drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/pm_domain.h>
  25 #include <linux/property.h>
  26 #include <linux/export.h>
  27 #include <linux/sched/rt.h>
  28 #include <uapi/linux/sched/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/kthread.h>
  31 #include <linux/ioport.h>
  32 #include <linux/acpi.h>
  33 #include <linux/highmem.h>
  34 #include <linux/idr.h>
  35 #include <linux/platform_data/x86/apple.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/spi.h>
  39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  41
  42 #include "internals.h"
  43
  44 static DEFINE_IDR(spi_master_idr);
  45
  46 static void spidev_release(struct device *dev)
  47 {
  48         struct spi_device       *spi = to_spi_device(dev);
  49
  50         /* spi controllers may cleanup for released devices */
  51         if (spi->controller->cleanup)
  52                 spi->controller->cleanup(spi);
  53
  54         spi_controller_put(spi->controller);
  55         kfree(spi->driver_override);
  56         kfree(spi);
  57 }
  58
  59 static ssize_t
  60 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  61 {
  62         const struct spi_device *spi = to_spi_device(dev);
  63         int len;
  64
  65         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  66         if (len != -ENODEV)
  67                 return len;
  68
  69         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  70 }
  71 static DEVICE_ATTR_RO(modalias);
  72
  73 static ssize_t driver_override_store(struct device *dev,
  74                                      struct device_attribute *a,
  75                                      const char *buf, size_t count)
  76 {
  77         struct spi_device *spi = to_spi_device(dev);
  78         const char *end = memchr(buf, '\n', count);
  79         const size_t len = end ? end - buf : count;
  80         const char *driver_override, *old;
  81
  82         /* We need to keep extra room for a newline when displaying value */
  83         if (len >= (PAGE_SIZE - 1))
  84                 return -EINVAL;
  85
  86         driver_override = kstrndup(buf, len, GFP_KERNEL);
  87         if (!driver_override)
  88                 return -ENOMEM;
  89
  90         device_lock(dev);
  91         old = spi->driver_override;
  92         if (len) {
  93                 spi->driver_override = driver_override;
  94         } else {
  95                 /* Empty string, disable driver override */
  96                 spi->driver_override = NULL;
  97                 kfree(driver_override);
  98         }
  99         device_unlock(dev);
 100         kfree(old);
 101
 102         return count;
 103 }
 104
 105 static ssize_t driver_override_show(struct device *dev,
 106                                     struct device_attribute *a, char *buf)
 107 {
 108         const struct spi_device *spi = to_spi_device(dev);
 109         ssize_t len;
 110
 111         device_lock(dev);
 112         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 113         device_unlock(dev);
 114         return len;
 115 }
 116 static DEVICE_ATTR_RW(driver_override);
 117
 118 #define SPI_STATISTICS_ATTRS(field, file)                               \
 119 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 120                                              struct device_attribute *attr, \
 121                                              char *buf)                 \
 122 {                                                                       \
 123         struct spi_controller *ctlr = container_of(dev,                 \
 124                                          struct spi_controller, dev);   \
 125         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 126 }                                                                       \
 127 static struct device_attribute dev_attr_spi_controller_##field = {      \
 128         .attr = { .name = file, .mode = 0444 },                         \
 129         .show = spi_controller_##field##_show,                          \
 130 };                                                                      \
 131 static ssize_t spi_device_##field##_show(struct device *dev,            \
 132                                          struct device_attribute *attr, \
 133                                         char *buf)                      \
 134 {                                                                       \
 135         struct spi_device *spi = to_spi_device(dev);                    \
 136         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 137 }                                                                       \
 138 static struct device_attribute dev_attr_spi_device_##field = {          \
 139         .attr = { .name = file, .mode = 0444 },                         \
 140         .show = spi_device_##field##_show,                              \
 141 }
 142
 143 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 144 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 145                                             char *buf)                  \
 146 {                                                                       \
 147         unsigned long flags;                                            \
 148         ssize_t len;                                                    \
 149         spin_lock_irqsave(&stat->lock, flags);                          \
 150         len = sprintf(buf, format_string, stat->field);                 \
 151         spin_unlock_irqrestore(&stat->lock, flags);                     \
 152         return len;                                                     \
 153 }                                                                       \
 154 SPI_STATISTICS_ATTRS(name, file)
 155
 156 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 157         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 158                                  field, format_string)
 159
 160 SPI_STATISTICS_SHOW(messages, "%lu");
 161 SPI_STATISTICS_SHOW(transfers, "%lu");
 162 SPI_STATISTICS_SHOW(errors, "%lu");
 163 SPI_STATISTICS_SHOW(timedout, "%lu");
 164
 165 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 166 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 167 SPI_STATISTICS_SHOW(spi_async, "%lu");
 168
 169 SPI_STATISTICS_SHOW(bytes, "%llu");
 170 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 171 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 172
 173 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 174         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 175                                  "transfer_bytes_histo_" number,        \
 176                                  transfer_bytes_histo[index],  "%lu")
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 192 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 193 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 194
 195 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 196
 197 static struct attribute *spi_dev_attrs[] = {
 198         &dev_attr_modalias.attr,
 199         &dev_attr_driver_override.attr,
 200         NULL,
 201 };
 202
 203 static const struct attribute_group spi_dev_group = {
 204         .attrs  = spi_dev_attrs,
 205 };
 206
 207 static struct attribute *spi_device_statistics_attrs[] = {
 208         &dev_attr_spi_device_messages.attr,
 209         &dev_attr_spi_device_transfers.attr,
 210         &dev_attr_spi_device_errors.attr,
 211         &dev_attr_spi_device_timedout.attr,
 212         &dev_attr_spi_device_spi_sync.attr,
 213         &dev_attr_spi_device_spi_sync_immediate.attr,
 214         &dev_attr_spi_device_spi_async.attr,
 215         &dev_attr_spi_device_bytes.attr,
 216         &dev_attr_spi_device_bytes_rx.attr,
 217         &dev_attr_spi_device_bytes_tx.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 232         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 233         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 234         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 235         &dev_attr_spi_device_transfers_split_maxsize.attr,
 236         NULL,
 237 };
 238
 239 static const struct attribute_group spi_device_statistics_group = {
 240         .name  = "statistics",
 241         .attrs  = spi_device_statistics_attrs,
 242 };
 243
 244 static const struct attribute_group *spi_dev_groups[] = {
 245         &spi_dev_group,
 246         &spi_device_statistics_group,
 247         NULL,
 248 };
 249
 250 static struct attribute *spi_controller_statistics_attrs[] = {
 251         &dev_attr_spi_controller_messages.attr,
 252         &dev_attr_spi_controller_transfers.attr,
 253         &dev_attr_spi_controller_errors.attr,
 254         &dev_attr_spi_controller_timedout.attr,
 255         &dev_attr_spi_controller_spi_sync.attr,
 256         &dev_attr_spi_controller_spi_sync_immediate.attr,
 257         &dev_attr_spi_controller_spi_async.attr,
 258         &dev_attr_spi_controller_bytes.attr,
 259         &dev_attr_spi_controller_bytes_rx.attr,
 260         &dev_attr_spi_controller_bytes_tx.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 275         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 276         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 277         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 278         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 279         NULL,
 280 };
 281
 282 static const struct attribute_group spi_controller_statistics_group = {
 283         .name  = "statistics",
 284         .attrs  = spi_controller_statistics_attrs,
 285 };
 286
 287 static const struct attribute_group *spi_master_groups[] = {
 288         &spi_controller_statistics_group,
 289         NULL,
 290 };
 291
 292 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 293                                        struct spi_transfer *xfer,
 294                                        struct spi_controller *ctlr)
 295 {
 296         unsigned long flags;
 297         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 298
 299         if (l2len < 0)
 300                 l2len = 0;
 301
 302         spin_lock_irqsave(&stats->lock, flags);
 303
 304         stats->transfers++;
 305         stats->transfer_bytes_histo[l2len]++;
 306
 307         stats->bytes += xfer->len;
 308         if ((xfer->tx_buf) &&
 309             (xfer->tx_buf != ctlr->dummy_tx))
 310                 stats->bytes_tx += xfer->len;
 311         if ((xfer->rx_buf) &&
 312             (xfer->rx_buf != ctlr->dummy_rx))
 313                 stats->bytes_rx += xfer->len;
 314
 315         spin_unlock_irqrestore(&stats->lock, flags);
 316 }
 317 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 318
 319 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 320  * and the sysfs version makes coldplug work too.
 321  */
 322
 323 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 324                                                 const struct spi_device *sdev)
 325 {
 326         while (id->name[0]) {
 327                 if (!strcmp(sdev->modalias, id->name))
 328                         return id;
 329                 id++;
 330         }
 331         return NULL;
 332 }
 333
 334 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 335 {
 336         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 337
 338         return spi_match_id(sdrv->id_table, sdev);
 339 }
 340 EXPORT_SYMBOL_GPL(spi_get_device_id);
 341
 342 static int spi_match_device(struct device *dev, struct device_driver *drv)
 343 {
 344         const struct spi_device *spi = to_spi_device(dev);
 345         const struct spi_driver *sdrv = to_spi_driver(drv);
 346
 347         /* Check override first, and if set, only use the named driver */
 348         if (spi->driver_override)
 349                 return strcmp(spi->driver_override, drv->name) == 0;
 350
 351         /* Attempt an OF style match */
 352         if (of_driver_match_device(dev, drv))
 353                 return 1;
 354
 355         /* Then try ACPI */
 356         if (acpi_driver_match_device(dev, drv))
 357                 return 1;
 358
 359         if (sdrv->id_table)
 360                 return !!spi_match_id(sdrv->id_table, spi);
 361
 362         return strcmp(spi->modalias, drv->name) == 0;
 363 }
 364
 365 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 366 {
 367         const struct spi_device         *spi = to_spi_device(dev);
 368         int rc;
 369
 370         rc = acpi_device_uevent_modalias(dev, env);
 371         if (rc != -ENODEV)
 372                 return rc;
 373
 374         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 375 }
 376
 377 struct bus_type spi_bus_type = {
 378         .name           = "spi",
 379         .dev_groups     = spi_dev_groups,
 380         .match          = spi_match_device,
 381         .uevent         = spi_uevent,
 382 };
 383 EXPORT_SYMBOL_GPL(spi_bus_type);
 384
 385
 386 static int spi_drv_probe(struct device *dev)
 387 {
 388         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 389         struct spi_device               *spi = to_spi_device(dev);
 390         int ret;
 391
 392         ret = of_clk_set_defaults(dev->of_node, false);
 393         if (ret)
 394                 return ret;
 395
 396         if (dev->of_node) {
 397                 spi->irq = of_irq_get(dev->of_node, 0);
 398                 if (spi->irq == -EPROBE_DEFER)
 399                         return -EPROBE_DEFER;
 400                 if (spi->irq < 0)
 401                         spi->irq = 0;
 402         }
 403
 404         ret = dev_pm_domain_attach(dev, true);
 405         if (ret)
 406                 return ret;
 407
 408         ret = sdrv->probe(spi);
 409         if (ret)
 410                 dev_pm_domain_detach(dev, true);
 411
 412         return ret;
 413 }
 414
 415 static int spi_drv_remove(struct device *dev)
 416 {
 417         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 418         int ret;
 419
 420         ret = sdrv->remove(to_spi_device(dev));
 421         dev_pm_domain_detach(dev, true);
 422
 423         return ret;
 424 }
 425
 426 static void spi_drv_shutdown(struct device *dev)
 427 {
 428         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 429
 430         sdrv->shutdown(to_spi_device(dev));
 431 }
 432
 433 /**
 434  * __spi_register_driver - register a SPI driver
 435  * @owner: owner module of the driver to register
 436  * @sdrv: the driver to register
 437  * Context: can sleep
 438  *
 439  * Return: zero on success, else a negative error code.
 440  */
 441 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 442 {
 443         sdrv->driver.owner = owner;
 444         sdrv->driver.bus = &spi_bus_type;
 445         if (sdrv->probe)
 446                 sdrv->driver.probe = spi_drv_probe;
 447         if (sdrv->remove)
 448                 sdrv->driver.remove = spi_drv_remove;
 449         if (sdrv->shutdown)
 450                 sdrv->driver.shutdown = spi_drv_shutdown;
 451         return driver_register(&sdrv->driver);
 452 }
 453 EXPORT_SYMBOL_GPL(__spi_register_driver);
 454
 455 /*-------------------------------------------------------------------------*/
 456
 457 /* SPI devices should normally not be created by SPI device drivers; that
 458  * would make them board-specific.  Similarly with SPI controller drivers.
 459  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 460  * with other readonly (flashable) information about mainboard devices.
 461  */
 462
 463 struct boardinfo {
 464         struct list_head        list;
 465         struct spi_board_info   board_info;
 466 };
 467
 468 static LIST_HEAD(board_list);
 469 static LIST_HEAD(spi_controller_list);
 470
 471 /*
 472  * Used to protect add/del operation for board_info list and
 473  * spi_controller list, and their matching process
 474  * also used to protect object of type struct idr
 475  */
 476 static DEFINE_MUTEX(board_lock);
 477
 478 /**
 479  * spi_alloc_device - Allocate a new SPI device
 480  * @ctlr: Controller to which device is connected
 481  * Context: can sleep
 482  *
 483  * Allows a driver to allocate and initialize a spi_device without
 484  * registering it immediately.  This allows a driver to directly
 485  * fill the spi_device with device parameters before calling
 486  * spi_add_device() on it.
 487  *
 488  * Caller is responsible to call spi_add_device() on the returned
 489  * spi_device structure to add it to the SPI controller.  If the caller
 490  * needs to discard the spi_device without adding it, then it should
 491  * call spi_dev_put() on it.
 492  *
 493  * Return: a pointer to the new device, or NULL.
 494  */
 495 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 496 {
 497         struct spi_device       *spi;
 498
 499         if (!spi_controller_get(ctlr))
 500                 return NULL;
 501
 502         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 503         if (!spi) {
 504                 spi_controller_put(ctlr);
 505                 return NULL;
 506         }
 507
 508         spi->master = spi->controller = ctlr;
 509         spi->dev.parent = &ctlr->dev;
 510         spi->dev.bus = &spi_bus_type;
 511         spi->dev.release = spidev_release;
 512         spi->cs_gpio = -ENOENT;
 513         spi->mode = ctlr->buswidth_override_bits;
 514
 515         spin_lock_init(&spi->statistics.lock);
 516
 517         device_initialize(&spi->dev);
 518         return spi;
 519 }
 520 EXPORT_SYMBOL_GPL(spi_alloc_device);
 521
 522 static void spi_dev_set_name(struct spi_device *spi)
 523 {
 524         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 525
 526         if (adev) {
 527                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 528                 return;
 529         }
 530
 531         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 532                      spi->chip_select);
 533 }
 534
 535 static int spi_dev_check(struct device *dev, void *data)
 536 {
 537         struct spi_device *spi = to_spi_device(dev);
 538         struct spi_device *new_spi = data;
 539
 540         if (spi->controller == new_spi->controller &&
 541             spi->chip_select == new_spi->chip_select)
 542                 return -EBUSY;
 543         return 0;
 544 }
 545
 546 /**
 547  * spi_add_device - Add spi_device allocated with spi_alloc_device
 548  * @spi: spi_device to register
 549  *
 550  * Companion function to spi_alloc_device.  Devices allocated with
 551  * spi_alloc_device can be added onto the spi bus with this function.
 552  *
 553  * Return: 0 on success; negative errno on failure
 554  */
 555 int spi_add_device(struct spi_device *spi)
 556 {
 557         static DEFINE_MUTEX(spi_add_lock);
 558         struct spi_controller *ctlr = spi->controller;
 559         struct device *dev = ctlr->dev.parent;
 560         int status;
 561
 562         /* Chipselects are numbered 0..max; validate. */
 563         if (spi->chip_select >= ctlr->num_chipselect) {
 564                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 565                         ctlr->num_chipselect);
 566                 return -EINVAL;
 567         }
 568
 569         /* Set the bus ID string */
 570         spi_dev_set_name(spi);
 571
 572         /* We need to make sure there's no other device with this
 573          * chipselect **BEFORE** we call setup(), else we'll trash
 574          * its configuration.  Lock against concurrent add() calls.
 575          */
 576         mutex_lock(&spi_add_lock);
 577
 578         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 579         if (status) {
 580                 dev_err(dev, "chipselect %d already in use\n",
 581                                 spi->chip_select);
 582                 goto done;
 583         }
 584
 585         /* Descriptors take precedence */
 586         if (ctlr->cs_gpiods)
 587                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 588         else if (ctlr->cs_gpios)
 589                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 590
 591         /* Drivers may modify this initial i/o setup, but will
 592          * normally rely on the device being setup.  Devices
 593          * using SPI_CS_HIGH can't coexist well otherwise...
 594          */
 595         status = spi_setup(spi);
 596         if (status < 0) {
 597                 dev_err(dev, "can't setup %s, status %d\n",
 598                                 dev_name(&spi->dev), status);
 599                 goto done;
 600         }
 601
 602         /* Device may be bound to an active driver when this returns */
 603         status = device_add(&spi->dev);
 604         if (status < 0)
 605                 dev_err(dev, "can't add %s, status %d\n",
 606                                 dev_name(&spi->dev), status);
 607         else
 608                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 609
 610 done:
 611         mutex_unlock(&spi_add_lock);
 612         return status;
 613 }
 614 EXPORT_SYMBOL_GPL(spi_add_device);
 615
 616 /**
 617  * spi_new_device - instantiate one new SPI device
 618  * @ctlr: Controller to which device is connected
 619  * @chip: Describes the SPI device
 620  * Context: can sleep
 621  *
 622  * On typical mainboards, this is purely internal; and it's not needed
 623  * after board init creates the hard-wired devices.  Some development
 624  * platforms may not be able to use spi_register_board_info though, and
 625  * this is exported so that for example a USB or parport based adapter
 626  * driver could add devices (which it would learn about out-of-band).
 627  *
 628  * Return: the new device, or NULL.
 629  */
 630 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 631                                   struct spi_board_info *chip)
 632 {
 633         struct spi_device       *proxy;
 634         int                     status;
 635
 636         /* NOTE:  caller did any chip->bus_num checks necessary.
 637          *
 638          * Also, unless we change the return value convention to use
 639          * error-or-pointer (not NULL-or-pointer), troubleshootability
 640          * suggests syslogged diagnostics are best here (ugh).
 641          */
 642
 643         proxy = spi_alloc_device(ctlr);
 644         if (!proxy)
 645                 return NULL;
 646
 647         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 648
 649         proxy->chip_select = chip->chip_select;
 650         proxy->max_speed_hz = chip->max_speed_hz;
 651         proxy->mode = chip->mode;
 652         proxy->irq = chip->irq;
 653         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 654         proxy->dev.platform_data = (void *) chip->platform_data;
 655         proxy->controller_data = chip->controller_data;
 656         proxy->controller_state = NULL;
 657
 658         if (chip->properties) {
 659                 status = device_add_properties(&proxy->dev, chip->properties);
 660                 if (status) {
 661                         dev_err(&ctlr->dev,
 662                                 "failed to add properties to '%s': %d\n",
 663                                 chip->modalias, status);
 664                         goto err_dev_put;
 665                 }
 666         }
 667
 668         status = spi_add_device(proxy);
 669         if (status < 0)
 670                 goto err_remove_props;
 671
 672         return proxy;
 673
 674 err_remove_props:
 675         if (chip->properties)
 676                 device_remove_properties(&proxy->dev);
 677 err_dev_put:
 678         spi_dev_put(proxy);
 679         return NULL;
 680 }
 681 EXPORT_SYMBOL_GPL(spi_new_device);
 682
 683 /**
 684  * spi_unregister_device - unregister a single SPI device
 685  * @spi: spi_device to unregister
 686  *
 687  * Start making the passed SPI device vanish. Normally this would be handled
 688  * by spi_unregister_controller().
 689  */
 690 void spi_unregister_device(struct spi_device *spi)
 691 {
 692         if (!spi)
 693                 return;
 694
 695         if (spi->dev.of_node) {
 696                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 697                 of_node_put(spi->dev.of_node);
 698         }
 699         if (ACPI_COMPANION(&spi->dev))
 700                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 701         device_unregister(&spi->dev);
 702 }
 703 EXPORT_SYMBOL_GPL(spi_unregister_device);
 704
 705 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 706                                               struct spi_board_info *bi)
 707 {
 708         struct spi_device *dev;
 709
 710         if (ctlr->bus_num != bi->bus_num)
 711                 return;
 712
 713         dev = spi_new_device(ctlr, bi);
 714         if (!dev)
 715                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 716                         bi->modalias);
 717 }
 718
 719 /**
 720  * spi_register_board_info - register SPI devices for a given board
 721  * @info: array of chip descriptors
 722  * @n: how many descriptors are provided
 723  * Context: can sleep
 724  *
 725  * Board-specific early init code calls this (probably during arch_initcall)
 726  * with segments of the SPI device table.  Any device nodes are created later,
 727  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 728  * this table of devices forever, so that reloading a controller driver will
 729  * not make Linux forget about these hard-wired devices.
 730  *
 731  * Other code can also call this, e.g. a particular add-on board might provide
 732  * SPI devices through its expansion connector, so code initializing that board
 733  * would naturally declare its SPI devices.
 734  *
 735  * The board info passed can safely be __initdata ... but be careful of
 736  * any embedded pointers (platform_data, etc), they're copied as-is.
 737  * Device properties are deep-copied though.
 738  *
 739  * Return: zero on success, else a negative error code.
 740  */
 741 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 742 {
 743         struct boardinfo *bi;
 744         int i;
 745
 746         if (!n)
 747                 return 0;
 748
 749         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 750         if (!bi)
 751                 return -ENOMEM;
 752
 753         for (i = 0; i < n; i++, bi++, info++) {
 754                 struct spi_controller *ctlr;
 755
 756                 memcpy(&bi->board_info, info, sizeof(*info));
 757                 if (info->properties) {
 758                         bi->board_info.properties =
 759                                         property_entries_dup(info->properties);
 760                         if (IS_ERR(bi->board_info.properties))
 761                                 return PTR_ERR(bi->board_info.properties);
 762                 }
 763
 764                 mutex_lock(&board_lock);
 765                 list_add_tail(&bi->list, &board_list);
 766                 list_for_each_entry(ctlr, &spi_controller_list, list)
 767                         spi_match_controller_to_boardinfo(ctlr,
 768                                                           &bi->board_info);
 769                 mutex_unlock(&board_lock);
 770         }
 771
 772         return 0;
 773 }
 774
 775 /*-------------------------------------------------------------------------*/
 776
 777 static void spi_set_cs(struct spi_device *spi, bool enable)
 778 {
 779         bool enable1 = enable;
 780
 781         if (!spi->controller->set_cs_timing) {
 782                 if (enable1)
 783                         spi_delay_exec(&spi->controller->cs_setup, NULL);
 784                 else
 785                         spi_delay_exec(&spi->controller->cs_hold, NULL);
 786         }
 787
 788         if (spi->mode & SPI_CS_HIGH)
 789                 enable = !enable;
 790
 791         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 792                 /*
 793                  * Honour the SPI_NO_CS flag and invert the enable line, as
 794                  * active low is default for SPI. Execution paths that handle
 795                  * polarity inversion in gpiolib (such as device tree) will
 796                  * enforce active high using the SPI_CS_HIGH resulting in a
 797                  * double inversion through the code above.
 798                  */
 799                 if (!(spi->mode & SPI_NO_CS)) {
 800                         if (spi->cs_gpiod)
 801                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 802                                                          !enable);
 803                         else
 804                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 805                 }
 806                 /* Some SPI masters need both GPIO CS & slave_select */
 807                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 808                     spi->controller->set_cs)
 809                         spi->controller->set_cs(spi, !enable);
 810         } else if (spi->controller->set_cs) {
 811                 spi->controller->set_cs(spi, !enable);
 812         }
 813
 814         if (!spi->controller->set_cs_timing) {
 815                 if (!enable1)
 816                         spi_delay_exec(&spi->controller->cs_inactive, NULL);
 817         }
 818 }
 819
 820 #ifdef CONFIG_HAS_DMA
 821 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 822                 struct sg_table *sgt, void *buf, size_t len,
 823                 enum dma_data_direction dir)
 824 {
 825         const bool vmalloced_buf = is_vmalloc_addr(buf);
 826         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 827 #ifdef CONFIG_HIGHMEM
 828         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 829                                 (unsigned long)buf < (PKMAP_BASE +
 830                                         (LAST_PKMAP * PAGE_SIZE)));
 831 #else
 832         const bool kmap_buf = false;
 833 #endif
 834         int desc_len;
 835         int sgs;
 836         struct page *vm_page;
 837         struct scatterlist *sg;
 838         void *sg_buf;
 839         size_t min;
 840         int i, ret;
 841
 842         if (vmalloced_buf || kmap_buf) {
 843                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 844                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 845         } else if (virt_addr_valid(buf)) {
 846                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 847                 sgs = DIV_ROUND_UP(len, desc_len);
 848         } else {
 849                 return -EINVAL;
 850         }
 851
 852         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 853         if (ret != 0)
 854                 return ret;
 855
 856         sg = &sgt->sgl[0];
 857         for (i = 0; i < sgs; i++) {
 858
 859                 if (vmalloced_buf || kmap_buf) {
 860                         /*
 861                          * Next scatterlist entry size is the minimum between
 862                          * the desc_len and the remaining buffer length that
 863                          * fits in a page.
 864                          */
 865                         min = min_t(size_t, desc_len,
 866                                     min_t(size_t, len,
 867                                           PAGE_SIZE - offset_in_page(buf)));
 868                         if (vmalloced_buf)
 869                                 vm_page = vmalloc_to_page(buf);
 870                         else
 871                                 vm_page = kmap_to_page(buf);
 872                         if (!vm_page) {
 873                                 sg_free_table(sgt);
 874                                 return -ENOMEM;
 875                         }
 876                         sg_set_page(sg, vm_page,
 877                                     min, offset_in_page(buf));
 878                 } else {
 879                         min = min_t(size_t, len, desc_len);
 880                         sg_buf = buf;
 881                         sg_set_buf(sg, sg_buf, min);
 882                 }
 883
 884                 buf += min;
 885                 len -= min;
 886                 sg = sg_next(sg);
 887         }
 888
 889         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 890         if (!ret)
 891                 ret = -ENOMEM;
 892         if (ret < 0) {
 893                 sg_free_table(sgt);
 894                 return ret;
 895         }
 896
 897         sgt->nents = ret;
 898
 899         return 0;
 900 }
 901
 902 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 903                    struct sg_table *sgt, enum dma_data_direction dir)
 904 {
 905         if (sgt->orig_nents) {
 906                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 907                 sg_free_table(sgt);
 908         }
 909 }
 910
 911 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 912 {
 913         struct device *tx_dev, *rx_dev;
 914         struct spi_transfer *xfer;
 915         int ret;
 916
 917         if (!ctlr->can_dma)
 918                 return 0;
 919
 920         if (ctlr->dma_tx)
 921                 tx_dev = ctlr->dma_tx->device->dev;
 922         else
 923                 tx_dev = ctlr->dev.parent;
 924
 925         if (ctlr->dma_rx)
 926                 rx_dev = ctlr->dma_rx->device->dev;
 927         else
 928                 rx_dev = ctlr->dev.parent;
 929
 930         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 931                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 932                         continue;
 933
 934                 if (xfer->tx_buf != NULL) {
 935                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 936                                           (void *)xfer->tx_buf, xfer->len,
 937                                           DMA_TO_DEVICE);
 938                         if (ret != 0)
 939                                 return ret;
 940                 }
 941
 942                 if (xfer->rx_buf != NULL) {
 943                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 944                                           xfer->rx_buf, xfer->len,
 945                                           DMA_FROM_DEVICE);
 946                         if (ret != 0) {
 947                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 948                                               DMA_TO_DEVICE);
 949                                 return ret;
 950                         }
 951                 }
 952         }
 953
 954         ctlr->cur_msg_mapped = true;
 955
 956         return 0;
 957 }
 958
 959 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 960 {
 961         struct spi_transfer *xfer;
 962         struct device *tx_dev, *rx_dev;
 963
 964         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 965                 return 0;
 966
 967         if (ctlr->dma_tx)
 968                 tx_dev = ctlr->dma_tx->device->dev;
 969         else
 970                 tx_dev = ctlr->dev.parent;
 971
 972         if (ctlr->dma_rx)
 973                 rx_dev = ctlr->dma_rx->device->dev;
 974         else
 975                 rx_dev = ctlr->dev.parent;
 976
 977         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 978                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 979                         continue;
 980
 981                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 982                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 983         }
 984
 985         return 0;
 986 }
 987 #else /* !CONFIG_HAS_DMA */
 988 static inline int __spi_map_msg(struct spi_controller *ctlr,
 989                                 struct spi_message *msg)
 990 {
 991         return 0;
 992 }
 993
 994 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 995                                   struct spi_message *msg)
 996 {
 997         return 0;
 998 }
 999 #endif /* !CONFIG_HAS_DMA */
1000
1001 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1002                                 struct spi_message *msg)
1003 {
1004         struct spi_transfer *xfer;
1005
1006         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1007                 /*
1008                  * Restore the original value of tx_buf or rx_buf if they are
1009                  * NULL.
1010                  */
1011                 if (xfer->tx_buf == ctlr->dummy_tx)
1012                         xfer->tx_buf = NULL;
1013                 if (xfer->rx_buf == ctlr->dummy_rx)
1014                         xfer->rx_buf = NULL;
1015         }
1016
1017         return __spi_unmap_msg(ctlr, msg);
1018 }
1019
1020 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1021 {
1022         struct spi_transfer *xfer;
1023         void *tmp;
1024         unsigned int max_tx, max_rx;
1025
1026         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
1027                 max_tx = 0;
1028                 max_rx = 0;
1029
1030                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1031                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1032                             !xfer->tx_buf)
1033                                 max_tx = max(xfer->len, max_tx);
1034                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1035                             !xfer->rx_buf)
1036                                 max_rx = max(xfer->len, max_rx);
1037                 }
1038
1039                 if (max_tx) {
1040                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1041                                        GFP_KERNEL | GFP_DMA);
1042                         if (!tmp)
1043                                 return -ENOMEM;
1044                         ctlr->dummy_tx = tmp;
1045                         memset(tmp, 0, max_tx);
1046                 }
1047
1048                 if (max_rx) {
1049                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1050                                        GFP_KERNEL | GFP_DMA);
1051                         if (!tmp)
1052                                 return -ENOMEM;
1053                         ctlr->dummy_rx = tmp;
1054                 }
1055
1056                 if (max_tx || max_rx) {
1057                         list_for_each_entry(xfer, &msg->transfers,
1058                                             transfer_list) {
1059                                 if (!xfer->len)
1060                                         continue;
1061                                 if (!xfer->tx_buf)
1062                                         xfer->tx_buf = ctlr->dummy_tx;
1063                                 if (!xfer->rx_buf)
1064                                         xfer->rx_buf = ctlr->dummy_rx;
1065                         }
1066                 }
1067         }
1068
1069         return __spi_map_msg(ctlr, msg);
1070 }
1071
1072 static int spi_transfer_wait(struct spi_controller *ctlr,
1073                              struct spi_message *msg,
1074                              struct spi_transfer *xfer)
1075 {
1076         struct spi_statistics *statm = &ctlr->statistics;
1077         struct spi_statistics *stats = &msg->spi->statistics;
1078         unsigned long long ms;
1079
1080         if (spi_controller_is_slave(ctlr)) {
1081                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1082                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1083                         return -EINTR;
1084                 }
1085         } else {
1086                 ms = 8LL * 1000LL * xfer->len;
1087                 do_div(ms, xfer->speed_hz);
1088                 ms += ms + 200; /* some tolerance */
1089
1090                 if (ms > UINT_MAX)
1091                         ms = UINT_MAX;
1092
1093                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1094                                                  msecs_to_jiffies(ms));
1095
1096                 if (ms == 0) {
1097                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1098                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1099                         dev_err(&msg->spi->dev,
1100                                 "SPI transfer timed out\n");
1101                         return -ETIMEDOUT;
1102                 }
1103         }
1104
1105         return 0;
1106 }
1107
1108 static void _spi_transfer_delay_ns(u32 ns)
1109 {
1110         if (!ns)
1111                 return;
1112         if (ns <= 1000) {
1113                 ndelay(ns);
1114         } else {
1115                 u32 us = DIV_ROUND_UP(ns, 1000);
1116
1117                 if (us <= 10)
1118                         udelay(us);
1119                 else
1120                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1121         }
1122 }
1123
1124 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1125 {
1126         u32 delay = _delay->value;
1127         u32 unit = _delay->unit;
1128         u32 hz;
1129
1130         if (!delay)
1131                 return 0;
1132
1133         switch (unit) {
1134         case SPI_DELAY_UNIT_USECS:
1135                 delay *= 1000;
1136                 break;
1137         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1138                 break;
1139         case SPI_DELAY_UNIT_SCK:
1140                 /* clock cycles need to be obtained from spi_transfer */
1141                 if (!xfer)
1142                         return -EINVAL;
1143                 /* if there is no effective speed know, then approximate
1144                  * by underestimating with half the requested hz
1145                  */
1146                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1147                 if (!hz)
1148                         return -EINVAL;
1149                 delay *= DIV_ROUND_UP(1000000000, hz);
1150                 break;
1151         default:
1152                 return -EINVAL;
1153         }
1154
1155         return delay;
1156 }
1157 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1158
1159 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1160 {
1161         int delay;
1162
1163         if (!_delay)
1164                 return -EINVAL;
1165
1166         delay = spi_delay_to_ns(_delay, xfer);
1167         if (delay < 0)
1168                 return delay;
1169
1170         _spi_transfer_delay_ns(delay);
1171
1172         return 0;
1173 }
1174 EXPORT_SYMBOL_GPL(spi_delay_exec);
1175
1176 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1177                                           struct spi_transfer *xfer)
1178 {
1179         u32 delay = xfer->cs_change_delay.value;
1180         u32 unit = xfer->cs_change_delay.unit;
1181         int ret;
1182
1183         /* return early on "fast" mode - for everything but USECS */
1184         if (!delay) {
1185                 if (unit == SPI_DELAY_UNIT_USECS)
1186                         _spi_transfer_delay_ns(10000);
1187                 return;
1188         }
1189
1190         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1191         if (ret) {
1192                 dev_err_once(&msg->spi->dev,
1193                              "Use of unsupported delay unit %i, using default of 10us\n",
1194                              unit);
1195                 _spi_transfer_delay_ns(10000);
1196         }
1197 }
1198
1199 /*
1200  * spi_transfer_one_message - Default implementation of transfer_one_message()
1201  *
1202  * This is a standard implementation of transfer_one_message() for
1203  * drivers which implement a transfer_one() operation.  It provides
1204  * standard handling of delays and chip select management.
1205  */
1206 static int spi_transfer_one_message(struct spi_controller *ctlr,
1207                                     struct spi_message *msg)
1208 {
1209         struct spi_transfer *xfer;
1210         bool keep_cs = false;
1211         int ret = 0;
1212         struct spi_statistics *statm = &ctlr->statistics;
1213         struct spi_statistics *stats = &msg->spi->statistics;
1214
1215         spi_set_cs(msg->spi, true);
1216
1217         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1218         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1219
1220         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1221                 trace_spi_transfer_start(msg, xfer);
1222
1223                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1224                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1225
1226                 if (!ctlr->ptp_sts_supported) {
1227                         xfer->ptp_sts_word_pre = 0;
1228                         ptp_read_system_prets(xfer->ptp_sts);
1229                 }
1230
1231                 if (xfer->tx_buf || xfer->rx_buf) {
1232                         reinit_completion(&ctlr->xfer_completion);
1233
1234                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1235                         if (ret < 0) {
1236                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1237                                                                errors);
1238                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1239                                                                errors);
1240                                 dev_err(&msg->spi->dev,
1241                                         "SPI transfer failed: %d\n", ret);
1242                                 goto out;
1243                         }
1244
1245                         if (ret > 0) {
1246                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1247                                 if (ret < 0)
1248                                         msg->status = ret;
1249                         }
1250                 } else {
1251                         if (xfer->len)
1252                                 dev_err(&msg->spi->dev,
1253                                         "Bufferless transfer has length %u\n",
1254                                         xfer->len);
1255                 }
1256
1257                 if (!ctlr->ptp_sts_supported) {
1258                         ptp_read_system_postts(xfer->ptp_sts);
1259                         xfer->ptp_sts_word_post = xfer->len;
1260                 }
1261
1262                 trace_spi_transfer_stop(msg, xfer);
1263
1264                 if (msg->status != -EINPROGRESS)
1265                         goto out;
1266
1267                 spi_transfer_delay_exec(xfer);
1268
1269                 if (xfer->cs_change) {
1270                         if (list_is_last(&xfer->transfer_list,
1271                                          &msg->transfers)) {
1272                                 keep_cs = true;
1273                         } else {
1274                                 spi_set_cs(msg->spi, false);
1275                                 _spi_transfer_cs_change_delay(msg, xfer);
1276                                 spi_set_cs(msg->spi, true);
1277                         }
1278                 }
1279
1280                 msg->actual_length += xfer->len;
1281         }
1282
1283 out:
1284         if (ret != 0 || !keep_cs)
1285                 spi_set_cs(msg->spi, false);
1286
1287         if (msg->status == -EINPROGRESS)
1288                 msg->status = ret;
1289
1290         if (msg->status && ctlr->handle_err)
1291                 ctlr->handle_err(ctlr, msg);
1292
1293         spi_res_release(ctlr, msg);
1294
1295         spi_finalize_current_message(ctlr);
1296
1297         return ret;
1298 }
1299
1300 /**
1301  * spi_finalize_current_transfer - report completion of a transfer
1302  * @ctlr: the controller reporting completion
1303  *
1304  * Called by SPI drivers using the core transfer_one_message()
1305  * implementation to notify it that the current interrupt driven
1306  * transfer has finished and the next one may be scheduled.
1307  */
1308 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1309 {
1310         complete(&ctlr->xfer_completion);
1311 }
1312 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1313
1314 /**
1315  * __spi_pump_messages - function which processes spi message queue
1316  * @ctlr: controller to process queue for
1317  * @in_kthread: true if we are in the context of the message pump thread
1318  *
1319  * This function checks if there is any spi message in the queue that
1320  * needs processing and if so call out to the driver to initialize hardware
1321  * and transfer each message.
1322  *
1323  * Note that it is called both from the kthread itself and also from
1324  * inside spi_sync(); the queue extraction handling at the top of the
1325  * function should deal with this safely.
1326  */
1327 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1328 {
1329         struct spi_transfer *xfer;
1330         struct spi_message *msg;
1331         bool was_busy = false;
1332         unsigned long flags;
1333         int ret;
1334
1335         /* Lock queue */
1336         spin_lock_irqsave(&ctlr->queue_lock, flags);
1337
1338         /* Make sure we are not already running a message */
1339         if (ctlr->cur_msg) {
1340                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1341                 return;
1342         }
1343
1344         /* If another context is idling the device then defer */
1345         if (ctlr->idling) {
1346                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1347                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1348                 return;
1349         }
1350
1351         /* Check if the queue is idle */
1352         if (list_empty(&ctlr->queue) || !ctlr->running) {
1353                 if (!ctlr->busy) {
1354                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1355                         return;
1356                 }
1357
1358                 /* Only do teardown in the thread */
1359                 if (!in_kthread) {
1360                         kthread_queue_work(&ctlr->kworker,
1361                                            &ctlr->pump_messages);
1362                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1363                         return;
1364                 }
1365
1366                 ctlr->busy = false;
1367                 ctlr->idling = true;
1368                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1369
1370                 kfree(ctlr->dummy_rx);
1371                 ctlr->dummy_rx = NULL;
1372                 kfree(ctlr->dummy_tx);
1373                 ctlr->dummy_tx = NULL;
1374                 if (ctlr->unprepare_transfer_hardware &&
1375                     ctlr->unprepare_transfer_hardware(ctlr))
1376                         dev_err(&ctlr->dev,
1377                                 "failed to unprepare transfer hardware\n");
1378                 if (ctlr->auto_runtime_pm) {
1379                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1380                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1381                 }
1382                 trace_spi_controller_idle(ctlr);
1383
1384                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1385                 ctlr->idling = false;
1386                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1387                 return;
1388         }
1389
1390         /* Extract head of queue */
1391         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1392         ctlr->cur_msg = msg;
1393
1394         list_del_init(&msg->queue);
1395         if (ctlr->busy)
1396                 was_busy = true;
1397         else
1398                 ctlr->busy = true;
1399         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1400
1401         mutex_lock(&ctlr->io_mutex);
1402
1403         if (!was_busy && ctlr->auto_runtime_pm) {
1404                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1405                 if (ret < 0) {
1406                         pm_runtime_put_noidle(ctlr->dev.parent);
1407                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1408                                 ret);
1409                         mutex_unlock(&ctlr->io_mutex);
1410                         return;
1411                 }
1412         }
1413
1414         if (!was_busy)
1415                 trace_spi_controller_busy(ctlr);
1416
1417         if (!was_busy && ctlr->prepare_transfer_hardware) {
1418                 ret = ctlr->prepare_transfer_hardware(ctlr);
1419                 if (ret) {
1420                         dev_err(&ctlr->dev,
1421                                 "failed to prepare transfer hardware: %d\n",
1422                                 ret);
1423
1424                         if (ctlr->auto_runtime_pm)
1425                                 pm_runtime_put(ctlr->dev.parent);
1426
1427                         msg->status = ret;
1428                         spi_finalize_current_message(ctlr);
1429
1430                         mutex_unlock(&ctlr->io_mutex);
1431                         return;
1432                 }
1433         }
1434
1435         trace_spi_message_start(msg);
1436
1437         if (ctlr->prepare_message) {
1438                 ret = ctlr->prepare_message(ctlr, msg);
1439                 if (ret) {
1440                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1441                                 ret);
1442                         msg->status = ret;
1443                         spi_finalize_current_message(ctlr);
1444                         goto out;
1445                 }
1446                 ctlr->cur_msg_prepared = true;
1447         }
1448
1449         ret = spi_map_msg(ctlr, msg);
1450         if (ret) {
1451                 msg->status = ret;
1452                 spi_finalize_current_message(ctlr);
1453                 goto out;
1454         }
1455
1456         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1457                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1458                         xfer->ptp_sts_word_pre = 0;
1459                         ptp_read_system_prets(xfer->ptp_sts);
1460                 }
1461         }
1462
1463         ret = ctlr->transfer_one_message(ctlr, msg);
1464         if (ret) {
1465                 dev_err(&ctlr->dev,
1466                         "failed to transfer one message from queue\n");
1467                 goto out;
1468         }
1469
1470 out:
1471         mutex_unlock(&ctlr->io_mutex);
1472
1473         /* Prod the scheduler in case transfer_one() was busy waiting */
1474         if (!ret)
1475                 cond_resched();
1476 }
1477
1478 /**
1479  * spi_pump_messages - kthread work function which processes spi message queue
1480  * @work: pointer to kthread work struct contained in the controller struct
1481  */
1482 static void spi_pump_messages(struct kthread_work *work)
1483 {
1484         struct spi_controller *ctlr =
1485                 container_of(work, struct spi_controller, pump_messages);
1486
1487         __spi_pump_messages(ctlr, true);
1488 }
1489
1490 /**
1491  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1492  *                          TX timestamp for the requested byte from the SPI
1493  *                          transfer. The frequency with which this function
1494  *                          must be called (once per word, once for the whole
1495  *                          transfer, once per batch of words etc) is arbitrary
1496  *                          as long as the @tx buffer offset is greater than or
1497  *                          equal to the requested byte at the time of the
1498  *                          call. The timestamp is only taken once, at the
1499  *                          first such call. It is assumed that the driver
1500  *                          advances its @tx buffer pointer monotonically.
1501  * @ctlr: Pointer to the spi_controller structure of the driver
1502  * @xfer: Pointer to the transfer being timestamped
1503  * @progress: How many words (not bytes) have been transferred so far
1504  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1505  *            transfer, for less jitter in time measurement. Only compatible
1506  *            with PIO drivers. If true, must follow up with
1507  *            spi_take_timestamp_post or otherwise system will crash.
1508  *            WARNING: for fully predictable results, the CPU frequency must
1509  *            also be under control (governor).
1510  */
1511 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1512                             struct spi_transfer *xfer,
1513                             size_t progress, bool irqs_off)
1514 {
1515         if (!xfer->ptp_sts)
1516                 return;
1517
1518         if (xfer->timestamped)
1519                 return;
1520
1521         if (progress > xfer->ptp_sts_word_pre)
1522                 return;
1523
1524         /* Capture the resolution of the timestamp */
1525         xfer->ptp_sts_word_pre = progress;
1526
1527         if (irqs_off) {
1528                 local_irq_save(ctlr->irq_flags);
1529                 preempt_disable();
1530         }
1531
1532         ptp_read_system_prets(xfer->ptp_sts);
1533 }
1534 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1535
1536 /**
1537  * spi_take_timestamp_post - helper for drivers to collect the end of the
1538  *                           TX timestamp for the requested byte from the SPI
1539  *                           transfer. Can be called with an arbitrary
1540  *                           frequency: only the first call where @tx exceeds
1541  *                           or is equal to the requested word will be
1542  *                           timestamped.
1543  * @ctlr: Pointer to the spi_controller structure of the driver
1544  * @xfer: Pointer to the transfer being timestamped
1545  * @progress: How many words (not bytes) have been transferred so far
1546  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1547  */
1548 void spi_take_timestamp_post(struct spi_controller *ctlr,
1549                              struct spi_transfer *xfer,
1550                              size_t progress, bool irqs_off)
1551 {
1552         if (!xfer->ptp_sts)
1553                 return;
1554
1555         if (xfer->timestamped)
1556                 return;
1557
1558         if (progress < xfer->ptp_sts_word_post)
1559                 return;
1560
1561         ptp_read_system_postts(xfer->ptp_sts);
1562
1563         if (irqs_off) {
1564                 local_irq_restore(ctlr->irq_flags);
1565                 preempt_enable();
1566         }
1567
1568         /* Capture the resolution of the timestamp */
1569         xfer->ptp_sts_word_post = progress;
1570
1571         xfer->timestamped = true;
1572 }
1573 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1574
1575 /**
1576  * spi_set_thread_rt - set the controller to pump at realtime priority
1577  * @ctlr: controller to boost priority of
1578  *
1579  * This can be called because the controller requested realtime priority
1580  * (by setting the ->rt value before calling spi_register_controller()) or
1581  * because a device on the bus said that its transfers needed realtime
1582  * priority.
1583  *
1584  * NOTE: at the moment if any device on a bus says it needs realtime then
1585  * the thread will be at realtime priority for all transfers on that
1586  * controller.  If this eventually becomes a problem we may see if we can
1587  * find a way to boost the priority only temporarily during relevant
1588  * transfers.
1589  */
1590 static void spi_set_thread_rt(struct spi_controller *ctlr)
1591 {
1592         struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
1593
1594         dev_info(&ctlr->dev,
1595                 "will run message pump with realtime priority\n");
1596         sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1597 }
1598
1599 static int spi_init_queue(struct spi_controller *ctlr)
1600 {
1601         ctlr->running = false;
1602         ctlr->busy = false;
1603
1604         kthread_init_worker(&ctlr->kworker);
1605         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1606                                          "%s", dev_name(&ctlr->dev));
1607         if (IS_ERR(ctlr->kworker_task)) {
1608                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1609                 return PTR_ERR(ctlr->kworker_task);
1610         }
1611         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1612
1613         /*
1614          * Controller config will indicate if this controller should run the
1615          * message pump with high (realtime) priority to reduce the transfer
1616          * latency on the bus by minimising the delay between a transfer
1617          * request and the scheduling of the message pump thread. Without this
1618          * setting the message pump thread will remain at default priority.
1619          */
1620         if (ctlr->rt)
1621                 spi_set_thread_rt(ctlr);
1622
1623         return 0;
1624 }
1625
1626 /**
1627  * spi_get_next_queued_message() - called by driver to check for queued
1628  * messages
1629  * @ctlr: the controller to check for queued messages
1630  *
1631  * If there are more messages in the queue, the next message is returned from
1632  * this call.
1633  *
1634  * Return: the next message in the queue, else NULL if the queue is empty.
1635  */
1636 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1637 {
1638         struct spi_message *next;
1639         unsigned long flags;
1640
1641         /* get a pointer to the next message, if any */
1642         spin_lock_irqsave(&ctlr->queue_lock, flags);
1643         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1644                                         queue);
1645         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1646
1647         return next;
1648 }
1649 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1650
1651 /**
1652  * spi_finalize_current_message() - the current message is complete
1653  * @ctlr: the controller to return the message to
1654  *
1655  * Called by the driver to notify the core that the message in the front of the
1656  * queue is complete and can be removed from the queue.
1657  */
1658 void spi_finalize_current_message(struct spi_controller *ctlr)
1659 {
1660         struct spi_transfer *xfer;
1661         struct spi_message *mesg;
1662         unsigned long flags;
1663         int ret;
1664
1665         spin_lock_irqsave(&ctlr->queue_lock, flags);
1666         mesg = ctlr->cur_msg;
1667         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1668
1669         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1670                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1671                         ptp_read_system_postts(xfer->ptp_sts);
1672                         xfer->ptp_sts_word_post = xfer->len;
1673                 }
1674         }
1675
1676         if (unlikely(ctlr->ptp_sts_supported))
1677                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1678                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1679
1680         spi_unmap_msg(ctlr, mesg);
1681
1682         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1683                 ret = ctlr->unprepare_message(ctlr, mesg);
1684                 if (ret) {
1685                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1686                                 ret);
1687                 }
1688         }
1689
1690         spin_lock_irqsave(&ctlr->queue_lock, flags);
1691         ctlr->cur_msg = NULL;
1692         ctlr->cur_msg_prepared = false;
1693         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1694         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1695
1696         trace_spi_message_done(mesg);
1697
1698         mesg->state = NULL;
1699         if (mesg->complete)
1700                 mesg->complete(mesg->context);
1701 }
1702 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1703
1704 static int spi_start_queue(struct spi_controller *ctlr)
1705 {
1706         unsigned long flags;
1707
1708         spin_lock_irqsave(&ctlr->queue_lock, flags);
1709
1710         if (ctlr->running || ctlr->busy) {
1711                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1712                 return -EBUSY;
1713         }
1714
1715         ctlr->running = true;
1716         ctlr->cur_msg = NULL;
1717         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1718
1719         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1720
1721         return 0;
1722 }
1723
1724 static int spi_stop_queue(struct spi_controller *ctlr)
1725 {
1726         unsigned long flags;
1727         unsigned limit = 500;
1728         int ret = 0;
1729
1730         spin_lock_irqsave(&ctlr->queue_lock, flags);
1731
1732         /*
1733          * This is a bit lame, but is optimized for the common execution path.
1734          * A wait_queue on the ctlr->busy could be used, but then the common
1735          * execution path (pump_messages) would be required to call wake_up or
1736          * friends on every SPI message. Do this instead.
1737          */
1738         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1739                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1740                 usleep_range(10000, 11000);
1741                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1742         }
1743
1744         if (!list_empty(&ctlr->queue) || ctlr->busy)
1745                 ret = -EBUSY;
1746         else
1747                 ctlr->running = false;
1748
1749         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1750
1751         if (ret) {
1752                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1753                 return ret;
1754         }
1755         return ret;
1756 }
1757
1758 static int spi_destroy_queue(struct spi_controller *ctlr)
1759 {
1760         int ret;
1761
1762         ret = spi_stop_queue(ctlr);
1763
1764         /*
1765          * kthread_flush_worker will block until all work is done.
1766          * If the reason that stop_queue timed out is that the work will never
1767          * finish, then it does no good to call flush/stop thread, so
1768          * return anyway.
1769          */
1770         if (ret) {
1771                 dev_err(&ctlr->dev, "problem destroying queue\n");
1772                 return ret;
1773         }
1774
1775         kthread_flush_worker(&ctlr->kworker);
1776         kthread_stop(ctlr->kworker_task);
1777
1778         return 0;
1779 }
1780
1781 static int __spi_queued_transfer(struct spi_device *spi,
1782                                  struct spi_message *msg,
1783                                  bool need_pump)
1784 {
1785         struct spi_controller *ctlr = spi->controller;
1786         unsigned long flags;
1787
1788         spin_lock_irqsave(&ctlr->queue_lock, flags);
1789
1790         if (!ctlr->running) {
1791                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1792                 return -ESHUTDOWN;
1793         }
1794         msg->actual_length = 0;
1795         msg->status = -EINPROGRESS;
1796
1797         list_add_tail(&msg->queue, &ctlr->queue);
1798         if (!ctlr->busy && need_pump)
1799                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1800
1801         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1802         return 0;
1803 }
1804
1805 /**
1806  * spi_queued_transfer - transfer function for queued transfers
1807  * @spi: spi device which is requesting transfer
1808  * @msg: spi message which is to handled is queued to driver queue
1809  *
1810  * Return: zero on success, else a negative error code.
1811  */
1812 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1813 {
1814         return __spi_queued_transfer(spi, msg, true);
1815 }
1816
1817 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1818 {
1819         int ret;
1820
1821         ctlr->transfer = spi_queued_transfer;
1822         if (!ctlr->transfer_one_message)
1823                 ctlr->transfer_one_message = spi_transfer_one_message;
1824
1825         /* Initialize and start queue */
1826         ret = spi_init_queue(ctlr);
1827         if (ret) {
1828                 dev_err(&ctlr->dev, "problem initializing queue\n");
1829                 goto err_init_queue;
1830         }
1831         ctlr->queued = true;
1832         ret = spi_start_queue(ctlr);
1833         if (ret) {
1834                 dev_err(&ctlr->dev, "problem starting queue\n");
1835                 goto err_start_queue;
1836         }
1837
1838         return 0;
1839
1840 err_start_queue:
1841         spi_destroy_queue(ctlr);
1842 err_init_queue:
1843         return ret;
1844 }
1845
1846 /**
1847  * spi_flush_queue - Send all pending messages in the queue from the callers'
1848  *                   context
1849  * @ctlr: controller to process queue for
1850  *
1851  * This should be used when one wants to ensure all pending messages have been
1852  * sent before doing something. Is used by the spi-mem code to make sure SPI
1853  * memory operations do not preempt regular SPI transfers that have been queued
1854  * before the spi-mem operation.
1855  */
1856 void spi_flush_queue(struct spi_controller *ctlr)
1857 {
1858         if (ctlr->transfer == spi_queued_transfer)
1859                 __spi_pump_messages(ctlr, false);
1860 }
1861
1862 /*-------------------------------------------------------------------------*/
1863
1864 #if defined(CONFIG_OF)
1865 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1866                            struct device_node *nc)
1867 {
1868         u32 value;
1869         int rc;
1870
1871         /* Mode (clock phase/polarity/etc.) */
1872         if (of_property_read_bool(nc, "spi-cpha"))
1873                 spi->mode |= SPI_CPHA;
1874         if (of_property_read_bool(nc, "spi-cpol"))
1875                 spi->mode |= SPI_CPOL;
1876         if (of_property_read_bool(nc, "spi-3wire"))
1877                 spi->mode |= SPI_3WIRE;
1878         if (of_property_read_bool(nc, "spi-lsb-first"))
1879                 spi->mode |= SPI_LSB_FIRST;
1880         if (of_property_read_bool(nc, "spi-cs-high"))
1881                 spi->mode |= SPI_CS_HIGH;
1882
1883         /* Device DUAL/QUAD mode */
1884         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1885                 switch (value) {
1886                 case 1:
1887                         break;
1888                 case 2:
1889                         spi->mode |= SPI_TX_DUAL;
1890                         break;
1891                 case 4:
1892                         spi->mode |= SPI_TX_QUAD;
1893                         break;
1894                 case 8:
1895                         spi->mode |= SPI_TX_OCTAL;
1896                         break;
1897                 default:
1898                         dev_warn(&ctlr->dev,
1899                                 "spi-tx-bus-width %d not supported\n",
1900                                 value);
1901                         break;
1902                 }
1903         }
1904
1905         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1906                 switch (value) {
1907                 case 1:
1908                         break;
1909                 case 2:
1910                         spi->mode |= SPI_RX_DUAL;
1911                         break;
1912                 case 4:
1913                         spi->mode |= SPI_RX_QUAD;
1914                         break;
1915                 case 8:
1916                         spi->mode |= SPI_RX_OCTAL;
1917                         break;
1918                 default:
1919                         dev_warn(&ctlr->dev,
1920                                 "spi-rx-bus-width %d not supported\n",
1921                                 value);
1922                         break;
1923                 }
1924         }
1925
1926         if (spi_controller_is_slave(ctlr)) {
1927                 if (!of_node_name_eq(nc, "slave")) {
1928                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1929                                 nc);
1930                         return -EINVAL;
1931                 }
1932                 return 0;
1933         }
1934
1935         /* Device address */
1936         rc = of_property_read_u32(nc, "reg", &value);
1937         if (rc) {
1938                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1939                         nc, rc);
1940                 return rc;
1941         }
1942         spi->chip_select = value;
1943
1944         /*
1945          * For descriptors associated with the device, polarity inversion is
1946          * handled in the gpiolib, so all gpio chip selects are "active high"
1947          * in the logical sense, the gpiolib will invert the line if need be.
1948          */
1949         if ((ctlr->use_gpio_descriptors) && ctlr->cs_gpiods &&
1950             ctlr->cs_gpiods[spi->chip_select])
1951                 spi->mode |= SPI_CS_HIGH;
1952
1953         /* Device speed */
1954         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
1955                 spi->max_speed_hz = value;
1956
1957         return 0;
1958 }
1959
1960 static struct spi_device *
1961 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1962 {
1963         struct spi_device *spi;
1964         int rc;
1965
1966         /* Alloc an spi_device */
1967         spi = spi_alloc_device(ctlr);
1968         if (!spi) {
1969                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1970                 rc = -ENOMEM;
1971                 goto err_out;
1972         }
1973
1974         /* Select device driver */
1975         rc = of_modalias_node(nc, spi->modalias,
1976                                 sizeof(spi->modalias));
1977         if (rc < 0) {
1978                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1979                 goto err_out;
1980         }
1981
1982         rc = of_spi_parse_dt(ctlr, spi, nc);
1983         if (rc)
1984                 goto err_out;
1985
1986         /* Store a pointer to the node in the device structure */
1987         of_node_get(nc);
1988         spi->dev.of_node = nc;
1989
1990         /* Register the new device */
1991         rc = spi_add_device(spi);
1992         if (rc) {
1993                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1994                 goto err_of_node_put;
1995         }
1996
1997         return spi;
1998
1999 err_of_node_put:
2000         of_node_put(nc);
2001 err_out:
2002         spi_dev_put(spi);
2003         return ERR_PTR(rc);
2004 }
2005
2006 /**
2007  * of_register_spi_devices() - Register child devices onto the SPI bus
2008  * @ctlr:       Pointer to spi_controller device
2009  *
2010  * Registers an spi_device for each child node of controller node which
2011  * represents a valid SPI slave.
2012  */
2013 static void of_register_spi_devices(struct spi_controller *ctlr)
2014 {
2015         struct spi_device *spi;
2016         struct device_node *nc;
2017
2018         if (!ctlr->dev.of_node)
2019                 return;
2020
2021         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2022                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2023                         continue;
2024                 spi = of_register_spi_device(ctlr, nc);
2025                 if (IS_ERR(spi)) {
2026                         dev_warn(&ctlr->dev,
2027                                  "Failed to create SPI device for %pOF\n", nc);
2028                         of_node_clear_flag(nc, OF_POPULATED);
2029                 }
2030         }
2031 }
2032 #else
2033 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2034 #endif
2035
2036 #ifdef CONFIG_ACPI
2037 struct acpi_spi_lookup {
2038         struct spi_controller   *ctlr;
2039         u32                     max_speed_hz;
2040         u32                     mode;
2041         int                     irq;
2042         u8                      bits_per_word;
2043         u8                      chip_select;
2044 };
2045
2046 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2047                                             struct acpi_spi_lookup *lookup)
2048 {
2049         const union acpi_object *obj;
2050
2051         if (!x86_apple_machine)
2052                 return;
2053
2054         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2055             && obj->buffer.length >= 4)
2056                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2057
2058         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2059             && obj->buffer.length == 8)
2060                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2061
2062         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2063             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2064                 lookup->mode |= SPI_LSB_FIRST;
2065
2066         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2067             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2068                 lookup->mode |= SPI_CPOL;
2069
2070         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2071             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2072                 lookup->mode |= SPI_CPHA;
2073 }
2074
2075 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2076 {
2077         struct acpi_spi_lookup *lookup = data;
2078         struct spi_controller *ctlr = lookup->ctlr;
2079
2080         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2081                 struct acpi_resource_spi_serialbus *sb;
2082                 acpi_handle parent_handle;
2083                 acpi_status status;
2084
2085                 sb = &ares->data.spi_serial_bus;
2086                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2087
2088                         status = acpi_get_handle(NULL,
2089                                                  sb->resource_source.string_ptr,
2090                                                  &parent_handle);
2091
2092                         if (ACPI_FAILURE(status) ||
2093                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2094                                 return -ENODEV;
2095
2096                         /*
2097                          * ACPI DeviceSelection numbering is handled by the
2098                          * host controller driver in Windows and can vary
2099                          * from driver to driver. In Linux we always expect
2100                          * 0 .. max - 1 so we need to ask the driver to
2101                          * translate between the two schemes.
2102                          */
2103                         if (ctlr->fw_translate_cs) {
2104                                 int cs = ctlr->fw_translate_cs(ctlr,
2105                                                 sb->device_selection);
2106                                 if (cs < 0)
2107                                         return cs;
2108                                 lookup->chip_select = cs;
2109                         } else {
2110                                 lookup->chip_select = sb->device_selection;
2111                         }
2112
2113                         lookup->max_speed_hz = sb->connection_speed;
2114                         lookup->bits_per_word = sb->data_bit_length;
2115
2116                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2117                                 lookup->mode |= SPI_CPHA;
2118                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2119                                 lookup->mode |= SPI_CPOL;
2120                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2121                                 lookup->mode |= SPI_CS_HIGH;
2122                 }
2123         } else if (lookup->irq < 0) {
2124                 struct resource r;
2125
2126                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2127                         lookup->irq = r.start;
2128         }
2129
2130         /* Always tell the ACPI core to skip this resource */
2131         return 1;
2132 }
2133
2134 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2135                                             struct acpi_device *adev)
2136 {
2137         acpi_handle parent_handle = NULL;
2138         struct list_head resource_list;
2139         struct acpi_spi_lookup lookup = {};
2140         struct spi_device *spi;
2141         int ret;
2142
2143         if (acpi_bus_get_status(adev) || !adev->status.present ||
2144             acpi_device_enumerated(adev))
2145                 return AE_OK;
2146
2147         lookup.ctlr             = ctlr;
2148         lookup.irq              = -1;
2149
2150         INIT_LIST_HEAD(&resource_list);
2151         ret = acpi_dev_get_resources(adev, &resource_list,
2152                                      acpi_spi_add_resource, &lookup);
2153         acpi_dev_free_resource_list(&resource_list);
2154
2155         if (ret < 0)
2156                 /* found SPI in _CRS but it points to another controller */
2157                 return AE_OK;
2158
2159         if (!lookup.max_speed_hz &&
2160             !ACPI_FAILURE(acpi_get_parent(adev->handle, &parent_handle)) &&
2161             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2162                 /* Apple does not use _CRS but nested devices for SPI slaves */
2163                 acpi_spi_parse_apple_properties(adev, &lookup);
2164         }
2165
2166         if (!lookup.max_speed_hz)
2167                 return AE_OK;
2168
2169         spi = spi_alloc_device(ctlr);
2170         if (!spi) {
2171                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2172                         dev_name(&adev->dev));
2173                 return AE_NO_MEMORY;
2174         }
2175
2176
2177         ACPI_COMPANION_SET(&spi->dev, adev);
2178         spi->max_speed_hz       = lookup.max_speed_hz;
2179         spi->mode               |= lookup.mode;
2180         spi->irq                = lookup.irq;
2181         spi->bits_per_word      = lookup.bits_per_word;
2182         spi->chip_select        = lookup.chip_select;
2183
2184         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2185                           sizeof(spi->modalias));
2186
2187         if (spi->irq < 0)
2188                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2189
2190         acpi_device_set_enumerated(adev);
2191
2192         adev->power.flags.ignore_parent = true;
2193         if (spi_add_device(spi)) {
2194                 adev->power.flags.ignore_parent = false;
2195                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2196                         dev_name(&adev->dev));
2197                 spi_dev_put(spi);
2198         }
2199
2200         return AE_OK;
2201 }
2202
2203 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2204                                        void *data, void **return_value)
2205 {
2206         struct spi_controller *ctlr = data;
2207         struct acpi_device *adev;
2208
2209         if (acpi_bus_get_device(handle, &adev))
2210                 return AE_OK;
2211
2212         return acpi_register_spi_device(ctlr, adev);
2213 }
2214
2215 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2216
2217 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2218 {
2219         acpi_status status;
2220         acpi_handle handle;
2221
2222         handle = ACPI_HANDLE(ctlr->dev.parent);
2223         if (!handle)
2224                 return;
2225
2226         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2227                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2228                                      acpi_spi_add_device, NULL, ctlr, NULL);
2229         if (ACPI_FAILURE(status))
2230                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2231 }
2232 #else
2233 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2234 #endif /* CONFIG_ACPI */
2235
2236 static void spi_controller_release(struct device *dev)
2237 {
2238         struct spi_controller *ctlr;
2239
2240         ctlr = container_of(dev, struct spi_controller, dev);
2241         kfree(ctlr);
2242 }
2243
2244 static struct class spi_master_class = {
2245         .name           = "spi_master",
2246         .owner          = THIS_MODULE,
2247         .dev_release    = spi_controller_release,
2248         .dev_groups     = spi_master_groups,
2249 };
2250
2251 #ifdef CONFIG_SPI_SLAVE
2252 /**
2253  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2254  *                   controller
2255  * @spi: device used for the current transfer
2256  */
2257 int spi_slave_abort(struct spi_device *spi)
2258 {
2259         struct spi_controller *ctlr = spi->controller;
2260
2261         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2262                 return ctlr->slave_abort(ctlr);
2263
2264         return -ENOTSUPP;
2265 }
2266 EXPORT_SYMBOL_GPL(spi_slave_abort);
2267
2268 static int match_true(struct device *dev, void *data)
2269 {
2270         return 1;
2271 }
2272
2273 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2274                           char *buf)
2275 {
2276         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2277                                                    dev);
2278         struct device *child;
2279
2280         child = device_find_child(&ctlr->dev, NULL, match_true);
2281         return sprintf(buf, "%s\n",
2282                        child ? to_spi_device(child)->modalias : NULL);
2283 }
2284
2285 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2286                            const char *buf, size_t count)
2287 {
2288         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2289                                                    dev);
2290         struct spi_device *spi;
2291         struct device *child;
2292         char name[32];
2293         int rc;
2294
2295         rc = sscanf(buf, "%31s", name);
2296         if (rc != 1 || !name[0])
2297                 return -EINVAL;
2298
2299         child = device_find_child(&ctlr->dev, NULL, match_true);
2300         if (child) {
2301                 /* Remove registered slave */
2302                 device_unregister(child);
2303                 put_device(child);
2304         }
2305
2306         if (strcmp(name, "(null)")) {
2307                 /* Register new slave */
2308                 spi = spi_alloc_device(ctlr);
2309                 if (!spi)
2310                         return -ENOMEM;
2311
2312                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2313
2314                 rc = spi_add_device(spi);
2315                 if (rc) {
2316                         spi_dev_put(spi);
2317                         return rc;
2318                 }
2319         }
2320
2321         return count;
2322 }
2323
2324 static DEVICE_ATTR_RW(slave);
2325
2326 static struct attribute *spi_slave_attrs[] = {
2327         &dev_attr_slave.attr,
2328         NULL,
2329 };
2330
2331 static const struct attribute_group spi_slave_group = {
2332         .attrs = spi_slave_attrs,
2333 };
2334
2335 static const struct attribute_group *spi_slave_groups[] = {
2336         &spi_controller_statistics_group,
2337         &spi_slave_group,
2338         NULL,
2339 };
2340
2341 static struct class spi_slave_class = {
2342         .name           = "spi_slave",
2343         .owner          = THIS_MODULE,
2344         .dev_release    = spi_controller_release,
2345         .dev_groups     = spi_slave_groups,
2346 };
2347 #else
2348 extern struct class spi_slave_class;    /* dummy */
2349 #endif
2350
2351 /**
2352  * __spi_alloc_controller - allocate an SPI master or slave controller
2353  * @dev: the controller, possibly using the platform_bus
2354  * @size: how much zeroed driver-private data to allocate; the pointer to this
2355  *      memory is in the driver_data field of the returned device, accessible
2356  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2357  *      drivers granting DMA access to portions of their private data need to
2358  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2359  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2360  *      slave (true) controller
2361  * Context: can sleep
2362  *
2363  * This call is used only by SPI controller drivers, which are the
2364  * only ones directly touching chip registers.  It's how they allocate
2365  * an spi_controller structure, prior to calling spi_register_controller().
2366  *
2367  * This must be called from context that can sleep.
2368  *
2369  * The caller is responsible for assigning the bus number and initializing the
2370  * controller's methods before calling spi_register_controller(); and (after
2371  * errors adding the device) calling spi_controller_put() to prevent a memory
2372  * leak.
2373  *
2374  * Return: the SPI controller structure on success, else NULL.
2375  */
2376 struct spi_controller *__spi_alloc_controller(struct device *dev,
2377                                               unsigned int size, bool slave)
2378 {
2379         struct spi_controller   *ctlr;
2380         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2381
2382         if (!dev)
2383                 return NULL;
2384
2385         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2386         if (!ctlr)
2387                 return NULL;
2388
2389         device_initialize(&ctlr->dev);
2390         ctlr->bus_num = -1;
2391         ctlr->num_chipselect = 1;
2392         ctlr->slave = slave;
2393         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2394                 ctlr->dev.class = &spi_slave_class;
2395         else
2396                 ctlr->dev.class = &spi_master_class;
2397         ctlr->dev.parent = dev;
2398         pm_suspend_ignore_children(&ctlr->dev, true);
2399         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2400
2401         return ctlr;
2402 }
2403 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2404
2405 #ifdef CONFIG_OF
2406 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2407 {
2408         int nb, i, *cs;
2409         struct device_node *np = ctlr->dev.of_node;
2410
2411         if (!np)
2412                 return 0;
2413
2414         nb = of_gpio_named_count(np, "cs-gpios");
2415         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2416
2417         /* Return error only for an incorrectly formed cs-gpios property */
2418         if (nb == 0 || nb == -ENOENT)
2419                 return 0;
2420         else if (nb < 0)
2421                 return nb;
2422
2423         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2424                           GFP_KERNEL);
2425         ctlr->cs_gpios = cs;
2426
2427         if (!ctlr->cs_gpios)
2428                 return -ENOMEM;
2429
2430         for (i = 0; i < ctlr->num_chipselect; i++)
2431                 cs[i] = -ENOENT;
2432
2433         for (i = 0; i < nb; i++)
2434                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2435
2436         return 0;
2437 }
2438 #else
2439 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2440 {
2441         return 0;
2442 }
2443 #endif
2444
2445 /**
2446  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2447  * @ctlr: The SPI master to grab GPIO descriptors for
2448  */
2449 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2450 {
2451         int nb, i;
2452         struct gpio_desc **cs;
2453         struct device *dev = &ctlr->dev;
2454         unsigned long native_cs_mask = 0;
2455         unsigned int num_cs_gpios = 0;
2456
2457         nb = gpiod_count(dev, "cs");
2458         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2459
2460         /* No GPIOs at all is fine, else return the error */
2461         if (nb == 0 || nb == -ENOENT)
2462                 return 0;
2463         else if (nb < 0)
2464                 return nb;
2465
2466         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2467                           GFP_KERNEL);
2468         if (!cs)
2469                 return -ENOMEM;
2470         ctlr->cs_gpiods = cs;
2471
2472         for (i = 0; i < nb; i++) {
2473                 /*
2474                  * Most chipselects are active low, the inverted
2475                  * semantics are handled by special quirks in gpiolib,
2476                  * so initializing them GPIOD_OUT_LOW here means
2477                  * "unasserted", in most cases this will drive the physical
2478                  * line high.
2479                  */
2480                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2481                                                       GPIOD_OUT_LOW);
2482                 if (IS_ERR(cs[i]))
2483                         return PTR_ERR(cs[i]);
2484
2485                 if (cs[i]) {
2486                         /*
2487                          * If we find a CS GPIO, name it after the device and
2488                          * chip select line.
2489                          */
2490                         char *gpioname;
2491
2492                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2493                                                   dev_name(dev), i);
2494                         if (!gpioname)
2495                                 return -ENOMEM;
2496                         gpiod_set_consumer_name(cs[i], gpioname);
2497                         num_cs_gpios++;
2498                         continue;
2499                 }
2500
2501                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2502                         dev_err(dev, "Invalid native chip select %d\n", i);
2503                         return -EINVAL;
2504                 }
2505                 native_cs_mask |= BIT(i);
2506         }
2507
2508         ctlr->unused_native_cs = ffz(native_cs_mask);
2509         if (num_cs_gpios && ctlr->max_native_cs &&
2510             ctlr->unused_native_cs >= ctlr->max_native_cs) {
2511                 dev_err(dev, "No unused native chip select available\n");
2512                 return -EINVAL;
2513         }
2514
2515         return 0;
2516 }
2517
2518 static int spi_controller_check_ops(struct spi_controller *ctlr)
2519 {
2520         /*
2521          * The controller may implement only the high-level SPI-memory like
2522          * operations if it does not support regular SPI transfers, and this is
2523          * valid use case.
2524          * If ->mem_ops is NULL, we request that at least one of the
2525          * ->transfer_xxx() method be implemented.
2526          */
2527         if (ctlr->mem_ops) {
2528                 if (!ctlr->mem_ops->exec_op)
2529                         return -EINVAL;
2530         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2531                    !ctlr->transfer_one_message) {
2532                 return -EINVAL;
2533         }
2534
2535         return 0;
2536 }
2537
2538 /**
2539  * spi_register_controller - register SPI master or slave controller
2540  * @ctlr: initialized master, originally from spi_alloc_master() or
2541  *      spi_alloc_slave()
2542  * Context: can sleep
2543  *
2544  * SPI controllers connect to their drivers using some non-SPI bus,
2545  * such as the platform bus.  The final stage of probe() in that code
2546  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2547  *
2548  * SPI controllers use board specific (often SOC specific) bus numbers,
2549  * and board-specific addressing for SPI devices combines those numbers
2550  * with chip select numbers.  Since SPI does not directly support dynamic
2551  * device identification, boards need configuration tables telling which
2552  * chip is at which address.
2553  *
2554  * This must be called from context that can sleep.  It returns zero on
2555  * success, else a negative error code (dropping the controller's refcount).
2556  * After a successful return, the caller is responsible for calling
2557  * spi_unregister_controller().
2558  *
2559  * Return: zero on success, else a negative error code.
2560  */
2561 int spi_register_controller(struct spi_controller *ctlr)
2562 {
2563         struct device           *dev = ctlr->dev.parent;
2564         struct boardinfo        *bi;
2565         int                     status;
2566         int                     id, first_dynamic;
2567
2568         if (!dev)
2569                 return -ENODEV;
2570
2571         /*
2572          * Make sure all necessary hooks are implemented before registering
2573          * the SPI controller.
2574          */
2575         status = spi_controller_check_ops(ctlr);
2576         if (status)
2577                 return status;
2578
2579         if (ctlr->bus_num >= 0) {
2580                 /* devices with a fixed bus num must check-in with the num */
2581                 mutex_lock(&board_lock);
2582                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2583                         ctlr->bus_num + 1, GFP_KERNEL);
2584                 mutex_unlock(&board_lock);
2585                 if (WARN(id < 0, "couldn't get idr"))
2586                         return id == -ENOSPC ? -EBUSY : id;
2587                 ctlr->bus_num = id;
2588         } else if (ctlr->dev.of_node) {
2589                 /* allocate dynamic bus number using Linux idr */
2590                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2591                 if (id >= 0) {
2592                         ctlr->bus_num = id;
2593                         mutex_lock(&board_lock);
2594                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2595                                        ctlr->bus_num + 1, GFP_KERNEL);
2596                         mutex_unlock(&board_lock);
2597                         if (WARN(id < 0, "couldn't get idr"))
2598                                 return id == -ENOSPC ? -EBUSY : id;
2599                 }
2600         }
2601         if (ctlr->bus_num < 0) {
2602                 first_dynamic = of_alias_get_highest_id("spi");
2603                 if (first_dynamic < 0)
2604                         first_dynamic = 0;
2605                 else
2606                         first_dynamic++;
2607
2608                 mutex_lock(&board_lock);
2609                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2610                                0, GFP_KERNEL);
2611                 mutex_unlock(&board_lock);
2612                 if (WARN(id < 0, "couldn't get idr"))
2613                         return id;
2614                 ctlr->bus_num = id;
2615         }
2616         INIT_LIST_HEAD(&ctlr->queue);
2617         spin_lock_init(&ctlr->queue_lock);
2618         spin_lock_init(&ctlr->bus_lock_spinlock);
2619         mutex_init(&ctlr->bus_lock_mutex);
2620         mutex_init(&ctlr->io_mutex);
2621         ctlr->bus_lock_flag = 0;
2622         init_completion(&ctlr->xfer_completion);
2623         if (!ctlr->max_dma_len)
2624                 ctlr->max_dma_len = INT_MAX;
2625
2626         /* register the device, then userspace will see it.
2627          * registration fails if the bus ID is in use.
2628          */
2629         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2630
2631         if (!spi_controller_is_slave(ctlr)) {
2632                 if (ctlr->use_gpio_descriptors) {
2633                         status = spi_get_gpio_descs(ctlr);
2634                         if (status)
2635                                 goto free_bus_id;
2636                         /*
2637                          * A controller using GPIO descriptors always
2638                          * supports SPI_CS_HIGH if need be.
2639                          */
2640                         ctlr->mode_bits |= SPI_CS_HIGH;
2641                 } else {
2642                         /* Legacy code path for GPIOs from DT */
2643                         status = of_spi_get_gpio_numbers(ctlr);
2644                         if (status)
2645                                 goto free_bus_id;
2646                 }
2647         }
2648
2649         /*
2650          * Even if it's just one always-selected device, there must
2651          * be at least one chipselect.
2652          */
2653         if (!ctlr->num_chipselect) {
2654                 status = -EINVAL;
2655                 goto free_bus_id;
2656         }
2657
2658         status = device_add(&ctlr->dev);
2659         if (status < 0)
2660                 goto free_bus_id;
2661         dev_dbg(dev, "registered %s %s\n",
2662                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2663                         dev_name(&ctlr->dev));
2664
2665         /*
2666          * If we're using a queued driver, start the queue. Note that we don't
2667          * need the queueing logic if the driver is only supporting high-level
2668          * memory operations.
2669          */
2670         if (ctlr->transfer) {
2671                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2672         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2673                 status = spi_controller_initialize_queue(ctlr);
2674                 if (status) {
2675                         device_del(&ctlr->dev);
2676                         goto free_bus_id;
2677                 }
2678         }
2679         /* add statistics */
2680         spin_lock_init(&ctlr->statistics.lock);
2681
2682         mutex_lock(&board_lock);
2683         list_add_tail(&ctlr->list, &spi_controller_list);
2684         list_for_each_entry(bi, &board_list, list)
2685                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2686         mutex_unlock(&board_lock);
2687
2688         /* Register devices from the device tree and ACPI */
2689         of_register_spi_devices(ctlr);
2690         acpi_register_spi_devices(ctlr);
2691         return status;
2692
2693 free_bus_id:
2694         mutex_lock(&board_lock);
2695         idr_remove(&spi_master_idr, ctlr->bus_num);
2696         mutex_unlock(&board_lock);
2697         return status;
2698 }
2699 EXPORT_SYMBOL_GPL(spi_register_controller);
2700
2701 static void devm_spi_unregister(struct device *dev, void *res)
2702 {
2703         spi_unregister_controller(*(struct spi_controller **)res);
2704 }
2705
2706 /**
2707  * devm_spi_register_controller - register managed SPI master or slave
2708  *      controller
2709  * @dev:    device managing SPI controller
2710  * @ctlr: initialized controller, originally from spi_alloc_master() or
2711  *      spi_alloc_slave()
2712  * Context: can sleep
2713  *
2714  * Register a SPI device as with spi_register_controller() which will
2715  * automatically be unregistered and freed.
2716  *
2717  * Return: zero on success, else a negative error code.
2718  */
2719 int devm_spi_register_controller(struct device *dev,
2720                                  struct spi_controller *ctlr)
2721 {
2722         struct spi_controller **ptr;
2723         int ret;
2724
2725         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2726         if (!ptr)
2727                 return -ENOMEM;
2728
2729         ret = spi_register_controller(ctlr);
2730         if (!ret) {
2731                 *ptr = ctlr;
2732                 devres_add(dev, ptr);
2733         } else {
2734                 devres_free(ptr);
2735         }
2736
2737         return ret;
2738 }
2739 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2740
2741 static int __unregister(struct device *dev, void *null)
2742 {
2743         spi_unregister_device(to_spi_device(dev));
2744         return 0;
2745 }
2746
2747 /**
2748  * spi_unregister_controller - unregister SPI master or slave controller
2749  * @ctlr: the controller being unregistered
2750  * Context: can sleep
2751  *
2752  * This call is used only by SPI controller drivers, which are the
2753  * only ones directly touching chip registers.
2754  *
2755  * This must be called from context that can sleep.
2756  *
2757  * Note that this function also drops a reference to the controller.
2758  */
2759 void spi_unregister_controller(struct spi_controller *ctlr)
2760 {
2761         struct spi_controller *found;
2762         int id = ctlr->bus_num;
2763
2764         device_for_each_child(&ctlr->dev, NULL, __unregister);
2765
2766         /* First make sure that this controller was ever added */
2767         mutex_lock(&board_lock);
2768         found = idr_find(&spi_master_idr, id);
2769         mutex_unlock(&board_lock);
2770         if (ctlr->queued) {
2771                 if (spi_destroy_queue(ctlr))
2772                         dev_err(&ctlr->dev, "queue remove failed\n");
2773         }
2774         mutex_lock(&board_lock);
2775         list_del(&ctlr->list);
2776         mutex_unlock(&board_lock);
2777
2778         device_unregister(&ctlr->dev);
2779         /* free bus id */
2780         mutex_lock(&board_lock);
2781         if (found == ctlr)
2782                 idr_remove(&spi_master_idr, id);
2783         mutex_unlock(&board_lock);
2784 }
2785 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2786
2787 int spi_controller_suspend(struct spi_controller *ctlr)
2788 {
2789         int ret;
2790
2791         /* Basically no-ops for non-queued controllers */
2792         if (!ctlr->queued)
2793                 return 0;
2794
2795         ret = spi_stop_queue(ctlr);
2796         if (ret)
2797                 dev_err(&ctlr->dev, "queue stop failed\n");
2798
2799         return ret;
2800 }
2801 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2802
2803 int spi_controller_resume(struct spi_controller *ctlr)
2804 {
2805         int ret;
2806
2807         if (!ctlr->queued)
2808                 return 0;
2809
2810         ret = spi_start_queue(ctlr);
2811         if (ret)
2812                 dev_err(&ctlr->dev, "queue restart failed\n");
2813
2814         return ret;
2815 }
2816 EXPORT_SYMBOL_GPL(spi_controller_resume);
2817
2818 static int __spi_controller_match(struct device *dev, const void *data)
2819 {
2820         struct spi_controller *ctlr;
2821         const u16 *bus_num = data;
2822
2823         ctlr = container_of(dev, struct spi_controller, dev);
2824         return ctlr->bus_num == *bus_num;
2825 }
2826
2827 /**
2828  * spi_busnum_to_master - look up master associated with bus_num
2829  * @bus_num: the master's bus number
2830  * Context: can sleep
2831  *
2832  * This call may be used with devices that are registered after
2833  * arch init time.  It returns a refcounted pointer to the relevant
2834  * spi_controller (which the caller must release), or NULL if there is
2835  * no such master registered.
2836  *
2837  * Return: the SPI master structure on success, else NULL.
2838  */
2839 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2840 {
2841         struct device           *dev;
2842         struct spi_controller   *ctlr = NULL;
2843
2844         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2845                                 __spi_controller_match);
2846         if (dev)
2847                 ctlr = container_of(dev, struct spi_controller, dev);
2848         /* reference got in class_find_device */
2849         return ctlr;
2850 }
2851 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2852
2853 /*-------------------------------------------------------------------------*/
2854
2855 /* Core methods for SPI resource management */
2856
2857 /**
2858  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2859  *                 during the processing of a spi_message while using
2860  *                 spi_transfer_one
2861  * @spi:     the spi device for which we allocate memory
2862  * @release: the release code to execute for this resource
2863  * @size:    size to alloc and return
2864  * @gfp:     GFP allocation flags
2865  *
2866  * Return: the pointer to the allocated data
2867  *
2868  * This may get enhanced in the future to allocate from a memory pool
2869  * of the @spi_device or @spi_controller to avoid repeated allocations.
2870  */
2871 void *spi_res_alloc(struct spi_device *spi,
2872                     spi_res_release_t release,
2873                     size_t size, gfp_t gfp)
2874 {
2875         struct spi_res *sres;
2876
2877         sres = kzalloc(sizeof(*sres) + size, gfp);
2878         if (!sres)
2879                 return NULL;
2880
2881         INIT_LIST_HEAD(&sres->entry);
2882         sres->release = release;
2883
2884         return sres->data;
2885 }
2886 EXPORT_SYMBOL_GPL(spi_res_alloc);
2887
2888 /**
2889  * spi_res_free - free an spi resource
2890  * @res: pointer to the custom data of a resource
2891  *
2892  */
2893 void spi_res_free(void *res)
2894 {
2895         struct spi_res *sres = container_of(res, struct spi_res, data);
2896
2897         if (!res)
2898                 return;
2899
2900         WARN_ON(!list_empty(&sres->entry));
2901         kfree(sres);
2902 }
2903 EXPORT_SYMBOL_GPL(spi_res_free);
2904
2905 /**
2906  * spi_res_add - add a spi_res to the spi_message
2907  * @message: the spi message
2908  * @res:     the spi_resource
2909  */
2910 void spi_res_add(struct spi_message *message, void *res)
2911 {
2912         struct spi_res *sres = container_of(res, struct spi_res, data);
2913
2914         WARN_ON(!list_empty(&sres->entry));
2915         list_add_tail(&sres->entry, &message->resources);
2916 }
2917 EXPORT_SYMBOL_GPL(spi_res_add);
2918
2919 /**
2920  * spi_res_release - release all spi resources for this message
2921  * @ctlr:  the @spi_controller
2922  * @message: the @spi_message
2923  */
2924 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2925 {
2926         struct spi_res *res, *tmp;
2927
2928         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
2929                 if (res->release)
2930                         res->release(ctlr, message, res->data);
2931
2932                 list_del(&res->entry);
2933
2934                 kfree(res);
2935         }
2936 }
2937 EXPORT_SYMBOL_GPL(spi_res_release);
2938
2939 /*-------------------------------------------------------------------------*/
2940
2941 /* Core methods for spi_message alterations */
2942
2943 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2944                                             struct spi_message *msg,
2945                                             void *res)
2946 {
2947         struct spi_replaced_transfers *rxfer = res;
2948         size_t i;
2949
2950         /* call extra callback if requested */
2951         if (rxfer->release)
2952                 rxfer->release(ctlr, msg, res);
2953
2954         /* insert replaced transfers back into the message */
2955         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2956
2957         /* remove the formerly inserted entries */
2958         for (i = 0; i < rxfer->inserted; i++)
2959                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2960 }
2961
2962 /**
2963  * spi_replace_transfers - replace transfers with several transfers
2964  *                         and register change with spi_message.resources
2965  * @msg:           the spi_message we work upon
2966  * @xfer_first:    the first spi_transfer we want to replace
2967  * @remove:        number of transfers to remove
2968  * @insert:        the number of transfers we want to insert instead
2969  * @release:       extra release code necessary in some circumstances
2970  * @extradatasize: extra data to allocate (with alignment guarantees
2971  *                 of struct @spi_transfer)
2972  * @gfp:           gfp flags
2973  *
2974  * Returns: pointer to @spi_replaced_transfers,
2975  *          PTR_ERR(...) in case of errors.
2976  */
2977 struct spi_replaced_transfers *spi_replace_transfers(
2978         struct spi_message *msg,
2979         struct spi_transfer *xfer_first,
2980         size_t remove,
2981         size_t insert,
2982         spi_replaced_release_t release,
2983         size_t extradatasize,
2984         gfp_t gfp)
2985 {
2986         struct spi_replaced_transfers *rxfer;
2987         struct spi_transfer *xfer;
2988         size_t i;
2989
2990         /* allocate the structure using spi_res */
2991         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2992                               struct_size(rxfer, inserted_transfers, insert)
2993                               + extradatasize,
2994                               gfp);
2995         if (!rxfer)
2996                 return ERR_PTR(-ENOMEM);
2997
2998         /* the release code to invoke before running the generic release */
2999         rxfer->release = release;
3000
3001         /* assign extradata */
3002         if (extradatasize)
3003                 rxfer->extradata =
3004                         &rxfer->inserted_transfers[insert];
3005
3006         /* init the replaced_transfers list */
3007         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3008
3009         /* assign the list_entry after which we should reinsert
3010          * the @replaced_transfers - it may be spi_message.messages!
3011          */
3012         rxfer->replaced_after = xfer_first->transfer_list.prev;
3013
3014         /* remove the requested number of transfers */
3015         for (i = 0; i < remove; i++) {
3016                 /* if the entry after replaced_after it is msg->transfers
3017                  * then we have been requested to remove more transfers
3018                  * than are in the list
3019                  */
3020                 if (rxfer->replaced_after->next == &msg->transfers) {
3021                         dev_err(&msg->spi->dev,
3022                                 "requested to remove more spi_transfers than are available\n");
3023                         /* insert replaced transfers back into the message */
3024                         list_splice(&rxfer->replaced_transfers,
3025                                     rxfer->replaced_after);
3026
3027                         /* free the spi_replace_transfer structure */
3028                         spi_res_free(rxfer);
3029
3030                         /* and return with an error */
3031                         return ERR_PTR(-EINVAL);
3032                 }
3033
3034                 /* remove the entry after replaced_after from list of
3035                  * transfers and add it to list of replaced_transfers
3036                  */
3037                 list_move_tail(rxfer->replaced_after->next,
3038                                &rxfer->replaced_transfers);
3039         }
3040
3041         /* create copy of the given xfer with identical settings
3042          * based on the first transfer to get removed
3043          */
3044         for (i = 0; i < insert; i++) {
3045                 /* we need to run in reverse order */
3046                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3047
3048                 /* copy all spi_transfer data */
3049                 memcpy(xfer, xfer_first, sizeof(*xfer));
3050
3051                 /* add to list */
3052                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3053
3054                 /* clear cs_change and delay for all but the last */
3055                 if (i) {
3056                         xfer->cs_change = false;
3057                         xfer->delay_usecs = 0;
3058                         xfer->delay.value = 0;
3059                 }
3060         }
3061
3062         /* set up inserted */
3063         rxfer->inserted = insert;
3064
3065         /* and register it with spi_res/spi_message */
3066         spi_res_add(msg, rxfer);
3067
3068         return rxfer;
3069 }
3070 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3071
3072 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3073                                         struct spi_message *msg,
3074                                         struct spi_transfer **xferp,
3075                                         size_t maxsize,
3076                                         gfp_t gfp)
3077 {
3078         struct spi_transfer *xfer = *xferp, *xfers;
3079         struct spi_replaced_transfers *srt;
3080         size_t offset;
3081         size_t count, i;
3082
3083         /* calculate how many we have to replace */
3084         count = DIV_ROUND_UP(xfer->len, maxsize);
3085
3086         /* create replacement */
3087         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3088         if (IS_ERR(srt))
3089                 return PTR_ERR(srt);
3090         xfers = srt->inserted_transfers;
3091
3092         /* now handle each of those newly inserted spi_transfers
3093          * note that the replacements spi_transfers all are preset
3094          * to the same values as *xferp, so tx_buf, rx_buf and len
3095          * are all identical (as well as most others)
3096          * so we just have to fix up len and the pointers.
3097          *
3098          * this also includes support for the depreciated
3099          * spi_message.is_dma_mapped interface
3100          */
3101
3102         /* the first transfer just needs the length modified, so we
3103          * run it outside the loop
3104          */
3105         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3106
3107         /* all the others need rx_buf/tx_buf also set */
3108         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3109                 /* update rx_buf, tx_buf and dma */
3110                 if (xfers[i].rx_buf)
3111                         xfers[i].rx_buf += offset;
3112                 if (xfers[i].rx_dma)
3113                         xfers[i].rx_dma += offset;
3114                 if (xfers[i].tx_buf)
3115                         xfers[i].tx_buf += offset;
3116                 if (xfers[i].tx_dma)
3117                         xfers[i].tx_dma += offset;
3118
3119                 /* update length */
3120                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3121         }
3122
3123         /* we set up xferp to the last entry we have inserted,
3124          * so that we skip those already split transfers
3125          */
3126         *xferp = &xfers[count - 1];
3127
3128         /* increment statistics counters */
3129         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3130                                        transfers_split_maxsize);
3131         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3132                                        transfers_split_maxsize);
3133
3134         return 0;
3135 }
3136
3137 /**
3138  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
3139  *                              when an individual transfer exceeds a
3140  *                              certain size
3141  * @ctlr:    the @spi_controller for this transfer
3142  * @msg:   the @spi_message to transform
3143  * @maxsize:  the maximum when to apply this
3144  * @gfp: GFP allocation flags
3145  *
3146  * Return: status of transformation
3147  */
3148 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3149                                 struct spi_message *msg,
3150                                 size_t maxsize,
3151                                 gfp_t gfp)
3152 {
3153         struct spi_transfer *xfer;
3154         int ret;
3155
3156         /* iterate over the transfer_list,
3157          * but note that xfer is advanced to the last transfer inserted
3158          * to avoid checking sizes again unnecessarily (also xfer does
3159          * potentiall belong to a different list by the time the
3160          * replacement has happened
3161          */
3162         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3163                 if (xfer->len > maxsize) {
3164                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3165                                                            maxsize, gfp);
3166                         if (ret)
3167                                 return ret;
3168                 }
3169         }
3170
3171         return 0;
3172 }
3173 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3174
3175 /*-------------------------------------------------------------------------*/
3176
3177 /* Core methods for SPI controller protocol drivers.  Some of the
3178  * other core methods are currently defined as inline functions.
3179  */
3180
3181 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3182                                         u8 bits_per_word)
3183 {
3184         if (ctlr->bits_per_word_mask) {
3185                 /* Only 32 bits fit in the mask */
3186                 if (bits_per_word > 32)
3187                         return -EINVAL;
3188                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3189                         return -EINVAL;
3190         }
3191
3192         return 0;
3193 }
3194
3195 /**
3196  * spi_setup - setup SPI mode and clock rate
3197  * @spi: the device whose settings are being modified
3198  * Context: can sleep, and no requests are queued to the device
3199  *
3200  * SPI protocol drivers may need to update the transfer mode if the
3201  * device doesn't work with its default.  They may likewise need
3202  * to update clock rates or word sizes from initial values.  This function
3203  * changes those settings, and must be called from a context that can sleep.
3204  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3205  * effect the next time the device is selected and data is transferred to
3206  * or from it.  When this function returns, the spi device is deselected.
3207  *
3208  * Note that this call will fail if the protocol driver specifies an option
3209  * that the underlying controller or its driver does not support.  For
3210  * example, not all hardware supports wire transfers using nine bit words,
3211  * LSB-first wire encoding, or active-high chipselects.
3212  *
3213  * Return: zero on success, else a negative error code.
3214  */
3215 int spi_setup(struct spi_device *spi)
3216 {
3217         unsigned        bad_bits, ugly_bits;
3218         int             status;
3219
3220         /* check mode to prevent that DUAL and QUAD set at the same time
3221          */
3222         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
3223                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
3224                 dev_err(&spi->dev,
3225                 "setup: can not select dual and quad at the same time\n");
3226                 return -EINVAL;
3227         }
3228         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3229          */
3230         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3231                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3232                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3233                 return -EINVAL;
3234         /* help drivers fail *cleanly* when they need options
3235          * that aren't supported with their current controller
3236          * SPI_CS_WORD has a fallback software implementation,
3237          * so it is ignored here.
3238          */
3239         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3240         /* nothing prevents from working with active-high CS in case if it
3241          * is driven by GPIO.
3242          */
3243         if (gpio_is_valid(spi->cs_gpio))
3244                 bad_bits &= ~SPI_CS_HIGH;
3245         ugly_bits = bad_bits &
3246                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3247                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3248         if (ugly_bits) {
3249                 dev_warn(&spi->dev,
3250                          "setup: ignoring unsupported mode bits %x\n",
3251                          ugly_bits);
3252                 spi->mode &= ~ugly_bits;
3253                 bad_bits &= ~ugly_bits;
3254         }
3255         if (bad_bits) {
3256                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3257                         bad_bits);
3258                 return -EINVAL;
3259         }
3260
3261         if (!spi->bits_per_word)
3262                 spi->bits_per_word = 8;
3263
3264         status = __spi_validate_bits_per_word(spi->controller,
3265                                               spi->bits_per_word);
3266         if (status)
3267                 return status;
3268
3269         if (!spi->max_speed_hz)
3270                 spi->max_speed_hz = spi->controller->max_speed_hz;
3271
3272         if (spi->controller->setup)
3273                 status = spi->controller->setup(spi);
3274
3275         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3276                 status = pm_runtime_get_sync(spi->controller->dev.parent);
3277                 if (status < 0) {
3278                         pm_runtime_put_noidle(spi->controller->dev.parent);
3279                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3280                                 status);
3281                         return status;
3282                 }
3283
3284                 /*
3285                  * We do not want to return positive value from pm_runtime_get,
3286                  * there are many instances of devices calling spi_setup() and
3287                  * checking for a non-zero return value instead of a negative
3288                  * return value.
3289                  */
3290                 status = 0;
3291
3292                 spi_set_cs(spi, false);
3293                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3294                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3295         } else {
3296                 spi_set_cs(spi, false);
3297         }
3298
3299         if (spi->rt && !spi->controller->rt) {
3300                 spi->controller->rt = true;
3301                 spi_set_thread_rt(spi->controller);
3302         }
3303
3304         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3305                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3306                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3307                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3308                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3309                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3310                         spi->bits_per_word, spi->max_speed_hz,
3311                         status);
3312
3313         return status;
3314 }
3315 EXPORT_SYMBOL_GPL(spi_setup);
3316
3317 /**
3318  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3319  * @spi: the device that requires specific CS timing configuration
3320  * @setup: CS setup time specified via @spi_delay
3321  * @hold: CS hold time specified via @spi_delay
3322  * @inactive: CS inactive delay between transfers specified via @spi_delay
3323  *
3324  * Return: zero on success, else a negative error code.
3325  */
3326 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
3327                       struct spi_delay *hold, struct spi_delay *inactive)
3328 {
3329         size_t len;
3330
3331         if (spi->controller->set_cs_timing)
3332                 return spi->controller->set_cs_timing(spi, setup, hold,
3333                                                       inactive);
3334
3335         if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
3336             (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
3337             (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
3338                 dev_err(&spi->dev,
3339                         "Clock-cycle delays for CS not supported in SW mode\n");
3340                 return -ENOTSUPP;
3341         }
3342
3343         len = sizeof(struct spi_delay);
3344
3345         /* copy delays to controller */
3346         if (setup)
3347                 memcpy(&spi->controller->cs_setup, setup, len);
3348         else
3349                 memset(&spi->controller->cs_setup, 0, len);
3350
3351         if (hold)
3352                 memcpy(&spi->controller->cs_hold, hold, len);
3353         else
3354                 memset(&spi->controller->cs_hold, 0, len);
3355
3356         if (inactive)
3357                 memcpy(&spi->controller->cs_inactive, inactive, len);
3358         else
3359                 memset(&spi->controller->cs_inactive, 0, len);
3360
3361         return 0;
3362 }
3363 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3364
3365 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3366                                        struct spi_device *spi)
3367 {
3368         int delay1, delay2;
3369
3370         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3371         if (delay1 < 0)
3372                 return delay1;
3373
3374         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3375         if (delay2 < 0)
3376                 return delay2;
3377
3378         if (delay1 < delay2)
3379                 memcpy(&xfer->word_delay, &spi->word_delay,
3380                        sizeof(xfer->word_delay));
3381
3382         return 0;
3383 }
3384
3385 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3386 {
3387         struct spi_controller *ctlr = spi->controller;
3388         struct spi_transfer *xfer;
3389         int w_size;
3390
3391         if (list_empty(&message->transfers))
3392                 return -EINVAL;
3393
3394         /* If an SPI controller does not support toggling the CS line on each
3395          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3396          * for the CS line, we can emulate the CS-per-word hardware function by
3397          * splitting transfers into one-word transfers and ensuring that
3398          * cs_change is set for each transfer.
3399          */
3400         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3401                                           spi->cs_gpiod ||
3402                                           gpio_is_valid(spi->cs_gpio))) {
3403                 size_t maxsize;
3404                 int ret;
3405
3406                 maxsize = (spi->bits_per_word + 7) / 8;
3407
3408                 /* spi_split_transfers_maxsize() requires message->spi */
3409                 message->spi = spi;
3410
3411                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3412                                                   GFP_KERNEL);
3413                 if (ret)
3414                         return ret;
3415
3416                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3417                         /* don't change cs_change on the last entry in the list */
3418                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3419                                 break;
3420                         xfer->cs_change = 1;
3421                 }
3422         }
3423
3424         /* Half-duplex links include original MicroWire, and ones with
3425          * only one data pin like SPI_3WIRE (switches direction) or where
3426          * either MOSI or MISO is missing.  They can also be caused by
3427          * software limitations.
3428          */
3429         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3430             (spi->mode & SPI_3WIRE)) {
3431                 unsigned flags = ctlr->flags;
3432
3433                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3434                         if (xfer->rx_buf && xfer->tx_buf)
3435                                 return -EINVAL;
3436                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3437                                 return -EINVAL;
3438                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3439                                 return -EINVAL;
3440                 }
3441         }
3442
3443         /**
3444          * Set transfer bits_per_word and max speed as spi device default if
3445          * it is not set for this transfer.
3446          * Set transfer tx_nbits and rx_nbits as single transfer default
3447          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3448          * Ensure transfer word_delay is at least as long as that required by
3449          * device itself.
3450          */
3451         message->frame_length = 0;
3452         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3453                 xfer->effective_speed_hz = 0;
3454                 message->frame_length += xfer->len;
3455                 if (!xfer->bits_per_word)
3456                         xfer->bits_per_word = spi->bits_per_word;
3457
3458                 if (!xfer->speed_hz)
3459                         xfer->speed_hz = spi->max_speed_hz;
3460
3461                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3462                         xfer->speed_hz = ctlr->max_speed_hz;
3463
3464                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3465                         return -EINVAL;
3466
3467                 /*
3468                  * SPI transfer length should be multiple of SPI word size
3469                  * where SPI word size should be power-of-two multiple
3470                  */
3471                 if (xfer->bits_per_word <= 8)
3472                         w_size = 1;
3473                 else if (xfer->bits_per_word <= 16)
3474                         w_size = 2;
3475                 else
3476                         w_size = 4;
3477
3478                 /* No partial transfers accepted */
3479                 if (xfer->len % w_size)
3480                         return -EINVAL;
3481
3482                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3483                     xfer->speed_hz < ctlr->min_speed_hz)
3484                         return -EINVAL;
3485
3486                 if (xfer->tx_buf && !xfer->tx_nbits)
3487                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3488                 if (xfer->rx_buf && !xfer->rx_nbits)
3489                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3490                 /* check transfer tx/rx_nbits:
3491                  * 1. check the value matches one of single, dual and quad
3492                  * 2. check tx/rx_nbits match the mode in spi_device
3493                  */
3494                 if (xfer->tx_buf) {
3495                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3496                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3497                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3498                                 return -EINVAL;
3499                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3500                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3501                                 return -EINVAL;
3502                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3503                                 !(spi->mode & SPI_TX_QUAD))
3504                                 return -EINVAL;
3505                 }
3506                 /* check transfer rx_nbits */
3507                 if (xfer->rx_buf) {
3508                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3509                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3510                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3511                                 return -EINVAL;
3512                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3513                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3514                                 return -EINVAL;
3515                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3516                                 !(spi->mode & SPI_RX_QUAD))
3517                                 return -EINVAL;
3518                 }
3519
3520                 if (_spi_xfer_word_delay_update(xfer, spi))
3521                         return -EINVAL;
3522         }
3523
3524         message->status = -EINPROGRESS;
3525
3526         return 0;
3527 }
3528
3529 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3530 {
3531         struct spi_controller *ctlr = spi->controller;
3532         struct spi_transfer *xfer;
3533
3534         /*
3535          * Some controllers do not support doing regular SPI transfers. Return
3536          * ENOTSUPP when this is the case.
3537          */
3538         if (!ctlr->transfer)
3539                 return -ENOTSUPP;
3540
3541         message->spi = spi;
3542
3543         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3544         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3545
3546         trace_spi_message_submit(message);
3547
3548         if (!ctlr->ptp_sts_supported) {
3549                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3550                         xfer->ptp_sts_word_pre = 0;
3551                         ptp_read_system_prets(xfer->ptp_sts);
3552                 }
3553         }
3554
3555         return ctlr->transfer(spi, message);
3556 }
3557
3558 /**
3559  * spi_async - asynchronous SPI transfer
3560  * @spi: device with which data will be exchanged
3561  * @message: describes the data transfers, including completion callback
3562  * Context: any (irqs may be blocked, etc)
3563  *
3564  * This call may be used in_irq and other contexts which can't sleep,
3565  * as well as from task contexts which can sleep.
3566  *
3567  * The completion callback is invoked in a context which can't sleep.
3568  * Before that invocation, the value of message->status is undefined.
3569  * When the callback is issued, message->status holds either zero (to
3570  * indicate complete success) or a negative error code.  After that
3571  * callback returns, the driver which issued the transfer request may
3572  * deallocate the associated memory; it's no longer in use by any SPI
3573  * core or controller driver code.
3574  *
3575  * Note that although all messages to a spi_device are handled in
3576  * FIFO order, messages may go to different devices in other orders.
3577  * Some device might be higher priority, or have various "hard" access
3578  * time requirements, for example.
3579  *
3580  * On detection of any fault during the transfer, processing of
3581  * the entire message is aborted, and the device is deselected.
3582  * Until returning from the associated message completion callback,
3583  * no other spi_message queued to that device will be processed.
3584  * (This rule applies equally to all the synchronous transfer calls,
3585  * which are wrappers around this core asynchronous primitive.)
3586  *
3587  * Return: zero on success, else a negative error code.
3588  */
3589 int spi_async(struct spi_device *spi, struct spi_message *message)
3590 {
3591         struct spi_controller *ctlr = spi->controller;
3592         int ret;
3593         unsigned long flags;
3594
3595         ret = __spi_validate(spi, message);
3596         if (ret != 0)
3597                 return ret;
3598
3599         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3600
3601         if (ctlr->bus_lock_flag)
3602                 ret = -EBUSY;
3603         else
3604                 ret = __spi_async(spi, message);
3605
3606         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3607
3608         return ret;
3609 }
3610 EXPORT_SYMBOL_GPL(spi_async);
3611
3612 /**
3613  * spi_async_locked - version of spi_async with exclusive bus usage
3614  * @spi: device with which data will be exchanged
3615  * @message: describes the data transfers, including completion callback
3616  * Context: any (irqs may be blocked, etc)
3617  *
3618  * This call may be used in_irq and other contexts which can't sleep,
3619  * as well as from task contexts which can sleep.
3620  *
3621  * The completion callback is invoked in a context which can't sleep.
3622  * Before that invocation, the value of message->status is undefined.
3623  * When the callback is issued, message->status holds either zero (to
3624  * indicate complete success) or a negative error code.  After that
3625  * callback returns, the driver which issued the transfer request may
3626  * deallocate the associated memory; it's no longer in use by any SPI
3627  * core or controller driver code.
3628  *
3629  * Note that although all messages to a spi_device are handled in
3630  * FIFO order, messages may go to different devices in other orders.
3631  * Some device might be higher priority, or have various "hard" access
3632  * time requirements, for example.
3633  *
3634  * On detection of any fault during the transfer, processing of
3635  * the entire message is aborted, and the device is deselected.
3636  * Until returning from the associated message completion callback,
3637  * no other spi_message queued to that device will be processed.
3638  * (This rule applies equally to all the synchronous transfer calls,
3639  * which are wrappers around this core asynchronous primitive.)
3640  *
3641  * Return: zero on success, else a negative error code.
3642  */
3643 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3644 {
3645         struct spi_controller *ctlr = spi->controller;
3646         int ret;
3647         unsigned long flags;
3648
3649         ret = __spi_validate(spi, message);
3650         if (ret != 0)
3651                 return ret;
3652
3653         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3654
3655         ret = __spi_async(spi, message);
3656
3657         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3658
3659         return ret;
3660
3661 }
3662 EXPORT_SYMBOL_GPL(spi_async_locked);
3663
3664 /*-------------------------------------------------------------------------*/
3665
3666 /* Utility methods for SPI protocol drivers, layered on
3667  * top of the core.  Some other utility methods are defined as
3668  * inline functions.
3669  */
3670
3671 static void spi_complete(void *arg)
3672 {
3673         complete(arg);
3674 }
3675
3676 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3677 {
3678         DECLARE_COMPLETION_ONSTACK(done);
3679         int status;
3680         struct spi_controller *ctlr = spi->controller;
3681         unsigned long flags;
3682
3683         status = __spi_validate(spi, message);
3684         if (status != 0)
3685                 return status;
3686
3687         message->complete = spi_complete;
3688         message->context = &done;
3689         message->spi = spi;
3690
3691         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3692         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3693
3694         /* If we're not using the legacy transfer method then we will
3695          * try to transfer in the calling context so special case.
3696          * This code would be less tricky if we could remove the
3697          * support for driver implemented message queues.
3698          */
3699         if (ctlr->transfer == spi_queued_transfer) {
3700                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3701
3702                 trace_spi_message_submit(message);
3703
3704                 status = __spi_queued_transfer(spi, message, false);
3705
3706                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3707         } else {
3708                 status = spi_async_locked(spi, message);
3709         }
3710
3711         if (status == 0) {
3712                 /* Push out the messages in the calling context if we
3713                  * can.
3714                  */
3715                 if (ctlr->transfer == spi_queued_transfer) {
3716                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3717                                                        spi_sync_immediate);
3718                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3719                                                        spi_sync_immediate);
3720                         __spi_pump_messages(ctlr, false);
3721                 }
3722
3723                 wait_for_completion(&done);
3724                 status = message->status;
3725         }
3726         message->context = NULL;
3727         return status;
3728 }
3729
3730 /**
3731  * spi_sync - blocking/synchronous SPI data transfers
3732  * @spi: device with which data will be exchanged
3733  * @message: describes the data transfers
3734  * Context: can sleep
3735  *
3736  * This call may only be used from a context that may sleep.  The sleep
3737  * is non-interruptible, and has no timeout.  Low-overhead controller
3738  * drivers may DMA directly into and out of the message buffers.
3739  *
3740  * Note that the SPI device's chip select is active during the message,
3741  * and then is normally disabled between messages.  Drivers for some
3742  * frequently-used devices may want to minimize costs of selecting a chip,
3743  * by leaving it selected in anticipation that the next message will go
3744  * to the same chip.  (That may increase power usage.)
3745  *
3746  * Also, the caller is guaranteeing that the memory associated with the
3747  * message will not be freed before this call returns.
3748  *
3749  * Return: zero on success, else a negative error code.
3750  */
3751 int spi_sync(struct spi_device *spi, struct spi_message *message)
3752 {
3753         int ret;
3754
3755         mutex_lock(&spi->controller->bus_lock_mutex);
3756         ret = __spi_sync(spi, message);
3757         mutex_unlock(&spi->controller->bus_lock_mutex);
3758
3759         return ret;
3760 }
3761 EXPORT_SYMBOL_GPL(spi_sync);
3762
3763 /**
3764  * spi_sync_locked - version of spi_sync with exclusive bus usage
3765  * @spi: device with which data will be exchanged
3766  * @message: describes the data transfers
3767  * Context: can sleep
3768  *
3769  * This call may only be used from a context that may sleep.  The sleep
3770  * is non-interruptible, and has no timeout.  Low-overhead controller
3771  * drivers may DMA directly into and out of the message buffers.
3772  *
3773  * This call should be used by drivers that require exclusive access to the
3774  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3775  * be released by a spi_bus_unlock call when the exclusive access is over.
3776  *
3777  * Return: zero on success, else a negative error code.
3778  */
3779 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3780 {
3781         return __spi_sync(spi, message);
3782 }
3783 EXPORT_SYMBOL_GPL(spi_sync_locked);
3784
3785 /**
3786  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3787  * @ctlr: SPI bus master that should be locked for exclusive bus access
3788  * Context: can sleep
3789  *
3790  * This call may only be used from a context that may sleep.  The sleep
3791  * is non-interruptible, and has no timeout.
3792  *
3793  * This call should be used by drivers that require exclusive access to the
3794  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3795  * exclusive access is over. Data transfer must be done by spi_sync_locked
3796  * and spi_async_locked calls when the SPI bus lock is held.
3797  *
3798  * Return: always zero.
3799  */
3800 int spi_bus_lock(struct spi_controller *ctlr)
3801 {
3802         unsigned long flags;
3803
3804         mutex_lock(&ctlr->bus_lock_mutex);
3805
3806         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3807         ctlr->bus_lock_flag = 1;
3808         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3809
3810         /* mutex remains locked until spi_bus_unlock is called */
3811
3812         return 0;
3813 }
3814 EXPORT_SYMBOL_GPL(spi_bus_lock);
3815
3816 /**
3817  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3818  * @ctlr: SPI bus master that was locked for exclusive bus access
3819  * Context: can sleep
3820  *
3821  * This call may only be used from a context that may sleep.  The sleep
3822  * is non-interruptible, and has no timeout.
3823  *
3824  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3825  * call.
3826  *
3827  * Return: always zero.
3828  */
3829 int spi_bus_unlock(struct spi_controller *ctlr)
3830 {
3831         ctlr->bus_lock_flag = 0;
3832
3833         mutex_unlock(&ctlr->bus_lock_mutex);
3834
3835         return 0;
3836 }
3837 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3838
3839 /* portable code must never pass more than 32 bytes */
3840 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3841
3842 static u8       *buf;
3843
3844 /**
3845  * spi_write_then_read - SPI synchronous write followed by read
3846  * @spi: device with which data will be exchanged
3847  * @txbuf: data to be written (need not be dma-safe)
3848  * @n_tx: size of txbuf, in bytes
3849  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3850  * @n_rx: size of rxbuf, in bytes
3851  * Context: can sleep
3852  *
3853  * This performs a half duplex MicroWire style transaction with the
3854  * device, sending txbuf and then reading rxbuf.  The return value
3855  * is zero for success, else a negative errno status code.
3856  * This call may only be used from a context that may sleep.
3857  *
3858  * Parameters to this routine are always copied using a small buffer;
3859  * portable code should never use this for more than 32 bytes.
3860  * Performance-sensitive or bulk transfer code should instead use
3861  * spi_{async,sync}() calls with dma-safe buffers.
3862  *
3863  * Return: zero on success, else a negative error code.
3864  */
3865 int spi_write_then_read(struct spi_device *spi,
3866                 const void *txbuf, unsigned n_tx,
3867                 void *rxbuf, unsigned n_rx)
3868 {
3869         static DEFINE_MUTEX(lock);
3870
3871         int                     status;
3872         struct spi_message      message;
3873         struct spi_transfer     x[2];
3874         u8                      *local_buf;
3875
3876         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3877          * copying here, (as a pure convenience thing), but we can
3878          * keep heap costs out of the hot path unless someone else is
3879          * using the pre-allocated buffer or the transfer is too large.
3880          */
3881         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3882                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3883                                     GFP_KERNEL | GFP_DMA);
3884                 if (!local_buf)
3885                         return -ENOMEM;
3886         } else {
3887                 local_buf = buf;
3888         }
3889
3890         spi_message_init(&message);
3891         memset(x, 0, sizeof(x));
3892         if (n_tx) {
3893                 x[0].len = n_tx;
3894                 spi_message_add_tail(&x[0], &message);
3895         }
3896         if (n_rx) {
3897                 x[1].len = n_rx;
3898                 spi_message_add_tail(&x[1], &message);
3899         }
3900
3901         memcpy(local_buf, txbuf, n_tx);
3902         x[0].tx_buf = local_buf;
3903         x[1].rx_buf = local_buf + n_tx;
3904
3905         /* do the i/o */
3906         status = spi_sync(spi, &message);
3907         if (status == 0)
3908                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3909
3910         if (x[0].tx_buf == buf)
3911                 mutex_unlock(&lock);
3912         else
3913                 kfree(local_buf);
3914
3915         return status;
3916 }
3917 EXPORT_SYMBOL_GPL(spi_write_then_read);
3918
3919 /*-------------------------------------------------------------------------*/
3920
3921 #if IS_ENABLED(CONFIG_OF)
3922 /* must call put_device() when done with returned spi_device device */
3923 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3924 {
3925         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
3926
3927         return dev ? to_spi_device(dev) : NULL;
3928 }
3929 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3930 #endif /* IS_ENABLED(CONFIG_OF) */
3931
3932 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3933 /* the spi controllers are not using spi_bus, so we find it with another way */
3934 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3935 {
3936         struct device *dev;
3937
3938         dev = class_find_device_by_of_node(&spi_master_class, node);
3939         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3940                 dev = class_find_device_by_of_node(&spi_slave_class, node);
3941         if (!dev)
3942                 return NULL;
3943
3944         /* reference got in class_find_device */
3945         return container_of(dev, struct spi_controller, dev);
3946 }
3947
3948 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3949                          void *arg)
3950 {
3951         struct of_reconfig_data *rd = arg;
3952         struct spi_controller *ctlr;
3953         struct spi_device *spi;
3954
3955         switch (of_reconfig_get_state_change(action, arg)) {
3956         case OF_RECONFIG_CHANGE_ADD:
3957                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3958                 if (ctlr == NULL)
3959                         return NOTIFY_OK;       /* not for us */
3960
3961                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3962                         put_device(&ctlr->dev);
3963                         return NOTIFY_OK;
3964                 }
3965
3966                 spi = of_register_spi_device(ctlr, rd->dn);
3967                 put_device(&ctlr->dev);
3968
3969                 if (IS_ERR(spi)) {
3970                         pr_err("%s: failed to create for '%pOF'\n",
3971                                         __func__, rd->dn);
3972                         of_node_clear_flag(rd->dn, OF_POPULATED);
3973                         return notifier_from_errno(PTR_ERR(spi));
3974                 }
3975                 break;
3976
3977         case OF_RECONFIG_CHANGE_REMOVE:
3978                 /* already depopulated? */
3979                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3980                         return NOTIFY_OK;
3981
3982                 /* find our device by node */
3983                 spi = of_find_spi_device_by_node(rd->dn);
3984                 if (spi == NULL)
3985                         return NOTIFY_OK;       /* no? not meant for us */
3986
3987                 /* unregister takes one ref away */
3988                 spi_unregister_device(spi);
3989
3990                 /* and put the reference of the find */
3991                 put_device(&spi->dev);
3992                 break;
3993         }
3994
3995         return NOTIFY_OK;
3996 }
3997
3998 static struct notifier_block spi_of_notifier = {
3999         .notifier_call = of_spi_notify,
4000 };
4001 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4002 extern struct notifier_block spi_of_notifier;
4003 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4004
4005 #if IS_ENABLED(CONFIG_ACPI)
4006 static int spi_acpi_controller_match(struct device *dev, const void *data)
4007 {
4008         return ACPI_COMPANION(dev->parent) == data;
4009 }
4010
4011 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4012 {
4013         struct device *dev;
4014
4015         dev = class_find_device(&spi_master_class, NULL, adev,
4016                                 spi_acpi_controller_match);
4017         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4018                 dev = class_find_device(&spi_slave_class, NULL, adev,
4019                                         spi_acpi_controller_match);
4020         if (!dev)
4021                 return NULL;
4022
4023         return container_of(dev, struct spi_controller, dev);
4024 }
4025
4026 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4027 {
4028         struct device *dev;
4029
4030         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4031         return to_spi_device(dev);
4032 }
4033
4034 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4035                            void *arg)
4036 {
4037         struct acpi_device *adev = arg;
4038         struct spi_controller *ctlr;
4039         struct spi_device *spi;
4040
4041         switch (value) {
4042         case ACPI_RECONFIG_DEVICE_ADD:
4043                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4044                 if (!ctlr)
4045                         break;
4046
4047                 acpi_register_spi_device(ctlr, adev);
4048                 put_device(&ctlr->dev);
4049                 break;
4050         case ACPI_RECONFIG_DEVICE_REMOVE:
4051                 if (!acpi_device_enumerated(adev))
4052                         break;
4053
4054                 spi = acpi_spi_find_device_by_adev(adev);
4055                 if (!spi)
4056                         break;
4057
4058                 spi_unregister_device(spi);
4059                 put_device(&spi->dev);
4060                 break;
4061         }
4062
4063         return NOTIFY_OK;
4064 }
4065
4066 static struct notifier_block spi_acpi_notifier = {
4067         .notifier_call = acpi_spi_notify,
4068 };
4069 #else
4070 extern struct notifier_block spi_acpi_notifier;
4071 #endif
4072
4073 static int __init spi_init(void)
4074 {
4075         int     status;
4076
4077         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4078         if (!buf) {
4079                 status = -ENOMEM;
4080                 goto err0;
4081         }
4082
4083         status = bus_register(&spi_bus_type);
4084         if (status < 0)
4085                 goto err1;
4086
4087         status = class_register(&spi_master_class);
4088         if (status < 0)
4089                 goto err2;
4090
4091         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4092                 status = class_register(&spi_slave_class);
4093                 if (status < 0)
4094                         goto err3;
4095         }
4096
4097         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4098                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4099         if (IS_ENABLED(CONFIG_ACPI))
4100                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4101
4102         return 0;
4103
4104 err3:
4105         class_unregister(&spi_master_class);
4106 err2:
4107         bus_unregister(&spi_bus_type);
4108 err1:
4109         kfree(buf);
4110         buf = NULL;
4111 err0:
4112         return status;
4113 }
4114
4115 /* board_info is normally registered in arch_initcall(),
4116  * but even essential drivers wait till later
4117  *
4118  * REVISIT only boardinfo really needs static linking. the rest (device and
4119  * driver registration) _could_ be dynamically linked (modular) ... costs
4120  * include needing to have boardinfo data structures be much more public.
4121  */
4122 postcore_initcall(spi_init);