drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/property.h>
  35 #include <linux/export.h>
  36 #include <linux/sched/rt.h>
  37 #include <uapi/linux/sched/types.h>
  38 #include <linux/delay.h>
  39 #include <linux/kthread.h>
  40 #include <linux/ioport.h>
  41 #include <linux/acpi.h>
  42 #include <linux/highmem.h>
  43 #include <linux/idr.h>
  44 #include <linux/platform_data/x86/apple.h>
  45
  46 #define CREATE_TRACE_POINTS
  47 #include <trace/events/spi.h>
  48
  49 static DEFINE_IDR(spi_master_idr);
  50
  51 static void spidev_release(struct device *dev)
  52 {
  53         struct spi_device       *spi = to_spi_device(dev);
  54
  55         /* spi controllers may cleanup for released devices */
  56         if (spi->controller->cleanup)
  57                 spi->controller->cleanup(spi);
  58
  59         spi_controller_put(spi->controller);
  60         kfree(spi);
  61 }
  62
  63 static ssize_t
  64 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  65 {
  66         const struct spi_device *spi = to_spi_device(dev);
  67         int len;
  68
  69         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  70         if (len != -ENODEV)
  71                 return len;
  72
  73         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  74 }
  75 static DEVICE_ATTR_RO(modalias);
  76
  77 #define SPI_STATISTICS_ATTRS(field, file)                               \
  78 static ssize_t spi_controller_##field##_show(struct device *dev,        \
  79                                              struct device_attribute *attr, \
  80                                              char *buf)                 \
  81 {                                                                       \
  82         struct spi_controller *ctlr = container_of(dev,                 \
  83                                          struct spi_controller, dev);   \
  84         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
  85 }                                                                       \
  86 static struct device_attribute dev_attr_spi_controller_##field = {      \
  87         .attr = { .name = file, .mode = 0444 },                         \
  88         .show = spi_controller_##field##_show,                          \
  89 };                                                                      \
  90 static ssize_t spi_device_##field##_show(struct device *dev,            \
  91                                          struct device_attribute *attr, \
  92                                         char *buf)                      \
  93 {                                                                       \
  94         struct spi_device *spi = to_spi_device(dev);                    \
  95         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  96 }                                                                       \
  97 static struct device_attribute dev_attr_spi_device_##field = {          \
  98         .attr = { .name = file, .mode = 0444 },                         \
  99         .show = spi_device_##field##_show,                              \
 100 }
 101
 102 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 103 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 104                                             char *buf)                  \
 105 {                                                                       \
 106         unsigned long flags;                                            \
 107         ssize_t len;                                                    \
 108         spin_lock_irqsave(&stat->lock, flags);                          \
 109         len = sprintf(buf, format_string, stat->field);                 \
 110         spin_unlock_irqrestore(&stat->lock, flags);                     \
 111         return len;                                                     \
 112 }                                                                       \
 113 SPI_STATISTICS_ATTRS(name, file)
 114
 115 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 116         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 117                                  field, format_string)
 118
 119 SPI_STATISTICS_SHOW(messages, "%lu");
 120 SPI_STATISTICS_SHOW(transfers, "%lu");
 121 SPI_STATISTICS_SHOW(errors, "%lu");
 122 SPI_STATISTICS_SHOW(timedout, "%lu");
 123
 124 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 125 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 126 SPI_STATISTICS_SHOW(spi_async, "%lu");
 127
 128 SPI_STATISTICS_SHOW(bytes, "%llu");
 129 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 130 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 131
 132 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 133         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 134                                  "transfer_bytes_histo_" number,        \
 135                                  transfer_bytes_histo[index],  "%lu")
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 147 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 148 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 149 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 150 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 151 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 152 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 153
 154 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 155
 156 static struct attribute *spi_dev_attrs[] = {
 157         &dev_attr_modalias.attr,
 158         NULL,
 159 };
 160
 161 static const struct attribute_group spi_dev_group = {
 162         .attrs  = spi_dev_attrs,
 163 };
 164
 165 static struct attribute *spi_device_statistics_attrs[] = {
 166         &dev_attr_spi_device_messages.attr,
 167         &dev_attr_spi_device_transfers.attr,
 168         &dev_attr_spi_device_errors.attr,
 169         &dev_attr_spi_device_timedout.attr,
 170         &dev_attr_spi_device_spi_sync.attr,
 171         &dev_attr_spi_device_spi_sync_immediate.attr,
 172         &dev_attr_spi_device_spi_async.attr,
 173         &dev_attr_spi_device_bytes.attr,
 174         &dev_attr_spi_device_bytes_rx.attr,
 175         &dev_attr_spi_device_bytes_tx.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 186         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 187         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 188         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 189         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 190         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 191         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 192         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 193         &dev_attr_spi_device_transfers_split_maxsize.attr,
 194         NULL,
 195 };
 196
 197 static const struct attribute_group spi_device_statistics_group = {
 198         .name  = "statistics",
 199         .attrs  = spi_device_statistics_attrs,
 200 };
 201
 202 static const struct attribute_group *spi_dev_groups[] = {
 203         &spi_dev_group,
 204         &spi_device_statistics_group,
 205         NULL,
 206 };
 207
 208 static struct attribute *spi_controller_statistics_attrs[] = {
 209         &dev_attr_spi_controller_messages.attr,
 210         &dev_attr_spi_controller_transfers.attr,
 211         &dev_attr_spi_controller_errors.attr,
 212         &dev_attr_spi_controller_timedout.attr,
 213         &dev_attr_spi_controller_spi_sync.attr,
 214         &dev_attr_spi_controller_spi_sync_immediate.attr,
 215         &dev_attr_spi_controller_spi_async.attr,
 216         &dev_attr_spi_controller_bytes.attr,
 217         &dev_attr_spi_controller_bytes_rx.attr,
 218         &dev_attr_spi_controller_bytes_tx.attr,
 219         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 220         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 221         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 222         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 223         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 224         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 225         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 226         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 227         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 228         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 229         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 230         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 231         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 232         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 233         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 234         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 235         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 236         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 237         NULL,
 238 };
 239
 240 static const struct attribute_group spi_controller_statistics_group = {
 241         .name  = "statistics",
 242         .attrs  = spi_controller_statistics_attrs,
 243 };
 244
 245 static const struct attribute_group *spi_master_groups[] = {
 246         &spi_controller_statistics_group,
 247         NULL,
 248 };
 249
 250 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 251                                        struct spi_transfer *xfer,
 252                                        struct spi_controller *ctlr)
 253 {
 254         unsigned long flags;
 255         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 256
 257         if (l2len < 0)
 258                 l2len = 0;
 259
 260         spin_lock_irqsave(&stats->lock, flags);
 261
 262         stats->transfers++;
 263         stats->transfer_bytes_histo[l2len]++;
 264
 265         stats->bytes += xfer->len;
 266         if ((xfer->tx_buf) &&
 267             (xfer->tx_buf != ctlr->dummy_tx))
 268                 stats->bytes_tx += xfer->len;
 269         if ((xfer->rx_buf) &&
 270             (xfer->rx_buf != ctlr->dummy_rx))
 271                 stats->bytes_rx += xfer->len;
 272
 273         spin_unlock_irqrestore(&stats->lock, flags);
 274 }
 275 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 276
 277 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 278  * and the sysfs version makes coldplug work too.
 279  */
 280
 281 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 282                                                 const struct spi_device *sdev)
 283 {
 284         while (id->name[0]) {
 285                 if (!strcmp(sdev->modalias, id->name))
 286                         return id;
 287                 id++;
 288         }
 289         return NULL;
 290 }
 291
 292 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 293 {
 294         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 295
 296         return spi_match_id(sdrv->id_table, sdev);
 297 }
 298 EXPORT_SYMBOL_GPL(spi_get_device_id);
 299
 300 static int spi_match_device(struct device *dev, struct device_driver *drv)
 301 {
 302         const struct spi_device *spi = to_spi_device(dev);
 303         const struct spi_driver *sdrv = to_spi_driver(drv);
 304
 305         /* Attempt an OF style match */
 306         if (of_driver_match_device(dev, drv))
 307                 return 1;
 308
 309         /* Then try ACPI */
 310         if (acpi_driver_match_device(dev, drv))
 311                 return 1;
 312
 313         if (sdrv->id_table)
 314                 return !!spi_match_id(sdrv->id_table, spi);
 315
 316         return strcmp(spi->modalias, drv->name) == 0;
 317 }
 318
 319 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 320 {
 321         const struct spi_device         *spi = to_spi_device(dev);
 322         int rc;
 323
 324         rc = acpi_device_uevent_modalias(dev, env);
 325         if (rc != -ENODEV)
 326                 return rc;
 327
 328         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 329 }
 330
 331 struct bus_type spi_bus_type = {
 332         .name           = "spi",
 333         .dev_groups     = spi_dev_groups,
 334         .match          = spi_match_device,
 335         .uevent         = spi_uevent,
 336 };
 337 EXPORT_SYMBOL_GPL(spi_bus_type);
 338
 339
 340 static int spi_drv_probe(struct device *dev)
 341 {
 342         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 343         struct spi_device               *spi = to_spi_device(dev);
 344         int ret;
 345
 346         ret = of_clk_set_defaults(dev->of_node, false);
 347         if (ret)
 348                 return ret;
 349
 350         if (dev->of_node) {
 351                 spi->irq = of_irq_get(dev->of_node, 0);
 352                 if (spi->irq == -EPROBE_DEFER)
 353                         return -EPROBE_DEFER;
 354                 if (spi->irq < 0)
 355                         spi->irq = 0;
 356         }
 357
 358         ret = dev_pm_domain_attach(dev, true);
 359         if (ret != -EPROBE_DEFER) {
 360                 ret = sdrv->probe(spi);
 361                 if (ret)
 362                         dev_pm_domain_detach(dev, true);
 363         }
 364
 365         return ret;
 366 }
 367
 368 static int spi_drv_remove(struct device *dev)
 369 {
 370         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 371         int ret;
 372
 373         ret = sdrv->remove(to_spi_device(dev));
 374         dev_pm_domain_detach(dev, true);
 375
 376         return ret;
 377 }
 378
 379 static void spi_drv_shutdown(struct device *dev)
 380 {
 381         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 382
 383         sdrv->shutdown(to_spi_device(dev));
 384 }
 385
 386 /**
 387  * __spi_register_driver - register a SPI driver
 388  * @owner: owner module of the driver to register
 389  * @sdrv: the driver to register
 390  * Context: can sleep
 391  *
 392  * Return: zero on success, else a negative error code.
 393  */
 394 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 395 {
 396         sdrv->driver.owner = owner;
 397         sdrv->driver.bus = &spi_bus_type;
 398         if (sdrv->probe)
 399                 sdrv->driver.probe = spi_drv_probe;
 400         if (sdrv->remove)
 401                 sdrv->driver.remove = spi_drv_remove;
 402         if (sdrv->shutdown)
 403                 sdrv->driver.shutdown = spi_drv_shutdown;
 404         return driver_register(&sdrv->driver);
 405 }
 406 EXPORT_SYMBOL_GPL(__spi_register_driver);
 407
 408 /*-------------------------------------------------------------------------*/
 409
 410 /* SPI devices should normally not be created by SPI device drivers; that
 411  * would make them board-specific.  Similarly with SPI controller drivers.
 412  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 413  * with other readonly (flashable) information about mainboard devices.
 414  */
 415
 416 struct boardinfo {
 417         struct list_head        list;
 418         struct spi_board_info   board_info;
 419 };
 420
 421 static LIST_HEAD(board_list);
 422 static LIST_HEAD(spi_controller_list);
 423
 424 /*
 425  * Used to protect add/del opertion for board_info list and
 426  * spi_controller list, and their matching process
 427  * also used to protect object of type struct idr
 428  */
 429 static DEFINE_MUTEX(board_lock);
 430
 431 /**
 432  * spi_alloc_device - Allocate a new SPI device
 433  * @ctlr: Controller to which device is connected
 434  * Context: can sleep
 435  *
 436  * Allows a driver to allocate and initialize a spi_device without
 437  * registering it immediately.  This allows a driver to directly
 438  * fill the spi_device with device parameters before calling
 439  * spi_add_device() on it.
 440  *
 441  * Caller is responsible to call spi_add_device() on the returned
 442  * spi_device structure to add it to the SPI controller.  If the caller
 443  * needs to discard the spi_device without adding it, then it should
 444  * call spi_dev_put() on it.
 445  *
 446  * Return: a pointer to the new device, or NULL.
 447  */
 448 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 449 {
 450         struct spi_device       *spi;
 451
 452         if (!spi_controller_get(ctlr))
 453                 return NULL;
 454
 455         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 456         if (!spi) {
 457                 spi_controller_put(ctlr);
 458                 return NULL;
 459         }
 460
 461         spi->master = spi->controller = ctlr;
 462         spi->dev.parent = &ctlr->dev;
 463         spi->dev.bus = &spi_bus_type;
 464         spi->dev.release = spidev_release;
 465         spi->cs_gpio = -ENOENT;
 466
 467         spin_lock_init(&spi->statistics.lock);
 468
 469         device_initialize(&spi->dev);
 470         return spi;
 471 }
 472 EXPORT_SYMBOL_GPL(spi_alloc_device);
 473
 474 static void spi_dev_set_name(struct spi_device *spi)
 475 {
 476         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 477
 478         if (adev) {
 479                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 480                 return;
 481         }
 482
 483         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 484                      spi->chip_select);
 485 }
 486
 487 static int spi_dev_check(struct device *dev, void *data)
 488 {
 489         struct spi_device *spi = to_spi_device(dev);
 490         struct spi_device *new_spi = data;
 491
 492         if (spi->controller == new_spi->controller &&
 493             spi->chip_select == new_spi->chip_select)
 494                 return -EBUSY;
 495         return 0;
 496 }
 497
 498 /**
 499  * spi_add_device - Add spi_device allocated with spi_alloc_device
 500  * @spi: spi_device to register
 501  *
 502  * Companion function to spi_alloc_device.  Devices allocated with
 503  * spi_alloc_device can be added onto the spi bus with this function.
 504  *
 505  * Return: 0 on success; negative errno on failure
 506  */
 507 int spi_add_device(struct spi_device *spi)
 508 {
 509         static DEFINE_MUTEX(spi_add_lock);
 510         struct spi_controller *ctlr = spi->controller;
 511         struct device *dev = ctlr->dev.parent;
 512         int status;
 513
 514         /* Chipselects are numbered 0..max; validate. */
 515         if (spi->chip_select >= ctlr->num_chipselect) {
 516                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 517                         ctlr->num_chipselect);
 518                 return -EINVAL;
 519         }
 520
 521         /* Set the bus ID string */
 522         spi_dev_set_name(spi);
 523
 524         /* We need to make sure there's no other device with this
 525          * chipselect **BEFORE** we call setup(), else we'll trash
 526          * its configuration.  Lock against concurrent add() calls.
 527          */
 528         mutex_lock(&spi_add_lock);
 529
 530         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 531         if (status) {
 532                 dev_err(dev, "chipselect %d already in use\n",
 533                                 spi->chip_select);
 534                 goto done;
 535         }
 536
 537         if (ctlr->cs_gpios)
 538                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 539
 540         /* Drivers may modify this initial i/o setup, but will
 541          * normally rely on the device being setup.  Devices
 542          * using SPI_CS_HIGH can't coexist well otherwise...
 543          */
 544         status = spi_setup(spi);
 545         if (status < 0) {
 546                 dev_err(dev, "can't setup %s, status %d\n",
 547                                 dev_name(&spi->dev), status);
 548                 goto done;
 549         }
 550
 551         /* Device may be bound to an active driver when this returns */
 552         status = device_add(&spi->dev);
 553         if (status < 0)
 554                 dev_err(dev, "can't add %s, status %d\n",
 555                                 dev_name(&spi->dev), status);
 556         else
 557                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 558
 559 done:
 560         mutex_unlock(&spi_add_lock);
 561         return status;
 562 }
 563 EXPORT_SYMBOL_GPL(spi_add_device);
 564
 565 /**
 566  * spi_new_device - instantiate one new SPI device
 567  * @ctlr: Controller to which device is connected
 568  * @chip: Describes the SPI device
 569  * Context: can sleep
 570  *
 571  * On typical mainboards, this is purely internal; and it's not needed
 572  * after board init creates the hard-wired devices.  Some development
 573  * platforms may not be able to use spi_register_board_info though, and
 574  * this is exported so that for example a USB or parport based adapter
 575  * driver could add devices (which it would learn about out-of-band).
 576  *
 577  * Return: the new device, or NULL.
 578  */
 579 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 580                                   struct spi_board_info *chip)
 581 {
 582         struct spi_device       *proxy;
 583         int                     status;
 584
 585         /* NOTE:  caller did any chip->bus_num checks necessary.
 586          *
 587          * Also, unless we change the return value convention to use
 588          * error-or-pointer (not NULL-or-pointer), troubleshootability
 589          * suggests syslogged diagnostics are best here (ugh).
 590          */
 591
 592         proxy = spi_alloc_device(ctlr);
 593         if (!proxy)
 594                 return NULL;
 595
 596         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 597
 598         proxy->chip_select = chip->chip_select;
 599         proxy->max_speed_hz = chip->max_speed_hz;
 600         proxy->mode = chip->mode;
 601         proxy->irq = chip->irq;
 602         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 603         proxy->dev.platform_data = (void *) chip->platform_data;
 604         proxy->controller_data = chip->controller_data;
 605         proxy->controller_state = NULL;
 606
 607         if (chip->properties) {
 608                 status = device_add_properties(&proxy->dev, chip->properties);
 609                 if (status) {
 610                         dev_err(&ctlr->dev,
 611                                 "failed to add properties to '%s': %d\n",
 612                                 chip->modalias, status);
 613                         goto err_dev_put;
 614                 }
 615         }
 616
 617         status = spi_add_device(proxy);
 618         if (status < 0)
 619                 goto err_remove_props;
 620
 621         return proxy;
 622
 623 err_remove_props:
 624         if (chip->properties)
 625                 device_remove_properties(&proxy->dev);
 626 err_dev_put:
 627         spi_dev_put(proxy);
 628         return NULL;
 629 }
 630 EXPORT_SYMBOL_GPL(spi_new_device);
 631
 632 /**
 633  * spi_unregister_device - unregister a single SPI device
 634  * @spi: spi_device to unregister
 635  *
 636  * Start making the passed SPI device vanish. Normally this would be handled
 637  * by spi_unregister_controller().
 638  */
 639 void spi_unregister_device(struct spi_device *spi)
 640 {
 641         if (!spi)
 642                 return;
 643
 644         if (spi->dev.of_node) {
 645                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 646                 of_node_put(spi->dev.of_node);
 647         }
 648         if (ACPI_COMPANION(&spi->dev))
 649                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 650         device_unregister(&spi->dev);
 651 }
 652 EXPORT_SYMBOL_GPL(spi_unregister_device);
 653
 654 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 655                                               struct spi_board_info *bi)
 656 {
 657         struct spi_device *dev;
 658
 659         if (ctlr->bus_num != bi->bus_num)
 660                 return;
 661
 662         dev = spi_new_device(ctlr, bi);
 663         if (!dev)
 664                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 665                         bi->modalias);
 666 }
 667
 668 /**
 669  * spi_register_board_info - register SPI devices for a given board
 670  * @info: array of chip descriptors
 671  * @n: how many descriptors are provided
 672  * Context: can sleep
 673  *
 674  * Board-specific early init code calls this (probably during arch_initcall)
 675  * with segments of the SPI device table.  Any device nodes are created later,
 676  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 677  * this table of devices forever, so that reloading a controller driver will
 678  * not make Linux forget about these hard-wired devices.
 679  *
 680  * Other code can also call this, e.g. a particular add-on board might provide
 681  * SPI devices through its expansion connector, so code initializing that board
 682  * would naturally declare its SPI devices.
 683  *
 684  * The board info passed can safely be __initdata ... but be careful of
 685  * any embedded pointers (platform_data, etc), they're copied as-is.
 686  * Device properties are deep-copied though.
 687  *
 688  * Return: zero on success, else a negative error code.
 689  */
 690 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 691 {
 692         struct boardinfo *bi;
 693         int i;
 694
 695         if (!n)
 696                 return 0;
 697
 698         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 699         if (!bi)
 700                 return -ENOMEM;
 701
 702         for (i = 0; i < n; i++, bi++, info++) {
 703                 struct spi_controller *ctlr;
 704
 705                 memcpy(&bi->board_info, info, sizeof(*info));
 706                 if (info->properties) {
 707                         bi->board_info.properties =
 708                                         property_entries_dup(info->properties);
 709                         if (IS_ERR(bi->board_info.properties))
 710                                 return PTR_ERR(bi->board_info.properties);
 711                 }
 712
 713                 mutex_lock(&board_lock);
 714                 list_add_tail(&bi->list, &board_list);
 715                 list_for_each_entry(ctlr, &spi_controller_list, list)
 716                         spi_match_controller_to_boardinfo(ctlr,
 717                                                           &bi->board_info);
 718                 mutex_unlock(&board_lock);
 719         }
 720
 721         return 0;
 722 }
 723
 724 /*-------------------------------------------------------------------------*/
 725
 726 static void spi_set_cs(struct spi_device *spi, bool enable)
 727 {
 728         if (spi->mode & SPI_CS_HIGH)
 729                 enable = !enable;
 730
 731         if (gpio_is_valid(spi->cs_gpio)) {
 732                 gpio_set_value(spi->cs_gpio, !enable);
 733                 /* Some SPI masters need both GPIO CS & slave_select */
 734                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 735                     spi->controller->set_cs)
 736                         spi->controller->set_cs(spi, !enable);
 737         } else if (spi->controller->set_cs) {
 738                 spi->controller->set_cs(spi, !enable);
 739         }
 740 }
 741
 742 #ifdef CONFIG_HAS_DMA
 743 static int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 744                        struct sg_table *sgt, void *buf, size_t len,
 745                        enum dma_data_direction dir)
 746 {
 747         const bool vmalloced_buf = is_vmalloc_addr(buf);
 748         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 749 #ifdef CONFIG_HIGHMEM
 750         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 751                                 (unsigned long)buf < (PKMAP_BASE +
 752                                         (LAST_PKMAP * PAGE_SIZE)));
 753 #else
 754         const bool kmap_buf = false;
 755 #endif
 756         int desc_len;
 757         int sgs;
 758         struct page *vm_page;
 759         struct scatterlist *sg;
 760         void *sg_buf;
 761         size_t min;
 762         int i, ret;
 763
 764         if (vmalloced_buf || kmap_buf) {
 765                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 766                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 767         } else if (virt_addr_valid(buf)) {
 768                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 769                 sgs = DIV_ROUND_UP(len, desc_len);
 770         } else {
 771                 return -EINVAL;
 772         }
 773
 774         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 775         if (ret != 0)
 776                 return ret;
 777
 778         sg = &sgt->sgl[0];
 779         for (i = 0; i < sgs; i++) {
 780
 781                 if (vmalloced_buf || kmap_buf) {
 782                         min = min_t(size_t,
 783                                     len, desc_len - offset_in_page(buf));
 784                         if (vmalloced_buf)
 785                                 vm_page = vmalloc_to_page(buf);
 786                         else
 787                                 vm_page = kmap_to_page(buf);
 788                         if (!vm_page) {
 789                                 sg_free_table(sgt);
 790                                 return -ENOMEM;
 791                         }
 792                         sg_set_page(sg, vm_page,
 793                                     min, offset_in_page(buf));
 794                 } else {
 795                         min = min_t(size_t, len, desc_len);
 796                         sg_buf = buf;
 797                         sg_set_buf(sg, sg_buf, min);
 798                 }
 799
 800                 buf += min;
 801                 len -= min;
 802                 sg = sg_next(sg);
 803         }
 804
 805         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 806         if (!ret)
 807                 ret = -ENOMEM;
 808         if (ret < 0) {
 809                 sg_free_table(sgt);
 810                 return ret;
 811         }
 812
 813         sgt->nents = ret;
 814
 815         return 0;
 816 }
 817
 818 static void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 819                           struct sg_table *sgt, enum dma_data_direction dir)
 820 {
 821         if (sgt->orig_nents) {
 822                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 823                 sg_free_table(sgt);
 824         }
 825 }
 826
 827 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 828 {
 829         struct device *tx_dev, *rx_dev;
 830         struct spi_transfer *xfer;
 831         int ret;
 832
 833         if (!ctlr->can_dma)
 834                 return 0;
 835
 836         if (ctlr->dma_tx)
 837                 tx_dev = ctlr->dma_tx->device->dev;
 838         else
 839                 tx_dev = ctlr->dev.parent;
 840
 841         if (ctlr->dma_rx)
 842                 rx_dev = ctlr->dma_rx->device->dev;
 843         else
 844                 rx_dev = ctlr->dev.parent;
 845
 846         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 847                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 848                         continue;
 849
 850                 if (xfer->tx_buf != NULL) {
 851                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 852                                           (void *)xfer->tx_buf, xfer->len,
 853                                           DMA_TO_DEVICE);
 854                         if (ret != 0)
 855                                 return ret;
 856                 }
 857
 858                 if (xfer->rx_buf != NULL) {
 859                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 860                                           xfer->rx_buf, xfer->len,
 861                                           DMA_FROM_DEVICE);
 862                         if (ret != 0) {
 863                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 864                                               DMA_TO_DEVICE);
 865                                 return ret;
 866                         }
 867                 }
 868         }
 869
 870         ctlr->cur_msg_mapped = true;
 871
 872         return 0;
 873 }
 874
 875 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 876 {
 877         struct spi_transfer *xfer;
 878         struct device *tx_dev, *rx_dev;
 879
 880         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 881                 return 0;
 882
 883         if (ctlr->dma_tx)
 884                 tx_dev = ctlr->dma_tx->device->dev;
 885         else
 886                 tx_dev = ctlr->dev.parent;
 887
 888         if (ctlr->dma_rx)
 889                 rx_dev = ctlr->dma_rx->device->dev;
 890         else
 891                 rx_dev = ctlr->dev.parent;
 892
 893         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 894                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 895                         continue;
 896
 897                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 898                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 899         }
 900
 901         return 0;
 902 }
 903 #else /* !CONFIG_HAS_DMA */
 904 static inline int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 905                               struct sg_table *sgt, void *buf, size_t len,
 906                               enum dma_data_direction dir)
 907 {
 908         return -EINVAL;
 909 }
 910
 911 static inline void spi_unmap_buf(struct spi_controller *ctlr,
 912                                  struct device *dev, struct sg_table *sgt,
 913                                  enum dma_data_direction dir)
 914 {
 915 }
 916
 917 static inline int __spi_map_msg(struct spi_controller *ctlr,
 918                                 struct spi_message *msg)
 919 {
 920         return 0;
 921 }
 922
 923 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 924                                   struct spi_message *msg)
 925 {
 926         return 0;
 927 }
 928 #endif /* !CONFIG_HAS_DMA */
 929
 930 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 931                                 struct spi_message *msg)
 932 {
 933         struct spi_transfer *xfer;
 934
 935         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 936                 /*
 937                  * Restore the original value of tx_buf or rx_buf if they are
 938                  * NULL.
 939                  */
 940                 if (xfer->tx_buf == ctlr->dummy_tx)
 941                         xfer->tx_buf = NULL;
 942                 if (xfer->rx_buf == ctlr->dummy_rx)
 943                         xfer->rx_buf = NULL;
 944         }
 945
 946         return __spi_unmap_msg(ctlr, msg);
 947 }
 948
 949 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 950 {
 951         struct spi_transfer *xfer;
 952         void *tmp;
 953         unsigned int max_tx, max_rx;
 954
 955         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
 956                 max_tx = 0;
 957                 max_rx = 0;
 958
 959                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 960                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
 961                             !xfer->tx_buf)
 962                                 max_tx = max(xfer->len, max_tx);
 963                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
 964                             !xfer->rx_buf)
 965                                 max_rx = max(xfer->len, max_rx);
 966                 }
 967
 968                 if (max_tx) {
 969                         tmp = krealloc(ctlr->dummy_tx, max_tx,
 970                                        GFP_KERNEL | GFP_DMA);
 971                         if (!tmp)
 972                                 return -ENOMEM;
 973                         ctlr->dummy_tx = tmp;
 974                         memset(tmp, 0, max_tx);
 975                 }
 976
 977                 if (max_rx) {
 978                         tmp = krealloc(ctlr->dummy_rx, max_rx,
 979                                        GFP_KERNEL | GFP_DMA);
 980                         if (!tmp)
 981                                 return -ENOMEM;
 982                         ctlr->dummy_rx = tmp;
 983                 }
 984
 985                 if (max_tx || max_rx) {
 986                         list_for_each_entry(xfer, &msg->transfers,
 987                                             transfer_list) {
 988                                 if (!xfer->tx_buf)
 989                                         xfer->tx_buf = ctlr->dummy_tx;
 990                                 if (!xfer->rx_buf)
 991                                         xfer->rx_buf = ctlr->dummy_rx;
 992                         }
 993                 }
 994         }
 995
 996         return __spi_map_msg(ctlr, msg);
 997 }
 998
 999 /*
1000  * spi_transfer_one_message - Default implementation of transfer_one_message()
1001  *
1002  * This is a standard implementation of transfer_one_message() for
1003  * drivers which implement a transfer_one() operation.  It provides
1004  * standard handling of delays and chip select management.
1005  */
1006 static int spi_transfer_one_message(struct spi_controller *ctlr,
1007                                     struct spi_message *msg)
1008 {
1009         struct spi_transfer *xfer;
1010         bool keep_cs = false;
1011         int ret = 0;
1012         unsigned long long ms = 1;
1013         struct spi_statistics *statm = &ctlr->statistics;
1014         struct spi_statistics *stats = &msg->spi->statistics;
1015
1016         spi_set_cs(msg->spi, true);
1017
1018         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1019         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1020
1021         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1022                 trace_spi_transfer_start(msg, xfer);
1023
1024                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1025                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1026
1027                 if (xfer->tx_buf || xfer->rx_buf) {
1028                         reinit_completion(&ctlr->xfer_completion);
1029
1030                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1031                         if (ret < 0) {
1032                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1033                                                                errors);
1034                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1035                                                                errors);
1036                                 dev_err(&msg->spi->dev,
1037                                         "SPI transfer failed: %d\n", ret);
1038                                 goto out;
1039                         }
1040
1041                         if (ret > 0) {
1042                                 ret = 0;
1043                                 ms = 8LL * 1000LL * xfer->len;
1044                                 do_div(ms, xfer->speed_hz);
1045                                 ms += ms + 200; /* some tolerance */
1046
1047                                 if (ms > UINT_MAX)
1048                                         ms = UINT_MAX;
1049
1050                                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1051                                                                  msecs_to_jiffies(ms));
1052                         }
1053
1054                         if (ms == 0) {
1055                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1056                                                                timedout);
1057                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1058                                                                timedout);
1059                                 dev_err(&msg->spi->dev,
1060                                         "SPI transfer timed out\n");
1061                                 msg->status = -ETIMEDOUT;
1062                         }
1063                 } else {
1064                         if (xfer->len)
1065                                 dev_err(&msg->spi->dev,
1066                                         "Bufferless transfer has length %u\n",
1067                                         xfer->len);
1068                 }
1069
1070                 trace_spi_transfer_stop(msg, xfer);
1071
1072                 if (msg->status != -EINPROGRESS)
1073                         goto out;
1074
1075                 if (xfer->delay_usecs) {
1076                         u16 us = xfer->delay_usecs;
1077
1078                         if (us <= 10)
1079                                 udelay(us);
1080                         else
1081                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1082                 }
1083
1084                 if (xfer->cs_change) {
1085                         if (list_is_last(&xfer->transfer_list,
1086                                          &msg->transfers)) {
1087                                 keep_cs = true;
1088                         } else {
1089                                 spi_set_cs(msg->spi, false);
1090                                 udelay(10);
1091                                 spi_set_cs(msg->spi, true);
1092                         }
1093                 }
1094
1095                 msg->actual_length += xfer->len;
1096         }
1097
1098 out:
1099         if (ret != 0 || !keep_cs)
1100                 spi_set_cs(msg->spi, false);
1101
1102         if (msg->status == -EINPROGRESS)
1103                 msg->status = ret;
1104
1105         if (msg->status && ctlr->handle_err)
1106                 ctlr->handle_err(ctlr, msg);
1107
1108         spi_res_release(ctlr, msg);
1109
1110         spi_finalize_current_message(ctlr);
1111
1112         return ret;
1113 }
1114
1115 /**
1116  * spi_finalize_current_transfer - report completion of a transfer
1117  * @ctlr: the controller reporting completion
1118  *
1119  * Called by SPI drivers using the core transfer_one_message()
1120  * implementation to notify it that the current interrupt driven
1121  * transfer has finished and the next one may be scheduled.
1122  */
1123 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1124 {
1125         complete(&ctlr->xfer_completion);
1126 }
1127 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1128
1129 /**
1130  * __spi_pump_messages - function which processes spi message queue
1131  * @ctlr: controller to process queue for
1132  * @in_kthread: true if we are in the context of the message pump thread
1133  *
1134  * This function checks if there is any spi message in the queue that
1135  * needs processing and if so call out to the driver to initialize hardware
1136  * and transfer each message.
1137  *
1138  * Note that it is called both from the kthread itself and also from
1139  * inside spi_sync(); the queue extraction handling at the top of the
1140  * function should deal with this safely.
1141  */
1142 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1143 {
1144         unsigned long flags;
1145         bool was_busy = false;
1146         int ret;
1147
1148         /* Lock queue */
1149         spin_lock_irqsave(&ctlr->queue_lock, flags);
1150
1151         /* Make sure we are not already running a message */
1152         if (ctlr->cur_msg) {
1153                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1154                 return;
1155         }
1156
1157         /* If another context is idling the device then defer */
1158         if (ctlr->idling) {
1159                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1160                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1161                 return;
1162         }
1163
1164         /* Check if the queue is idle */
1165         if (list_empty(&ctlr->queue) || !ctlr->running) {
1166                 if (!ctlr->busy) {
1167                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1168                         return;
1169                 }
1170
1171                 /* Only do teardown in the thread */
1172                 if (!in_kthread) {
1173                         kthread_queue_work(&ctlr->kworker,
1174                                            &ctlr->pump_messages);
1175                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1176                         return;
1177                 }
1178
1179                 ctlr->busy = false;
1180                 ctlr->idling = true;
1181                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1182
1183                 kfree(ctlr->dummy_rx);
1184                 ctlr->dummy_rx = NULL;
1185                 kfree(ctlr->dummy_tx);
1186                 ctlr->dummy_tx = NULL;
1187                 if (ctlr->unprepare_transfer_hardware &&
1188                     ctlr->unprepare_transfer_hardware(ctlr))
1189                         dev_err(&ctlr->dev,
1190                                 "failed to unprepare transfer hardware\n");
1191                 if (ctlr->auto_runtime_pm) {
1192                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1193                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1194                 }
1195                 trace_spi_controller_idle(ctlr);
1196
1197                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1198                 ctlr->idling = false;
1199                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1200                 return;
1201         }
1202
1203         /* Extract head of queue */
1204         ctlr->cur_msg =
1205                 list_first_entry(&ctlr->queue, struct spi_message, queue);
1206
1207         list_del_init(&ctlr->cur_msg->queue);
1208         if (ctlr->busy)
1209                 was_busy = true;
1210         else
1211                 ctlr->busy = true;
1212         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1213
1214         mutex_lock(&ctlr->io_mutex);
1215
1216         if (!was_busy && ctlr->auto_runtime_pm) {
1217                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1218                 if (ret < 0) {
1219                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1220                                 ret);
1221                         mutex_unlock(&ctlr->io_mutex);
1222                         return;
1223                 }
1224         }
1225
1226         if (!was_busy)
1227                 trace_spi_controller_busy(ctlr);
1228
1229         if (!was_busy && ctlr->prepare_transfer_hardware) {
1230                 ret = ctlr->prepare_transfer_hardware(ctlr);
1231                 if (ret) {
1232                         dev_err(&ctlr->dev,
1233                                 "failed to prepare transfer hardware\n");
1234
1235                         if (ctlr->auto_runtime_pm)
1236                                 pm_runtime_put(ctlr->dev.parent);
1237                         mutex_unlock(&ctlr->io_mutex);
1238                         return;
1239                 }
1240         }
1241
1242         trace_spi_message_start(ctlr->cur_msg);
1243
1244         if (ctlr->prepare_message) {
1245                 ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1246                 if (ret) {
1247                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1248                                 ret);
1249                         ctlr->cur_msg->status = ret;
1250                         spi_finalize_current_message(ctlr);
1251                         goto out;
1252                 }
1253                 ctlr->cur_msg_prepared = true;
1254         }
1255
1256         ret = spi_map_msg(ctlr, ctlr->cur_msg);
1257         if (ret) {
1258                 ctlr->cur_msg->status = ret;
1259                 spi_finalize_current_message(ctlr);
1260                 goto out;
1261         }
1262
1263         ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1264         if (ret) {
1265                 dev_err(&ctlr->dev,
1266                         "failed to transfer one message from queue\n");
1267                 goto out;
1268         }
1269
1270 out:
1271         mutex_unlock(&ctlr->io_mutex);
1272
1273         /* Prod the scheduler in case transfer_one() was busy waiting */
1274         if (!ret)
1275                 cond_resched();
1276 }
1277
1278 /**
1279  * spi_pump_messages - kthread work function which processes spi message queue
1280  * @work: pointer to kthread work struct contained in the controller struct
1281  */
1282 static void spi_pump_messages(struct kthread_work *work)
1283 {
1284         struct spi_controller *ctlr =
1285                 container_of(work, struct spi_controller, pump_messages);
1286
1287         __spi_pump_messages(ctlr, true);
1288 }
1289
1290 static int spi_init_queue(struct spi_controller *ctlr)
1291 {
1292         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1293
1294         ctlr->running = false;
1295         ctlr->busy = false;
1296
1297         kthread_init_worker(&ctlr->kworker);
1298         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1299                                          "%s", dev_name(&ctlr->dev));
1300         if (IS_ERR(ctlr->kworker_task)) {
1301                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1302                 return PTR_ERR(ctlr->kworker_task);
1303         }
1304         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1305
1306         /*
1307          * Controller config will indicate if this controller should run the
1308          * message pump with high (realtime) priority to reduce the transfer
1309          * latency on the bus by minimising the delay between a transfer
1310          * request and the scheduling of the message pump thread. Without this
1311          * setting the message pump thread will remain at default priority.
1312          */
1313         if (ctlr->rt) {
1314                 dev_info(&ctlr->dev,
1315                         "will run message pump with realtime priority\n");
1316                 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1317         }
1318
1319         return 0;
1320 }
1321
1322 /**
1323  * spi_get_next_queued_message() - called by driver to check for queued
1324  * messages
1325  * @ctlr: the controller to check for queued messages
1326  *
1327  * If there are more messages in the queue, the next message is returned from
1328  * this call.
1329  *
1330  * Return: the next message in the queue, else NULL if the queue is empty.
1331  */
1332 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1333 {
1334         struct spi_message *next;
1335         unsigned long flags;
1336
1337         /* get a pointer to the next message, if any */
1338         spin_lock_irqsave(&ctlr->queue_lock, flags);
1339         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1340                                         queue);
1341         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1342
1343         return next;
1344 }
1345 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1346
1347 /**
1348  * spi_finalize_current_message() - the current message is complete
1349  * @ctlr: the controller to return the message to
1350  *
1351  * Called by the driver to notify the core that the message in the front of the
1352  * queue is complete and can be removed from the queue.
1353  */
1354 void spi_finalize_current_message(struct spi_controller *ctlr)
1355 {
1356         struct spi_message *mesg;
1357         unsigned long flags;
1358         int ret;
1359
1360         spin_lock_irqsave(&ctlr->queue_lock, flags);
1361         mesg = ctlr->cur_msg;
1362         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1363
1364         spi_unmap_msg(ctlr, mesg);
1365
1366         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1367                 ret = ctlr->unprepare_message(ctlr, mesg);
1368                 if (ret) {
1369                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1370                                 ret);
1371                 }
1372         }
1373
1374         spin_lock_irqsave(&ctlr->queue_lock, flags);
1375         ctlr->cur_msg = NULL;
1376         ctlr->cur_msg_prepared = false;
1377         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1378         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1379
1380         trace_spi_message_done(mesg);
1381
1382         mesg->state = NULL;
1383         if (mesg->complete)
1384                 mesg->complete(mesg->context);
1385 }
1386 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1387
1388 static int spi_start_queue(struct spi_controller *ctlr)
1389 {
1390         unsigned long flags;
1391
1392         spin_lock_irqsave(&ctlr->queue_lock, flags);
1393
1394         if (ctlr->running || ctlr->busy) {
1395                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1396                 return -EBUSY;
1397         }
1398
1399         ctlr->running = true;
1400         ctlr->cur_msg = NULL;
1401         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1402
1403         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1404
1405         return 0;
1406 }
1407
1408 static int spi_stop_queue(struct spi_controller *ctlr)
1409 {
1410         unsigned long flags;
1411         unsigned limit = 500;
1412         int ret = 0;
1413
1414         spin_lock_irqsave(&ctlr->queue_lock, flags);
1415
1416         /*
1417          * This is a bit lame, but is optimized for the common execution path.
1418          * A wait_queue on the ctlr->busy could be used, but then the common
1419          * execution path (pump_messages) would be required to call wake_up or
1420          * friends on every SPI message. Do this instead.
1421          */
1422         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1423                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1424                 usleep_range(10000, 11000);
1425                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1426         }
1427
1428         if (!list_empty(&ctlr->queue) || ctlr->busy)
1429                 ret = -EBUSY;
1430         else
1431                 ctlr->running = false;
1432
1433         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1434
1435         if (ret) {
1436                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1437                 return ret;
1438         }
1439         return ret;
1440 }
1441
1442 static int spi_destroy_queue(struct spi_controller *ctlr)
1443 {
1444         int ret;
1445
1446         ret = spi_stop_queue(ctlr);
1447
1448         /*
1449          * kthread_flush_worker will block until all work is done.
1450          * If the reason that stop_queue timed out is that the work will never
1451          * finish, then it does no good to call flush/stop thread, so
1452          * return anyway.
1453          */
1454         if (ret) {
1455                 dev_err(&ctlr->dev, "problem destroying queue\n");
1456                 return ret;
1457         }
1458
1459         kthread_flush_worker(&ctlr->kworker);
1460         kthread_stop(ctlr->kworker_task);
1461
1462         return 0;
1463 }
1464
1465 static int __spi_queued_transfer(struct spi_device *spi,
1466                                  struct spi_message *msg,
1467                                  bool need_pump)
1468 {
1469         struct spi_controller *ctlr = spi->controller;
1470         unsigned long flags;
1471
1472         spin_lock_irqsave(&ctlr->queue_lock, flags);
1473
1474         if (!ctlr->running) {
1475                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1476                 return -ESHUTDOWN;
1477         }
1478         msg->actual_length = 0;
1479         msg->status = -EINPROGRESS;
1480
1481         list_add_tail(&msg->queue, &ctlr->queue);
1482         if (!ctlr->busy && need_pump)
1483                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1484
1485         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1486         return 0;
1487 }
1488
1489 /**
1490  * spi_queued_transfer - transfer function for queued transfers
1491  * @spi: spi device which is requesting transfer
1492  * @msg: spi message which is to handled is queued to driver queue
1493  *
1494  * Return: zero on success, else a negative error code.
1495  */
1496 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1497 {
1498         return __spi_queued_transfer(spi, msg, true);
1499 }
1500
1501 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1502 {
1503         int ret;
1504
1505         ctlr->transfer = spi_queued_transfer;
1506         if (!ctlr->transfer_one_message)
1507                 ctlr->transfer_one_message = spi_transfer_one_message;
1508
1509         /* Initialize and start queue */
1510         ret = spi_init_queue(ctlr);
1511         if (ret) {
1512                 dev_err(&ctlr->dev, "problem initializing queue\n");
1513                 goto err_init_queue;
1514         }
1515         ctlr->queued = true;
1516         ret = spi_start_queue(ctlr);
1517         if (ret) {
1518                 dev_err(&ctlr->dev, "problem starting queue\n");
1519                 goto err_start_queue;
1520         }
1521
1522         return 0;
1523
1524 err_start_queue:
1525         spi_destroy_queue(ctlr);
1526 err_init_queue:
1527         return ret;
1528 }
1529
1530 /*-------------------------------------------------------------------------*/
1531
1532 #if defined(CONFIG_OF)
1533 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1534                            struct device_node *nc)
1535 {
1536         u32 value;
1537         int rc;
1538
1539         /* Mode (clock phase/polarity/etc.) */
1540         if (of_property_read_bool(nc, "spi-cpha"))
1541                 spi->mode |= SPI_CPHA;
1542         if (of_property_read_bool(nc, "spi-cpol"))
1543                 spi->mode |= SPI_CPOL;
1544         if (of_property_read_bool(nc, "spi-cs-high"))
1545                 spi->mode |= SPI_CS_HIGH;
1546         if (of_property_read_bool(nc, "spi-3wire"))
1547                 spi->mode |= SPI_3WIRE;
1548         if (of_property_read_bool(nc, "spi-lsb-first"))
1549                 spi->mode |= SPI_LSB_FIRST;
1550
1551         /* Device DUAL/QUAD mode */
1552         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1553                 switch (value) {
1554                 case 1:
1555                         break;
1556                 case 2:
1557                         spi->mode |= SPI_TX_DUAL;
1558                         break;
1559                 case 4:
1560                         spi->mode |= SPI_TX_QUAD;
1561                         break;
1562                 default:
1563                         dev_warn(&ctlr->dev,
1564                                 "spi-tx-bus-width %d not supported\n",
1565                                 value);
1566                         break;
1567                 }
1568         }
1569
1570         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1571                 switch (value) {
1572                 case 1:
1573                         break;
1574                 case 2:
1575                         spi->mode |= SPI_RX_DUAL;
1576                         break;
1577                 case 4:
1578                         spi->mode |= SPI_RX_QUAD;
1579                         break;
1580                 default:
1581                         dev_warn(&ctlr->dev,
1582                                 "spi-rx-bus-width %d not supported\n",
1583                                 value);
1584                         break;
1585                 }
1586         }
1587
1588         if (spi_controller_is_slave(ctlr)) {
1589                 if (strcmp(nc->name, "slave")) {
1590                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1591                                 nc);
1592                         return -EINVAL;
1593                 }
1594                 return 0;
1595         }
1596
1597         /* Device address */
1598         rc = of_property_read_u32(nc, "reg", &value);
1599         if (rc) {
1600                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1601                         nc, rc);
1602                 return rc;
1603         }
1604         spi->chip_select = value;
1605
1606         /* Device speed */
1607         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1608         if (rc) {
1609                 dev_err(&ctlr->dev,
1610                         "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1611                 return rc;
1612         }
1613         spi->max_speed_hz = value;
1614
1615         return 0;
1616 }
1617
1618 static struct spi_device *
1619 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1620 {
1621         struct spi_device *spi;
1622         int rc;
1623
1624         /* Alloc an spi_device */
1625         spi = spi_alloc_device(ctlr);
1626         if (!spi) {
1627                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1628                 rc = -ENOMEM;
1629                 goto err_out;
1630         }
1631
1632         /* Select device driver */
1633         rc = of_modalias_node(nc, spi->modalias,
1634                                 sizeof(spi->modalias));
1635         if (rc < 0) {
1636                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1637                 goto err_out;
1638         }
1639
1640         rc = of_spi_parse_dt(ctlr, spi, nc);
1641         if (rc)
1642                 goto err_out;
1643
1644         /* Store a pointer to the node in the device structure */
1645         of_node_get(nc);
1646         spi->dev.of_node = nc;
1647
1648         /* Register the new device */
1649         rc = spi_add_device(spi);
1650         if (rc) {
1651                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1652                 goto err_of_node_put;
1653         }
1654
1655         return spi;
1656
1657 err_of_node_put:
1658         of_node_put(nc);
1659 err_out:
1660         spi_dev_put(spi);
1661         return ERR_PTR(rc);
1662 }
1663
1664 /**
1665  * of_register_spi_devices() - Register child devices onto the SPI bus
1666  * @ctlr:       Pointer to spi_controller device
1667  *
1668  * Registers an spi_device for each child node of controller node which
1669  * represents a valid SPI slave.
1670  */
1671 static void of_register_spi_devices(struct spi_controller *ctlr)
1672 {
1673         struct spi_device *spi;
1674         struct device_node *nc;
1675
1676         if (!ctlr->dev.of_node)
1677                 return;
1678
1679         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1680                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1681                         continue;
1682                 spi = of_register_spi_device(ctlr, nc);
1683                 if (IS_ERR(spi)) {
1684                         dev_warn(&ctlr->dev,
1685                                  "Failed to create SPI device for %pOF\n", nc);
1686                         of_node_clear_flag(nc, OF_POPULATED);
1687                 }
1688         }
1689 }
1690 #else
1691 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1692 #endif
1693
1694 #ifdef CONFIG_ACPI
1695 static void acpi_spi_parse_apple_properties(struct spi_device *spi)
1696 {
1697         struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
1698         const union acpi_object *obj;
1699
1700         if (!x86_apple_machine)
1701                 return;
1702
1703         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1704             && obj->buffer.length >= 4)
1705                 spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1706
1707         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1708             && obj->buffer.length == 8)
1709                 spi->bits_per_word = *(u64 *)obj->buffer.pointer;
1710
1711         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1712             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1713                 spi->mode |= SPI_LSB_FIRST;
1714
1715         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1716             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1717                 spi->mode |= SPI_CPOL;
1718
1719         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1720             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1721                 spi->mode |= SPI_CPHA;
1722 }
1723
1724 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1725 {
1726         struct spi_device *spi = data;
1727         struct spi_controller *ctlr = spi->controller;
1728
1729         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1730                 struct acpi_resource_spi_serialbus *sb;
1731
1732                 sb = &ares->data.spi_serial_bus;
1733                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1734                         /*
1735                          * ACPI DeviceSelection numbering is handled by the
1736                          * host controller driver in Windows and can vary
1737                          * from driver to driver. In Linux we always expect
1738                          * 0 .. max - 1 so we need to ask the driver to
1739                          * translate between the two schemes.
1740                          */
1741                         if (ctlr->fw_translate_cs) {
1742                                 int cs = ctlr->fw_translate_cs(ctlr,
1743                                                 sb->device_selection);
1744                                 if (cs < 0)
1745                                         return cs;
1746                                 spi->chip_select = cs;
1747                         } else {
1748                                 spi->chip_select = sb->device_selection;
1749                         }
1750
1751                         spi->max_speed_hz = sb->connection_speed;
1752
1753                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1754                                 spi->mode |= SPI_CPHA;
1755                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1756                                 spi->mode |= SPI_CPOL;
1757                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1758                                 spi->mode |= SPI_CS_HIGH;
1759                 }
1760         } else if (spi->irq < 0) {
1761                 struct resource r;
1762
1763                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1764                         spi->irq = r.start;
1765         }
1766
1767         /* Always tell the ACPI core to skip this resource */
1768         return 1;
1769 }
1770
1771 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1772                                             struct acpi_device *adev)
1773 {
1774         struct list_head resource_list;
1775         struct spi_device *spi;
1776         int ret;
1777
1778         if (acpi_bus_get_status(adev) || !adev->status.present ||
1779             acpi_device_enumerated(adev))
1780                 return AE_OK;
1781
1782         spi = spi_alloc_device(ctlr);
1783         if (!spi) {
1784                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1785                         dev_name(&adev->dev));
1786                 return AE_NO_MEMORY;
1787         }
1788
1789         ACPI_COMPANION_SET(&spi->dev, adev);
1790         spi->irq = -1;
1791
1792         INIT_LIST_HEAD(&resource_list);
1793         ret = acpi_dev_get_resources(adev, &resource_list,
1794                                      acpi_spi_add_resource, spi);
1795         acpi_dev_free_resource_list(&resource_list);
1796
1797         acpi_spi_parse_apple_properties(spi);
1798
1799         if (ret < 0 || !spi->max_speed_hz) {
1800                 spi_dev_put(spi);
1801                 return AE_OK;
1802         }
1803
1804         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1805                           sizeof(spi->modalias));
1806
1807         if (spi->irq < 0)
1808                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1809
1810         acpi_device_set_enumerated(adev);
1811
1812         adev->power.flags.ignore_parent = true;
1813         if (spi_add_device(spi)) {
1814                 adev->power.flags.ignore_parent = false;
1815                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1816                         dev_name(&adev->dev));
1817                 spi_dev_put(spi);
1818         }
1819
1820         return AE_OK;
1821 }
1822
1823 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1824                                        void *data, void **return_value)
1825 {
1826         struct spi_controller *ctlr = data;
1827         struct acpi_device *adev;
1828
1829         if (acpi_bus_get_device(handle, &adev))
1830                 return AE_OK;
1831
1832         return acpi_register_spi_device(ctlr, adev);
1833 }
1834
1835 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1836 {
1837         acpi_status status;
1838         acpi_handle handle;
1839
1840         handle = ACPI_HANDLE(ctlr->dev.parent);
1841         if (!handle)
1842                 return;
1843
1844         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1845                                      acpi_spi_add_device, NULL, ctlr, NULL);
1846         if (ACPI_FAILURE(status))
1847                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1848 }
1849 #else
1850 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1851 #endif /* CONFIG_ACPI */
1852
1853 static void spi_controller_release(struct device *dev)
1854 {
1855         struct spi_controller *ctlr;
1856
1857         ctlr = container_of(dev, struct spi_controller, dev);
1858         kfree(ctlr);
1859 }
1860
1861 static struct class spi_master_class = {
1862         .name           = "spi_master",
1863         .owner          = THIS_MODULE,
1864         .dev_release    = spi_controller_release,
1865         .dev_groups     = spi_master_groups,
1866 };
1867
1868 #ifdef CONFIG_SPI_SLAVE
1869 /**
1870  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1871  *                   controller
1872  * @spi: device used for the current transfer
1873  */
1874 int spi_slave_abort(struct spi_device *spi)
1875 {
1876         struct spi_controller *ctlr = spi->controller;
1877
1878         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1879                 return ctlr->slave_abort(ctlr);
1880
1881         return -ENOTSUPP;
1882 }
1883 EXPORT_SYMBOL_GPL(spi_slave_abort);
1884
1885 static int match_true(struct device *dev, void *data)
1886 {
1887         return 1;
1888 }
1889
1890 static ssize_t spi_slave_show(struct device *dev,
1891                               struct device_attribute *attr, char *buf)
1892 {
1893         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1894                                                    dev);
1895         struct device *child;
1896
1897         child = device_find_child(&ctlr->dev, NULL, match_true);
1898         return sprintf(buf, "%s\n",
1899                        child ? to_spi_device(child)->modalias : NULL);
1900 }
1901
1902 static ssize_t spi_slave_store(struct device *dev,
1903                                struct device_attribute *attr, const char *buf,
1904                                size_t count)
1905 {
1906         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1907                                                    dev);
1908         struct spi_device *spi;
1909         struct device *child;
1910         char name[32];
1911         int rc;
1912
1913         rc = sscanf(buf, "%31s", name);
1914         if (rc != 1 || !name[0])
1915                 return -EINVAL;
1916
1917         child = device_find_child(&ctlr->dev, NULL, match_true);
1918         if (child) {
1919                 /* Remove registered slave */
1920                 device_unregister(child);
1921                 put_device(child);
1922         }
1923
1924         if (strcmp(name, "(null)")) {
1925                 /* Register new slave */
1926                 spi = spi_alloc_device(ctlr);
1927                 if (!spi)
1928                         return -ENOMEM;
1929
1930                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
1931
1932                 rc = spi_add_device(spi);
1933                 if (rc) {
1934                         spi_dev_put(spi);
1935                         return rc;
1936                 }
1937         }
1938
1939         return count;
1940 }
1941
1942 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
1943
1944 static struct attribute *spi_slave_attrs[] = {
1945         &dev_attr_slave.attr,
1946         NULL,
1947 };
1948
1949 static const struct attribute_group spi_slave_group = {
1950         .attrs = spi_slave_attrs,
1951 };
1952
1953 static const struct attribute_group *spi_slave_groups[] = {
1954         &spi_controller_statistics_group,
1955         &spi_slave_group,
1956         NULL,
1957 };
1958
1959 static struct class spi_slave_class = {
1960         .name           = "spi_slave",
1961         .owner          = THIS_MODULE,
1962         .dev_release    = spi_controller_release,
1963         .dev_groups     = spi_slave_groups,
1964 };
1965 #else
1966 extern struct class spi_slave_class;    /* dummy */
1967 #endif
1968
1969 /**
1970  * __spi_alloc_controller - allocate an SPI master or slave controller
1971  * @dev: the controller, possibly using the platform_bus
1972  * @size: how much zeroed driver-private data to allocate; the pointer to this
1973  *      memory is in the driver_data field of the returned device,
1974  *      accessible with spi_controller_get_devdata().
1975  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
1976  *      slave (true) controller
1977  * Context: can sleep
1978  *
1979  * This call is used only by SPI controller drivers, which are the
1980  * only ones directly touching chip registers.  It's how they allocate
1981  * an spi_controller structure, prior to calling spi_register_controller().
1982  *
1983  * This must be called from context that can sleep.
1984  *
1985  * The caller is responsible for assigning the bus number and initializing the
1986  * controller's methods before calling spi_register_controller(); and (after
1987  * errors adding the device) calling spi_controller_put() to prevent a memory
1988  * leak.
1989  *
1990  * Return: the SPI controller structure on success, else NULL.
1991  */
1992 struct spi_controller *__spi_alloc_controller(struct device *dev,
1993                                               unsigned int size, bool slave)
1994 {
1995         struct spi_controller   *ctlr;
1996
1997         if (!dev)
1998                 return NULL;
1999
2000         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
2001         if (!ctlr)
2002                 return NULL;
2003
2004         device_initialize(&ctlr->dev);
2005         ctlr->bus_num = -1;
2006         ctlr->num_chipselect = 1;
2007         ctlr->slave = slave;
2008         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2009                 ctlr->dev.class = &spi_slave_class;
2010         else
2011                 ctlr->dev.class = &spi_master_class;
2012         ctlr->dev.parent = dev;
2013         pm_suspend_ignore_children(&ctlr->dev, true);
2014         spi_controller_set_devdata(ctlr, &ctlr[1]);
2015
2016         return ctlr;
2017 }
2018 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2019
2020 #ifdef CONFIG_OF
2021 static int of_spi_register_master(struct spi_controller *ctlr)
2022 {
2023         int nb, i, *cs;
2024         struct device_node *np = ctlr->dev.of_node;
2025
2026         if (!np)
2027                 return 0;
2028
2029         nb = of_gpio_named_count(np, "cs-gpios");
2030         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2031
2032         /* Return error only for an incorrectly formed cs-gpios property */
2033         if (nb == 0 || nb == -ENOENT)
2034                 return 0;
2035         else if (nb < 0)
2036                 return nb;
2037
2038         cs = devm_kzalloc(&ctlr->dev, sizeof(int) * ctlr->num_chipselect,
2039                           GFP_KERNEL);
2040         ctlr->cs_gpios = cs;
2041
2042         if (!ctlr->cs_gpios)
2043                 return -ENOMEM;
2044
2045         for (i = 0; i < ctlr->num_chipselect; i++)
2046                 cs[i] = -ENOENT;
2047
2048         for (i = 0; i < nb; i++)
2049                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2050
2051         return 0;
2052 }
2053 #else
2054 static int of_spi_register_master(struct spi_controller *ctlr)
2055 {
2056         return 0;
2057 }
2058 #endif
2059
2060 /**
2061  * spi_register_controller - register SPI master or slave controller
2062  * @ctlr: initialized master, originally from spi_alloc_master() or
2063  *      spi_alloc_slave()
2064  * Context: can sleep
2065  *
2066  * SPI controllers connect to their drivers using some non-SPI bus,
2067  * such as the platform bus.  The final stage of probe() in that code
2068  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2069  *
2070  * SPI controllers use board specific (often SOC specific) bus numbers,
2071  * and board-specific addressing for SPI devices combines those numbers
2072  * with chip select numbers.  Since SPI does not directly support dynamic
2073  * device identification, boards need configuration tables telling which
2074  * chip is at which address.
2075  *
2076  * This must be called from context that can sleep.  It returns zero on
2077  * success, else a negative error code (dropping the controller's refcount).
2078  * After a successful return, the caller is responsible for calling
2079  * spi_unregister_controller().
2080  *
2081  * Return: zero on success, else a negative error code.
2082  */
2083 int spi_register_controller(struct spi_controller *ctlr)
2084 {
2085         struct device           *dev = ctlr->dev.parent;
2086         struct boardinfo        *bi;
2087         int                     status = -ENODEV;
2088         int                     id, first_dynamic;
2089
2090         if (!dev)
2091                 return -ENODEV;
2092
2093         if (!spi_controller_is_slave(ctlr)) {
2094                 status = of_spi_register_master(ctlr);
2095                 if (status)
2096                         return status;
2097         }
2098
2099         /* even if it's just one always-selected device, there must
2100          * be at least one chipselect
2101          */
2102         if (ctlr->num_chipselect == 0)
2103                 return -EINVAL;
2104         /* allocate dynamic bus number using Linux idr */
2105         if ((ctlr->bus_num < 0) && ctlr->dev.of_node) {
2106                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2107                 if (id >= 0) {
2108                         ctlr->bus_num = id;
2109                         mutex_lock(&board_lock);
2110                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2111                                        ctlr->bus_num + 1, GFP_KERNEL);
2112                         mutex_unlock(&board_lock);
2113                         if (WARN(id < 0, "couldn't get idr"))
2114                                 return id == -ENOSPC ? -EBUSY : id;
2115                 }
2116         }
2117         if (ctlr->bus_num < 0) {
2118                 first_dynamic = of_alias_get_highest_id("spi");
2119                 if (first_dynamic < 0)
2120                         first_dynamic = 0;
2121                 else
2122                         first_dynamic++;
2123
2124                 mutex_lock(&board_lock);
2125                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2126                                0, GFP_KERNEL);
2127                 mutex_unlock(&board_lock);
2128                 if (WARN(id < 0, "couldn't get idr"))
2129                         return id;
2130                 ctlr->bus_num = id;
2131         }
2132         INIT_LIST_HEAD(&ctlr->queue);
2133         spin_lock_init(&ctlr->queue_lock);
2134         spin_lock_init(&ctlr->bus_lock_spinlock);
2135         mutex_init(&ctlr->bus_lock_mutex);
2136         mutex_init(&ctlr->io_mutex);
2137         ctlr->bus_lock_flag = 0;
2138         init_completion(&ctlr->xfer_completion);
2139         if (!ctlr->max_dma_len)
2140                 ctlr->max_dma_len = INT_MAX;
2141
2142         /* register the device, then userspace will see it.
2143          * registration fails if the bus ID is in use.
2144          */
2145         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2146         status = device_add(&ctlr->dev);
2147         if (status < 0) {
2148                 /* free bus id */
2149                 mutex_lock(&board_lock);
2150                 idr_remove(&spi_master_idr, ctlr->bus_num);
2151                 mutex_unlock(&board_lock);
2152                 goto done;
2153         }
2154         dev_dbg(dev, "registered %s %s\n",
2155                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2156                         dev_name(&ctlr->dev));
2157
2158         /* If we're using a queued driver, start the queue */
2159         if (ctlr->transfer)
2160                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2161         else {
2162                 status = spi_controller_initialize_queue(ctlr);
2163                 if (status) {
2164                         device_del(&ctlr->dev);
2165                         /* free bus id */
2166                         mutex_lock(&board_lock);
2167                         idr_remove(&spi_master_idr, ctlr->bus_num);
2168                         mutex_unlock(&board_lock);
2169                         goto done;
2170                 }
2171         }
2172         /* add statistics */
2173         spin_lock_init(&ctlr->statistics.lock);
2174
2175         mutex_lock(&board_lock);
2176         list_add_tail(&ctlr->list, &spi_controller_list);
2177         list_for_each_entry(bi, &board_list, list)
2178                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2179         mutex_unlock(&board_lock);
2180
2181         /* Register devices from the device tree and ACPI */
2182         of_register_spi_devices(ctlr);
2183         acpi_register_spi_devices(ctlr);
2184 done:
2185         return status;
2186 }
2187 EXPORT_SYMBOL_GPL(spi_register_controller);
2188
2189 static void devm_spi_unregister(struct device *dev, void *res)
2190 {
2191         spi_unregister_controller(*(struct spi_controller **)res);
2192 }
2193
2194 /**
2195  * devm_spi_register_controller - register managed SPI master or slave
2196  *      controller
2197  * @dev:    device managing SPI controller
2198  * @ctlr: initialized controller, originally from spi_alloc_master() or
2199  *      spi_alloc_slave()
2200  * Context: can sleep
2201  *
2202  * Register a SPI device as with spi_register_controller() which will
2203  * automatically be unregister
2204  *
2205  * Return: zero on success, else a negative error code.
2206  */
2207 int devm_spi_register_controller(struct device *dev,
2208                                  struct spi_controller *ctlr)
2209 {
2210         struct spi_controller **ptr;
2211         int ret;
2212
2213         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2214         if (!ptr)
2215                 return -ENOMEM;
2216
2217         ret = spi_register_controller(ctlr);
2218         if (!ret) {
2219                 *ptr = ctlr;
2220                 devres_add(dev, ptr);
2221         } else {
2222                 devres_free(ptr);
2223         }
2224
2225         return ret;
2226 }
2227 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2228
2229 static int __unregister(struct device *dev, void *null)
2230 {
2231         spi_unregister_device(to_spi_device(dev));
2232         return 0;
2233 }
2234
2235 /**
2236  * spi_unregister_controller - unregister SPI master or slave controller
2237  * @ctlr: the controller being unregistered
2238  * Context: can sleep
2239  *
2240  * This call is used only by SPI controller drivers, which are the
2241  * only ones directly touching chip registers.
2242  *
2243  * This must be called from context that can sleep.
2244  */
2245 void spi_unregister_controller(struct spi_controller *ctlr)
2246 {
2247         struct spi_controller *found;
2248         int dummy;
2249
2250         /* First make sure that this controller was ever added */
2251         mutex_lock(&board_lock);
2252         found = idr_find(&spi_master_idr, ctlr->bus_num);
2253         mutex_unlock(&board_lock);
2254         if (found != ctlr) {
2255                 dev_dbg(&ctlr->dev,
2256                         "attempting to delete unregistered controller [%s]\n",
2257                         dev_name(&ctlr->dev));
2258                 return;
2259         }
2260         if (ctlr->queued) {
2261                 if (spi_destroy_queue(ctlr))
2262                         dev_err(&ctlr->dev, "queue remove failed\n");
2263         }
2264         mutex_lock(&board_lock);
2265         list_del(&ctlr->list);
2266         mutex_unlock(&board_lock);
2267
2268         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2269         device_unregister(&ctlr->dev);
2270         /* free bus id */
2271         mutex_lock(&board_lock);
2272         idr_remove(&spi_master_idr, ctlr->bus_num);
2273         mutex_unlock(&board_lock);
2274 }
2275 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2276
2277 int spi_controller_suspend(struct spi_controller *ctlr)
2278 {
2279         int ret;
2280
2281         /* Basically no-ops for non-queued controllers */
2282         if (!ctlr->queued)
2283                 return 0;
2284
2285         ret = spi_stop_queue(ctlr);
2286         if (ret)
2287                 dev_err(&ctlr->dev, "queue stop failed\n");
2288
2289         return ret;
2290 }
2291 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2292
2293 int spi_controller_resume(struct spi_controller *ctlr)
2294 {
2295         int ret;
2296
2297         if (!ctlr->queued)
2298                 return 0;
2299
2300         ret = spi_start_queue(ctlr);
2301         if (ret)
2302                 dev_err(&ctlr->dev, "queue restart failed\n");
2303
2304         return ret;
2305 }
2306 EXPORT_SYMBOL_GPL(spi_controller_resume);
2307
2308 static int __spi_controller_match(struct device *dev, const void *data)
2309 {
2310         struct spi_controller *ctlr;
2311         const u16 *bus_num = data;
2312
2313         ctlr = container_of(dev, struct spi_controller, dev);
2314         return ctlr->bus_num == *bus_num;
2315 }
2316
2317 /**
2318  * spi_busnum_to_master - look up master associated with bus_num
2319  * @bus_num: the master's bus number
2320  * Context: can sleep
2321  *
2322  * This call may be used with devices that are registered after
2323  * arch init time.  It returns a refcounted pointer to the relevant
2324  * spi_controller (which the caller must release), or NULL if there is
2325  * no such master registered.
2326  *
2327  * Return: the SPI master structure on success, else NULL.
2328  */
2329 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2330 {
2331         struct device           *dev;
2332         struct spi_controller   *ctlr = NULL;
2333
2334         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2335                                 __spi_controller_match);
2336         if (dev)
2337                 ctlr = container_of(dev, struct spi_controller, dev);
2338         /* reference got in class_find_device */
2339         return ctlr;
2340 }
2341 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2342
2343 /*-------------------------------------------------------------------------*/
2344
2345 /* Core methods for SPI resource management */
2346
2347 /**
2348  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2349  *                 during the processing of a spi_message while using
2350  *                 spi_transfer_one
2351  * @spi:     the spi device for which we allocate memory
2352  * @release: the release code to execute for this resource
2353  * @size:    size to alloc and return
2354  * @gfp:     GFP allocation flags
2355  *
2356  * Return: the pointer to the allocated data
2357  *
2358  * This may get enhanced in the future to allocate from a memory pool
2359  * of the @spi_device or @spi_controller to avoid repeated allocations.
2360  */
2361 void *spi_res_alloc(struct spi_device *spi,
2362                     spi_res_release_t release,
2363                     size_t size, gfp_t gfp)
2364 {
2365         struct spi_res *sres;
2366
2367         sres = kzalloc(sizeof(*sres) + size, gfp);
2368         if (!sres)
2369                 return NULL;
2370
2371         INIT_LIST_HEAD(&sres->entry);
2372         sres->release = release;
2373
2374         return sres->data;
2375 }
2376 EXPORT_SYMBOL_GPL(spi_res_alloc);
2377
2378 /**
2379  * spi_res_free - free an spi resource
2380  * @res: pointer to the custom data of a resource
2381  *
2382  */
2383 void spi_res_free(void *res)
2384 {
2385         struct spi_res *sres = container_of(res, struct spi_res, data);
2386
2387         if (!res)
2388                 return;
2389
2390         WARN_ON(!list_empty(&sres->entry));
2391         kfree(sres);
2392 }
2393 EXPORT_SYMBOL_GPL(spi_res_free);
2394
2395 /**
2396  * spi_res_add - add a spi_res to the spi_message
2397  * @message: the spi message
2398  * @res:     the spi_resource
2399  */
2400 void spi_res_add(struct spi_message *message, void *res)
2401 {
2402         struct spi_res *sres = container_of(res, struct spi_res, data);
2403
2404         WARN_ON(!list_empty(&sres->entry));
2405         list_add_tail(&sres->entry, &message->resources);
2406 }
2407 EXPORT_SYMBOL_GPL(spi_res_add);
2408
2409 /**
2410  * spi_res_release - release all spi resources for this message
2411  * @ctlr:  the @spi_controller
2412  * @message: the @spi_message
2413  */
2414 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2415 {
2416         struct spi_res *res;
2417
2418         while (!list_empty(&message->resources)) {
2419                 res = list_last_entry(&message->resources,
2420                                       struct spi_res, entry);
2421
2422                 if (res->release)
2423                         res->release(ctlr, message, res->data);
2424
2425                 list_del(&res->entry);
2426
2427                 kfree(res);
2428         }
2429 }
2430 EXPORT_SYMBOL_GPL(spi_res_release);
2431
2432 /*-------------------------------------------------------------------------*/
2433
2434 /* Core methods for spi_message alterations */
2435
2436 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2437                                             struct spi_message *msg,
2438                                             void *res)
2439 {
2440         struct spi_replaced_transfers *rxfer = res;
2441         size_t i;
2442
2443         /* call extra callback if requested */
2444         if (rxfer->release)
2445                 rxfer->release(ctlr, msg, res);
2446
2447         /* insert replaced transfers back into the message */
2448         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2449
2450         /* remove the formerly inserted entries */
2451         for (i = 0; i < rxfer->inserted; i++)
2452                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2453 }
2454
2455 /**
2456  * spi_replace_transfers - replace transfers with several transfers
2457  *                         and register change with spi_message.resources
2458  * @msg:           the spi_message we work upon
2459  * @xfer_first:    the first spi_transfer we want to replace
2460  * @remove:        number of transfers to remove
2461  * @insert:        the number of transfers we want to insert instead
2462  * @release:       extra release code necessary in some circumstances
2463  * @extradatasize: extra data to allocate (with alignment guarantees
2464  *                 of struct @spi_transfer)
2465  * @gfp:           gfp flags
2466  *
2467  * Returns: pointer to @spi_replaced_transfers,
2468  *          PTR_ERR(...) in case of errors.
2469  */
2470 struct spi_replaced_transfers *spi_replace_transfers(
2471         struct spi_message *msg,
2472         struct spi_transfer *xfer_first,
2473         size_t remove,
2474         size_t insert,
2475         spi_replaced_release_t release,
2476         size_t extradatasize,
2477         gfp_t gfp)
2478 {
2479         struct spi_replaced_transfers *rxfer;
2480         struct spi_transfer *xfer;
2481         size_t i;
2482
2483         /* allocate the structure using spi_res */
2484         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2485                               insert * sizeof(struct spi_transfer)
2486                               + sizeof(struct spi_replaced_transfers)
2487                               + extradatasize,
2488                               gfp);
2489         if (!rxfer)
2490                 return ERR_PTR(-ENOMEM);
2491
2492         /* the release code to invoke before running the generic release */
2493         rxfer->release = release;
2494
2495         /* assign extradata */
2496         if (extradatasize)
2497                 rxfer->extradata =
2498                         &rxfer->inserted_transfers[insert];
2499
2500         /* init the replaced_transfers list */
2501         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2502
2503         /* assign the list_entry after which we should reinsert
2504          * the @replaced_transfers - it may be spi_message.messages!
2505          */
2506         rxfer->replaced_after = xfer_first->transfer_list.prev;
2507
2508         /* remove the requested number of transfers */
2509         for (i = 0; i < remove; i++) {
2510                 /* if the entry after replaced_after it is msg->transfers
2511                  * then we have been requested to remove more transfers
2512                  * than are in the list
2513                  */
2514                 if (rxfer->replaced_after->next == &msg->transfers) {
2515                         dev_err(&msg->spi->dev,
2516                                 "requested to remove more spi_transfers than are available\n");
2517                         /* insert replaced transfers back into the message */
2518                         list_splice(&rxfer->replaced_transfers,
2519                                     rxfer->replaced_after);
2520
2521                         /* free the spi_replace_transfer structure */
2522                         spi_res_free(rxfer);
2523
2524                         /* and return with an error */
2525                         return ERR_PTR(-EINVAL);
2526                 }
2527
2528                 /* remove the entry after replaced_after from list of
2529                  * transfers and add it to list of replaced_transfers
2530                  */
2531                 list_move_tail(rxfer->replaced_after->next,
2532                                &rxfer->replaced_transfers);
2533         }
2534
2535         /* create copy of the given xfer with identical settings
2536          * based on the first transfer to get removed
2537          */
2538         for (i = 0; i < insert; i++) {
2539                 /* we need to run in reverse order */
2540                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2541
2542                 /* copy all spi_transfer data */
2543                 memcpy(xfer, xfer_first, sizeof(*xfer));
2544
2545                 /* add to list */
2546                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2547
2548                 /* clear cs_change and delay_usecs for all but the last */
2549                 if (i) {
2550                         xfer->cs_change = false;
2551                         xfer->delay_usecs = 0;
2552                 }
2553         }
2554
2555         /* set up inserted */
2556         rxfer->inserted = insert;
2557
2558         /* and register it with spi_res/spi_message */
2559         spi_res_add(msg, rxfer);
2560
2561         return rxfer;
2562 }
2563 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2564
2565 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2566                                         struct spi_message *msg,
2567                                         struct spi_transfer **xferp,
2568                                         size_t maxsize,
2569                                         gfp_t gfp)
2570 {
2571         struct spi_transfer *xfer = *xferp, *xfers;
2572         struct spi_replaced_transfers *srt;
2573         size_t offset;
2574         size_t count, i;
2575
2576         /* warn once about this fact that we are splitting a transfer */
2577         dev_warn_once(&msg->spi->dev,
2578                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2579                       xfer->len, maxsize);
2580
2581         /* calculate how many we have to replace */
2582         count = DIV_ROUND_UP(xfer->len, maxsize);
2583
2584         /* create replacement */
2585         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2586         if (IS_ERR(srt))
2587                 return PTR_ERR(srt);
2588         xfers = srt->inserted_transfers;
2589
2590         /* now handle each of those newly inserted spi_transfers
2591          * note that the replacements spi_transfers all are preset
2592          * to the same values as *xferp, so tx_buf, rx_buf and len
2593          * are all identical (as well as most others)
2594          * so we just have to fix up len and the pointers.
2595          *
2596          * this also includes support for the depreciated
2597          * spi_message.is_dma_mapped interface
2598          */
2599
2600         /* the first transfer just needs the length modified, so we
2601          * run it outside the loop
2602          */
2603         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2604
2605         /* all the others need rx_buf/tx_buf also set */
2606         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2607                 /* update rx_buf, tx_buf and dma */
2608                 if (xfers[i].rx_buf)
2609                         xfers[i].rx_buf += offset;
2610                 if (xfers[i].rx_dma)
2611                         xfers[i].rx_dma += offset;
2612                 if (xfers[i].tx_buf)
2613                         xfers[i].tx_buf += offset;
2614                 if (xfers[i].tx_dma)
2615                         xfers[i].tx_dma += offset;
2616
2617                 /* update length */
2618                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2619         }
2620
2621         /* we set up xferp to the last entry we have inserted,
2622          * so that we skip those already split transfers
2623          */
2624         *xferp = &xfers[count - 1];
2625
2626         /* increment statistics counters */
2627         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2628                                        transfers_split_maxsize);
2629         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2630                                        transfers_split_maxsize);
2631
2632         return 0;
2633 }
2634
2635 /**
2636  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2637  *                              when an individual transfer exceeds a
2638  *                              certain size
2639  * @ctlr:    the @spi_controller for this transfer
2640  * @msg:   the @spi_message to transform
2641  * @maxsize:  the maximum when to apply this
2642  * @gfp: GFP allocation flags
2643  *
2644  * Return: status of transformation
2645  */
2646 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2647                                 struct spi_message *msg,
2648                                 size_t maxsize,
2649                                 gfp_t gfp)
2650 {
2651         struct spi_transfer *xfer;
2652         int ret;
2653
2654         /* iterate over the transfer_list,
2655          * but note that xfer is advanced to the last transfer inserted
2656          * to avoid checking sizes again unnecessarily (also xfer does
2657          * potentiall belong to a different list by the time the
2658          * replacement has happened
2659          */
2660         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2661                 if (xfer->len > maxsize) {
2662                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2663                                                            maxsize, gfp);
2664                         if (ret)
2665                                 return ret;
2666                 }
2667         }
2668
2669         return 0;
2670 }
2671 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2672
2673 /*-------------------------------------------------------------------------*/
2674
2675 /* Core methods for SPI controller protocol drivers.  Some of the
2676  * other core methods are currently defined as inline functions.
2677  */
2678
2679 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2680                                         u8 bits_per_word)
2681 {
2682         if (ctlr->bits_per_word_mask) {
2683                 /* Only 32 bits fit in the mask */
2684                 if (bits_per_word > 32)
2685                         return -EINVAL;
2686                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2687                         return -EINVAL;
2688         }
2689
2690         return 0;
2691 }
2692
2693 /**
2694  * spi_setup - setup SPI mode and clock rate
2695  * @spi: the device whose settings are being modified
2696  * Context: can sleep, and no requests are queued to the device
2697  *
2698  * SPI protocol drivers may need to update the transfer mode if the
2699  * device doesn't work with its default.  They may likewise need
2700  * to update clock rates or word sizes from initial values.  This function
2701  * changes those settings, and must be called from a context that can sleep.
2702  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2703  * effect the next time the device is selected and data is transferred to
2704  * or from it.  When this function returns, the spi device is deselected.
2705  *
2706  * Note that this call will fail if the protocol driver specifies an option
2707  * that the underlying controller or its driver does not support.  For
2708  * example, not all hardware supports wire transfers using nine bit words,
2709  * LSB-first wire encoding, or active-high chipselects.
2710  *
2711  * Return: zero on success, else a negative error code.
2712  */
2713 int spi_setup(struct spi_device *spi)
2714 {
2715         unsigned        bad_bits, ugly_bits;
2716         int             status;
2717
2718         /* check mode to prevent that DUAL and QUAD set at the same time
2719          */
2720         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2721                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2722                 dev_err(&spi->dev,
2723                 "setup: can not select dual and quad at the same time\n");
2724                 return -EINVAL;
2725         }
2726         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2727          */
2728         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2729                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2730                 return -EINVAL;
2731         /* help drivers fail *cleanly* when they need options
2732          * that aren't supported with their current controller
2733          */
2734         bad_bits = spi->mode & ~spi->controller->mode_bits;
2735         ugly_bits = bad_bits &
2736                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2737         if (ugly_bits) {
2738                 dev_warn(&spi->dev,
2739                          "setup: ignoring unsupported mode bits %x\n",
2740                          ugly_bits);
2741                 spi->mode &= ~ugly_bits;
2742                 bad_bits &= ~ugly_bits;
2743         }
2744         if (bad_bits) {
2745                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2746                         bad_bits);
2747                 return -EINVAL;
2748         }
2749
2750         if (!spi->bits_per_word)
2751                 spi->bits_per_word = 8;
2752
2753         status = __spi_validate_bits_per_word(spi->controller,
2754                                               spi->bits_per_word);
2755         if (status)
2756                 return status;
2757
2758         if (!spi->max_speed_hz)
2759                 spi->max_speed_hz = spi->controller->max_speed_hz;
2760
2761         if (spi->controller->setup)
2762                 status = spi->controller->setup(spi);
2763
2764         spi_set_cs(spi, false);
2765
2766         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2767                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2768                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2769                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2770                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2771                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2772                         spi->bits_per_word, spi->max_speed_hz,
2773                         status);
2774
2775         return status;
2776 }
2777 EXPORT_SYMBOL_GPL(spi_setup);
2778
2779 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2780 {
2781         struct spi_controller *ctlr = spi->controller;
2782         struct spi_transfer *xfer;
2783         int w_size;
2784
2785         if (list_empty(&message->transfers))
2786                 return -EINVAL;
2787
2788         /* Half-duplex links include original MicroWire, and ones with
2789          * only one data pin like SPI_3WIRE (switches direction) or where
2790          * either MOSI or MISO is missing.  They can also be caused by
2791          * software limitations.
2792          */
2793         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
2794             (spi->mode & SPI_3WIRE)) {
2795                 unsigned flags = ctlr->flags;
2796
2797                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2798                         if (xfer->rx_buf && xfer->tx_buf)
2799                                 return -EINVAL;
2800                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
2801                                 return -EINVAL;
2802                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
2803                                 return -EINVAL;
2804                 }
2805         }
2806
2807         /**
2808          * Set transfer bits_per_word and max speed as spi device default if
2809          * it is not set for this transfer.
2810          * Set transfer tx_nbits and rx_nbits as single transfer default
2811          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2812          */
2813         message->frame_length = 0;
2814         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2815                 message->frame_length += xfer->len;
2816                 if (!xfer->bits_per_word)
2817                         xfer->bits_per_word = spi->bits_per_word;
2818
2819                 if (!xfer->speed_hz)
2820                         xfer->speed_hz = spi->max_speed_hz;
2821                 if (!xfer->speed_hz)
2822                         xfer->speed_hz = ctlr->max_speed_hz;
2823
2824                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
2825                         xfer->speed_hz = ctlr->max_speed_hz;
2826
2827                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
2828                         return -EINVAL;
2829
2830                 /*
2831                  * SPI transfer length should be multiple of SPI word size
2832                  * where SPI word size should be power-of-two multiple
2833                  */
2834                 if (xfer->bits_per_word <= 8)
2835                         w_size = 1;
2836                 else if (xfer->bits_per_word <= 16)
2837                         w_size = 2;
2838                 else
2839                         w_size = 4;
2840
2841                 /* No partial transfers accepted */
2842                 if (xfer->len % w_size)
2843                         return -EINVAL;
2844
2845                 if (xfer->speed_hz && ctlr->min_speed_hz &&
2846                     xfer->speed_hz < ctlr->min_speed_hz)
2847                         return -EINVAL;
2848
2849                 if (xfer->tx_buf && !xfer->tx_nbits)
2850                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2851                 if (xfer->rx_buf && !xfer->rx_nbits)
2852                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2853                 /* check transfer tx/rx_nbits:
2854                  * 1. check the value matches one of single, dual and quad
2855                  * 2. check tx/rx_nbits match the mode in spi_device
2856                  */
2857                 if (xfer->tx_buf) {
2858                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2859                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2860                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2861                                 return -EINVAL;
2862                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2863                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2864                                 return -EINVAL;
2865                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2866                                 !(spi->mode & SPI_TX_QUAD))
2867                                 return -EINVAL;
2868                 }
2869                 /* check transfer rx_nbits */
2870                 if (xfer->rx_buf) {
2871                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2872                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2873                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2874                                 return -EINVAL;
2875                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2876                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2877                                 return -EINVAL;
2878                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2879                                 !(spi->mode & SPI_RX_QUAD))
2880                                 return -EINVAL;
2881                 }
2882         }
2883
2884         message->status = -EINPROGRESS;
2885
2886         return 0;
2887 }
2888
2889 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2890 {
2891         struct spi_controller *ctlr = spi->controller;
2892
2893         message->spi = spi;
2894
2895         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
2896         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2897
2898         trace_spi_message_submit(message);
2899
2900         return ctlr->transfer(spi, message);
2901 }
2902
2903 /**
2904  * spi_async - asynchronous SPI transfer
2905  * @spi: device with which data will be exchanged
2906  * @message: describes the data transfers, including completion callback
2907  * Context: any (irqs may be blocked, etc)
2908  *
2909  * This call may be used in_irq and other contexts which can't sleep,
2910  * as well as from task contexts which can sleep.
2911  *
2912  * The completion callback is invoked in a context which can't sleep.
2913  * Before that invocation, the value of message->status is undefined.
2914  * When the callback is issued, message->status holds either zero (to
2915  * indicate complete success) or a negative error code.  After that
2916  * callback returns, the driver which issued the transfer request may
2917  * deallocate the associated memory; it's no longer in use by any SPI
2918  * core or controller driver code.
2919  *
2920  * Note that although all messages to a spi_device are handled in
2921  * FIFO order, messages may go to different devices in other orders.
2922  * Some device might be higher priority, or have various "hard" access
2923  * time requirements, for example.
2924  *
2925  * On detection of any fault during the transfer, processing of
2926  * the entire message is aborted, and the device is deselected.
2927  * Until returning from the associated message completion callback,
2928  * no other spi_message queued to that device will be processed.
2929  * (This rule applies equally to all the synchronous transfer calls,
2930  * which are wrappers around this core asynchronous primitive.)
2931  *
2932  * Return: zero on success, else a negative error code.
2933  */
2934 int spi_async(struct spi_device *spi, struct spi_message *message)
2935 {
2936         struct spi_controller *ctlr = spi->controller;
2937         int ret;
2938         unsigned long flags;
2939
2940         ret = __spi_validate(spi, message);
2941         if (ret != 0)
2942                 return ret;
2943
2944         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2945
2946         if (ctlr->bus_lock_flag)
2947                 ret = -EBUSY;
2948         else
2949                 ret = __spi_async(spi, message);
2950
2951         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2952
2953         return ret;
2954 }
2955 EXPORT_SYMBOL_GPL(spi_async);
2956
2957 /**
2958  * spi_async_locked - version of spi_async with exclusive bus usage
2959  * @spi: device with which data will be exchanged
2960  * @message: describes the data transfers, including completion callback
2961  * Context: any (irqs may be blocked, etc)
2962  *
2963  * This call may be used in_irq and other contexts which can't sleep,
2964  * as well as from task contexts which can sleep.
2965  *
2966  * The completion callback is invoked in a context which can't sleep.
2967  * Before that invocation, the value of message->status is undefined.
2968  * When the callback is issued, message->status holds either zero (to
2969  * indicate complete success) or a negative error code.  After that
2970  * callback returns, the driver which issued the transfer request may
2971  * deallocate the associated memory; it's no longer in use by any SPI
2972  * core or controller driver code.
2973  *
2974  * Note that although all messages to a spi_device are handled in
2975  * FIFO order, messages may go to different devices in other orders.
2976  * Some device might be higher priority, or have various "hard" access
2977  * time requirements, for example.
2978  *
2979  * On detection of any fault during the transfer, processing of
2980  * the entire message is aborted, and the device is deselected.
2981  * Until returning from the associated message completion callback,
2982  * no other spi_message queued to that device will be processed.
2983  * (This rule applies equally to all the synchronous transfer calls,
2984  * which are wrappers around this core asynchronous primitive.)
2985  *
2986  * Return: zero on success, else a negative error code.
2987  */
2988 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2989 {
2990         struct spi_controller *ctlr = spi->controller;
2991         int ret;
2992         unsigned long flags;
2993
2994         ret = __spi_validate(spi, message);
2995         if (ret != 0)
2996                 return ret;
2997
2998         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2999
3000         ret = __spi_async(spi, message);
3001
3002         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3003
3004         return ret;
3005
3006 }
3007 EXPORT_SYMBOL_GPL(spi_async_locked);
3008
3009
3010 int spi_flash_read(struct spi_device *spi,
3011                    struct spi_flash_read_message *msg)
3012
3013 {
3014         struct spi_controller *master = spi->controller;
3015         struct device *rx_dev = NULL;
3016         int ret;
3017
3018         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
3019              msg->addr_nbits == SPI_NBITS_DUAL) &&
3020             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3021                 return -EINVAL;
3022         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
3023              msg->addr_nbits == SPI_NBITS_QUAD) &&
3024             !(spi->mode & SPI_TX_QUAD))
3025                 return -EINVAL;
3026         if (msg->data_nbits == SPI_NBITS_DUAL &&
3027             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3028                 return -EINVAL;
3029         if (msg->data_nbits == SPI_NBITS_QUAD &&
3030             !(spi->mode &  SPI_RX_QUAD))
3031                 return -EINVAL;
3032
3033         if (master->auto_runtime_pm) {
3034                 ret = pm_runtime_get_sync(master->dev.parent);
3035                 if (ret < 0) {
3036                         dev_err(&master->dev, "Failed to power device: %d\n",
3037                                 ret);
3038                         return ret;
3039                 }
3040         }
3041
3042         mutex_lock(&master->bus_lock_mutex);
3043         mutex_lock(&master->io_mutex);
3044         if (master->dma_rx && master->spi_flash_can_dma(spi, msg)) {
3045                 rx_dev = master->dma_rx->device->dev;
3046                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
3047                                   msg->buf, msg->len,
3048                                   DMA_FROM_DEVICE);
3049                 if (!ret)
3050                         msg->cur_msg_mapped = true;
3051         }
3052         ret = master->spi_flash_read(spi, msg);
3053         if (msg->cur_msg_mapped)
3054                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
3055                               DMA_FROM_DEVICE);
3056         mutex_unlock(&master->io_mutex);
3057         mutex_unlock(&master->bus_lock_mutex);
3058
3059         if (master->auto_runtime_pm)
3060                 pm_runtime_put(master->dev.parent);
3061
3062         return ret;
3063 }
3064 EXPORT_SYMBOL_GPL(spi_flash_read);
3065
3066 /*-------------------------------------------------------------------------*/
3067
3068 /* Utility methods for SPI protocol drivers, layered on
3069  * top of the core.  Some other utility methods are defined as
3070  * inline functions.
3071  */
3072
3073 static void spi_complete(void *arg)
3074 {
3075         complete(arg);
3076 }
3077
3078 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3079 {
3080         DECLARE_COMPLETION_ONSTACK(done);
3081         int status;
3082         struct spi_controller *ctlr = spi->controller;
3083         unsigned long flags;
3084
3085         status = __spi_validate(spi, message);
3086         if (status != 0)
3087                 return status;
3088
3089         message->complete = spi_complete;
3090         message->context = &done;
3091         message->spi = spi;
3092
3093         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3094         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3095
3096         /* If we're not using the legacy transfer method then we will
3097          * try to transfer in the calling context so special case.
3098          * This code would be less tricky if we could remove the
3099          * support for driver implemented message queues.
3100          */
3101         if (ctlr->transfer == spi_queued_transfer) {
3102                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3103
3104                 trace_spi_message_submit(message);
3105
3106                 status = __spi_queued_transfer(spi, message, false);
3107
3108                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3109         } else {
3110                 status = spi_async_locked(spi, message);
3111         }
3112
3113         if (status == 0) {
3114                 /* Push out the messages in the calling context if we
3115                  * can.
3116                  */
3117                 if (ctlr->transfer == spi_queued_transfer) {
3118                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3119                                                        spi_sync_immediate);
3120                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3121                                                        spi_sync_immediate);
3122                         __spi_pump_messages(ctlr, false);
3123                 }
3124
3125                 wait_for_completion(&done);
3126                 status = message->status;
3127         }
3128         message->context = NULL;
3129         return status;
3130 }
3131
3132 /**
3133  * spi_sync - blocking/synchronous SPI data transfers
3134  * @spi: device with which data will be exchanged
3135  * @message: describes the data transfers
3136  * Context: can sleep
3137  *
3138  * This call may only be used from a context that may sleep.  The sleep
3139  * is non-interruptible, and has no timeout.  Low-overhead controller
3140  * drivers may DMA directly into and out of the message buffers.
3141  *
3142  * Note that the SPI device's chip select is active during the message,
3143  * and then is normally disabled between messages.  Drivers for some
3144  * frequently-used devices may want to minimize costs of selecting a chip,
3145  * by leaving it selected in anticipation that the next message will go
3146  * to the same chip.  (That may increase power usage.)
3147  *
3148  * Also, the caller is guaranteeing that the memory associated with the
3149  * message will not be freed before this call returns.
3150  *
3151  * Return: zero on success, else a negative error code.
3152  */
3153 int spi_sync(struct spi_device *spi, struct spi_message *message)
3154 {
3155         int ret;
3156
3157         mutex_lock(&spi->controller->bus_lock_mutex);
3158         ret = __spi_sync(spi, message);
3159         mutex_unlock(&spi->controller->bus_lock_mutex);
3160
3161         return ret;
3162 }
3163 EXPORT_SYMBOL_GPL(spi_sync);
3164
3165 /**
3166  * spi_sync_locked - version of spi_sync with exclusive bus usage
3167  * @spi: device with which data will be exchanged
3168  * @message: describes the data transfers
3169  * Context: can sleep
3170  *
3171  * This call may only be used from a context that may sleep.  The sleep
3172  * is non-interruptible, and has no timeout.  Low-overhead controller
3173  * drivers may DMA directly into and out of the message buffers.
3174  *
3175  * This call should be used by drivers that require exclusive access to the
3176  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3177  * be released by a spi_bus_unlock call when the exclusive access is over.
3178  *
3179  * Return: zero on success, else a negative error code.
3180  */
3181 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3182 {
3183         return __spi_sync(spi, message);
3184 }
3185 EXPORT_SYMBOL_GPL(spi_sync_locked);
3186
3187 /**
3188  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3189  * @ctlr: SPI bus master that should be locked for exclusive bus access
3190  * Context: can sleep
3191  *
3192  * This call may only be used from a context that may sleep.  The sleep
3193  * is non-interruptible, and has no timeout.
3194  *
3195  * This call should be used by drivers that require exclusive access to the
3196  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3197  * exclusive access is over. Data transfer must be done by spi_sync_locked
3198  * and spi_async_locked calls when the SPI bus lock is held.
3199  *
3200  * Return: always zero.
3201  */
3202 int spi_bus_lock(struct spi_controller *ctlr)
3203 {
3204         unsigned long flags;
3205
3206         mutex_lock(&ctlr->bus_lock_mutex);
3207
3208         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3209         ctlr->bus_lock_flag = 1;
3210         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3211
3212         /* mutex remains locked until spi_bus_unlock is called */
3213
3214         return 0;
3215 }
3216 EXPORT_SYMBOL_GPL(spi_bus_lock);
3217
3218 /**
3219  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3220  * @ctlr: SPI bus master that was locked for exclusive bus access
3221  * Context: can sleep
3222  *
3223  * This call may only be used from a context that may sleep.  The sleep
3224  * is non-interruptible, and has no timeout.
3225  *
3226  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3227  * call.
3228  *
3229  * Return: always zero.
3230  */
3231 int spi_bus_unlock(struct spi_controller *ctlr)
3232 {
3233         ctlr->bus_lock_flag = 0;
3234
3235         mutex_unlock(&ctlr->bus_lock_mutex);
3236
3237         return 0;
3238 }
3239 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3240
3241 /* portable code must never pass more than 32 bytes */
3242 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3243
3244 static u8       *buf;
3245
3246 /**
3247  * spi_write_then_read - SPI synchronous write followed by read
3248  * @spi: device with which data will be exchanged
3249  * @txbuf: data to be written (need not be dma-safe)
3250  * @n_tx: size of txbuf, in bytes
3251  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3252  * @n_rx: size of rxbuf, in bytes
3253  * Context: can sleep
3254  *
3255  * This performs a half duplex MicroWire style transaction with the
3256  * device, sending txbuf and then reading rxbuf.  The return value
3257  * is zero for success, else a negative errno status code.
3258  * This call may only be used from a context that may sleep.
3259  *
3260  * Parameters to this routine are always copied using a small buffer;
3261  * portable code should never use this for more than 32 bytes.
3262  * Performance-sensitive or bulk transfer code should instead use
3263  * spi_{async,sync}() calls with dma-safe buffers.
3264  *
3265  * Return: zero on success, else a negative error code.
3266  */
3267 int spi_write_then_read(struct spi_device *spi,
3268                 const void *txbuf, unsigned n_tx,
3269                 void *rxbuf, unsigned n_rx)
3270 {
3271         static DEFINE_MUTEX(lock);
3272
3273         int                     status;
3274         struct spi_message      message;
3275         struct spi_transfer     x[2];
3276         u8                      *local_buf;
3277
3278         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3279          * copying here, (as a pure convenience thing), but we can
3280          * keep heap costs out of the hot path unless someone else is
3281          * using the pre-allocated buffer or the transfer is too large.
3282          */
3283         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3284                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3285                                     GFP_KERNEL | GFP_DMA);
3286                 if (!local_buf)
3287                         return -ENOMEM;
3288         } else {
3289                 local_buf = buf;
3290         }
3291
3292         spi_message_init(&message);
3293         memset(x, 0, sizeof(x));
3294         if (n_tx) {
3295                 x[0].len = n_tx;
3296                 spi_message_add_tail(&x[0], &message);
3297         }
3298         if (n_rx) {
3299                 x[1].len = n_rx;
3300                 spi_message_add_tail(&x[1], &message);
3301         }
3302
3303         memcpy(local_buf, txbuf, n_tx);
3304         x[0].tx_buf = local_buf;
3305         x[1].rx_buf = local_buf + n_tx;
3306
3307         /* do the i/o */
3308         status = spi_sync(spi, &message);
3309         if (status == 0)
3310                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3311
3312         if (x[0].tx_buf == buf)
3313                 mutex_unlock(&lock);
3314         else
3315                 kfree(local_buf);
3316
3317         return status;
3318 }
3319 EXPORT_SYMBOL_GPL(spi_write_then_read);
3320
3321 /*-------------------------------------------------------------------------*/
3322
3323 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3324 static int __spi_of_device_match(struct device *dev, void *data)
3325 {
3326         return dev->of_node == data;
3327 }
3328
3329 /* must call put_device() when done with returned spi_device device */
3330 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3331 {
3332         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3333                                                 __spi_of_device_match);
3334         return dev ? to_spi_device(dev) : NULL;
3335 }
3336
3337 static int __spi_of_controller_match(struct device *dev, const void *data)
3338 {
3339         return dev->of_node == data;
3340 }
3341
3342 /* the spi controllers are not using spi_bus, so we find it with another way */
3343 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3344 {
3345         struct device *dev;
3346
3347         dev = class_find_device(&spi_master_class, NULL, node,
3348                                 __spi_of_controller_match);
3349         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3350                 dev = class_find_device(&spi_slave_class, NULL, node,
3351                                         __spi_of_controller_match);
3352         if (!dev)
3353                 return NULL;
3354
3355         /* reference got in class_find_device */
3356         return container_of(dev, struct spi_controller, dev);
3357 }
3358
3359 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3360                          void *arg)
3361 {
3362         struct of_reconfig_data *rd = arg;
3363         struct spi_controller *ctlr;
3364         struct spi_device *spi;
3365
3366         switch (of_reconfig_get_state_change(action, arg)) {
3367         case OF_RECONFIG_CHANGE_ADD:
3368                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3369                 if (ctlr == NULL)
3370                         return NOTIFY_OK;       /* not for us */
3371
3372                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3373                         put_device(&ctlr->dev);
3374                         return NOTIFY_OK;
3375                 }
3376
3377                 spi = of_register_spi_device(ctlr, rd->dn);
3378                 put_device(&ctlr->dev);
3379
3380                 if (IS_ERR(spi)) {
3381                         pr_err("%s: failed to create for '%pOF'\n",
3382                                         __func__, rd->dn);
3383                         of_node_clear_flag(rd->dn, OF_POPULATED);
3384                         return notifier_from_errno(PTR_ERR(spi));
3385                 }
3386                 break;
3387
3388         case OF_RECONFIG_CHANGE_REMOVE:
3389                 /* already depopulated? */
3390                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3391                         return NOTIFY_OK;
3392
3393                 /* find our device by node */
3394                 spi = of_find_spi_device_by_node(rd->dn);
3395                 if (spi == NULL)
3396                         return NOTIFY_OK;       /* no? not meant for us */
3397
3398                 /* unregister takes one ref away */
3399                 spi_unregister_device(spi);
3400
3401                 /* and put the reference of the find */
3402                 put_device(&spi->dev);
3403                 break;
3404         }
3405
3406         return NOTIFY_OK;
3407 }
3408
3409 static struct notifier_block spi_of_notifier = {
3410         .notifier_call = of_spi_notify,
3411 };
3412 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3413 extern struct notifier_block spi_of_notifier;
3414 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3415
3416 #if IS_ENABLED(CONFIG_ACPI)
3417 static int spi_acpi_controller_match(struct device *dev, const void *data)
3418 {
3419         return ACPI_COMPANION(dev->parent) == data;
3420 }
3421
3422 static int spi_acpi_device_match(struct device *dev, void *data)
3423 {
3424         return ACPI_COMPANION(dev) == data;
3425 }
3426
3427 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3428 {
3429         struct device *dev;
3430
3431         dev = class_find_device(&spi_master_class, NULL, adev,
3432                                 spi_acpi_controller_match);
3433         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3434                 dev = class_find_device(&spi_slave_class, NULL, adev,
3435                                         spi_acpi_controller_match);
3436         if (!dev)
3437                 return NULL;
3438
3439         return container_of(dev, struct spi_controller, dev);
3440 }
3441
3442 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3443 {
3444         struct device *dev;
3445
3446         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3447
3448         return dev ? to_spi_device(dev) : NULL;
3449 }
3450
3451 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3452                            void *arg)
3453 {
3454         struct acpi_device *adev = arg;
3455         struct spi_controller *ctlr;
3456         struct spi_device *spi;
3457
3458         switch (value) {
3459         case ACPI_RECONFIG_DEVICE_ADD:
3460                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3461                 if (!ctlr)
3462                         break;
3463
3464                 acpi_register_spi_device(ctlr, adev);
3465                 put_device(&ctlr->dev);
3466                 break;
3467         case ACPI_RECONFIG_DEVICE_REMOVE:
3468                 if (!acpi_device_enumerated(adev))
3469                         break;
3470
3471                 spi = acpi_spi_find_device_by_adev(adev);
3472                 if (!spi)
3473                         break;
3474
3475                 spi_unregister_device(spi);
3476                 put_device(&spi->dev);
3477                 break;
3478         }
3479
3480         return NOTIFY_OK;
3481 }
3482
3483 static struct notifier_block spi_acpi_notifier = {
3484         .notifier_call = acpi_spi_notify,
3485 };
3486 #else
3487 extern struct notifier_block spi_acpi_notifier;
3488 #endif
3489
3490 static int __init spi_init(void)
3491 {
3492         int     status;
3493
3494         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3495         if (!buf) {
3496                 status = -ENOMEM;
3497                 goto err0;
3498         }
3499
3500         status = bus_register(&spi_bus_type);
3501         if (status < 0)
3502                 goto err1;
3503
3504         status = class_register(&spi_master_class);
3505         if (status < 0)
3506                 goto err2;
3507
3508         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3509                 status = class_register(&spi_slave_class);
3510                 if (status < 0)
3511                         goto err3;
3512         }
3513
3514         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3515                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3516         if (IS_ENABLED(CONFIG_ACPI))
3517                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3518
3519         return 0;
3520
3521 err3:
3522         class_unregister(&spi_master_class);
3523 err2:
3524         bus_unregister(&spi_bus_type);
3525 err1:
3526         kfree(buf);
3527         buf = NULL;
3528 err0:
3529         return status;
3530 }
3531
3532 /* board_info is normally registered in arch_initcall(),
3533  * but even essential drivers wait till later
3534  *
3535  * REVISIT only boardinfo really needs static linking. the rest (device and
3536  * driver registration) _could_ be dynamically linked (modular) ... costs
3537  * include needing to have boardinfo data structures be much more public.
3538  */
3539 postcore_initcall(spi_init);
3540