4227
4228         spi_message_init(&message);
4229         memset(x, 0, sizeof(x));
4230         if (n_tx) {
4231                 x[0].len = n_tx;
4232                 spi_message_add_tail(&x[0], &message);
4233         }
4234         if (n_rx) {
4235                 x[1].len = n_rx;
4236                 spi_message_add_tail(&x[1], &message);
4237         }
4238
4239         memcpy(local_buf, txbuf, n_tx);
4240         x[0].tx_buf = local_buf;
4241         x[1].rx_buf = local_buf + n_tx;
4242
4243         /* Do the i/o */
4244         status = spi_sync(spi, &message);
4245         if (status == 0)
4246                 memcpy(rxbuf, x[1].rx_buf, n_rx);
4247
4248         if (x[0].tx_buf == buf)
4249                 mutex_unlock(&lock);
4250         else
4251                 kfree(local_buf);
4252
4253         return status;
4254 }
4255 EXPORT_SYMBOL_GPL(spi_write_then_read);
4256
4257 /*-------------------------------------------------------------------------*/
4258
4259 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4260 /* Must call put_device() when done with returned spi_device device */
4261 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4262 {
4263         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4264
4265         return dev ? to_spi_device(dev) : NULL;
4266 }
4267
4268 /* The spi controllers are not using spi_bus, so we find it with another way */
4269 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4270 {
4271         struct device *dev;
4272
4273         dev = class_find_device_by_of_node(&spi_master_class, node);
4274         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4275                 dev = class_find_device_by_of_node(&spi_slave_class, node);
4276         if (!dev)
4277                 return NULL;
4278
4279         /* Reference got in class_find_device */
4280         return container_of(dev, struct spi_controller, dev);
4281 }
4282
4283 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4284                          void *arg)
4285 {
4286         struct of_reconfig_data *rd = arg;
4287         struct spi_controller *ctlr;
4288         struct spi_device *spi;
4289
4290         switch (of_reconfig_get_state_change(action, arg)) {
4291         case OF_RECONFIG_CHANGE_ADD:
4292                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4293                 if (ctlr == NULL)
4294                         return NOTIFY_OK;       /* Not for us */
4295
4296                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4297                         put_device(&ctlr->dev);
4298                         return NOTIFY_OK;
4299                 }
4300
4301                 spi = of_register_spi_device(ctlr, rd->dn);
4302                 put_device(&ctlr->dev);
4303
4304                 if (IS_ERR(spi)) {
4305                         pr_err("%s: failed to create for '%pOF'\n",
4306                                         __func__, rd->dn);
4307                         of_node_clear_flag(rd->dn, OF_POPULATED);
4308                         return notifier_from_errno(PTR_ERR(spi));
4309                 }
4310                 break;
4311
4312         case OF_RECONFIG_CHANGE_REMOVE:
4313                 /* Already depopulated? */
4314                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4315                         return NOTIFY_OK;
4316
4317                 /* Find our device by node */
4318                 spi = of_find_spi_device_by_node(rd->dn);
4319                 if (spi == NULL)
4320                         return NOTIFY_OK;       /* No? not meant for us */
4321
4322                 /* Unregister takes one ref away */
4323                 spi_unregister_device(spi);
4324
4325                 /* And put the reference of the find */
4326                 put_device(&spi->dev);
4327                 break;
4328         }
4329
4330         return NOTIFY_OK;
4331 }
4332
4333 static struct notifier_block spi_of_notifier = {
4334         .notifier_call = of_spi_notify,
4335 };
4336 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4337 extern struct notifier_block spi_of_notifier;
4338 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4339
4340 #if IS_ENABLED(CONFIG_ACPI)
4341 static int spi_acpi_controller_match(struct device *dev, const void *data)
4342 {
4343         return ACPI_COMPANION(dev->parent) == data;
4344 }
4345
4346 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4347 {
4348         struct device *dev;
4349
4350         dev = class_find_device(&spi_master_class, NULL, adev,
4351                                 spi_acpi_controller_match);
4352         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4353                 dev = class_find_device(&spi_slave_class, NULL, adev,
4354                                         spi_acpi_controller_match);
4355         if (!dev)
4356                 return NULL;
4357
4358         return container_of(dev, struct spi_controller, dev);
4359 }
4360
4361 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4362 {
4363         struct device *dev;
4364
4365         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4366         return to_spi_device(dev);
4367 }
4368
4369 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4370                            void *arg)
4371 {
4372         struct acpi_device *adev = arg;
4373         struct spi_controller *ctlr;
4374         struct spi_device *spi;
4375
4376         switch (value) {
4377         case ACPI_RECONFIG_DEVICE_ADD:
4378                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4379                 if (!ctlr)
4380                         break;
4381
4382                 acpi_register_spi_device(ctlr, adev);
4383                 put_device(&ctlr->dev);
4384                 break;
4385         case ACPI_RECONFIG_DEVICE_REMOVE:
4386                 if (!acpi_device_enumerated(adev))
4387                         break;
4388
4389                 spi = acpi_spi_find_device_by_adev(adev);
4390                 if (!spi)
4391                         break;
4392
4393                 spi_unregister_device(spi);
4394                 put_device(&spi->dev);
4395                 break;
4396         }
4397
4398         return NOTIFY_OK;
4399 }
4400
4401 static struct notifier_block spi_acpi_notifier = {
4402         .notifier_call = acpi_spi_notify,
4403 };
4404 #else
4405 extern struct notifier_block spi_acpi_notifier;
4406 #endif
4407
4408 static int __init spi_init(void)
4409 {
4410         int     status;
4411
4412         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4413         if (!buf) {
4414                 status = -ENOMEM;
4415                 goto err0;
4416         }
4417
4418         status = bus_register(&spi_bus_type);
4419         if (status < 0)
4420                 goto err1;
4421
4422         status = class_register(&spi_master_class);
4423         if (status < 0)
4424                 goto err2;
4425
4426         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4427                 status = class_register(&spi_slave_class);
4428                 if (status < 0)
4429                         goto err3;
4430         }
4431
4432         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4433                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4434         if (IS_ENABLED(CONFIG_ACPI))
4435                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4436
4437         return 0;
4438
4439 err3:
4440         class_unregister(&spi_master_class);
4441 err2:
4442         bus_unregister(&spi_bus_type);
4443 err1:
4444         kfree(buf);
4445         buf = NULL;
4446 err0:
4447         return status;
4448 }
4449
4450 /*
4451  * A board_info is normally registered in arch_initcall(),
4452  * but even essential drivers wait till later.
4453  *
4454  * REVISIT only boardinfo really needs static linking. The rest (device and
4455  * driver registration) _could_ be dynamically linked (modular) ... Costs
4456  * include needing to have boardinfo data structures be much more public.
4457  */
4458 postcore_initcall(spi_init);