drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/property.h>
  35 #include <linux/export.h>
  36 #include <linux/sched/rt.h>
  37 #include <uapi/linux/sched/types.h>
  38 #include <linux/delay.h>
  39 #include <linux/kthread.h>
  40 #include <linux/ioport.h>
  41 #include <linux/acpi.h>
  42 #include <linux/highmem.h>
  43
  44 #define CREATE_TRACE_POINTS
  45 #include <trace/events/spi.h>
  46
  47 static void spidev_release(struct device *dev)
  48 {
  49         struct spi_device       *spi = to_spi_device(dev);
  50
  51         /* spi controllers may cleanup for released devices */
  52         if (spi->controller->cleanup)
  53                 spi->controller->cleanup(spi);
  54
  55         spi_controller_put(spi->controller);
  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 #define SPI_STATISTICS_ATTRS(field, file)                               \
  74 static ssize_t spi_controller_##field##_show(struct device *dev,        \
  75                                              struct device_attribute *attr, \
  76                                              char *buf)                 \
  77 {                                                                       \
  78         struct spi_controller *ctlr = container_of(dev,                 \
  79                                          struct spi_controller, dev);   \
  80         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
  81 }                                                                       \
  82 static struct device_attribute dev_attr_spi_controller_##field = {      \
  83         .attr = { .name = file, .mode = 0444 },                         \
  84         .show = spi_controller_##field##_show,                          \
  85 };                                                                      \
  86 static ssize_t spi_device_##field##_show(struct device *dev,            \
  87                                          struct device_attribute *attr, \
  88                                         char *buf)                      \
  89 {                                                                       \
  90         struct spi_device *spi = to_spi_device(dev);                    \
  91         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  92 }                                                                       \
  93 static struct device_attribute dev_attr_spi_device_##field = {          \
  94         .attr = { .name = file, .mode = 0444 },                         \
  95         .show = spi_device_##field##_show,                              \
  96 }
  97
  98 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  99 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 100                                             char *buf)                  \
 101 {                                                                       \
 102         unsigned long flags;                                            \
 103         ssize_t len;                                                    \
 104         spin_lock_irqsave(&stat->lock, flags);                          \
 105         len = sprintf(buf, format_string, stat->field);                 \
 106         spin_unlock_irqrestore(&stat->lock, flags);                     \
 107         return len;                                                     \
 108 }                                                                       \
 109 SPI_STATISTICS_ATTRS(name, file)
 110
 111 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 112         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 113                                  field, format_string)
 114
 115 SPI_STATISTICS_SHOW(messages, "%lu");
 116 SPI_STATISTICS_SHOW(transfers, "%lu");
 117 SPI_STATISTICS_SHOW(errors, "%lu");
 118 SPI_STATISTICS_SHOW(timedout, "%lu");
 119
 120 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 121 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 122 SPI_STATISTICS_SHOW(spi_async, "%lu");
 123
 124 SPI_STATISTICS_SHOW(bytes, "%llu");
 125 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 126 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 127
 128 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 129         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 130                                  "transfer_bytes_histo_" number,        \
 131                                  transfer_bytes_histo[index],  "%lu")
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 147 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 148 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 149
 150 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 151
 152 static struct attribute *spi_dev_attrs[] = {
 153         &dev_attr_modalias.attr,
 154         NULL,
 155 };
 156
 157 static const struct attribute_group spi_dev_group = {
 158         .attrs  = spi_dev_attrs,
 159 };
 160
 161 static struct attribute *spi_device_statistics_attrs[] = {
 162         &dev_attr_spi_device_messages.attr,
 163         &dev_attr_spi_device_transfers.attr,
 164         &dev_attr_spi_device_errors.attr,
 165         &dev_attr_spi_device_timedout.attr,
 166         &dev_attr_spi_device_spi_sync.attr,
 167         &dev_attr_spi_device_spi_sync_immediate.attr,
 168         &dev_attr_spi_device_spi_async.attr,
 169         &dev_attr_spi_device_bytes.attr,
 170         &dev_attr_spi_device_bytes_rx.attr,
 171         &dev_attr_spi_device_bytes_tx.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 186         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 187         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 188         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 189         &dev_attr_spi_device_transfers_split_maxsize.attr,
 190         NULL,
 191 };
 192
 193 static const struct attribute_group spi_device_statistics_group = {
 194         .name  = "statistics",
 195         .attrs  = spi_device_statistics_attrs,
 196 };
 197
 198 static const struct attribute_group *spi_dev_groups[] = {
 199         &spi_dev_group,
 200         &spi_device_statistics_group,
 201         NULL,
 202 };
 203
 204 static struct attribute *spi_controller_statistics_attrs[] = {
 205         &dev_attr_spi_controller_messages.attr,
 206         &dev_attr_spi_controller_transfers.attr,
 207         &dev_attr_spi_controller_errors.attr,
 208         &dev_attr_spi_controller_timedout.attr,
 209         &dev_attr_spi_controller_spi_sync.attr,
 210         &dev_attr_spi_controller_spi_sync_immediate.attr,
 211         &dev_attr_spi_controller_spi_async.attr,
 212         &dev_attr_spi_controller_bytes.attr,
 213         &dev_attr_spi_controller_bytes_rx.attr,
 214         &dev_attr_spi_controller_bytes_tx.attr,
 215         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 216         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 217         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 218         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 219         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 220         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 221         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 222         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 223         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 224         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 225         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 226         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 227         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 228         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 229         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 230         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 231         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 232         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 233         NULL,
 234 };
 235
 236 static const struct attribute_group spi_controller_statistics_group = {
 237         .name  = "statistics",
 238         .attrs  = spi_controller_statistics_attrs,
 239 };
 240
 241 static const struct attribute_group *spi_master_groups[] = {
 242         &spi_controller_statistics_group,
 243         NULL,
 244 };
 245
 246 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 247                                        struct spi_transfer *xfer,
 248                                        struct spi_controller *ctlr)
 249 {
 250         unsigned long flags;
 251         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 252
 253         if (l2len < 0)
 254                 l2len = 0;
 255
 256         spin_lock_irqsave(&stats->lock, flags);
 257
 258         stats->transfers++;
 259         stats->transfer_bytes_histo[l2len]++;
 260
 261         stats->bytes += xfer->len;
 262         if ((xfer->tx_buf) &&
 263             (xfer->tx_buf != ctlr->dummy_tx))
 264                 stats->bytes_tx += xfer->len;
 265         if ((xfer->rx_buf) &&
 266             (xfer->rx_buf != ctlr->dummy_rx))
 267                 stats->bytes_rx += xfer->len;
 268
 269         spin_unlock_irqrestore(&stats->lock, flags);
 270 }
 271 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 272
 273 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 274  * and the sysfs version makes coldplug work too.
 275  */
 276
 277 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 278                                                 const struct spi_device *sdev)
 279 {
 280         while (id->name[0]) {
 281                 if (!strcmp(sdev->modalias, id->name))
 282                         return id;
 283                 id++;
 284         }
 285         return NULL;
 286 }
 287
 288 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 289 {
 290         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 291
 292         return spi_match_id(sdrv->id_table, sdev);
 293 }
 294 EXPORT_SYMBOL_GPL(spi_get_device_id);
 295
 296 static int spi_match_device(struct device *dev, struct device_driver *drv)
 297 {
 298         const struct spi_device *spi = to_spi_device(dev);
 299         const struct spi_driver *sdrv = to_spi_driver(drv);
 300
 301         /* Attempt an OF style match */
 302         if (of_driver_match_device(dev, drv))
 303                 return 1;
 304
 305         /* Then try ACPI */
 306         if (acpi_driver_match_device(dev, drv))
 307                 return 1;
 308
 309         if (sdrv->id_table)
 310                 return !!spi_match_id(sdrv->id_table, spi);
 311
 312         return strcmp(spi->modalias, drv->name) == 0;
 313 }
 314
 315 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 316 {
 317         const struct spi_device         *spi = to_spi_device(dev);
 318         int rc;
 319
 320         rc = acpi_device_uevent_modalias(dev, env);
 321         if (rc != -ENODEV)
 322                 return rc;
 323
 324         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 325         return 0;
 326 }
 327
 328 struct bus_type spi_bus_type = {
 329         .name           = "spi",
 330         .dev_groups     = spi_dev_groups,
 331         .match          = spi_match_device,
 332         .uevent         = spi_uevent,
 333 };
 334 EXPORT_SYMBOL_GPL(spi_bus_type);
 335
 336
 337 static int spi_drv_probe(struct device *dev)
 338 {
 339         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 340         struct spi_device               *spi = to_spi_device(dev);
 341         int ret;
 342
 343         ret = of_clk_set_defaults(dev->of_node, false);
 344         if (ret)
 345                 return ret;
 346
 347         if (dev->of_node) {
 348                 spi->irq = of_irq_get(dev->of_node, 0);
 349                 if (spi->irq == -EPROBE_DEFER)
 350                         return -EPROBE_DEFER;
 351                 if (spi->irq < 0)
 352                         spi->irq = 0;
 353         }
 354
 355         ret = dev_pm_domain_attach(dev, true);
 356         if (ret != -EPROBE_DEFER) {
 357                 ret = sdrv->probe(spi);
 358                 if (ret)
 359                         dev_pm_domain_detach(dev, true);
 360         }
 361
 362         return ret;
 363 }
 364
 365 static int spi_drv_remove(struct device *dev)
 366 {
 367         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 368         int ret;
 369
 370         ret = sdrv->remove(to_spi_device(dev));
 371         dev_pm_domain_detach(dev, true);
 372
 373         return ret;
 374 }
 375
 376 static void spi_drv_shutdown(struct device *dev)
 377 {
 378         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 379
 380         sdrv->shutdown(to_spi_device(dev));
 381 }
 382
 383 /**
 384  * __spi_register_driver - register a SPI driver
 385  * @owner: owner module of the driver to register
 386  * @sdrv: the driver to register
 387  * Context: can sleep
 388  *
 389  * Return: zero on success, else a negative error code.
 390  */
 391 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 392 {
 393         sdrv->driver.owner = owner;
 394         sdrv->driver.bus = &spi_bus_type;
 395         if (sdrv->probe)
 396                 sdrv->driver.probe = spi_drv_probe;
 397         if (sdrv->remove)
 398                 sdrv->driver.remove = spi_drv_remove;
 399         if (sdrv->shutdown)
 400                 sdrv->driver.shutdown = spi_drv_shutdown;
 401         return driver_register(&sdrv->driver);
 402 }
 403 EXPORT_SYMBOL_GPL(__spi_register_driver);
 404
 405 /*-------------------------------------------------------------------------*/
 406
 407 /* SPI devices should normally not be created by SPI device drivers; that
 408  * would make them board-specific.  Similarly with SPI controller drivers.
 409  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 410  * with other readonly (flashable) information about mainboard devices.
 411  */
 412
 413 struct boardinfo {
 414         struct list_head        list;
 415         struct spi_board_info   board_info;
 416 };
 417
 418 static LIST_HEAD(board_list);
 419 static LIST_HEAD(spi_controller_list);
 420
 421 /*
 422  * Used to protect add/del opertion for board_info list and
 423  * spi_controller list, and their matching process
 424  */
 425 static DEFINE_MUTEX(board_lock);
 426
 427 /**
 428  * spi_alloc_device - Allocate a new SPI device
 429  * @ctlr: Controller to which device is connected
 430  * Context: can sleep
 431  *
 432  * Allows a driver to allocate and initialize a spi_device without
 433  * registering it immediately.  This allows a driver to directly
 434  * fill the spi_device with device parameters before calling
 435  * spi_add_device() on it.
 436  *
 437  * Caller is responsible to call spi_add_device() on the returned
 438  * spi_device structure to add it to the SPI controller.  If the caller
 439  * needs to discard the spi_device without adding it, then it should
 440  * call spi_dev_put() on it.
 441  *
 442  * Return: a pointer to the new device, or NULL.
 443  */
 444 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 445 {
 446         struct spi_device       *spi;
 447
 448         if (!spi_controller_get(ctlr))
 449                 return NULL;
 450
 451         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 452         if (!spi) {
 453                 spi_controller_put(ctlr);
 454                 return NULL;
 455         }
 456
 457         spi->master = spi->controller = ctlr;
 458         spi->dev.parent = &ctlr->dev;
 459         spi->dev.bus = &spi_bus_type;
 460         spi->dev.release = spidev_release;
 461         spi->cs_gpio = -ENOENT;
 462
 463         spin_lock_init(&spi->statistics.lock);
 464
 465         device_initialize(&spi->dev);
 466         return spi;
 467 }
 468 EXPORT_SYMBOL_GPL(spi_alloc_device);
 469
 470 static void spi_dev_set_name(struct spi_device *spi)
 471 {
 472         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 473
 474         if (adev) {
 475                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 476                 return;
 477         }
 478
 479         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 480                      spi->chip_select);
 481 }
 482
 483 static int spi_dev_check(struct device *dev, void *data)
 484 {
 485         struct spi_device *spi = to_spi_device(dev);
 486         struct spi_device *new_spi = data;
 487
 488         if (spi->controller == new_spi->controller &&
 489             spi->chip_select == new_spi->chip_select)
 490                 return -EBUSY;
 491         return 0;
 492 }
 493
 494 /**
 495  * spi_add_device - Add spi_device allocated with spi_alloc_device
 496  * @spi: spi_device to register
 497  *
 498  * Companion function to spi_alloc_device.  Devices allocated with
 499  * spi_alloc_device can be added onto the spi bus with this function.
 500  *
 501  * Return: 0 on success; negative errno on failure
 502  */
 503 int spi_add_device(struct spi_device *spi)
 504 {
 505         static DEFINE_MUTEX(spi_add_lock);
 506         struct spi_controller *ctlr = spi->controller;
 507         struct device *dev = ctlr->dev.parent;
 508         int status;
 509
 510         /* Chipselects are numbered 0..max; validate. */
 511         if (spi->chip_select >= ctlr->num_chipselect) {
 512                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 513                         ctlr->num_chipselect);
 514                 return -EINVAL;
 515         }
 516
 517         /* Set the bus ID string */
 518         spi_dev_set_name(spi);
 519
 520         /* We need to make sure there's no other device with this
 521          * chipselect **BEFORE** we call setup(), else we'll trash
 522          * its configuration.  Lock against concurrent add() calls.
 523          */
 524         mutex_lock(&spi_add_lock);
 525
 526         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 527         if (status) {
 528                 dev_err(dev, "chipselect %d already in use\n",
 529                                 spi->chip_select);
 530                 goto done;
 531         }
 532
 533         if (ctlr->cs_gpios)
 534                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 535
 536         /* Drivers may modify this initial i/o setup, but will
 537          * normally rely on the device being setup.  Devices
 538          * using SPI_CS_HIGH can't coexist well otherwise...
 539          */
 540         status = spi_setup(spi);
 541         if (status < 0) {
 542                 dev_err(dev, "can't setup %s, status %d\n",
 543                                 dev_name(&spi->dev), status);
 544                 goto done;
 545         }
 546
 547         /* Device may be bound to an active driver when this returns */
 548         status = device_add(&spi->dev);
 549         if (status < 0)
 550                 dev_err(dev, "can't add %s, status %d\n",
 551                                 dev_name(&spi->dev), status);
 552         else
 553                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 554
 555 done:
 556         mutex_unlock(&spi_add_lock);
 557         return status;
 558 }
 559 EXPORT_SYMBOL_GPL(spi_add_device);
 560
 561 /**
 562  * spi_new_device - instantiate one new SPI device
 563  * @ctlr: Controller to which device is connected
 564  * @chip: Describes the SPI device
 565  * Context: can sleep
 566  *
 567  * On typical mainboards, this is purely internal; and it's not needed
 568  * after board init creates the hard-wired devices.  Some development
 569  * platforms may not be able to use spi_register_board_info though, and
 570  * this is exported so that for example a USB or parport based adapter
 571  * driver could add devices (which it would learn about out-of-band).
 572  *
 573  * Return: the new device, or NULL.
 574  */
 575 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 576                                   struct spi_board_info *chip)
 577 {
 578         struct spi_device       *proxy;
 579         int                     status;
 580
 581         /* NOTE:  caller did any chip->bus_num checks necessary.
 582          *
 583          * Also, unless we change the return value convention to use
 584          * error-or-pointer (not NULL-or-pointer), troubleshootability
 585          * suggests syslogged diagnostics are best here (ugh).
 586          */
 587
 588         proxy = spi_alloc_device(ctlr);
 589         if (!proxy)
 590                 return NULL;
 591
 592         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 593
 594         proxy->chip_select = chip->chip_select;
 595         proxy->max_speed_hz = chip->max_speed_hz;
 596         proxy->mode = chip->mode;
 597         proxy->irq = chip->irq;
 598         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 599         proxy->dev.platform_data = (void *) chip->platform_data;
 600         proxy->controller_data = chip->controller_data;
 601         proxy->controller_state = NULL;
 602
 603         if (chip->properties) {
 604                 status = device_add_properties(&proxy->dev, chip->properties);
 605                 if (status) {
 606                         dev_err(&ctlr->dev,
 607                                 "failed to add properties to '%s': %d\n",
 608                                 chip->modalias, status);
 609                         goto err_dev_put;
 610                 }
 611         }
 612
 613         status = spi_add_device(proxy);
 614         if (status < 0)
 615                 goto err_remove_props;
 616
 617         return proxy;
 618
 619 err_remove_props:
 620         if (chip->properties)
 621                 device_remove_properties(&proxy->dev);
 622 err_dev_put:
 623         spi_dev_put(proxy);
 624         return NULL;
 625 }
 626 EXPORT_SYMBOL_GPL(spi_new_device);
 627
 628 /**
 629  * spi_unregister_device - unregister a single SPI device
 630  * @spi: spi_device to unregister
 631  *
 632  * Start making the passed SPI device vanish. Normally this would be handled
 633  * by spi_unregister_controller().
 634  */
 635 void spi_unregister_device(struct spi_device *spi)
 636 {
 637         if (!spi)
 638                 return;
 639
 640         if (spi->dev.of_node) {
 641                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 642                 of_node_put(spi->dev.of_node);
 643         }
 644         if (ACPI_COMPANION(&spi->dev))
 645                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 646         device_unregister(&spi->dev);
 647 }
 648 EXPORT_SYMBOL_GPL(spi_unregister_device);
 649
 650 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 651                                               struct spi_board_info *bi)
 652 {
 653         struct spi_device *dev;
 654
 655         if (ctlr->bus_num != bi->bus_num)
 656                 return;
 657
 658         dev = spi_new_device(ctlr, bi);
 659         if (!dev)
 660                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 661                         bi->modalias);
 662 }
 663
 664 /**
 665  * spi_register_board_info - register SPI devices for a given board
 666  * @info: array of chip descriptors
 667  * @n: how many descriptors are provided
 668  * Context: can sleep
 669  *
 670  * Board-specific early init code calls this (probably during arch_initcall)
 671  * with segments of the SPI device table.  Any device nodes are created later,
 672  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 673  * this table of devices forever, so that reloading a controller driver will
 674  * not make Linux forget about these hard-wired devices.
 675  *
 676  * Other code can also call this, e.g. a particular add-on board might provide
 677  * SPI devices through its expansion connector, so code initializing that board
 678  * would naturally declare its SPI devices.
 679  *
 680  * The board info passed can safely be __initdata ... but be careful of
 681  * any embedded pointers (platform_data, etc), they're copied as-is.
 682  * Device properties are deep-copied though.
 683  *
 684  * Return: zero on success, else a negative error code.
 685  */
 686 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 687 {
 688         struct boardinfo *bi;
 689         int i;
 690
 691         if (!n)
 692                 return 0;
 693
 694         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 695         if (!bi)
 696                 return -ENOMEM;
 697
 698         for (i = 0; i < n; i++, bi++, info++) {
 699                 struct spi_controller *ctlr;
 700
 701                 memcpy(&bi->board_info, info, sizeof(*info));
 702                 if (info->properties) {
 703                         bi->board_info.properties =
 704                                         property_entries_dup(info->properties);
 705                         if (IS_ERR(bi->board_info.properties))
 706                                 return PTR_ERR(bi->board_info.properties);
 707                 }
 708
 709                 mutex_lock(&board_lock);
 710                 list_add_tail(&bi->list, &board_list);
 711                 list_for_each_entry(ctlr, &spi_controller_list, list)
 712                         spi_match_controller_to_boardinfo(ctlr,
 713                                                           &bi->board_info);
 714                 mutex_unlock(&board_lock);
 715         }
 716
 717         return 0;
 718 }
 719
 720 /*-------------------------------------------------------------------------*/
 721
 722 static void spi_set_cs(struct spi_device *spi, bool enable)
 723 {
 724         if (spi->mode & SPI_CS_HIGH)
 725                 enable = !enable;
 726
 727         if (gpio_is_valid(spi->cs_gpio)) {
 728                 gpio_set_value(spi->cs_gpio, !enable);
 729                 /* Some SPI masters need both GPIO CS & slave_select */
 730                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 731                     spi->controller->set_cs)
 732                         spi->controller->set_cs(spi, !enable);
 733         } else if (spi->controller->set_cs) {
 734                 spi->controller->set_cs(spi, !enable);
 735         }
 736 }
 737
 738 #ifdef CONFIG_HAS_DMA
 739 static int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 740                        struct sg_table *sgt, void *buf, size_t len,
 741                        enum dma_data_direction dir)
 742 {
 743         const bool vmalloced_buf = is_vmalloc_addr(buf);
 744         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 745 #ifdef CONFIG_HIGHMEM
 746         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 747                                 (unsigned long)buf < (PKMAP_BASE +
 748                                         (LAST_PKMAP * PAGE_SIZE)));
 749 #else
 750         const bool kmap_buf = false;
 751 #endif
 752         int desc_len;
 753         int sgs;
 754         struct page *vm_page;
 755         struct scatterlist *sg;
 756         void *sg_buf;
 757         size_t min;
 758         int i, ret;
 759
 760         if (vmalloced_buf || kmap_buf) {
 761                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 762                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 763         } else if (virt_addr_valid(buf)) {
 764                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 765                 sgs = DIV_ROUND_UP(len, desc_len);
 766         } else {
 767                 return -EINVAL;
 768         }
 769
 770         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 771         if (ret != 0)
 772                 return ret;
 773
 774         sg = &sgt->sgl[0];
 775         for (i = 0; i < sgs; i++) {
 776
 777                 if (vmalloced_buf || kmap_buf) {
 778                         min = min_t(size_t,
 779                                     len, desc_len - offset_in_page(buf));
 780                         if (vmalloced_buf)
 781                                 vm_page = vmalloc_to_page(buf);
 782                         else
 783                                 vm_page = kmap_to_page(buf);
 784                         if (!vm_page) {
 785                                 sg_free_table(sgt);
 786                                 return -ENOMEM;
 787                         }
 788                         sg_set_page(sg, vm_page,
 789                                     min, offset_in_page(buf));
 790                 } else {
 791                         min = min_t(size_t, len, desc_len);
 792                         sg_buf = buf;
 793                         sg_set_buf(sg, sg_buf, min);
 794                 }
 795
 796                 buf += min;
 797                 len -= min;
 798                 sg = sg_next(sg);
 799         }
 800
 801         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 802         if (!ret)
 803                 ret = -ENOMEM;
 804         if (ret < 0) {
 805                 sg_free_table(sgt);
 806                 return ret;
 807         }
 808
 809         sgt->nents = ret;
 810
 811         return 0;
 812 }
 813
 814 static void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 815                           struct sg_table *sgt, enum dma_data_direction dir)
 816 {
 817         if (sgt->orig_nents) {
 818                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 819                 sg_free_table(sgt);
 820         }
 821 }
 822
 823 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 824 {
 825         struct device *tx_dev, *rx_dev;
 826         struct spi_transfer *xfer;
 827         int ret;
 828
 829         if (!ctlr->can_dma)
 830                 return 0;
 831
 832         if (ctlr->dma_tx)
 833                 tx_dev = ctlr->dma_tx->device->dev;
 834         else
 835                 tx_dev = ctlr->dev.parent;
 836
 837         if (ctlr->dma_rx)
 838                 rx_dev = ctlr->dma_rx->device->dev;
 839         else
 840                 rx_dev = ctlr->dev.parent;
 841
 842         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 843                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 844                         continue;
 845
 846                 if (xfer->tx_buf != NULL) {
 847                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 848                                           (void *)xfer->tx_buf, xfer->len,
 849                                           DMA_TO_DEVICE);
 850                         if (ret != 0)
 851                                 return ret;
 852                 }
 853
 854                 if (xfer->rx_buf != NULL) {
 855                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 856                                           xfer->rx_buf, xfer->len,
 857                                           DMA_FROM_DEVICE);
 858                         if (ret != 0) {
 859                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 860                                               DMA_TO_DEVICE);
 861                                 return ret;
 862                         }
 863                 }
 864         }
 865
 866         ctlr->cur_msg_mapped = true;
 867
 868         return 0;
 869 }
 870
 871 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 872 {
 873         struct spi_transfer *xfer;
 874         struct device *tx_dev, *rx_dev;
 875
 876         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 877                 return 0;
 878
 879         if (ctlr->dma_tx)
 880                 tx_dev = ctlr->dma_tx->device->dev;
 881         else
 882                 tx_dev = ctlr->dev.parent;
 883
 884         if (ctlr->dma_rx)
 885                 rx_dev = ctlr->dma_rx->device->dev;
 886         else
 887                 rx_dev = ctlr->dev.parent;
 888
 889         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 890                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 891                         continue;
 892
 893                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 894                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 895         }
 896
 897         return 0;
 898 }
 899 #else /* !CONFIG_HAS_DMA */
 900 static inline int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 901                               struct sg_table *sgt, void *buf, size_t len,
 902                               enum dma_data_direction dir)
 903 {
 904         return -EINVAL;
 905 }
 906
 907 static inline void spi_unmap_buf(struct spi_controller *ctlr,
 908                                  struct device *dev, struct sg_table *sgt,
 909                                  enum dma_data_direction dir)
 910 {
 911 }
 912
 913 static inline int __spi_map_msg(struct spi_controller *ctlr,
 914                                 struct spi_message *msg)
 915 {
 916         return 0;
 917 }
 918
 919 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 920                                   struct spi_message *msg)
 921 {
 922         return 0;
 923 }
 924 #endif /* !CONFIG_HAS_DMA */
 925
 926 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 927                                 struct spi_message *msg)
 928 {
 929         struct spi_transfer *xfer;
 930
 931         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 932                 /*
 933                  * Restore the original value of tx_buf or rx_buf if they are
 934                  * NULL.
 935                  */
 936                 if (xfer->tx_buf == ctlr->dummy_tx)
 937                         xfer->tx_buf = NULL;
 938                 if (xfer->rx_buf == ctlr->dummy_rx)
 939                         xfer->rx_buf = NULL;
 940         }
 941
 942         return __spi_unmap_msg(ctlr, msg);
 943 }
 944
 945 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 946 {
 947         struct spi_transfer *xfer;
 948         void *tmp;
 949         unsigned int max_tx, max_rx;
 950
 951         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
 952                 max_tx = 0;
 953                 max_rx = 0;
 954
 955                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 956                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
 957                             !xfer->tx_buf)
 958                                 max_tx = max(xfer->len, max_tx);
 959                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
 960                             !xfer->rx_buf)
 961                                 max_rx = max(xfer->len, max_rx);
 962                 }
 963
 964                 if (max_tx) {
 965                         tmp = krealloc(ctlr->dummy_tx, max_tx,
 966                                        GFP_KERNEL | GFP_DMA);
 967                         if (!tmp)
 968                                 return -ENOMEM;
 969                         ctlr->dummy_tx = tmp;
 970                         memset(tmp, 0, max_tx);
 971                 }
 972
 973                 if (max_rx) {
 974                         tmp = krealloc(ctlr->dummy_rx, max_rx,
 975                                        GFP_KERNEL | GFP_DMA);
 976                         if (!tmp)
 977                                 return -ENOMEM;
 978                         ctlr->dummy_rx = tmp;
 979                 }
 980
 981                 if (max_tx || max_rx) {
 982                         list_for_each_entry(xfer, &msg->transfers,
 983                                             transfer_list) {
 984                                 if (!xfer->tx_buf)
 985                                         xfer->tx_buf = ctlr->dummy_tx;
 986                                 if (!xfer->rx_buf)
 987                                         xfer->rx_buf = ctlr->dummy_rx;
 988                         }
 989                 }
 990         }
 991
 992         return __spi_map_msg(ctlr, msg);
 993 }
 994
 995 /*
 996  * spi_transfer_one_message - Default implementation of transfer_one_message()
 997  *
 998  * This is a standard implementation of transfer_one_message() for
 999  * drivers which implement a transfer_one() operation.  It provides
1000  * standard handling of delays and chip select management.
1001  */
1002 static int spi_transfer_one_message(struct spi_controller *ctlr,
1003                                     struct spi_message *msg)
1004 {
1005         struct spi_transfer *xfer;
1006         bool keep_cs = false;
1007         int ret = 0;
1008         unsigned long long ms = 1;
1009         struct spi_statistics *statm = &ctlr->statistics;
1010         struct spi_statistics *stats = &msg->spi->statistics;
1011
1012         spi_set_cs(msg->spi, true);
1013
1014         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1015         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1016
1017         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1018                 trace_spi_transfer_start(msg, xfer);
1019
1020                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1021                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1022
1023                 if (xfer->tx_buf || xfer->rx_buf) {
1024                         reinit_completion(&ctlr->xfer_completion);
1025
1026                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1027                         if (ret < 0) {
1028                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1029                                                                errors);
1030                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1031                                                                errors);
1032                                 dev_err(&msg->spi->dev,
1033                                         "SPI transfer failed: %d\n", ret);
1034                                 goto out;
1035                         }
1036
1037                         if (ret > 0) {
1038                                 ret = 0;
1039                                 ms = 8LL * 1000LL * xfer->len;
1040                                 do_div(ms, xfer->speed_hz);
1041                                 ms += ms + 200; /* some tolerance */
1042
1043                                 if (ms > UINT_MAX)
1044                                         ms = UINT_MAX;
1045
1046                                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1047                                                                  msecs_to_jiffies(ms));
1048                         }
1049
1050                         if (ms == 0) {
1051                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1052                                                                timedout);
1053                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1054                                                                timedout);
1055                                 dev_err(&msg->spi->dev,
1056                                         "SPI transfer timed out\n");
1057                                 msg->status = -ETIMEDOUT;
1058                         }
1059                 } else {
1060                         if (xfer->len)
1061                                 dev_err(&msg->spi->dev,
1062                                         "Bufferless transfer has length %u\n",
1063                                         xfer->len);
1064                 }
1065
1066                 trace_spi_transfer_stop(msg, xfer);
1067
1068                 if (msg->status != -EINPROGRESS)
1069                         goto out;
1070
1071                 if (xfer->delay_usecs) {
1072                         u16 us = xfer->delay_usecs;
1073
1074                         if (us <= 10)
1075                                 udelay(us);
1076                         else
1077                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1078                 }
1079
1080                 if (xfer->cs_change) {
1081                         if (list_is_last(&xfer->transfer_list,
1082                                          &msg->transfers)) {
1083                                 keep_cs = true;
1084                         } else {
1085                                 spi_set_cs(msg->spi, false);
1086                                 udelay(10);
1087                                 spi_set_cs(msg->spi, true);
1088                         }
1089                 }
1090
1091                 msg->actual_length += xfer->len;
1092         }
1093
1094 out:
1095         if (ret != 0 || !keep_cs)
1096                 spi_set_cs(msg->spi, false);
1097
1098         if (msg->status == -EINPROGRESS)
1099                 msg->status = ret;
1100
1101         if (msg->status && ctlr->handle_err)
1102                 ctlr->handle_err(ctlr, msg);
1103
1104         spi_res_release(ctlr, msg);
1105
1106         spi_finalize_current_message(ctlr);
1107
1108         return ret;
1109 }
1110
1111 /**
1112  * spi_finalize_current_transfer - report completion of a transfer
1113  * @ctlr: the controller reporting completion
1114  *
1115  * Called by SPI drivers using the core transfer_one_message()
1116  * implementation to notify it that the current interrupt driven
1117  * transfer has finished and the next one may be scheduled.
1118  */
1119 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1120 {
1121         complete(&ctlr->xfer_completion);
1122 }
1123 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1124
1125 /**
1126  * __spi_pump_messages - function which processes spi message queue
1127  * @ctlr: controller to process queue for
1128  * @in_kthread: true if we are in the context of the message pump thread
1129  *
1130  * This function checks if there is any spi message in the queue that
1131  * needs processing and if so call out to the driver to initialize hardware
1132  * and transfer each message.
1133  *
1134  * Note that it is called both from the kthread itself and also from
1135  * inside spi_sync(); the queue extraction handling at the top of the
1136  * function should deal with this safely.
1137  */
1138 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1139 {
1140         unsigned long flags;
1141         bool was_busy = false;
1142         int ret;
1143
1144         /* Lock queue */
1145         spin_lock_irqsave(&ctlr->queue_lock, flags);
1146
1147         /* Make sure we are not already running a message */
1148         if (ctlr->cur_msg) {
1149                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1150                 return;
1151         }
1152
1153         /* If another context is idling the device then defer */
1154         if (ctlr->idling) {
1155                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1156                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1157                 return;
1158         }
1159
1160         /* Check if the queue is idle */
1161         if (list_empty(&ctlr->queue) || !ctlr->running) {
1162                 if (!ctlr->busy) {
1163                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1164                         return;
1165                 }
1166
1167                 /* Only do teardown in the thread */
1168                 if (!in_kthread) {
1169                         kthread_queue_work(&ctlr->kworker,
1170                                            &ctlr->pump_messages);
1171                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1172                         return;
1173                 }
1174
1175                 ctlr->busy = false;
1176                 ctlr->idling = true;
1177                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1178
1179                 kfree(ctlr->dummy_rx);
1180                 ctlr->dummy_rx = NULL;
1181                 kfree(ctlr->dummy_tx);
1182                 ctlr->dummy_tx = NULL;
1183                 if (ctlr->unprepare_transfer_hardware &&
1184                     ctlr->unprepare_transfer_hardware(ctlr))
1185                         dev_err(&ctlr->dev,
1186                                 "failed to unprepare transfer hardware\n");
1187                 if (ctlr->auto_runtime_pm) {
1188                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1189                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1190                 }
1191                 trace_spi_controller_idle(ctlr);
1192
1193                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1194                 ctlr->idling = false;
1195                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1196                 return;
1197         }
1198
1199         /* Extract head of queue */
1200         ctlr->cur_msg =
1201                 list_first_entry(&ctlr->queue, struct spi_message, queue);
1202
1203         list_del_init(&ctlr->cur_msg->queue);
1204         if (ctlr->busy)
1205                 was_busy = true;
1206         else
1207                 ctlr->busy = true;
1208         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1209
1210         mutex_lock(&ctlr->io_mutex);
1211
1212         if (!was_busy && ctlr->auto_runtime_pm) {
1213                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1214                 if (ret < 0) {
1215                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1216                                 ret);
1217                         mutex_unlock(&ctlr->io_mutex);
1218                         return;
1219                 }
1220         }
1221
1222         if (!was_busy)
1223                 trace_spi_controller_busy(ctlr);
1224
1225         if (!was_busy && ctlr->prepare_transfer_hardware) {
1226                 ret = ctlr->prepare_transfer_hardware(ctlr);
1227                 if (ret) {
1228                         dev_err(&ctlr->dev,
1229                                 "failed to prepare transfer hardware\n");
1230
1231                         if (ctlr->auto_runtime_pm)
1232                                 pm_runtime_put(ctlr->dev.parent);
1233                         mutex_unlock(&ctlr->io_mutex);
1234                         return;
1235                 }
1236         }
1237
1238         trace_spi_message_start(ctlr->cur_msg);
1239
1240         if (ctlr->prepare_message) {
1241                 ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1242                 if (ret) {
1243                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1244                                 ret);
1245                         ctlr->cur_msg->status = ret;
1246                         spi_finalize_current_message(ctlr);
1247                         goto out;
1248                 }
1249                 ctlr->cur_msg_prepared = true;
1250         }
1251
1252         ret = spi_map_msg(ctlr, ctlr->cur_msg);
1253         if (ret) {
1254                 ctlr->cur_msg->status = ret;
1255                 spi_finalize_current_message(ctlr);
1256                 goto out;
1257         }
1258
1259         ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1260         if (ret) {
1261                 dev_err(&ctlr->dev,
1262                         "failed to transfer one message from queue\n");
1263                 goto out;
1264         }
1265
1266 out:
1267         mutex_unlock(&ctlr->io_mutex);
1268
1269         /* Prod the scheduler in case transfer_one() was busy waiting */
1270         if (!ret)
1271                 cond_resched();
1272 }
1273
1274 /**
1275  * spi_pump_messages - kthread work function which processes spi message queue
1276  * @work: pointer to kthread work struct contained in the controller struct
1277  */
1278 static void spi_pump_messages(struct kthread_work *work)
1279 {
1280         struct spi_controller *ctlr =
1281                 container_of(work, struct spi_controller, pump_messages);
1282
1283         __spi_pump_messages(ctlr, true);
1284 }
1285
1286 static int spi_init_queue(struct spi_controller *ctlr)
1287 {
1288         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1289
1290         ctlr->running = false;
1291         ctlr->busy = false;
1292
1293         kthread_init_worker(&ctlr->kworker);
1294         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1295                                          "%s", dev_name(&ctlr->dev));
1296         if (IS_ERR(ctlr->kworker_task)) {
1297                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1298                 return PTR_ERR(ctlr->kworker_task);
1299         }
1300         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1301
1302         /*
1303          * Controller config will indicate if this controller should run the
1304          * message pump with high (realtime) priority to reduce the transfer
1305          * latency on the bus by minimising the delay between a transfer
1306          * request and the scheduling of the message pump thread. Without this
1307          * setting the message pump thread will remain at default priority.
1308          */
1309         if (ctlr->rt) {
1310                 dev_info(&ctlr->dev,
1311                         "will run message pump with realtime priority\n");
1312                 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1313         }
1314
1315         return 0;
1316 }
1317
1318 /**
1319  * spi_get_next_queued_message() - called by driver to check for queued
1320  * messages
1321  * @ctlr: the controller to check for queued messages
1322  *
1323  * If there are more messages in the queue, the next message is returned from
1324  * this call.
1325  *
1326  * Return: the next message in the queue, else NULL if the queue is empty.
1327  */
1328 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1329 {
1330         struct spi_message *next;
1331         unsigned long flags;
1332
1333         /* get a pointer to the next message, if any */
1334         spin_lock_irqsave(&ctlr->queue_lock, flags);
1335         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1336                                         queue);
1337         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1338
1339         return next;
1340 }
1341 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1342
1343 /**
1344  * spi_finalize_current_message() - the current message is complete
1345  * @ctlr: the controller to return the message to
1346  *
1347  * Called by the driver to notify the core that the message in the front of the
1348  * queue is complete and can be removed from the queue.
1349  */
1350 void spi_finalize_current_message(struct spi_controller *ctlr)
1351 {
1352         struct spi_message *mesg;
1353         unsigned long flags;
1354         int ret;
1355
1356         spin_lock_irqsave(&ctlr->queue_lock, flags);
1357         mesg = ctlr->cur_msg;
1358         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1359
1360         spi_unmap_msg(ctlr, mesg);
1361
1362         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1363                 ret = ctlr->unprepare_message(ctlr, mesg);
1364                 if (ret) {
1365                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1366                                 ret);
1367                 }
1368         }
1369
1370         spin_lock_irqsave(&ctlr->queue_lock, flags);
1371         ctlr->cur_msg = NULL;
1372         ctlr->cur_msg_prepared = false;
1373         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1374         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1375
1376         trace_spi_message_done(mesg);
1377
1378         mesg->state = NULL;
1379         if (mesg->complete)
1380                 mesg->complete(mesg->context);
1381 }
1382 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1383
1384 static int spi_start_queue(struct spi_controller *ctlr)
1385 {
1386         unsigned long flags;
1387
1388         spin_lock_irqsave(&ctlr->queue_lock, flags);
1389
1390         if (ctlr->running || ctlr->busy) {
1391                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1392                 return -EBUSY;
1393         }
1394
1395         ctlr->running = true;
1396         ctlr->cur_msg = NULL;
1397         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1398
1399         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1400
1401         return 0;
1402 }
1403
1404 static int spi_stop_queue(struct spi_controller *ctlr)
1405 {
1406         unsigned long flags;
1407         unsigned limit = 500;
1408         int ret = 0;
1409
1410         spin_lock_irqsave(&ctlr->queue_lock, flags);
1411
1412         /*
1413          * This is a bit lame, but is optimized for the common execution path.
1414          * A wait_queue on the ctlr->busy could be used, but then the common
1415          * execution path (pump_messages) would be required to call wake_up or
1416          * friends on every SPI message. Do this instead.
1417          */
1418         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1419                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1420                 usleep_range(10000, 11000);
1421                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1422         }
1423
1424         if (!list_empty(&ctlr->queue) || ctlr->busy)
1425                 ret = -EBUSY;
1426         else
1427                 ctlr->running = false;
1428
1429         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1430
1431         if (ret) {
1432                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1433                 return ret;
1434         }
1435         return ret;
1436 }
1437
1438 static int spi_destroy_queue(struct spi_controller *ctlr)
1439 {
1440         int ret;
1441
1442         ret = spi_stop_queue(ctlr);
1443
1444         /*
1445          * kthread_flush_worker will block until all work is done.
1446          * If the reason that stop_queue timed out is that the work will never
1447          * finish, then it does no good to call flush/stop thread, so
1448          * return anyway.
1449          */
1450         if (ret) {
1451                 dev_err(&ctlr->dev, "problem destroying queue\n");
1452                 return ret;
1453         }
1454
1455         kthread_flush_worker(&ctlr->kworker);
1456         kthread_stop(ctlr->kworker_task);
1457
1458         return 0;
1459 }
1460
1461 static int __spi_queued_transfer(struct spi_device *spi,
1462                                  struct spi_message *msg,
1463                                  bool need_pump)
1464 {
1465         struct spi_controller *ctlr = spi->controller;
1466         unsigned long flags;
1467
1468         spin_lock_irqsave(&ctlr->queue_lock, flags);
1469
1470         if (!ctlr->running) {
1471                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1472                 return -ESHUTDOWN;
1473         }
1474         msg->actual_length = 0;
1475         msg->status = -EINPROGRESS;
1476
1477         list_add_tail(&msg->queue, &ctlr->queue);
1478         if (!ctlr->busy && need_pump)
1479                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1480
1481         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1482         return 0;
1483 }
1484
1485 /**
1486  * spi_queued_transfer - transfer function for queued transfers
1487  * @spi: spi device which is requesting transfer
1488  * @msg: spi message which is to handled is queued to driver queue
1489  *
1490  * Return: zero on success, else a negative error code.
1491  */
1492 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1493 {
1494         return __spi_queued_transfer(spi, msg, true);
1495 }
1496
1497 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1498 {
1499         int ret;
1500
1501         ctlr->transfer = spi_queued_transfer;
1502         if (!ctlr->transfer_one_message)
1503                 ctlr->transfer_one_message = spi_transfer_one_message;
1504
1505         /* Initialize and start queue */
1506         ret = spi_init_queue(ctlr);
1507         if (ret) {
1508                 dev_err(&ctlr->dev, "problem initializing queue\n");
1509                 goto err_init_queue;
1510         }
1511         ctlr->queued = true;
1512         ret = spi_start_queue(ctlr);
1513         if (ret) {
1514                 dev_err(&ctlr->dev, "problem starting queue\n");
1515                 goto err_start_queue;
1516         }
1517
1518         return 0;
1519
1520 err_start_queue:
1521         spi_destroy_queue(ctlr);
1522 err_init_queue:
1523         return ret;
1524 }
1525
1526 /*-------------------------------------------------------------------------*/
1527
1528 #if defined(CONFIG_OF)
1529 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1530                            struct device_node *nc)
1531 {
1532         u32 value;
1533         int rc;
1534
1535         /* Mode (clock phase/polarity/etc.) */
1536         if (of_find_property(nc, "spi-cpha", NULL))
1537                 spi->mode |= SPI_CPHA;
1538         if (of_find_property(nc, "spi-cpol", NULL))
1539                 spi->mode |= SPI_CPOL;
1540         if (of_find_property(nc, "spi-cs-high", NULL))
1541                 spi->mode |= SPI_CS_HIGH;
1542         if (of_find_property(nc, "spi-3wire", NULL))
1543                 spi->mode |= SPI_3WIRE;
1544         if (of_find_property(nc, "spi-lsb-first", NULL))
1545                 spi->mode |= SPI_LSB_FIRST;
1546
1547         /* Device DUAL/QUAD mode */
1548         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1549                 switch (value) {
1550                 case 1:
1551                         break;
1552                 case 2:
1553                         spi->mode |= SPI_TX_DUAL;
1554                         break;
1555                 case 4:
1556                         spi->mode |= SPI_TX_QUAD;
1557                         break;
1558                 default:
1559                         dev_warn(&ctlr->dev,
1560                                 "spi-tx-bus-width %d not supported\n",
1561                                 value);
1562                         break;
1563                 }
1564         }
1565
1566         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1567                 switch (value) {
1568                 case 1:
1569                         break;
1570                 case 2:
1571                         spi->mode |= SPI_RX_DUAL;
1572                         break;
1573                 case 4:
1574                         spi->mode |= SPI_RX_QUAD;
1575                         break;
1576                 default:
1577                         dev_warn(&ctlr->dev,
1578                                 "spi-rx-bus-width %d not supported\n",
1579                                 value);
1580                         break;
1581                 }
1582         }
1583
1584         if (spi_controller_is_slave(ctlr)) {
1585                 if (strcmp(nc->name, "slave")) {
1586                         dev_err(&ctlr->dev, "%s is not called 'slave'\n",
1587                                 nc->full_name);
1588                         return -EINVAL;
1589                 }
1590                 return 0;
1591         }
1592
1593         /* Device address */
1594         rc = of_property_read_u32(nc, "reg", &value);
1595         if (rc) {
1596                 dev_err(&ctlr->dev, "%s has no valid 'reg' property (%d)\n",
1597                         nc->full_name, rc);
1598                 return rc;
1599         }
1600         spi->chip_select = value;
1601
1602         /* Device speed */
1603         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1604         if (rc) {
1605                 dev_err(&ctlr->dev,
1606                         "%s has no valid 'spi-max-frequency' property (%d)\n",
1607                         nc->full_name, rc);
1608                 return rc;
1609         }
1610         spi->max_speed_hz = value;
1611
1612         return 0;
1613 }
1614
1615 static struct spi_device *
1616 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1617 {
1618         struct spi_device *spi;
1619         int rc;
1620
1621         /* Alloc an spi_device */
1622         spi = spi_alloc_device(ctlr);
1623         if (!spi) {
1624                 dev_err(&ctlr->dev, "spi_device alloc error for %s\n",
1625                         nc->full_name);
1626                 rc = -ENOMEM;
1627                 goto err_out;
1628         }
1629
1630         /* Select device driver */
1631         rc = of_modalias_node(nc, spi->modalias,
1632                                 sizeof(spi->modalias));
1633         if (rc < 0) {
1634                 dev_err(&ctlr->dev, "cannot find modalias for %s\n",
1635                         nc->full_name);
1636                 goto err_out;
1637         }
1638
1639         rc = of_spi_parse_dt(ctlr, spi, nc);
1640         if (rc)
1641                 goto err_out;
1642
1643         /* Store a pointer to the node in the device structure */
1644         of_node_get(nc);
1645         spi->dev.of_node = nc;
1646
1647         /* Register the new device */
1648         rc = spi_add_device(spi);
1649         if (rc) {
1650                 dev_err(&ctlr->dev, "spi_device register error %s\n",
1651                         nc->full_name);
1652                 goto err_of_node_put;
1653         }
1654
1655         return spi;
1656
1657 err_of_node_put:
1658         of_node_put(nc);
1659 err_out:
1660         spi_dev_put(spi);
1661         return ERR_PTR(rc);
1662 }
1663
1664 /**
1665  * of_register_spi_devices() - Register child devices onto the SPI bus
1666  * @ctlr:       Pointer to spi_controller device
1667  *
1668  * Registers an spi_device for each child node of controller node which
1669  * represents a valid SPI slave.
1670  */
1671 static void of_register_spi_devices(struct spi_controller *ctlr)
1672 {
1673         struct spi_device *spi;
1674         struct device_node *nc;
1675
1676         if (!ctlr->dev.of_node)
1677                 return;
1678
1679         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1680                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1681                         continue;
1682                 spi = of_register_spi_device(ctlr, nc);
1683                 if (IS_ERR(spi)) {
1684                         dev_warn(&ctlr->dev,
1685                                  "Failed to create SPI device for %s\n",
1686                                  nc->full_name);
1687                         of_node_clear_flag(nc, OF_POPULATED);
1688                 }
1689         }
1690 }
1691 #else
1692 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1693 #endif
1694
1695 #ifdef CONFIG_ACPI
1696 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1697 {
1698         struct spi_device *spi = data;
1699         struct spi_controller *ctlr = spi->controller;
1700
1701         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1702                 struct acpi_resource_spi_serialbus *sb;
1703
1704                 sb = &ares->data.spi_serial_bus;
1705                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1706                         /*
1707                          * ACPI DeviceSelection numbering is handled by the
1708                          * host controller driver in Windows and can vary
1709                          * from driver to driver. In Linux we always expect
1710                          * 0 .. max - 1 so we need to ask the driver to
1711                          * translate between the two schemes.
1712                          */
1713                         if (ctlr->fw_translate_cs) {
1714                                 int cs = ctlr->fw_translate_cs(ctlr,
1715                                                 sb->device_selection);
1716                                 if (cs < 0)
1717                                         return cs;
1718                                 spi->chip_select = cs;
1719                         } else {
1720                                 spi->chip_select = sb->device_selection;
1721                         }
1722
1723                         spi->max_speed_hz = sb->connection_speed;
1724
1725                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1726                                 spi->mode |= SPI_CPHA;
1727                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1728                                 spi->mode |= SPI_CPOL;
1729                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1730                                 spi->mode |= SPI_CS_HIGH;
1731                 }
1732         } else if (spi->irq < 0) {
1733                 struct resource r;
1734
1735                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1736                         spi->irq = r.start;
1737         }
1738
1739         /* Always tell the ACPI core to skip this resource */
1740         return 1;
1741 }
1742
1743 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1744                                             struct acpi_device *adev)
1745 {
1746         struct list_head resource_list;
1747         struct spi_device *spi;
1748         int ret;
1749
1750         if (acpi_bus_get_status(adev) || !adev->status.present ||
1751             acpi_device_enumerated(adev))
1752                 return AE_OK;
1753
1754         spi = spi_alloc_device(ctlr);
1755         if (!spi) {
1756                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1757                         dev_name(&adev->dev));
1758                 return AE_NO_MEMORY;
1759         }
1760
1761         ACPI_COMPANION_SET(&spi->dev, adev);
1762         spi->irq = -1;
1763
1764         INIT_LIST_HEAD(&resource_list);
1765         ret = acpi_dev_get_resources(adev, &resource_list,
1766                                      acpi_spi_add_resource, spi);
1767         acpi_dev_free_resource_list(&resource_list);
1768
1769         if (ret < 0 || !spi->max_speed_hz) {
1770                 spi_dev_put(spi);
1771                 return AE_OK;
1772         }
1773
1774         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1775                           sizeof(spi->modalias));
1776
1777         if (spi->irq < 0)
1778                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1779
1780         acpi_device_set_enumerated(adev);
1781
1782         adev->power.flags.ignore_parent = true;
1783         if (spi_add_device(spi)) {
1784                 adev->power.flags.ignore_parent = false;
1785                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1786                         dev_name(&adev->dev));
1787                 spi_dev_put(spi);
1788         }
1789
1790         return AE_OK;
1791 }
1792
1793 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1794                                        void *data, void **return_value)
1795 {
1796         struct spi_controller *ctlr = data;
1797         struct acpi_device *adev;
1798
1799         if (acpi_bus_get_device(handle, &adev))
1800                 return AE_OK;
1801
1802         return acpi_register_spi_device(ctlr, adev);
1803 }
1804
1805 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1806 {
1807         acpi_status status;
1808         acpi_handle handle;
1809
1810         handle = ACPI_HANDLE(ctlr->dev.parent);
1811         if (!handle)
1812                 return;
1813
1814         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1815                                      acpi_spi_add_device, NULL, ctlr, NULL);
1816         if (ACPI_FAILURE(status))
1817                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1818 }
1819 #else
1820 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1821 #endif /* CONFIG_ACPI */
1822
1823 static void spi_controller_release(struct device *dev)
1824 {
1825         struct spi_controller *ctlr;
1826
1827         ctlr = container_of(dev, struct spi_controller, dev);
1828         kfree(ctlr);
1829 }
1830
1831 static struct class spi_master_class = {
1832         .name           = "spi_master",
1833         .owner          = THIS_MODULE,
1834         .dev_release    = spi_controller_release,
1835         .dev_groups     = spi_master_groups,
1836 };
1837
1838 #ifdef CONFIG_SPI_SLAVE
1839 /**
1840  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1841  *                   controller
1842  * @spi: device used for the current transfer
1843  */
1844 int spi_slave_abort(struct spi_device *spi)
1845 {
1846         struct spi_controller *ctlr = spi->controller;
1847
1848         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1849                 return ctlr->slave_abort(ctlr);
1850
1851         return -ENOTSUPP;
1852 }
1853 EXPORT_SYMBOL_GPL(spi_slave_abort);
1854
1855 static int match_true(struct device *dev, void *data)
1856 {
1857         return 1;
1858 }
1859
1860 static ssize_t spi_slave_show(struct device *dev,
1861                               struct device_attribute *attr, char *buf)
1862 {
1863         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1864                                                    dev);
1865         struct device *child;
1866
1867         child = device_find_child(&ctlr->dev, NULL, match_true);
1868         return sprintf(buf, "%s\n",
1869                        child ? to_spi_device(child)->modalias : NULL);
1870 }
1871
1872 static ssize_t spi_slave_store(struct device *dev,
1873                                struct device_attribute *attr, const char *buf,
1874                                size_t count)
1875 {
1876         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1877                                                    dev);
1878         struct spi_device *spi;
1879         struct device *child;
1880         char name[32];
1881         int rc;
1882
1883         rc = sscanf(buf, "%31s", name);
1884         if (rc != 1 || !name[0])
1885                 return -EINVAL;
1886
1887         child = device_find_child(&ctlr->dev, NULL, match_true);
1888         if (child) {
1889                 /* Remove registered slave */
1890                 device_unregister(child);
1891                 put_device(child);
1892         }
1893
1894         if (strcmp(name, "(null)")) {
1895                 /* Register new slave */
1896                 spi = spi_alloc_device(ctlr);
1897                 if (!spi)
1898                         return -ENOMEM;
1899
1900                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
1901
1902                 rc = spi_add_device(spi);
1903                 if (rc) {
1904                         spi_dev_put(spi);
1905                         return rc;
1906                 }
1907         }
1908
1909         return count;
1910 }
1911
1912 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
1913
1914 static struct attribute *spi_slave_attrs[] = {
1915         &dev_attr_slave.attr,
1916         NULL,
1917 };
1918
1919 static const struct attribute_group spi_slave_group = {
1920         .attrs = spi_slave_attrs,
1921 };
1922
1923 static const struct attribute_group *spi_slave_groups[] = {
1924         &spi_controller_statistics_group,
1925         &spi_slave_group,
1926         NULL,
1927 };
1928
1929 static struct class spi_slave_class = {
1930         .name           = "spi_slave",
1931         .owner          = THIS_MODULE,
1932         .dev_release    = spi_controller_release,
1933         .dev_groups     = spi_slave_groups,
1934 };
1935 #else
1936 extern struct class spi_slave_class;    /* dummy */
1937 #endif
1938
1939 /**
1940  * __spi_alloc_controller - allocate an SPI master or slave controller
1941  * @dev: the controller, possibly using the platform_bus
1942  * @size: how much zeroed driver-private data to allocate; the pointer to this
1943  *      memory is in the driver_data field of the returned device,
1944  *      accessible with spi_controller_get_devdata().
1945  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
1946  *      slave (true) controller
1947  * Context: can sleep
1948  *
1949  * This call is used only by SPI controller drivers, which are the
1950  * only ones directly touching chip registers.  It's how they allocate
1951  * an spi_controller structure, prior to calling spi_register_controller().
1952  *
1953  * This must be called from context that can sleep.
1954  *
1955  * The caller is responsible for assigning the bus number and initializing the
1956  * controller's methods before calling spi_register_controller(); and (after
1957  * errors adding the device) calling spi_controller_put() to prevent a memory
1958  * leak.
1959  *
1960  * Return: the SPI controller structure on success, else NULL.
1961  */
1962 struct spi_controller *__spi_alloc_controller(struct device *dev,
1963                                               unsigned int size, bool slave)
1964 {
1965         struct spi_controller   *ctlr;
1966
1967         if (!dev)
1968                 return NULL;
1969
1970         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
1971         if (!ctlr)
1972                 return NULL;
1973
1974         device_initialize(&ctlr->dev);
1975         ctlr->bus_num = -1;
1976         ctlr->num_chipselect = 1;
1977         ctlr->slave = slave;
1978         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
1979                 ctlr->dev.class = &spi_slave_class;
1980         else
1981                 ctlr->dev.class = &spi_master_class;
1982         ctlr->dev.parent = dev;
1983         pm_suspend_ignore_children(&ctlr->dev, true);
1984         spi_controller_set_devdata(ctlr, &ctlr[1]);
1985
1986         return ctlr;
1987 }
1988 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
1989
1990 #ifdef CONFIG_OF
1991 static int of_spi_register_master(struct spi_controller *ctlr)
1992 {
1993         int nb, i, *cs;
1994         struct device_node *np = ctlr->dev.of_node;
1995
1996         if (!np)
1997                 return 0;
1998
1999         nb = of_gpio_named_count(np, "cs-gpios");
2000         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2001
2002         /* Return error only for an incorrectly formed cs-gpios property */
2003         if (nb == 0 || nb == -ENOENT)
2004                 return 0;
2005         else if (nb < 0)
2006                 return nb;
2007
2008         cs = devm_kzalloc(&ctlr->dev, sizeof(int) * ctlr->num_chipselect,
2009                           GFP_KERNEL);
2010         ctlr->cs_gpios = cs;
2011
2012         if (!ctlr->cs_gpios)
2013                 return -ENOMEM;
2014
2015         for (i = 0; i < ctlr->num_chipselect; i++)
2016                 cs[i] = -ENOENT;
2017
2018         for (i = 0; i < nb; i++)
2019                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2020
2021         return 0;
2022 }
2023 #else
2024 static int of_spi_register_master(struct spi_controller *ctlr)
2025 {
2026         return 0;
2027 }
2028 #endif
2029
2030 /**
2031  * spi_register_controller - register SPI master or slave controller
2032  * @ctlr: initialized master, originally from spi_alloc_master() or
2033  *      spi_alloc_slave()
2034  * Context: can sleep
2035  *
2036  * SPI controllers connect to their drivers using some non-SPI bus,
2037  * such as the platform bus.  The final stage of probe() in that code
2038  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2039  *
2040  * SPI controllers use board specific (often SOC specific) bus numbers,
2041  * and board-specific addressing for SPI devices combines those numbers
2042  * with chip select numbers.  Since SPI does not directly support dynamic
2043  * device identification, boards need configuration tables telling which
2044  * chip is at which address.
2045  *
2046  * This must be called from context that can sleep.  It returns zero on
2047  * success, else a negative error code (dropping the controller's refcount).
2048  * After a successful return, the caller is responsible for calling
2049  * spi_unregister_controller().
2050  *
2051  * Return: zero on success, else a negative error code.
2052  */
2053 int spi_register_controller(struct spi_controller *ctlr)
2054 {
2055         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
2056         struct device           *dev = ctlr->dev.parent;
2057         struct boardinfo        *bi;
2058         int                     status = -ENODEV;
2059         int                     dynamic = 0;
2060
2061         if (!dev)
2062                 return -ENODEV;
2063
2064         if (!spi_controller_is_slave(ctlr)) {
2065                 status = of_spi_register_master(ctlr);
2066                 if (status)
2067                         return status;
2068         }
2069
2070         /* even if it's just one always-selected device, there must
2071          * be at least one chipselect
2072          */
2073         if (ctlr->num_chipselect == 0)
2074                 return -EINVAL;
2075
2076         if ((ctlr->bus_num < 0) && ctlr->dev.of_node)
2077                 ctlr->bus_num = of_alias_get_id(ctlr->dev.of_node, "spi");
2078
2079         /* convention:  dynamically assigned bus IDs count down from the max */
2080         if (ctlr->bus_num < 0) {
2081                 /* FIXME switch to an IDR based scheme, something like
2082                  * I2C now uses, so we can't run out of "dynamic" IDs
2083                  */
2084                 ctlr->bus_num = atomic_dec_return(&dyn_bus_id);
2085                 dynamic = 1;
2086         }
2087
2088         INIT_LIST_HEAD(&ctlr->queue);
2089         spin_lock_init(&ctlr->queue_lock);
2090         spin_lock_init(&ctlr->bus_lock_spinlock);
2091         mutex_init(&ctlr->bus_lock_mutex);
2092         mutex_init(&ctlr->io_mutex);
2093         ctlr->bus_lock_flag = 0;
2094         init_completion(&ctlr->xfer_completion);
2095         if (!ctlr->max_dma_len)
2096                 ctlr->max_dma_len = INT_MAX;
2097
2098         /* register the device, then userspace will see it.
2099          * registration fails if the bus ID is in use.
2100          */
2101         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2102         status = device_add(&ctlr->dev);
2103         if (status < 0)
2104                 goto done;
2105         dev_dbg(dev, "registered %s %s%s\n",
2106                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2107                         dev_name(&ctlr->dev), dynamic ? " (dynamic)" : "");
2108
2109         /* If we're using a queued driver, start the queue */
2110         if (ctlr->transfer)
2111                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2112         else {
2113                 status = spi_controller_initialize_queue(ctlr);
2114                 if (status) {
2115                         device_del(&ctlr->dev);
2116                         goto done;
2117                 }
2118         }
2119         /* add statistics */
2120         spin_lock_init(&ctlr->statistics.lock);
2121
2122         mutex_lock(&board_lock);
2123         list_add_tail(&ctlr->list, &spi_controller_list);
2124         list_for_each_entry(bi, &board_list, list)
2125                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2126         mutex_unlock(&board_lock);
2127
2128         /* Register devices from the device tree and ACPI */
2129         of_register_spi_devices(ctlr);
2130         acpi_register_spi_devices(ctlr);
2131 done:
2132         return status;
2133 }
2134 EXPORT_SYMBOL_GPL(spi_register_controller);
2135
2136 static void devm_spi_unregister(struct device *dev, void *res)
2137 {
2138         spi_unregister_controller(*(struct spi_controller **)res);
2139 }
2140
2141 /**
2142  * devm_spi_register_controller - register managed SPI master or slave
2143  *      controller
2144  * @dev:    device managing SPI controller
2145  * @ctlr: initialized controller, originally from spi_alloc_master() or
2146  *      spi_alloc_slave()
2147  * Context: can sleep
2148  *
2149  * Register a SPI device as with spi_register_controller() which will
2150  * automatically be unregister
2151  *
2152  * Return: zero on success, else a negative error code.
2153  */
2154 int devm_spi_register_controller(struct device *dev,
2155                                  struct spi_controller *ctlr)
2156 {
2157         struct spi_controller **ptr;
2158         int ret;
2159
2160         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2161         if (!ptr)
2162                 return -ENOMEM;
2163
2164         ret = spi_register_controller(ctlr);
2165         if (!ret) {
2166                 *ptr = ctlr;
2167                 devres_add(dev, ptr);
2168         } else {
2169                 devres_free(ptr);
2170         }
2171
2172         return ret;
2173 }
2174 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2175
2176 static int __unregister(struct device *dev, void *null)
2177 {
2178         spi_unregister_device(to_spi_device(dev));
2179         return 0;
2180 }
2181
2182 /**
2183  * spi_unregister_controller - unregister SPI master or slave controller
2184  * @ctlr: the controller being unregistered
2185  * Context: can sleep
2186  *
2187  * This call is used only by SPI controller drivers, which are the
2188  * only ones directly touching chip registers.
2189  *
2190  * This must be called from context that can sleep.
2191  */
2192 void spi_unregister_controller(struct spi_controller *ctlr)
2193 {
2194         int dummy;
2195
2196         if (ctlr->queued) {
2197                 if (spi_destroy_queue(ctlr))
2198                         dev_err(&ctlr->dev, "queue remove failed\n");
2199         }
2200
2201         mutex_lock(&board_lock);
2202         list_del(&ctlr->list);
2203         mutex_unlock(&board_lock);
2204
2205         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2206         device_unregister(&ctlr->dev);
2207 }
2208 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2209
2210 int spi_controller_suspend(struct spi_controller *ctlr)
2211 {
2212         int ret;
2213
2214         /* Basically no-ops for non-queued controllers */
2215         if (!ctlr->queued)
2216                 return 0;
2217
2218         ret = spi_stop_queue(ctlr);
2219         if (ret)
2220                 dev_err(&ctlr->dev, "queue stop failed\n");
2221
2222         return ret;
2223 }
2224 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2225
2226 int spi_controller_resume(struct spi_controller *ctlr)
2227 {
2228         int ret;
2229
2230         if (!ctlr->queued)
2231                 return 0;
2232
2233         ret = spi_start_queue(ctlr);
2234         if (ret)
2235                 dev_err(&ctlr->dev, "queue restart failed\n");
2236
2237         return ret;
2238 }
2239 EXPORT_SYMBOL_GPL(spi_controller_resume);
2240
2241 static int __spi_controller_match(struct device *dev, const void *data)
2242 {
2243         struct spi_controller *ctlr;
2244         const u16 *bus_num = data;
2245
2246         ctlr = container_of(dev, struct spi_controller, dev);
2247         return ctlr->bus_num == *bus_num;
2248 }
2249
2250 /**
2251  * spi_busnum_to_master - look up master associated with bus_num
2252  * @bus_num: the master's bus number
2253  * Context: can sleep
2254  *
2255  * This call may be used with devices that are registered after
2256  * arch init time.  It returns a refcounted pointer to the relevant
2257  * spi_controller (which the caller must release), or NULL if there is
2258  * no such master registered.
2259  *
2260  * Return: the SPI master structure on success, else NULL.
2261  */
2262 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2263 {
2264         struct device           *dev;
2265         struct spi_controller   *ctlr = NULL;
2266
2267         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2268                                 __spi_controller_match);
2269         if (dev)
2270                 ctlr = container_of(dev, struct spi_controller, dev);
2271         /* reference got in class_find_device */
2272         return ctlr;
2273 }
2274 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2275
2276 /*-------------------------------------------------------------------------*/
2277
2278 /* Core methods for SPI resource management */
2279
2280 /**
2281  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2282  *                 during the processing of a spi_message while using
2283  *                 spi_transfer_one
2284  * @spi:     the spi device for which we allocate memory
2285  * @release: the release code to execute for this resource
2286  * @size:    size to alloc and return
2287  * @gfp:     GFP allocation flags
2288  *
2289  * Return: the pointer to the allocated data
2290  *
2291  * This may get enhanced in the future to allocate from a memory pool
2292  * of the @spi_device or @spi_controller to avoid repeated allocations.
2293  */
2294 void *spi_res_alloc(struct spi_device *spi,
2295                     spi_res_release_t release,
2296                     size_t size, gfp_t gfp)
2297 {
2298         struct spi_res *sres;
2299
2300         sres = kzalloc(sizeof(*sres) + size, gfp);
2301         if (!sres)
2302                 return NULL;
2303
2304         INIT_LIST_HEAD(&sres->entry);
2305         sres->release = release;
2306
2307         return sres->data;
2308 }
2309 EXPORT_SYMBOL_GPL(spi_res_alloc);
2310
2311 /**
2312  * spi_res_free - free an spi resource
2313  * @res: pointer to the custom data of a resource
2314  *
2315  */
2316 void spi_res_free(void *res)
2317 {
2318         struct spi_res *sres = container_of(res, struct spi_res, data);
2319
2320         if (!res)
2321                 return;
2322
2323         WARN_ON(!list_empty(&sres->entry));
2324         kfree(sres);
2325 }
2326 EXPORT_SYMBOL_GPL(spi_res_free);
2327
2328 /**
2329  * spi_res_add - add a spi_res to the spi_message
2330  * @message: the spi message
2331  * @res:     the spi_resource
2332  */
2333 void spi_res_add(struct spi_message *message, void *res)
2334 {
2335         struct spi_res *sres = container_of(res, struct spi_res, data);
2336
2337         WARN_ON(!list_empty(&sres->entry));
2338         list_add_tail(&sres->entry, &message->resources);
2339 }
2340 EXPORT_SYMBOL_GPL(spi_res_add);
2341
2342 /**
2343  * spi_res_release - release all spi resources for this message
2344  * @ctlr:  the @spi_controller
2345  * @message: the @spi_message
2346  */
2347 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2348 {
2349         struct spi_res *res;
2350
2351         while (!list_empty(&message->resources)) {
2352                 res = list_last_entry(&message->resources,
2353                                       struct spi_res, entry);
2354
2355                 if (res->release)
2356                         res->release(ctlr, message, res->data);
2357
2358                 list_del(&res->entry);
2359
2360                 kfree(res);
2361         }
2362 }
2363 EXPORT_SYMBOL_GPL(spi_res_release);
2364
2365 /*-------------------------------------------------------------------------*/
2366
2367 /* Core methods for spi_message alterations */
2368
2369 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2370                                             struct spi_message *msg,
2371                                             void *res)
2372 {
2373         struct spi_replaced_transfers *rxfer = res;
2374         size_t i;
2375
2376         /* call extra callback if requested */
2377         if (rxfer->release)
2378                 rxfer->release(ctlr, msg, res);
2379
2380         /* insert replaced transfers back into the message */
2381         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2382
2383         /* remove the formerly inserted entries */
2384         for (i = 0; i < rxfer->inserted; i++)
2385                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2386 }
2387
2388 /**
2389  * spi_replace_transfers - replace transfers with several transfers
2390  *                         and register change with spi_message.resources
2391  * @msg:           the spi_message we work upon
2392  * @xfer_first:    the first spi_transfer we want to replace
2393  * @remove:        number of transfers to remove
2394  * @insert:        the number of transfers we want to insert instead
2395  * @release:       extra release code necessary in some circumstances
2396  * @extradatasize: extra data to allocate (with alignment guarantees
2397  *                 of struct @spi_transfer)
2398  * @gfp:           gfp flags
2399  *
2400  * Returns: pointer to @spi_replaced_transfers,
2401  *          PTR_ERR(...) in case of errors.
2402  */
2403 struct spi_replaced_transfers *spi_replace_transfers(
2404         struct spi_message *msg,
2405         struct spi_transfer *xfer_first,
2406         size_t remove,
2407         size_t insert,
2408         spi_replaced_release_t release,
2409         size_t extradatasize,
2410         gfp_t gfp)
2411 {
2412         struct spi_replaced_transfers *rxfer;
2413         struct spi_transfer *xfer;
2414         size_t i;
2415
2416         /* allocate the structure using spi_res */
2417         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2418                               insert * sizeof(struct spi_transfer)
2419                               + sizeof(struct spi_replaced_transfers)
2420                               + extradatasize,
2421                               gfp);
2422         if (!rxfer)
2423                 return ERR_PTR(-ENOMEM);
2424
2425         /* the release code to invoke before running the generic release */
2426         rxfer->release = release;
2427
2428         /* assign extradata */
2429         if (extradatasize)
2430                 rxfer->extradata =
2431                         &rxfer->inserted_transfers[insert];
2432
2433         /* init the replaced_transfers list */
2434         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2435
2436         /* assign the list_entry after which we should reinsert
2437          * the @replaced_transfers - it may be spi_message.messages!
2438          */
2439         rxfer->replaced_after = xfer_first->transfer_list.prev;
2440
2441         /* remove the requested number of transfers */
2442         for (i = 0; i < remove; i++) {
2443                 /* if the entry after replaced_after it is msg->transfers
2444                  * then we have been requested to remove more transfers
2445                  * than are in the list
2446                  */
2447                 if (rxfer->replaced_after->next == &msg->transfers) {
2448                         dev_err(&msg->spi->dev,
2449                                 "requested to remove more spi_transfers than are available\n");
2450                         /* insert replaced transfers back into the message */
2451                         list_splice(&rxfer->replaced_transfers,
2452                                     rxfer->replaced_after);
2453
2454                         /* free the spi_replace_transfer structure */
2455                         spi_res_free(rxfer);
2456
2457                         /* and return with an error */
2458                         return ERR_PTR(-EINVAL);
2459                 }
2460
2461                 /* remove the entry after replaced_after from list of
2462                  * transfers and add it to list of replaced_transfers
2463                  */
2464                 list_move_tail(rxfer->replaced_after->next,
2465                                &rxfer->replaced_transfers);
2466         }
2467
2468         /* create copy of the given xfer with identical settings
2469          * based on the first transfer to get removed
2470          */
2471         for (i = 0; i < insert; i++) {
2472                 /* we need to run in reverse order */
2473                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2474
2475                 /* copy all spi_transfer data */
2476                 memcpy(xfer, xfer_first, sizeof(*xfer));
2477
2478                 /* add to list */
2479                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2480
2481                 /* clear cs_change and delay_usecs for all but the last */
2482                 if (i) {
2483                         xfer->cs_change = false;
2484                         xfer->delay_usecs = 0;
2485                 }
2486         }
2487
2488         /* set up inserted */
2489         rxfer->inserted = insert;
2490
2491         /* and register it with spi_res/spi_message */
2492         spi_res_add(msg, rxfer);
2493
2494         return rxfer;
2495 }
2496 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2497
2498 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2499                                         struct spi_message *msg,
2500                                         struct spi_transfer **xferp,
2501                                         size_t maxsize,
2502                                         gfp_t gfp)
2503 {
2504         struct spi_transfer *xfer = *xferp, *xfers;
2505         struct spi_replaced_transfers *srt;
2506         size_t offset;
2507         size_t count, i;
2508
2509         /* warn once about this fact that we are splitting a transfer */
2510         dev_warn_once(&msg->spi->dev,
2511                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2512                       xfer->len, maxsize);
2513
2514         /* calculate how many we have to replace */
2515         count = DIV_ROUND_UP(xfer->len, maxsize);
2516
2517         /* create replacement */
2518         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2519         if (IS_ERR(srt))
2520                 return PTR_ERR(srt);
2521         xfers = srt->inserted_transfers;
2522
2523         /* now handle each of those newly inserted spi_transfers
2524          * note that the replacements spi_transfers all are preset
2525          * to the same values as *xferp, so tx_buf, rx_buf and len
2526          * are all identical (as well as most others)
2527          * so we just have to fix up len and the pointers.
2528          *
2529          * this also includes support for the depreciated
2530          * spi_message.is_dma_mapped interface
2531          */
2532
2533         /* the first transfer just needs the length modified, so we
2534          * run it outside the loop
2535          */
2536         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2537
2538         /* all the others need rx_buf/tx_buf also set */
2539         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2540                 /* update rx_buf, tx_buf and dma */
2541                 if (xfers[i].rx_buf)
2542                         xfers[i].rx_buf += offset;
2543                 if (xfers[i].rx_dma)
2544                         xfers[i].rx_dma += offset;
2545                 if (xfers[i].tx_buf)
2546                         xfers[i].tx_buf += offset;
2547                 if (xfers[i].tx_dma)
2548                         xfers[i].tx_dma += offset;
2549
2550                 /* update length */
2551                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2552         }
2553
2554         /* we set up xferp to the last entry we have inserted,
2555          * so that we skip those already split transfers
2556          */
2557         *xferp = &xfers[count - 1];
2558
2559         /* increment statistics counters */
2560         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2561                                        transfers_split_maxsize);
2562         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2563                                        transfers_split_maxsize);
2564
2565         return 0;
2566 }
2567
2568 /**
2569  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2570  *                              when an individual transfer exceeds a
2571  *                              certain size
2572  * @ctlr:    the @spi_controller for this transfer
2573  * @msg:   the @spi_message to transform
2574  * @maxsize:  the maximum when to apply this
2575  * @gfp: GFP allocation flags
2576  *
2577  * Return: status of transformation
2578  */
2579 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2580                                 struct spi_message *msg,
2581                                 size_t maxsize,
2582                                 gfp_t gfp)
2583 {
2584         struct spi_transfer *xfer;
2585         int ret;
2586
2587         /* iterate over the transfer_list,
2588          * but note that xfer is advanced to the last transfer inserted
2589          * to avoid checking sizes again unnecessarily (also xfer does
2590          * potentiall belong to a different list by the time the
2591          * replacement has happened
2592          */
2593         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2594                 if (xfer->len > maxsize) {
2595                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2596                                                            maxsize, gfp);
2597                         if (ret)
2598                                 return ret;
2599                 }
2600         }
2601
2602         return 0;
2603 }
2604 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2605
2606 /*-------------------------------------------------------------------------*/
2607
2608 /* Core methods for SPI controller protocol drivers.  Some of the
2609  * other core methods are currently defined as inline functions.
2610  */
2611
2612 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2613                                         u8 bits_per_word)
2614 {
2615         if (ctlr->bits_per_word_mask) {
2616                 /* Only 32 bits fit in the mask */
2617                 if (bits_per_word > 32)
2618                         return -EINVAL;
2619                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2620                         return -EINVAL;
2621         }
2622
2623         return 0;
2624 }
2625
2626 /**
2627  * spi_setup - setup SPI mode and clock rate
2628  * @spi: the device whose settings are being modified
2629  * Context: can sleep, and no requests are queued to the device
2630  *
2631  * SPI protocol drivers may need to update the transfer mode if the
2632  * device doesn't work with its default.  They may likewise need
2633  * to update clock rates or word sizes from initial values.  This function
2634  * changes those settings, and must be called from a context that can sleep.
2635  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2636  * effect the next time the device is selected and data is transferred to
2637  * or from it.  When this function returns, the spi device is deselected.
2638  *
2639  * Note that this call will fail if the protocol driver specifies an option
2640  * that the underlying controller or its driver does not support.  For
2641  * example, not all hardware supports wire transfers using nine bit words,
2642  * LSB-first wire encoding, or active-high chipselects.
2643  *
2644  * Return: zero on success, else a negative error code.
2645  */
2646 int spi_setup(struct spi_device *spi)
2647 {
2648         unsigned        bad_bits, ugly_bits;
2649         int             status;
2650
2651         /* check mode to prevent that DUAL and QUAD set at the same time
2652          */
2653         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2654                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2655                 dev_err(&spi->dev,
2656                 "setup: can not select dual and quad at the same time\n");
2657                 return -EINVAL;
2658         }
2659         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2660          */
2661         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2662                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2663                 return -EINVAL;
2664         /* help drivers fail *cleanly* when they need options
2665          * that aren't supported with their current controller
2666          */
2667         bad_bits = spi->mode & ~spi->controller->mode_bits;
2668         ugly_bits = bad_bits &
2669                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2670         if (ugly_bits) {
2671                 dev_warn(&spi->dev,
2672                          "setup: ignoring unsupported mode bits %x\n",
2673                          ugly_bits);
2674                 spi->mode &= ~ugly_bits;
2675                 bad_bits &= ~ugly_bits;
2676         }
2677         if (bad_bits) {
2678                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2679                         bad_bits);
2680                 return -EINVAL;
2681         }
2682
2683         if (!spi->bits_per_word)
2684                 spi->bits_per_word = 8;
2685
2686         status = __spi_validate_bits_per_word(spi->controller,
2687                                               spi->bits_per_word);
2688         if (status)
2689                 return status;
2690
2691         if (!spi->max_speed_hz)
2692                 spi->max_speed_hz = spi->controller->max_speed_hz;
2693
2694         if (spi->controller->setup)
2695                 status = spi->controller->setup(spi);
2696
2697         spi_set_cs(spi, false);
2698
2699         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2700                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2701                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2702                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2703                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2704                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2705                         spi->bits_per_word, spi->max_speed_hz,
2706                         status);
2707
2708         return status;
2709 }
2710 EXPORT_SYMBOL_GPL(spi_setup);
2711
2712 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2713 {
2714         struct spi_controller *ctlr = spi->controller;
2715         struct spi_transfer *xfer;
2716         int w_size;
2717
2718         if (list_empty(&message->transfers))
2719                 return -EINVAL;
2720
2721         /* Half-duplex links include original MicroWire, and ones with
2722          * only one data pin like SPI_3WIRE (switches direction) or where
2723          * either MOSI or MISO is missing.  They can also be caused by
2724          * software limitations.
2725          */
2726         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
2727             (spi->mode & SPI_3WIRE)) {
2728                 unsigned flags = ctlr->flags;
2729
2730                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2731                         if (xfer->rx_buf && xfer->tx_buf)
2732                                 return -EINVAL;
2733                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
2734                                 return -EINVAL;
2735                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
2736                                 return -EINVAL;
2737                 }
2738         }
2739
2740         /**
2741          * Set transfer bits_per_word and max speed as spi device default if
2742          * it is not set for this transfer.
2743          * Set transfer tx_nbits and rx_nbits as single transfer default
2744          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2745          */
2746         message->frame_length = 0;
2747         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2748                 message->frame_length += xfer->len;
2749                 if (!xfer->bits_per_word)
2750                         xfer->bits_per_word = spi->bits_per_word;
2751
2752                 if (!xfer->speed_hz)
2753                         xfer->speed_hz = spi->max_speed_hz;
2754                 if (!xfer->speed_hz)
2755                         xfer->speed_hz = ctlr->max_speed_hz;
2756
2757                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
2758                         xfer->speed_hz = ctlr->max_speed_hz;
2759
2760                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
2761                         return -EINVAL;
2762
2763                 /*
2764                  * SPI transfer length should be multiple of SPI word size
2765                  * where SPI word size should be power-of-two multiple
2766                  */
2767                 if (xfer->bits_per_word <= 8)
2768                         w_size = 1;
2769                 else if (xfer->bits_per_word <= 16)
2770                         w_size = 2;
2771                 else
2772                         w_size = 4;
2773
2774                 /* No partial transfers accepted */
2775                 if (xfer->len % w_size)
2776                         return -EINVAL;
2777
2778                 if (xfer->speed_hz && ctlr->min_speed_hz &&
2779                     xfer->speed_hz < ctlr->min_speed_hz)
2780                         return -EINVAL;
2781
2782                 if (xfer->tx_buf && !xfer->tx_nbits)
2783                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2784                 if (xfer->rx_buf && !xfer->rx_nbits)
2785                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2786                 /* check transfer tx/rx_nbits:
2787                  * 1. check the value matches one of single, dual and quad
2788                  * 2. check tx/rx_nbits match the mode in spi_device
2789                  */
2790                 if (xfer->tx_buf) {
2791                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2792                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2793                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2794                                 return -EINVAL;
2795                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2796                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2797                                 return -EINVAL;
2798                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2799                                 !(spi->mode & SPI_TX_QUAD))
2800                                 return -EINVAL;
2801                 }
2802                 /* check transfer rx_nbits */
2803                 if (xfer->rx_buf) {
2804                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2805                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2806                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2807                                 return -EINVAL;
2808                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2809                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2810                                 return -EINVAL;
2811                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2812                                 !(spi->mode & SPI_RX_QUAD))
2813                                 return -EINVAL;
2814                 }
2815         }
2816
2817         message->status = -EINPROGRESS;
2818
2819         return 0;
2820 }
2821
2822 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2823 {
2824         struct spi_controller *ctlr = spi->controller;
2825
2826         message->spi = spi;
2827
2828         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
2829         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2830
2831         trace_spi_message_submit(message);
2832
2833         return ctlr->transfer(spi, message);
2834 }
2835
2836 /**
2837  * spi_async - asynchronous SPI transfer
2838  * @spi: device with which data will be exchanged
2839  * @message: describes the data transfers, including completion callback
2840  * Context: any (irqs may be blocked, etc)
2841  *
2842  * This call may be used in_irq and other contexts which can't sleep,
2843  * as well as from task contexts which can sleep.
2844  *
2845  * The completion callback is invoked in a context which can't sleep.
2846  * Before that invocation, the value of message->status is undefined.
2847  * When the callback is issued, message->status holds either zero (to
2848  * indicate complete success) or a negative error code.  After that
2849  * callback returns, the driver which issued the transfer request may
2850  * deallocate the associated memory; it's no longer in use by any SPI
2851  * core or controller driver code.
2852  *
2853  * Note that although all messages to a spi_device are handled in
2854  * FIFO order, messages may go to different devices in other orders.
2855  * Some device might be higher priority, or have various "hard" access
2856  * time requirements, for example.
2857  *
2858  * On detection of any fault during the transfer, processing of
2859  * the entire message is aborted, and the device is deselected.
2860  * Until returning from the associated message completion callback,
2861  * no other spi_message queued to that device will be processed.
2862  * (This rule applies equally to all the synchronous transfer calls,
2863  * which are wrappers around this core asynchronous primitive.)
2864  *
2865  * Return: zero on success, else a negative error code.
2866  */
2867 int spi_async(struct spi_device *spi, struct spi_message *message)
2868 {
2869         struct spi_controller *ctlr = spi->controller;
2870         int ret;
2871         unsigned long flags;
2872
2873         ret = __spi_validate(spi, message);
2874         if (ret != 0)
2875                 return ret;
2876
2877         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2878
2879         if (ctlr->bus_lock_flag)
2880                 ret = -EBUSY;
2881         else
2882                 ret = __spi_async(spi, message);
2883
2884         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2885
2886         return ret;
2887 }
2888 EXPORT_SYMBOL_GPL(spi_async);
2889
2890 /**
2891  * spi_async_locked - version of spi_async with exclusive bus usage
2892  * @spi: device with which data will be exchanged
2893  * @message: describes the data transfers, including completion callback
2894  * Context: any (irqs may be blocked, etc)
2895  *
2896  * This call may be used in_irq and other contexts which can't sleep,
2897  * as well as from task contexts which can sleep.
2898  *
2899  * The completion callback is invoked in a context which can't sleep.
2900  * Before that invocation, the value of message->status is undefined.
2901  * When the callback is issued, message->status holds either zero (to
2902  * indicate complete success) or a negative error code.  After that
2903  * callback returns, the driver which issued the transfer request may
2904  * deallocate the associated memory; it's no longer in use by any SPI
2905  * core or controller driver code.
2906  *
2907  * Note that although all messages to a spi_device are handled in
2908  * FIFO order, messages may go to different devices in other orders.
2909  * Some device might be higher priority, or have various "hard" access
2910  * time requirements, for example.
2911  *
2912  * On detection of any fault during the transfer, processing of
2913  * the entire message is aborted, and the device is deselected.
2914  * Until returning from the associated message completion callback,
2915  * no other spi_message queued to that device will be processed.
2916  * (This rule applies equally to all the synchronous transfer calls,
2917  * which are wrappers around this core asynchronous primitive.)
2918  *
2919  * Return: zero on success, else a negative error code.
2920  */
2921 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2922 {
2923         struct spi_controller *ctlr = spi->controller;
2924         int ret;
2925         unsigned long flags;
2926
2927         ret = __spi_validate(spi, message);
2928         if (ret != 0)
2929                 return ret;
2930
2931         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2932
2933         ret = __spi_async(spi, message);
2934
2935         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2936
2937         return ret;
2938
2939 }
2940 EXPORT_SYMBOL_GPL(spi_async_locked);
2941
2942
2943 int spi_flash_read(struct spi_device *spi,
2944                    struct spi_flash_read_message *msg)
2945
2946 {
2947         struct spi_controller *master = spi->controller;
2948         struct device *rx_dev = NULL;
2949         int ret;
2950
2951         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2952              msg->addr_nbits == SPI_NBITS_DUAL) &&
2953             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2954                 return -EINVAL;
2955         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2956              msg->addr_nbits == SPI_NBITS_QUAD) &&
2957             !(spi->mode & SPI_TX_QUAD))
2958                 return -EINVAL;
2959         if (msg->data_nbits == SPI_NBITS_DUAL &&
2960             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2961                 return -EINVAL;
2962         if (msg->data_nbits == SPI_NBITS_QUAD &&
2963             !(spi->mode &  SPI_RX_QUAD))
2964                 return -EINVAL;
2965
2966         if (master->auto_runtime_pm) {
2967                 ret = pm_runtime_get_sync(master->dev.parent);
2968                 if (ret < 0) {
2969                         dev_err(&master->dev, "Failed to power device: %d\n",
2970                                 ret);
2971                         return ret;
2972                 }
2973         }
2974
2975         mutex_lock(&master->bus_lock_mutex);
2976         mutex_lock(&master->io_mutex);
2977         if (master->dma_rx && master->spi_flash_can_dma(spi, msg)) {
2978                 rx_dev = master->dma_rx->device->dev;
2979                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2980                                   msg->buf, msg->len,
2981                                   DMA_FROM_DEVICE);
2982                 if (!ret)
2983                         msg->cur_msg_mapped = true;
2984         }
2985         ret = master->spi_flash_read(spi, msg);
2986         if (msg->cur_msg_mapped)
2987                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2988                               DMA_FROM_DEVICE);
2989         mutex_unlock(&master->io_mutex);
2990         mutex_unlock(&master->bus_lock_mutex);
2991
2992         if (master->auto_runtime_pm)
2993                 pm_runtime_put(master->dev.parent);
2994
2995         return ret;
2996 }
2997 EXPORT_SYMBOL_GPL(spi_flash_read);
2998
2999 /*-------------------------------------------------------------------------*/
3000
3001 /* Utility methods for SPI protocol drivers, layered on
3002  * top of the core.  Some other utility methods are defined as
3003  * inline functions.
3004  */
3005
3006 static void spi_complete(void *arg)
3007 {
3008         complete(arg);
3009 }
3010
3011 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3012 {
3013         DECLARE_COMPLETION_ONSTACK(done);
3014         int status;
3015         struct spi_controller *ctlr = spi->controller;
3016         unsigned long flags;
3017
3018         status = __spi_validate(spi, message);
3019         if (status != 0)
3020                 return status;
3021
3022         message->complete = spi_complete;
3023         message->context = &done;
3024         message->spi = spi;
3025
3026         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3027         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3028
3029         /* If we're not using the legacy transfer method then we will
3030          * try to transfer in the calling context so special case.
3031          * This code would be less tricky if we could remove the
3032          * support for driver implemented message queues.
3033          */
3034         if (ctlr->transfer == spi_queued_transfer) {
3035                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3036
3037                 trace_spi_message_submit(message);
3038
3039                 status = __spi_queued_transfer(spi, message, false);
3040
3041                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3042         } else {
3043                 status = spi_async_locked(spi, message);
3044         }
3045
3046         if (status == 0) {
3047                 /* Push out the messages in the calling context if we
3048                  * can.
3049                  */
3050                 if (ctlr->transfer == spi_queued_transfer) {
3051                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3052                                                        spi_sync_immediate);
3053                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3054                                                        spi_sync_immediate);
3055                         __spi_pump_messages(ctlr, false);
3056                 }
3057
3058                 wait_for_completion(&done);
3059                 status = message->status;
3060         }
3061         message->context = NULL;
3062         return status;
3063 }
3064
3065 /**
3066  * spi_sync - blocking/synchronous SPI data transfers
3067  * @spi: device with which data will be exchanged
3068  * @message: describes the data transfers
3069  * Context: can sleep
3070  *
3071  * This call may only be used from a context that may sleep.  The sleep
3072  * is non-interruptible, and has no timeout.  Low-overhead controller
3073  * drivers may DMA directly into and out of the message buffers.
3074  *
3075  * Note that the SPI device's chip select is active during the message,
3076  * and then is normally disabled between messages.  Drivers for some
3077  * frequently-used devices may want to minimize costs of selecting a chip,
3078  * by leaving it selected in anticipation that the next message will go
3079  * to the same chip.  (That may increase power usage.)
3080  *
3081  * Also, the caller is guaranteeing that the memory associated with the
3082  * message will not be freed before this call returns.
3083  *
3084  * Return: zero on success, else a negative error code.
3085  */
3086 int spi_sync(struct spi_device *spi, struct spi_message *message)
3087 {
3088         int ret;
3089
3090         mutex_lock(&spi->controller->bus_lock_mutex);
3091         ret = __spi_sync(spi, message);
3092         mutex_unlock(&spi->controller->bus_lock_mutex);
3093
3094         return ret;
3095 }
3096 EXPORT_SYMBOL_GPL(spi_sync);
3097
3098 /**
3099  * spi_sync_locked - version of spi_sync with exclusive bus usage
3100  * @spi: device with which data will be exchanged
3101  * @message: describes the data transfers
3102  * Context: can sleep
3103  *
3104  * This call may only be used from a context that may sleep.  The sleep
3105  * is non-interruptible, and has no timeout.  Low-overhead controller
3106  * drivers may DMA directly into and out of the message buffers.
3107  *
3108  * This call should be used by drivers that require exclusive access to the
3109  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3110  * be released by a spi_bus_unlock call when the exclusive access is over.
3111  *
3112  * Return: zero on success, else a negative error code.
3113  */
3114 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3115 {
3116         return __spi_sync(spi, message);
3117 }
3118 EXPORT_SYMBOL_GPL(spi_sync_locked);
3119
3120 /**
3121  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3122  * @ctlr: SPI bus master that should be locked for exclusive bus access
3123  * Context: can sleep
3124  *
3125  * This call may only be used from a context that may sleep.  The sleep
3126  * is non-interruptible, and has no timeout.
3127  *
3128  * This call should be used by drivers that require exclusive access to the
3129  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3130  * exclusive access is over. Data transfer must be done by spi_sync_locked
3131  * and spi_async_locked calls when the SPI bus lock is held.
3132  *
3133  * Return: always zero.
3134  */
3135 int spi_bus_lock(struct spi_controller *ctlr)
3136 {
3137         unsigned long flags;
3138
3139         mutex_lock(&ctlr->bus_lock_mutex);
3140
3141         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3142         ctlr->bus_lock_flag = 1;
3143         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3144
3145         /* mutex remains locked until spi_bus_unlock is called */
3146
3147         return 0;
3148 }
3149 EXPORT_SYMBOL_GPL(spi_bus_lock);
3150
3151 /**
3152  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3153  * @ctlr: SPI bus master that was locked for exclusive bus access
3154  * Context: can sleep
3155  *
3156  * This call may only be used from a context that may sleep.  The sleep
3157  * is non-interruptible, and has no timeout.
3158  *
3159  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3160  * call.
3161  *
3162  * Return: always zero.
3163  */
3164 int spi_bus_unlock(struct spi_controller *ctlr)
3165 {
3166         ctlr->bus_lock_flag = 0;
3167
3168         mutex_unlock(&ctlr->bus_lock_mutex);
3169
3170         return 0;
3171 }
3172 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3173
3174 /* portable code must never pass more than 32 bytes */
3175 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3176
3177 static u8       *buf;
3178
3179 /**
3180  * spi_write_then_read - SPI synchronous write followed by read
3181  * @spi: device with which data will be exchanged
3182  * @txbuf: data to be written (need not be dma-safe)
3183  * @n_tx: size of txbuf, in bytes
3184  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3185  * @n_rx: size of rxbuf, in bytes
3186  * Context: can sleep
3187  *
3188  * This performs a half duplex MicroWire style transaction with the
3189  * device, sending txbuf and then reading rxbuf.  The return value
3190  * is zero for success, else a negative errno status code.
3191  * This call may only be used from a context that may sleep.
3192  *
3193  * Parameters to this routine are always copied using a small buffer;
3194  * portable code should never use this for more than 32 bytes.
3195  * Performance-sensitive or bulk transfer code should instead use
3196  * spi_{async,sync}() calls with dma-safe buffers.
3197  *
3198  * Return: zero on success, else a negative error code.
3199  */
3200 int spi_write_then_read(struct spi_device *spi,
3201                 const void *txbuf, unsigned n_tx,
3202                 void *rxbuf, unsigned n_rx)
3203 {
3204         static DEFINE_MUTEX(lock);
3205
3206         int                     status;
3207         struct spi_message      message;
3208         struct spi_transfer     x[2];
3209         u8                      *local_buf;
3210
3211         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3212          * copying here, (as a pure convenience thing), but we can
3213          * keep heap costs out of the hot path unless someone else is
3214          * using the pre-allocated buffer or the transfer is too large.
3215          */
3216         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3217                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3218                                     GFP_KERNEL | GFP_DMA);
3219                 if (!local_buf)
3220                         return -ENOMEM;
3221         } else {
3222                 local_buf = buf;
3223         }
3224
3225         spi_message_init(&message);
3226         memset(x, 0, sizeof(x));
3227         if (n_tx) {
3228                 x[0].len = n_tx;
3229                 spi_message_add_tail(&x[0], &message);
3230         }
3231         if (n_rx) {
3232                 x[1].len = n_rx;
3233                 spi_message_add_tail(&x[1], &message);
3234         }
3235
3236         memcpy(local_buf, txbuf, n_tx);
3237         x[0].tx_buf = local_buf;
3238         x[1].rx_buf = local_buf + n_tx;
3239
3240         /* do the i/o */
3241         status = spi_sync(spi, &message);
3242         if (status == 0)
3243                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3244
3245         if (x[0].tx_buf == buf)
3246                 mutex_unlock(&lock);
3247         else
3248                 kfree(local_buf);
3249
3250         return status;
3251 }
3252 EXPORT_SYMBOL_GPL(spi_write_then_read);
3253
3254 /*-------------------------------------------------------------------------*/
3255
3256 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3257 static int __spi_of_device_match(struct device *dev, void *data)
3258 {
3259         return dev->of_node == data;
3260 }
3261
3262 /* must call put_device() when done with returned spi_device device */
3263 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3264 {
3265         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3266                                                 __spi_of_device_match);
3267         return dev ? to_spi_device(dev) : NULL;
3268 }
3269
3270 static int __spi_of_controller_match(struct device *dev, const void *data)
3271 {
3272         return dev->of_node == data;
3273 }
3274
3275 /* the spi controllers are not using spi_bus, so we find it with another way */
3276 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3277 {
3278         struct device *dev;
3279
3280         dev = class_find_device(&spi_master_class, NULL, node,
3281                                 __spi_of_controller_match);
3282         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3283                 dev = class_find_device(&spi_slave_class, NULL, node,
3284                                         __spi_of_controller_match);
3285         if (!dev)
3286                 return NULL;
3287
3288         /* reference got in class_find_device */
3289         return container_of(dev, struct spi_controller, dev);
3290 }
3291
3292 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3293                          void *arg)
3294 {
3295         struct of_reconfig_data *rd = arg;
3296         struct spi_controller *ctlr;
3297         struct spi_device *spi;
3298
3299         switch (of_reconfig_get_state_change(action, arg)) {
3300         case OF_RECONFIG_CHANGE_ADD:
3301                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3302                 if (ctlr == NULL)
3303                         return NOTIFY_OK;       /* not for us */
3304
3305                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3306                         put_device(&ctlr->dev);
3307                         return NOTIFY_OK;
3308                 }
3309
3310                 spi = of_register_spi_device(ctlr, rd->dn);
3311                 put_device(&ctlr->dev);
3312
3313                 if (IS_ERR(spi)) {
3314                         pr_err("%s: failed to create for '%s'\n",
3315                                         __func__, rd->dn->full_name);
3316                         of_node_clear_flag(rd->dn, OF_POPULATED);
3317                         return notifier_from_errno(PTR_ERR(spi));
3318                 }
3319                 break;
3320
3321         case OF_RECONFIG_CHANGE_REMOVE:
3322                 /* already depopulated? */
3323                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3324                         return NOTIFY_OK;
3325
3326                 /* find our device by node */
3327                 spi = of_find_spi_device_by_node(rd->dn);
3328                 if (spi == NULL)
3329                         return NOTIFY_OK;       /* no? not meant for us */
3330
3331                 /* unregister takes one ref away */
3332                 spi_unregister_device(spi);
3333
3334                 /* and put the reference of the find */
3335                 put_device(&spi->dev);
3336                 break;
3337         }
3338
3339         return NOTIFY_OK;
3340 }
3341
3342 static struct notifier_block spi_of_notifier = {
3343         .notifier_call = of_spi_notify,
3344 };
3345 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3346 extern struct notifier_block spi_of_notifier;
3347 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3348
3349 #if IS_ENABLED(CONFIG_ACPI)
3350 static int spi_acpi_controller_match(struct device *dev, const void *data)
3351 {
3352         return ACPI_COMPANION(dev->parent) == data;
3353 }
3354
3355 static int spi_acpi_device_match(struct device *dev, void *data)
3356 {
3357         return ACPI_COMPANION(dev) == data;
3358 }
3359
3360 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3361 {
3362         struct device *dev;
3363
3364         dev = class_find_device(&spi_master_class, NULL, adev,
3365                                 spi_acpi_controller_match);
3366         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3367                 dev = class_find_device(&spi_slave_class, NULL, adev,
3368                                         spi_acpi_controller_match);
3369         if (!dev)
3370                 return NULL;
3371
3372         return container_of(dev, struct spi_controller, dev);
3373 }
3374
3375 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3376 {
3377         struct device *dev;
3378
3379         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3380
3381         return dev ? to_spi_device(dev) : NULL;
3382 }
3383
3384 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3385                            void *arg)
3386 {
3387         struct acpi_device *adev = arg;
3388         struct spi_controller *ctlr;
3389         struct spi_device *spi;
3390
3391         switch (value) {
3392         case ACPI_RECONFIG_DEVICE_ADD:
3393                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3394                 if (!ctlr)
3395                         break;
3396
3397                 acpi_register_spi_device(ctlr, adev);
3398                 put_device(&ctlr->dev);
3399                 break;
3400         case ACPI_RECONFIG_DEVICE_REMOVE:
3401                 if (!acpi_device_enumerated(adev))
3402                         break;
3403
3404                 spi = acpi_spi_find_device_by_adev(adev);
3405                 if (!spi)
3406                         break;
3407
3408                 spi_unregister_device(spi);
3409                 put_device(&spi->dev);
3410                 break;
3411         }
3412
3413         return NOTIFY_OK;
3414 }
3415
3416 static struct notifier_block spi_acpi_notifier = {
3417         .notifier_call = acpi_spi_notify,
3418 };
3419 #else
3420 extern struct notifier_block spi_acpi_notifier;
3421 #endif
3422
3423 static int __init spi_init(void)
3424 {
3425         int     status;
3426
3427         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3428         if (!buf) {
3429                 status = -ENOMEM;
3430                 goto err0;
3431         }
3432
3433         status = bus_register(&spi_bus_type);
3434         if (status < 0)
3435                 goto err1;
3436
3437         status = class_register(&spi_master_class);
3438         if (status < 0)
3439                 goto err2;
3440
3441         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3442                 status = class_register(&spi_slave_class);
3443                 if (status < 0)
3444                         goto err3;
3445         }
3446
3447         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3448                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3449         if (IS_ENABLED(CONFIG_ACPI))
3450                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3451
3452         return 0;
3453
3454 err3:
3455         class_unregister(&spi_master_class);
3456 err2:
3457         bus_unregister(&spi_bus_type);
3458 err1:
3459         kfree(buf);
3460         buf = NULL;
3461 err0:
3462         return status;
3463 }
3464
3465 /* board_info is normally registered in arch_initcall(),
3466  * but even essential drivers wait till later
3467  *
3468  * REVISIT only boardinfo really needs static linking. the rest (device and
3469  * driver registration) _could_ be dynamically linked (modular) ... costs
3470  * include needing to have boardinfo data structures be much more public.
3471  */
3472 postcore_initcall(spi_init);
3473