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
  45 #define CREATE_TRACE_POINTS
  46 #include <trace/events/spi.h>
  47 #define SPI_DYN_FIRST_BUS_NUM 0
  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, "%s is not called 'slave'\n",
1591                                 nc->full_name);
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, "%s has no valid 'reg' property (%d)\n",
1601                         nc->full_name, 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                         "%s has no valid 'spi-max-frequency' property (%d)\n",
1611                         nc->full_name, rc);
1612                 return rc;
1613         }
1614         spi->max_speed_hz = value;
1615
1616         return 0;
1617 }
1618
1619 static struct spi_device *
1620 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1621 {
1622         struct spi_device *spi;
1623         int rc;
1624
1625         /* Alloc an spi_device */
1626         spi = spi_alloc_device(ctlr);
1627         if (!spi) {
1628                 dev_err(&ctlr->dev, "spi_device alloc error for %s\n",
1629                         nc->full_name);
1630                 rc = -ENOMEM;
1631                 goto err_out;
1632         }
1633
1634         /* Select device driver */
1635         rc = of_modalias_node(nc, spi->modalias,
1636                                 sizeof(spi->modalias));
1637         if (rc < 0) {
1638                 dev_err(&ctlr->dev, "cannot find modalias for %s\n",
1639                         nc->full_name);
1640                 goto err_out;
1641         }
1642
1643         rc = of_spi_parse_dt(ctlr, spi, nc);
1644         if (rc)
1645                 goto err_out;
1646
1647         /* Store a pointer to the node in the device structure */
1648         of_node_get(nc);
1649         spi->dev.of_node = nc;
1650
1651         /* Register the new device */
1652         rc = spi_add_device(spi);
1653         if (rc) {
1654                 dev_err(&ctlr->dev, "spi_device register error %s\n",
1655                         nc->full_name);
1656                 goto err_of_node_put;
1657         }
1658
1659         return spi;
1660
1661 err_of_node_put:
1662         of_node_put(nc);
1663 err_out:
1664         spi_dev_put(spi);
1665         return ERR_PTR(rc);
1666 }
1667
1668 /**
1669  * of_register_spi_devices() - Register child devices onto the SPI bus
1670  * @ctlr:       Pointer to spi_controller device
1671  *
1672  * Registers an spi_device for each child node of controller node which
1673  * represents a valid SPI slave.
1674  */
1675 static void of_register_spi_devices(struct spi_controller *ctlr)
1676 {
1677         struct spi_device *spi;
1678         struct device_node *nc;
1679
1680         if (!ctlr->dev.of_node)
1681                 return;
1682
1683         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1684                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1685                         continue;
1686                 spi = of_register_spi_device(ctlr, nc);
1687                 if (IS_ERR(spi)) {
1688                         dev_warn(&ctlr->dev,
1689                                  "Failed to create SPI device for %s\n",
1690                                  nc->full_name);
1691                         of_node_clear_flag(nc, OF_POPULATED);
1692                 }
1693         }
1694 }
1695 #else
1696 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1697 #endif
1698
1699 #ifdef CONFIG_ACPI
1700 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1701 {
1702         struct spi_device *spi = data;
1703         struct spi_controller *ctlr = spi->controller;
1704
1705         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1706                 struct acpi_resource_spi_serialbus *sb;
1707
1708                 sb = &ares->data.spi_serial_bus;
1709                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1710                         /*
1711                          * ACPI DeviceSelection numbering is handled by the
1712                          * host controller driver in Windows and can vary
1713                          * from driver to driver. In Linux we always expect
1714                          * 0 .. max - 1 so we need to ask the driver to
1715                          * translate between the two schemes.
1716                          */
1717                         if (ctlr->fw_translate_cs) {
1718                                 int cs = ctlr->fw_translate_cs(ctlr,
1719                                                 sb->device_selection);
1720                                 if (cs < 0)
1721                                         return cs;
1722                                 spi->chip_select = cs;
1723                         } else {
1724                                 spi->chip_select = sb->device_selection;
1725                         }
1726
1727                         spi->max_speed_hz = sb->connection_speed;
1728
1729                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1730                                 spi->mode |= SPI_CPHA;
1731                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1732                                 spi->mode |= SPI_CPOL;
1733                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1734                                 spi->mode |= SPI_CS_HIGH;
1735                 }
1736         } else if (spi->irq < 0) {
1737                 struct resource r;
1738
1739                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1740                         spi->irq = r.start;
1741         }
1742
1743         /* Always tell the ACPI core to skip this resource */
1744         return 1;
1745 }
1746
1747 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1748                                             struct acpi_device *adev)
1749 {
1750         struct list_head resource_list;
1751         struct spi_device *spi;
1752         int ret;
1753
1754         if (acpi_bus_get_status(adev) || !adev->status.present ||
1755             acpi_device_enumerated(adev))
1756                 return AE_OK;
1757
1758         spi = spi_alloc_device(ctlr);
1759         if (!spi) {
1760                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1761                         dev_name(&adev->dev));
1762                 return AE_NO_MEMORY;
1763         }
1764
1765         ACPI_COMPANION_SET(&spi->dev, adev);
1766         spi->irq = -1;
1767
1768         INIT_LIST_HEAD(&resource_list);
1769         ret = acpi_dev_get_resources(adev, &resource_list,
1770                                      acpi_spi_add_resource, spi);
1771         acpi_dev_free_resource_list(&resource_list);
1772
1773         if (ret < 0 || !spi->max_speed_hz) {
1774                 spi_dev_put(spi);
1775                 return AE_OK;
1776         }
1777
1778         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1779                           sizeof(spi->modalias));
1780
1781         if (spi->irq < 0)
1782                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1783
1784         acpi_device_set_enumerated(adev);
1785
1786         adev->power.flags.ignore_parent = true;
1787         if (spi_add_device(spi)) {
1788                 adev->power.flags.ignore_parent = false;
1789                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1790                         dev_name(&adev->dev));
1791                 spi_dev_put(spi);
1792         }
1793
1794         return AE_OK;
1795 }
1796
1797 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1798                                        void *data, void **return_value)
1799 {
1800         struct spi_controller *ctlr = data;
1801         struct acpi_device *adev;
1802
1803         if (acpi_bus_get_device(handle, &adev))
1804                 return AE_OK;
1805
1806         return acpi_register_spi_device(ctlr, adev);
1807 }
1808
1809 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1810 {
1811         acpi_status status;
1812         acpi_handle handle;
1813
1814         handle = ACPI_HANDLE(ctlr->dev.parent);
1815         if (!handle)
1816                 return;
1817
1818         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1819                                      acpi_spi_add_device, NULL, ctlr, NULL);
1820         if (ACPI_FAILURE(status))
1821                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1822 }
1823 #else
1824 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1825 #endif /* CONFIG_ACPI */
1826
1827 static void spi_controller_release(struct device *dev)
1828 {
1829         struct spi_controller *ctlr;
1830
1831         ctlr = container_of(dev, struct spi_controller, dev);
1832         kfree(ctlr);
1833 }
1834
1835 static struct class spi_master_class = {
1836         .name           = "spi_master",
1837         .owner          = THIS_MODULE,
1838         .dev_release    = spi_controller_release,
1839         .dev_groups     = spi_master_groups,
1840 };
1841
1842 #ifdef CONFIG_SPI_SLAVE
1843 /**
1844  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1845  *                   controller
1846  * @spi: device used for the current transfer
1847  */
1848 int spi_slave_abort(struct spi_device *spi)
1849 {
1850         struct spi_controller *ctlr = spi->controller;
1851
1852         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1853                 return ctlr->slave_abort(ctlr);
1854
1855         return -ENOTSUPP;
1856 }
1857 EXPORT_SYMBOL_GPL(spi_slave_abort);
1858
1859 static int match_true(struct device *dev, void *data)
1860 {
1861         return 1;
1862 }
1863
1864 static ssize_t spi_slave_show(struct device *dev,
1865                               struct device_attribute *attr, char *buf)
1866 {
1867         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1868                                                    dev);
1869         struct device *child;
1870
1871         child = device_find_child(&ctlr->dev, NULL, match_true);
1872         return sprintf(buf, "%s\n",
1873                        child ? to_spi_device(child)->modalias : NULL);
1874 }
1875
1876 static ssize_t spi_slave_store(struct device *dev,
1877                                struct device_attribute *attr, const char *buf,
1878                                size_t count)
1879 {
1880         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1881                                                    dev);
1882         struct spi_device *spi;
1883         struct device *child;
1884         char name[32];
1885         int rc;
1886
1887         rc = sscanf(buf, "%31s", name);
1888         if (rc != 1 || !name[0])
1889                 return -EINVAL;
1890
1891         child = device_find_child(&ctlr->dev, NULL, match_true);
1892         if (child) {
1893                 /* Remove registered slave */
1894                 device_unregister(child);
1895                 put_device(child);
1896         }
1897
1898         if (strcmp(name, "(null)")) {
1899                 /* Register new slave */
1900                 spi = spi_alloc_device(ctlr);
1901                 if (!spi)
1902                         return -ENOMEM;
1903
1904                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
1905
1906                 rc = spi_add_device(spi);
1907                 if (rc) {
1908                         spi_dev_put(spi);
1909                         return rc;
1910                 }
1911         }
1912
1913         return count;
1914 }
1915
1916 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
1917
1918 static struct attribute *spi_slave_attrs[] = {
1919         &dev_attr_slave.attr,
1920         NULL,
1921 };
1922
1923 static const struct attribute_group spi_slave_group = {
1924         .attrs = spi_slave_attrs,
1925 };
1926
1927 static const struct attribute_group *spi_slave_groups[] = {
1928         &spi_controller_statistics_group,
1929         &spi_slave_group,
1930         NULL,
1931 };
1932
1933 static struct class spi_slave_class = {
1934         .name           = "spi_slave",
1935         .owner          = THIS_MODULE,
1936         .dev_release    = spi_controller_release,
1937         .dev_groups     = spi_slave_groups,
1938 };
1939 #else
1940 extern struct class spi_slave_class;    /* dummy */
1941 #endif
1942
1943 /**
1944  * __spi_alloc_controller - allocate an SPI master or slave controller
1945  * @dev: the controller, possibly using the platform_bus
1946  * @size: how much zeroed driver-private data to allocate; the pointer to this
1947  *      memory is in the driver_data field of the returned device,
1948  *      accessible with spi_controller_get_devdata().
1949  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
1950  *      slave (true) controller
1951  * Context: can sleep
1952  *
1953  * This call is used only by SPI controller drivers, which are the
1954  * only ones directly touching chip registers.  It's how they allocate
1955  * an spi_controller structure, prior to calling spi_register_controller().
1956  *
1957  * This must be called from context that can sleep.
1958  *
1959  * The caller is responsible for assigning the bus number and initializing the
1960  * controller's methods before calling spi_register_controller(); and (after
1961  * errors adding the device) calling spi_controller_put() to prevent a memory
1962  * leak.
1963  *
1964  * Return: the SPI controller structure on success, else NULL.
1965  */
1966 struct spi_controller *__spi_alloc_controller(struct device *dev,
1967                                               unsigned int size, bool slave)
1968 {
1969         struct spi_controller   *ctlr;
1970
1971         if (!dev)
1972                 return NULL;
1973
1974         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
1975         if (!ctlr)
1976                 return NULL;
1977
1978         device_initialize(&ctlr->dev);
1979         ctlr->bus_num = -1;
1980         ctlr->num_chipselect = 1;
1981         ctlr->slave = slave;
1982         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
1983                 ctlr->dev.class = &spi_slave_class;
1984         else
1985                 ctlr->dev.class = &spi_master_class;
1986         ctlr->dev.parent = dev;
1987         pm_suspend_ignore_children(&ctlr->dev, true);
1988         spi_controller_set_devdata(ctlr, &ctlr[1]);
1989
1990         return ctlr;
1991 }
1992 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
1993
1994 #ifdef CONFIG_OF
1995 static int of_spi_register_master(struct spi_controller *ctlr)
1996 {
1997         int nb, i, *cs;
1998         struct device_node *np = ctlr->dev.of_node;
1999
2000         if (!np)
2001                 return 0;
2002
2003         nb = of_gpio_named_count(np, "cs-gpios");
2004         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2005
2006         /* Return error only for an incorrectly formed cs-gpios property */
2007         if (nb == 0 || nb == -ENOENT)
2008                 return 0;
2009         else if (nb < 0)
2010                 return nb;
2011
2012         cs = devm_kzalloc(&ctlr->dev, sizeof(int) * ctlr->num_chipselect,
2013                           GFP_KERNEL);
2014         ctlr->cs_gpios = cs;
2015
2016         if (!ctlr->cs_gpios)
2017                 return -ENOMEM;
2018
2019         for (i = 0; i < ctlr->num_chipselect; i++)
2020                 cs[i] = -ENOENT;
2021
2022         for (i = 0; i < nb; i++)
2023                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2024
2025         return 0;
2026 }
2027 #else
2028 static int of_spi_register_master(struct spi_controller *ctlr)
2029 {
2030         return 0;
2031 }
2032 #endif
2033
2034 /**
2035  * spi_register_controller - register SPI master or slave controller
2036  * @ctlr: initialized master, originally from spi_alloc_master() or
2037  *      spi_alloc_slave()
2038  * Context: can sleep
2039  *
2040  * SPI controllers connect to their drivers using some non-SPI bus,
2041  * such as the platform bus.  The final stage of probe() in that code
2042  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2043  *
2044  * SPI controllers use board specific (often SOC specific) bus numbers,
2045  * and board-specific addressing for SPI devices combines those numbers
2046  * with chip select numbers.  Since SPI does not directly support dynamic
2047  * device identification, boards need configuration tables telling which
2048  * chip is at which address.
2049  *
2050  * This must be called from context that can sleep.  It returns zero on
2051  * success, else a negative error code (dropping the controller's refcount).
2052  * After a successful return, the caller is responsible for calling
2053  * spi_unregister_controller().
2054  *
2055  * Return: zero on success, else a negative error code.
2056  */
2057 int spi_register_controller(struct spi_controller *ctlr)
2058 {
2059         struct device           *dev = ctlr->dev.parent;
2060         struct boardinfo        *bi;
2061         int                     status = -ENODEV;
2062         int                     id;
2063
2064         if (!dev)
2065                 return -ENODEV;
2066
2067         if (!spi_controller_is_slave(ctlr)) {
2068                 status = of_spi_register_master(ctlr);
2069                 if (status)
2070                         return status;
2071         }
2072
2073         /* even if it's just one always-selected device, there must
2074          * be at least one chipselect
2075          */
2076         if (ctlr->num_chipselect == 0)
2077                 return -EINVAL;
2078         /* allocate dynamic bus number using Linux idr */
2079         if ((ctlr->bus_num < 0) && ctlr->dev.of_node) {
2080                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2081                 if (id >= 0) {
2082                         ctlr->bus_num = id;
2083                         mutex_lock(&board_lock);
2084                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2085                                        ctlr->bus_num + 1, GFP_KERNEL);
2086                         mutex_unlock(&board_lock);
2087                         if (WARN(id < 0, "couldn't get idr"))
2088                                 return id == -ENOSPC ? -EBUSY : id;
2089                 }
2090         }
2091         if (ctlr->bus_num < 0) {
2092                 mutex_lock(&board_lock);
2093                 id = idr_alloc(&spi_master_idr, ctlr, SPI_DYN_FIRST_BUS_NUM, 0,
2094                                GFP_KERNEL);
2095                 mutex_unlock(&board_lock);
2096                 if (WARN(id < 0, "couldn't get idr"))
2097                         return id;
2098                 ctlr->bus_num = id;
2099         }
2100         INIT_LIST_HEAD(&ctlr->queue);
2101         spin_lock_init(&ctlr->queue_lock);
2102         spin_lock_init(&ctlr->bus_lock_spinlock);
2103         mutex_init(&ctlr->bus_lock_mutex);
2104         mutex_init(&ctlr->io_mutex);
2105         ctlr->bus_lock_flag = 0;
2106         init_completion(&ctlr->xfer_completion);
2107         if (!ctlr->max_dma_len)
2108                 ctlr->max_dma_len = INT_MAX;
2109
2110         /* register the device, then userspace will see it.
2111          * registration fails if the bus ID is in use.
2112          */
2113         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2114         status = device_add(&ctlr->dev);
2115         if (status < 0) {
2116                 /* free bus id */
2117                 mutex_lock(&board_lock);
2118                 idr_remove(&spi_master_idr, ctlr->bus_num);
2119                 mutex_unlock(&board_lock);
2120                 goto done;
2121         }
2122         dev_dbg(dev, "registered %s %s\n",
2123                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2124                         dev_name(&ctlr->dev));
2125
2126         /* If we're using a queued driver, start the queue */
2127         if (ctlr->transfer)
2128                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2129         else {
2130                 status = spi_controller_initialize_queue(ctlr);
2131                 if (status) {
2132                         device_del(&ctlr->dev);
2133                         /* free bus id */
2134                         mutex_lock(&board_lock);
2135                         idr_remove(&spi_master_idr, ctlr->bus_num);
2136                         mutex_unlock(&board_lock);
2137                         goto done;
2138                 }
2139         }
2140         /* add statistics */
2141         spin_lock_init(&ctlr->statistics.lock);
2142
2143         mutex_lock(&board_lock);
2144         list_add_tail(&ctlr->list, &spi_controller_list);
2145         list_for_each_entry(bi, &board_list, list)
2146                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2147         mutex_unlock(&board_lock);
2148
2149         /* Register devices from the device tree and ACPI */
2150         of_register_spi_devices(ctlr);
2151         acpi_register_spi_devices(ctlr);
2152 done:
2153         return status;
2154 }
2155 EXPORT_SYMBOL_GPL(spi_register_controller);
2156
2157 static void devm_spi_unregister(struct device *dev, void *res)
2158 {
2159         spi_unregister_controller(*(struct spi_controller **)res);
2160 }
2161
2162 /**
2163  * devm_spi_register_controller - register managed SPI master or slave
2164  *      controller
2165  * @dev:    device managing SPI controller
2166  * @ctlr: initialized controller, originally from spi_alloc_master() or
2167  *      spi_alloc_slave()
2168  * Context: can sleep
2169  *
2170  * Register a SPI device as with spi_register_controller() which will
2171  * automatically be unregister
2172  *
2173  * Return: zero on success, else a negative error code.
2174  */
2175 int devm_spi_register_controller(struct device *dev,
2176                                  struct spi_controller *ctlr)
2177 {
2178         struct spi_controller **ptr;
2179         int ret;
2180
2181         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2182         if (!ptr)
2183                 return -ENOMEM;
2184
2185         ret = spi_register_controller(ctlr);
2186         if (!ret) {
2187                 *ptr = ctlr;
2188                 devres_add(dev, ptr);
2189         } else {
2190                 devres_free(ptr);
2191         }
2192
2193         return ret;
2194 }
2195 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2196
2197 static int __unregister(struct device *dev, void *null)
2198 {
2199         spi_unregister_device(to_spi_device(dev));
2200         return 0;
2201 }
2202
2203 /**
2204  * spi_unregister_controller - unregister SPI master or slave controller
2205  * @ctlr: the controller being unregistered
2206  * Context: can sleep
2207  *
2208  * This call is used only by SPI controller drivers, which are the
2209  * only ones directly touching chip registers.
2210  *
2211  * This must be called from context that can sleep.
2212  */
2213 void spi_unregister_controller(struct spi_controller *ctlr)
2214 {
2215         struct spi_controller *found;
2216         int dummy;
2217
2218         /* First make sure that this controller was ever added */
2219         mutex_lock(&board_lock);
2220         found = idr_find(&spi_master_idr, ctlr->bus_num);
2221         mutex_unlock(&board_lock);
2222         if (found != ctlr) {
2223                 dev_dbg(&ctlr->dev,
2224                         "attempting to delete unregistered controller [%s]\n",
2225                         dev_name(&ctlr->dev));
2226                 return;
2227         }
2228         if (ctlr->queued) {
2229                 if (spi_destroy_queue(ctlr))
2230                         dev_err(&ctlr->dev, "queue remove failed\n");
2231         }
2232         mutex_lock(&board_lock);
2233         list_del(&ctlr->list);
2234         mutex_unlock(&board_lock);
2235
2236         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2237         device_unregister(&ctlr->dev);
2238         /* free bus id */
2239         mutex_lock(&board_lock);
2240         idr_remove(&spi_master_idr, ctlr->bus_num);
2241         mutex_unlock(&board_lock);
2242 }
2243 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2244
2245 int spi_controller_suspend(struct spi_controller *ctlr)
2246 {
2247         int ret;
2248
2249         /* Basically no-ops for non-queued controllers */
2250         if (!ctlr->queued)
2251                 return 0;
2252
2253         ret = spi_stop_queue(ctlr);
2254         if (ret)
2255                 dev_err(&ctlr->dev, "queue stop failed\n");
2256
2257         return ret;
2258 }
2259 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2260
2261 int spi_controller_resume(struct spi_controller *ctlr)
2262 {
2263         int ret;
2264
2265         if (!ctlr->queued)
2266                 return 0;
2267
2268         ret = spi_start_queue(ctlr);
2269         if (ret)
2270                 dev_err(&ctlr->dev, "queue restart failed\n");
2271
2272         return ret;
2273 }
2274 EXPORT_SYMBOL_GPL(spi_controller_resume);
2275
2276 static int __spi_controller_match(struct device *dev, const void *data)
2277 {
2278         struct spi_controller *ctlr;
2279         const u16 *bus_num = data;
2280
2281         ctlr = container_of(dev, struct spi_controller, dev);
2282         return ctlr->bus_num == *bus_num;
2283 }
2284
2285 /**
2286  * spi_busnum_to_master - look up master associated with bus_num
2287  * @bus_num: the master's bus number
2288  * Context: can sleep
2289  *
2290  * This call may be used with devices that are registered after
2291  * arch init time.  It returns a refcounted pointer to the relevant
2292  * spi_controller (which the caller must release), or NULL if there is
2293  * no such master registered.
2294  *
2295  * Return: the SPI master structure on success, else NULL.
2296  */
2297 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2298 {
2299         struct device           *dev;
2300         struct spi_controller   *ctlr = NULL;
2301
2302         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2303                                 __spi_controller_match);
2304         if (dev)
2305                 ctlr = container_of(dev, struct spi_controller, dev);
2306         /* reference got in class_find_device */
2307         return ctlr;
2308 }
2309 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2310
2311 /*-------------------------------------------------------------------------*/
2312
2313 /* Core methods for SPI resource management */
2314
2315 /**
2316  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2317  *                 during the processing of a spi_message while using
2318  *                 spi_transfer_one
2319  * @spi:     the spi device for which we allocate memory
2320  * @release: the release code to execute for this resource
2321  * @size:    size to alloc and return
2322  * @gfp:     GFP allocation flags
2323  *
2324  * Return: the pointer to the allocated data
2325  *
2326  * This may get enhanced in the future to allocate from a memory pool
2327  * of the @spi_device or @spi_controller to avoid repeated allocations.
2328  */
2329 void *spi_res_alloc(struct spi_device *spi,
2330                     spi_res_release_t release,
2331                     size_t size, gfp_t gfp)
2332 {
2333         struct spi_res *sres;
2334
2335         sres = kzalloc(sizeof(*sres) + size, gfp);
2336         if (!sres)
2337                 return NULL;
2338
2339         INIT_LIST_HEAD(&sres->entry);
2340         sres->release = release;
2341
2342         return sres->data;
2343 }
2344 EXPORT_SYMBOL_GPL(spi_res_alloc);
2345
2346 /**
2347  * spi_res_free - free an spi resource
2348  * @res: pointer to the custom data of a resource
2349  *
2350  */
2351 void spi_res_free(void *res)
2352 {
2353         struct spi_res *sres = container_of(res, struct spi_res, data);
2354
2355         if (!res)
2356                 return;
2357
2358         WARN_ON(!list_empty(&sres->entry));
2359         kfree(sres);
2360 }
2361 EXPORT_SYMBOL_GPL(spi_res_free);
2362
2363 /**
2364  * spi_res_add - add a spi_res to the spi_message
2365  * @message: the spi message
2366  * @res:     the spi_resource
2367  */
2368 void spi_res_add(struct spi_message *message, void *res)
2369 {
2370         struct spi_res *sres = container_of(res, struct spi_res, data);
2371
2372         WARN_ON(!list_empty(&sres->entry));
2373         list_add_tail(&sres->entry, &message->resources);
2374 }
2375 EXPORT_SYMBOL_GPL(spi_res_add);
2376
2377 /**
2378  * spi_res_release - release all spi resources for this message
2379  * @ctlr:  the @spi_controller
2380  * @message: the @spi_message
2381  */
2382 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2383 {
2384         struct spi_res *res;
2385
2386         while (!list_empty(&message->resources)) {
2387                 res = list_last_entry(&message->resources,
2388                                       struct spi_res, entry);
2389
2390                 if (res->release)
2391                         res->release(ctlr, message, res->data);
2392
2393                 list_del(&res->entry);
2394
2395                 kfree(res);
2396         }
2397 }
2398 EXPORT_SYMBOL_GPL(spi_res_release);
2399
2400 /*-------------------------------------------------------------------------*/
2401
2402 /* Core methods for spi_message alterations */
2403
2404 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2405                                             struct spi_message *msg,
2406                                             void *res)
2407 {
2408         struct spi_replaced_transfers *rxfer = res;
2409         size_t i;
2410
2411         /* call extra callback if requested */
2412         if (rxfer->release)
2413                 rxfer->release(ctlr, msg, res);
2414
2415         /* insert replaced transfers back into the message */
2416         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2417
2418         /* remove the formerly inserted entries */
2419         for (i = 0; i < rxfer->inserted; i++)
2420                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2421 }
2422
2423 /**
2424  * spi_replace_transfers - replace transfers with several transfers
2425  *                         and register change with spi_message.resources
2426  * @msg:           the spi_message we work upon
2427  * @xfer_first:    the first spi_transfer we want to replace
2428  * @remove:        number of transfers to remove
2429  * @insert:        the number of transfers we want to insert instead
2430  * @release:       extra release code necessary in some circumstances
2431  * @extradatasize: extra data to allocate (with alignment guarantees
2432  *                 of struct @spi_transfer)
2433  * @gfp:           gfp flags
2434  *
2435  * Returns: pointer to @spi_replaced_transfers,
2436  *          PTR_ERR(...) in case of errors.
2437  */
2438 struct spi_replaced_transfers *spi_replace_transfers(
2439         struct spi_message *msg,
2440         struct spi_transfer *xfer_first,
2441         size_t remove,
2442         size_t insert,
2443         spi_replaced_release_t release,
2444         size_t extradatasize,
2445         gfp_t gfp)
2446 {
2447         struct spi_replaced_transfers *rxfer;
2448         struct spi_transfer *xfer;
2449         size_t i;
2450
2451         /* allocate the structure using spi_res */
2452         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2453                               insert * sizeof(struct spi_transfer)
2454                               + sizeof(struct spi_replaced_transfers)
2455                               + extradatasize,
2456                               gfp);
2457         if (!rxfer)
2458                 return ERR_PTR(-ENOMEM);
2459
2460         /* the release code to invoke before running the generic release */
2461         rxfer->release = release;
2462
2463         /* assign extradata */
2464         if (extradatasize)
2465                 rxfer->extradata =
2466                         &rxfer->inserted_transfers[insert];
2467
2468         /* init the replaced_transfers list */
2469         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2470
2471         /* assign the list_entry after which we should reinsert
2472          * the @replaced_transfers - it may be spi_message.messages!
2473          */
2474         rxfer->replaced_after = xfer_first->transfer_list.prev;
2475
2476         /* remove the requested number of transfers */
2477         for (i = 0; i < remove; i++) {
2478                 /* if the entry after replaced_after it is msg->transfers
2479                  * then we have been requested to remove more transfers
2480                  * than are in the list
2481                  */
2482                 if (rxfer->replaced_after->next == &msg->transfers) {
2483                         dev_err(&msg->spi->dev,
2484                                 "requested to remove more spi_transfers than are available\n");
2485                         /* insert replaced transfers back into the message */
2486                         list_splice(&rxfer->replaced_transfers,
2487                                     rxfer->replaced_after);
2488
2489                         /* free the spi_replace_transfer structure */
2490                         spi_res_free(rxfer);
2491
2492                         /* and return with an error */
2493                         return ERR_PTR(-EINVAL);
2494                 }
2495
2496                 /* remove the entry after replaced_after from list of
2497                  * transfers and add it to list of replaced_transfers
2498                  */
2499                 list_move_tail(rxfer->replaced_after->next,
2500                                &rxfer->replaced_transfers);
2501         }
2502
2503         /* create copy of the given xfer with identical settings
2504          * based on the first transfer to get removed
2505          */
2506         for (i = 0; i < insert; i++) {
2507                 /* we need to run in reverse order */
2508                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2509
2510                 /* copy all spi_transfer data */
2511                 memcpy(xfer, xfer_first, sizeof(*xfer));
2512
2513                 /* add to list */
2514                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2515
2516                 /* clear cs_change and delay_usecs for all but the last */
2517                 if (i) {
2518                         xfer->cs_change = false;
2519                         xfer->delay_usecs = 0;
2520                 }
2521         }
2522
2523         /* set up inserted */
2524         rxfer->inserted = insert;
2525
2526         /* and register it with spi_res/spi_message */
2527         spi_res_add(msg, rxfer);
2528
2529         return rxfer;
2530 }
2531 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2532
2533 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2534                                         struct spi_message *msg,
2535                                         struct spi_transfer **xferp,
2536                                         size_t maxsize,
2537                                         gfp_t gfp)
2538 {
2539         struct spi_transfer *xfer = *xferp, *xfers;
2540         struct spi_replaced_transfers *srt;
2541         size_t offset;
2542         size_t count, i;
2543
2544         /* warn once about this fact that we are splitting a transfer */
2545         dev_warn_once(&msg->spi->dev,
2546                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2547                       xfer->len, maxsize);
2548
2549         /* calculate how many we have to replace */
2550         count = DIV_ROUND_UP(xfer->len, maxsize);
2551
2552         /* create replacement */
2553         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2554         if (IS_ERR(srt))
2555                 return PTR_ERR(srt);
2556         xfers = srt->inserted_transfers;
2557
2558         /* now handle each of those newly inserted spi_transfers
2559          * note that the replacements spi_transfers all are preset
2560          * to the same values as *xferp, so tx_buf, rx_buf and len
2561          * are all identical (as well as most others)
2562          * so we just have to fix up len and the pointers.
2563          *
2564          * this also includes support for the depreciated
2565          * spi_message.is_dma_mapped interface
2566          */
2567
2568         /* the first transfer just needs the length modified, so we
2569          * run it outside the loop
2570          */
2571         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2572
2573         /* all the others need rx_buf/tx_buf also set */
2574         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2575                 /* update rx_buf, tx_buf and dma */
2576                 if (xfers[i].rx_buf)
2577                         xfers[i].rx_buf += offset;
2578                 if (xfers[i].rx_dma)
2579                         xfers[i].rx_dma += offset;
2580                 if (xfers[i].tx_buf)
2581                         xfers[i].tx_buf += offset;
2582                 if (xfers[i].tx_dma)
2583                         xfers[i].tx_dma += offset;
2584
2585                 /* update length */
2586                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2587         }
2588
2589         /* we set up xferp to the last entry we have inserted,
2590          * so that we skip those already split transfers
2591          */
2592         *xferp = &xfers[count - 1];
2593
2594         /* increment statistics counters */
2595         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2596                                        transfers_split_maxsize);
2597         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2598                                        transfers_split_maxsize);
2599
2600         return 0;
2601 }
2602
2603 /**
2604  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2605  *                              when an individual transfer exceeds a
2606  *                              certain size
2607  * @ctlr:    the @spi_controller for this transfer
2608  * @msg:   the @spi_message to transform
2609  * @maxsize:  the maximum when to apply this
2610  * @gfp: GFP allocation flags
2611  *
2612  * Return: status of transformation
2613  */
2614 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2615                                 struct spi_message *msg,
2616                                 size_t maxsize,
2617                                 gfp_t gfp)
2618 {
2619         struct spi_transfer *xfer;
2620         int ret;
2621
2622         /* iterate over the transfer_list,
2623          * but note that xfer is advanced to the last transfer inserted
2624          * to avoid checking sizes again unnecessarily (also xfer does
2625          * potentiall belong to a different list by the time the
2626          * replacement has happened
2627          */
2628         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2629                 if (xfer->len > maxsize) {
2630                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2631                                                            maxsize, gfp);
2632                         if (ret)
2633                                 return ret;
2634                 }
2635         }
2636
2637         return 0;
2638 }
2639 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2640
2641 /*-------------------------------------------------------------------------*/
2642
2643 /* Core methods for SPI controller protocol drivers.  Some of the
2644  * other core methods are currently defined as inline functions.
2645  */
2646
2647 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2648                                         u8 bits_per_word)
2649 {
2650         if (ctlr->bits_per_word_mask) {
2651                 /* Only 32 bits fit in the mask */
2652                 if (bits_per_word > 32)
2653                         return -EINVAL;
2654                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2655                         return -EINVAL;
2656         }
2657
2658         return 0;
2659 }
2660
2661 /**
2662  * spi_setup - setup SPI mode and clock rate
2663  * @spi: the device whose settings are being modified
2664  * Context: can sleep, and no requests are queued to the device
2665  *
2666  * SPI protocol drivers may need to update the transfer mode if the
2667  * device doesn't work with its default.  They may likewise need
2668  * to update clock rates or word sizes from initial values.  This function
2669  * changes those settings, and must be called from a context that can sleep.
2670  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2671  * effect the next time the device is selected and data is transferred to
2672  * or from it.  When this function returns, the spi device is deselected.
2673  *
2674  * Note that this call will fail if the protocol driver specifies an option
2675  * that the underlying controller or its driver does not support.  For
2676  * example, not all hardware supports wire transfers using nine bit words,
2677  * LSB-first wire encoding, or active-high chipselects.
2678  *
2679  * Return: zero on success, else a negative error code.
2680  */
2681 int spi_setup(struct spi_device *spi)
2682 {
2683         unsigned        bad_bits, ugly_bits;
2684         int             status;
2685
2686         /* check mode to prevent that DUAL and QUAD set at the same time
2687          */
2688         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2689                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2690                 dev_err(&spi->dev,
2691                 "setup: can not select dual and quad at the same time\n");
2692                 return -EINVAL;
2693         }
2694         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2695          */
2696         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2697                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2698                 return -EINVAL;
2699         /* help drivers fail *cleanly* when they need options
2700          * that aren't supported with their current controller
2701          */
2702         bad_bits = spi->mode & ~spi->controller->mode_bits;
2703         ugly_bits = bad_bits &
2704                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2705         if (ugly_bits) {
2706                 dev_warn(&spi->dev,
2707                          "setup: ignoring unsupported mode bits %x\n",
2708                          ugly_bits);
2709                 spi->mode &= ~ugly_bits;
2710                 bad_bits &= ~ugly_bits;
2711         }
2712         if (bad_bits) {
2713                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2714                         bad_bits);
2715                 return -EINVAL;
2716         }
2717
2718         if (!spi->bits_per_word)
2719                 spi->bits_per_word = 8;
2720
2721         status = __spi_validate_bits_per_word(spi->controller,
2722                                               spi->bits_per_word);
2723         if (status)
2724                 return status;
2725
2726         if (!spi->max_speed_hz)
2727                 spi->max_speed_hz = spi->controller->max_speed_hz;
2728
2729         if (spi->controller->setup)
2730                 status = spi->controller->setup(spi);
2731
2732         spi_set_cs(spi, false);
2733
2734         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2735                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2736                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2737                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2738                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2739                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2740                         spi->bits_per_word, spi->max_speed_hz,
2741                         status);
2742
2743         return status;
2744 }
2745 EXPORT_SYMBOL_GPL(spi_setup);
2746
2747 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2748 {
2749         struct spi_controller *ctlr = spi->controller;
2750         struct spi_transfer *xfer;
2751         int w_size;
2752
2753         if (list_empty(&message->transfers))
2754                 return -EINVAL;
2755
2756         /* Half-duplex links include original MicroWire, and ones with
2757          * only one data pin like SPI_3WIRE (switches direction) or where
2758          * either MOSI or MISO is missing.  They can also be caused by
2759          * software limitations.
2760          */
2761         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
2762             (spi->mode & SPI_3WIRE)) {
2763                 unsigned flags = ctlr->flags;
2764
2765                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2766                         if (xfer->rx_buf && xfer->tx_buf)
2767                                 return -EINVAL;
2768                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
2769                                 return -EINVAL;
2770                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
2771                                 return -EINVAL;
2772                 }
2773         }
2774
2775         /**
2776          * Set transfer bits_per_word and max speed as spi device default if
2777          * it is not set for this transfer.
2778          * Set transfer tx_nbits and rx_nbits as single transfer default
2779          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2780          */
2781         message->frame_length = 0;
2782         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2783                 message->frame_length += xfer->len;
2784                 if (!xfer->bits_per_word)
2785                         xfer->bits_per_word = spi->bits_per_word;
2786
2787                 if (!xfer->speed_hz)
2788                         xfer->speed_hz = spi->max_speed_hz;
2789                 if (!xfer->speed_hz)
2790                         xfer->speed_hz = ctlr->max_speed_hz;
2791
2792                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
2793                         xfer->speed_hz = ctlr->max_speed_hz;
2794
2795                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
2796                         return -EINVAL;
2797
2798                 /*
2799                  * SPI transfer length should be multiple of SPI word size
2800                  * where SPI word size should be power-of-two multiple
2801                  */
2802                 if (xfer->bits_per_word <= 8)
2803                         w_size = 1;
2804                 else if (xfer->bits_per_word <= 16)
2805                         w_size = 2;
2806                 else
2807                         w_size = 4;
2808
2809                 /* No partial transfers accepted */
2810                 if (xfer->len % w_size)
2811                         return -EINVAL;
2812
2813                 if (xfer->speed_hz && ctlr->min_speed_hz &&
2814                     xfer->speed_hz < ctlr->min_speed_hz)
2815                         return -EINVAL;
2816
2817                 if (xfer->tx_buf && !xfer->tx_nbits)
2818                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2819                 if (xfer->rx_buf && !xfer->rx_nbits)
2820                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2821                 /* check transfer tx/rx_nbits:
2822                  * 1. check the value matches one of single, dual and quad
2823                  * 2. check tx/rx_nbits match the mode in spi_device
2824                  */
2825                 if (xfer->tx_buf) {
2826                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2827                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2828                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2829                                 return -EINVAL;
2830                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2831                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2832                                 return -EINVAL;
2833                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2834                                 !(spi->mode & SPI_TX_QUAD))
2835                                 return -EINVAL;
2836                 }
2837                 /* check transfer rx_nbits */
2838                 if (xfer->rx_buf) {
2839                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2840                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2841                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2842                                 return -EINVAL;
2843                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2844                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2845                                 return -EINVAL;
2846                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2847                                 !(spi->mode & SPI_RX_QUAD))
2848                                 return -EINVAL;
2849                 }
2850         }
2851
2852         message->status = -EINPROGRESS;
2853
2854         return 0;
2855 }
2856
2857 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2858 {
2859         struct spi_controller *ctlr = spi->controller;
2860
2861         message->spi = spi;
2862
2863         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
2864         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2865
2866         trace_spi_message_submit(message);
2867
2868         return ctlr->transfer(spi, message);
2869 }
2870
2871 /**
2872  * spi_async - asynchronous SPI transfer
2873  * @spi: device with which data will be exchanged
2874  * @message: describes the data transfers, including completion callback
2875  * Context: any (irqs may be blocked, etc)
2876  *
2877  * This call may be used in_irq and other contexts which can't sleep,
2878  * as well as from task contexts which can sleep.
2879  *
2880  * The completion callback is invoked in a context which can't sleep.
2881  * Before that invocation, the value of message->status is undefined.
2882  * When the callback is issued, message->status holds either zero (to
2883  * indicate complete success) or a negative error code.  After that
2884  * callback returns, the driver which issued the transfer request may
2885  * deallocate the associated memory; it's no longer in use by any SPI
2886  * core or controller driver code.
2887  *
2888  * Note that although all messages to a spi_device are handled in
2889  * FIFO order, messages may go to different devices in other orders.
2890  * Some device might be higher priority, or have various "hard" access
2891  * time requirements, for example.
2892  *
2893  * On detection of any fault during the transfer, processing of
2894  * the entire message is aborted, and the device is deselected.
2895  * Until returning from the associated message completion callback,
2896  * no other spi_message queued to that device will be processed.
2897  * (This rule applies equally to all the synchronous transfer calls,
2898  * which are wrappers around this core asynchronous primitive.)
2899  *
2900  * Return: zero on success, else a negative error code.
2901  */
2902 int spi_async(struct spi_device *spi, struct spi_message *message)
2903 {
2904         struct spi_controller *ctlr = spi->controller;
2905         int ret;
2906         unsigned long flags;
2907
2908         ret = __spi_validate(spi, message);
2909         if (ret != 0)
2910                 return ret;
2911
2912         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2913
2914         if (ctlr->bus_lock_flag)
2915                 ret = -EBUSY;
2916         else
2917                 ret = __spi_async(spi, message);
2918
2919         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2920
2921         return ret;
2922 }
2923 EXPORT_SYMBOL_GPL(spi_async);
2924
2925 /**
2926  * spi_async_locked - version of spi_async with exclusive bus usage
2927  * @spi: device with which data will be exchanged
2928  * @message: describes the data transfers, including completion callback
2929  * Context: any (irqs may be blocked, etc)
2930  *
2931  * This call may be used in_irq and other contexts which can't sleep,
2932  * as well as from task contexts which can sleep.
2933  *
2934  * The completion callback is invoked in a context which can't sleep.
2935  * Before that invocation, the value of message->status is undefined.
2936  * When the callback is issued, message->status holds either zero (to
2937  * indicate complete success) or a negative error code.  After that
2938  * callback returns, the driver which issued the transfer request may
2939  * deallocate the associated memory; it's no longer in use by any SPI
2940  * core or controller driver code.
2941  *
2942  * Note that although all messages to a spi_device are handled in
2943  * FIFO order, messages may go to different devices in other orders.
2944  * Some device might be higher priority, or have various "hard" access
2945  * time requirements, for example.
2946  *
2947  * On detection of any fault during the transfer, processing of
2948  * the entire message is aborted, and the device is deselected.
2949  * Until returning from the associated message completion callback,
2950  * no other spi_message queued to that device will be processed.
2951  * (This rule applies equally to all the synchronous transfer calls,
2952  * which are wrappers around this core asynchronous primitive.)
2953  *
2954  * Return: zero on success, else a negative error code.
2955  */
2956 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2957 {
2958         struct spi_controller *ctlr = spi->controller;
2959         int ret;
2960         unsigned long flags;
2961
2962         ret = __spi_validate(spi, message);
2963         if (ret != 0)
2964                 return ret;
2965
2966         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2967
2968         ret = __spi_async(spi, message);
2969
2970         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2971
2972         return ret;
2973
2974 }
2975 EXPORT_SYMBOL_GPL(spi_async_locked);
2976
2977
2978 int spi_flash_read(struct spi_device *spi,
2979                    struct spi_flash_read_message *msg)
2980
2981 {
2982         struct spi_controller *master = spi->controller;
2983         struct device *rx_dev = NULL;
2984         int ret;
2985
2986         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2987              msg->addr_nbits == SPI_NBITS_DUAL) &&
2988             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2989                 return -EINVAL;
2990         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2991              msg->addr_nbits == SPI_NBITS_QUAD) &&
2992             !(spi->mode & SPI_TX_QUAD))
2993                 return -EINVAL;
2994         if (msg->data_nbits == SPI_NBITS_DUAL &&
2995             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2996                 return -EINVAL;
2997         if (msg->data_nbits == SPI_NBITS_QUAD &&
2998             !(spi->mode &  SPI_RX_QUAD))
2999                 return -EINVAL;
3000
3001         if (master->auto_runtime_pm) {
3002                 ret = pm_runtime_get_sync(master->dev.parent);
3003                 if (ret < 0) {
3004                         dev_err(&master->dev, "Failed to power device: %d\n",
3005                                 ret);
3006                         return ret;
3007                 }
3008         }
3009
3010         mutex_lock(&master->bus_lock_mutex);
3011         mutex_lock(&master->io_mutex);
3012         if (master->dma_rx && master->spi_flash_can_dma(spi, msg)) {
3013                 rx_dev = master->dma_rx->device->dev;
3014                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
3015                                   msg->buf, msg->len,
3016                                   DMA_FROM_DEVICE);
3017                 if (!ret)
3018                         msg->cur_msg_mapped = true;
3019         }
3020         ret = master->spi_flash_read(spi, msg);
3021         if (msg->cur_msg_mapped)
3022                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
3023                               DMA_FROM_DEVICE);
3024         mutex_unlock(&master->io_mutex);
3025         mutex_unlock(&master->bus_lock_mutex);
3026
3027         if (master->auto_runtime_pm)
3028                 pm_runtime_put(master->dev.parent);
3029
3030         return ret;
3031 }
3032 EXPORT_SYMBOL_GPL(spi_flash_read);
3033
3034 /*-------------------------------------------------------------------------*/
3035
3036 /* Utility methods for SPI protocol drivers, layered on
3037  * top of the core.  Some other utility methods are defined as
3038  * inline functions.
3039  */
3040
3041 static void spi_complete(void *arg)
3042 {
3043         complete(arg);
3044 }
3045
3046 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3047 {
3048         DECLARE_COMPLETION_ONSTACK(done);
3049         int status;
3050         struct spi_controller *ctlr = spi->controller;
3051         unsigned long flags;
3052
3053         status = __spi_validate(spi, message);
3054         if (status != 0)
3055                 return status;
3056
3057         message->complete = spi_complete;
3058         message->context = &done;
3059         message->spi = spi;
3060
3061         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3062         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3063
3064         /* If we're not using the legacy transfer method then we will
3065          * try to transfer in the calling context so special case.
3066          * This code would be less tricky if we could remove the
3067          * support for driver implemented message queues.
3068          */
3069         if (ctlr->transfer == spi_queued_transfer) {
3070                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3071
3072                 trace_spi_message_submit(message);
3073
3074                 status = __spi_queued_transfer(spi, message, false);
3075
3076                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3077         } else {
3078                 status = spi_async_locked(spi, message);
3079         }
3080
3081         if (status == 0) {
3082                 /* Push out the messages in the calling context if we
3083                  * can.
3084                  */
3085                 if (ctlr->transfer == spi_queued_transfer) {
3086                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3087                                                        spi_sync_immediate);
3088                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3089                                                        spi_sync_immediate);
3090                         __spi_pump_messages(ctlr, false);
3091                 }
3092
3093                 wait_for_completion(&done);
3094                 status = message->status;
3095         }
3096         message->context = NULL;
3097         return status;
3098 }
3099
3100 /**
3101  * spi_sync - blocking/synchronous SPI data transfers
3102  * @spi: device with which data will be exchanged
3103  * @message: describes the data transfers
3104  * Context: can sleep
3105  *
3106  * This call may only be used from a context that may sleep.  The sleep
3107  * is non-interruptible, and has no timeout.  Low-overhead controller
3108  * drivers may DMA directly into and out of the message buffers.
3109  *
3110  * Note that the SPI device's chip select is active during the message,
3111  * and then is normally disabled between messages.  Drivers for some
3112  * frequently-used devices may want to minimize costs of selecting a chip,
3113  * by leaving it selected in anticipation that the next message will go
3114  * to the same chip.  (That may increase power usage.)
3115  *
3116  * Also, the caller is guaranteeing that the memory associated with the
3117  * message will not be freed before this call returns.
3118  *
3119  * Return: zero on success, else a negative error code.
3120  */
3121 int spi_sync(struct spi_device *spi, struct spi_message *message)
3122 {
3123         int ret;
3124
3125         mutex_lock(&spi->controller->bus_lock_mutex);
3126         ret = __spi_sync(spi, message);
3127         mutex_unlock(&spi->controller->bus_lock_mutex);
3128
3129         return ret;
3130 }
3131 EXPORT_SYMBOL_GPL(spi_sync);
3132
3133 /**
3134  * spi_sync_locked - version of spi_sync with exclusive bus usage
3135  * @spi: device with which data will be exchanged
3136  * @message: describes the data transfers
3137  * Context: can sleep
3138  *
3139  * This call may only be used from a context that may sleep.  The sleep
3140  * is non-interruptible, and has no timeout.  Low-overhead controller
3141  * drivers may DMA directly into and out of the message buffers.
3142  *
3143  * This call should be used by drivers that require exclusive access to the
3144  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3145  * be released by a spi_bus_unlock call when the exclusive access is over.
3146  *
3147  * Return: zero on success, else a negative error code.
3148  */
3149 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3150 {
3151         return __spi_sync(spi, message);
3152 }
3153 EXPORT_SYMBOL_GPL(spi_sync_locked);
3154
3155 /**
3156  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3157  * @ctlr: SPI bus master that should be locked for exclusive bus access
3158  * Context: can sleep
3159  *
3160  * This call may only be used from a context that may sleep.  The sleep
3161  * is non-interruptible, and has no timeout.
3162  *
3163  * This call should be used by drivers that require exclusive access to the
3164  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3165  * exclusive access is over. Data transfer must be done by spi_sync_locked
3166  * and spi_async_locked calls when the SPI bus lock is held.
3167  *
3168  * Return: always zero.
3169  */
3170 int spi_bus_lock(struct spi_controller *ctlr)
3171 {
3172         unsigned long flags;
3173
3174         mutex_lock(&ctlr->bus_lock_mutex);
3175
3176         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3177         ctlr->bus_lock_flag = 1;
3178         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3179
3180         /* mutex remains locked until spi_bus_unlock is called */
3181
3182         return 0;
3183 }
3184 EXPORT_SYMBOL_GPL(spi_bus_lock);
3185
3186 /**
3187  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3188  * @ctlr: SPI bus master that was locked for exclusive bus access
3189  * Context: can sleep
3190  *
3191  * This call may only be used from a context that may sleep.  The sleep
3192  * is non-interruptible, and has no timeout.
3193  *
3194  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3195  * call.
3196  *
3197  * Return: always zero.
3198  */
3199 int spi_bus_unlock(struct spi_controller *ctlr)
3200 {
3201         ctlr->bus_lock_flag = 0;
3202
3203         mutex_unlock(&ctlr->bus_lock_mutex);
3204
3205         return 0;
3206 }
3207 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3208
3209 /* portable code must never pass more than 32 bytes */
3210 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3211
3212 static u8       *buf;
3213
3214 /**
3215  * spi_write_then_read - SPI synchronous write followed by read
3216  * @spi: device with which data will be exchanged
3217  * @txbuf: data to be written (need not be dma-safe)
3218  * @n_tx: size of txbuf, in bytes
3219  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3220  * @n_rx: size of rxbuf, in bytes
3221  * Context: can sleep
3222  *
3223  * This performs a half duplex MicroWire style transaction with the
3224  * device, sending txbuf and then reading rxbuf.  The return value
3225  * is zero for success, else a negative errno status code.
3226  * This call may only be used from a context that may sleep.
3227  *
3228  * Parameters to this routine are always copied using a small buffer;
3229  * portable code should never use this for more than 32 bytes.
3230  * Performance-sensitive or bulk transfer code should instead use
3231  * spi_{async,sync}() calls with dma-safe buffers.
3232  *
3233  * Return: zero on success, else a negative error code.
3234  */
3235 int spi_write_then_read(struct spi_device *spi,
3236                 const void *txbuf, unsigned n_tx,
3237                 void *rxbuf, unsigned n_rx)
3238 {
3239         static DEFINE_MUTEX(lock);
3240
3241         int                     status;
3242         struct spi_message      message;
3243         struct spi_transfer     x[2];
3244         u8                      *local_buf;
3245
3246         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3247          * copying here, (as a pure convenience thing), but we can
3248          * keep heap costs out of the hot path unless someone else is
3249          * using the pre-allocated buffer or the transfer is too large.
3250          */
3251         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3252                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3253                                     GFP_KERNEL | GFP_DMA);
3254                 if (!local_buf)
3255                         return -ENOMEM;
3256         } else {
3257                 local_buf = buf;
3258         }
3259
3260         spi_message_init(&message);
3261         memset(x, 0, sizeof(x));
3262         if (n_tx) {
3263                 x[0].len = n_tx;
3264                 spi_message_add_tail(&x[0], &message);
3265         }
3266         if (n_rx) {
3267                 x[1].len = n_rx;
3268                 spi_message_add_tail(&x[1], &message);
3269         }
3270
3271         memcpy(local_buf, txbuf, n_tx);
3272         x[0].tx_buf = local_buf;
3273         x[1].rx_buf = local_buf + n_tx;
3274
3275         /* do the i/o */
3276         status = spi_sync(spi, &message);
3277         if (status == 0)
3278                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3279
3280         if (x[0].tx_buf == buf)
3281                 mutex_unlock(&lock);
3282         else
3283                 kfree(local_buf);
3284
3285         return status;
3286 }
3287 EXPORT_SYMBOL_GPL(spi_write_then_read);
3288
3289 /*-------------------------------------------------------------------------*/
3290
3291 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3292 static int __spi_of_device_match(struct device *dev, void *data)
3293 {
3294         return dev->of_node == data;
3295 }
3296
3297 /* must call put_device() when done with returned spi_device device */
3298 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3299 {
3300         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3301                                                 __spi_of_device_match);
3302         return dev ? to_spi_device(dev) : NULL;
3303 }
3304
3305 static int __spi_of_controller_match(struct device *dev, const void *data)
3306 {
3307         return dev->of_node == data;
3308 }
3309
3310 /* the spi controllers are not using spi_bus, so we find it with another way */
3311 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3312 {
3313         struct device *dev;
3314
3315         dev = class_find_device(&spi_master_class, NULL, node,
3316                                 __spi_of_controller_match);
3317         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))