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/export.h>
  35 #include <linux/sched/rt.h>
  36 #include <linux/delay.h>
  37 #include <linux/kthread.h>
  38 #include <linux/ioport.h>
  39 #include <linux/acpi.h>
  40
  41 #define CREATE_TRACE_POINTS
  42 #include <trace/events/spi.h>
  43
  44 static void spidev_release(struct device *dev)
  45 {
  46         struct spi_device       *spi = to_spi_device(dev);
  47
  48         /* spi masters may cleanup for released devices */
  49         if (spi->master->cleanup)
  50                 spi->master->cleanup(spi);
  51
  52         spi_master_put(spi->master);
  53         kfree(spi);
  54 }
  55
  56 static ssize_t
  57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  58 {
  59         const struct spi_device *spi = to_spi_device(dev);
  60         int len;
  61
  62         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  63         if (len != -ENODEV)
  64                 return len;
  65
  66         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  67 }
  68 static DEVICE_ATTR_RO(modalias);
  69
  70 #define SPI_STATISTICS_ATTRS(field, file)                               \
  71 static ssize_t spi_master_##field##_show(struct device *dev,            \
  72                                          struct device_attribute *attr, \
  73                                          char *buf)                     \
  74 {                                                                       \
  75         struct spi_master *master = container_of(dev,                   \
  76                                                  struct spi_master, dev); \
  77         return spi_statistics_##field##_show(&master->statistics, buf); \
  78 }                                                                       \
  79 static struct device_attribute dev_attr_spi_master_##field = {          \
  80         .attr = { .name = file, .mode = S_IRUGO },                      \
  81         .show = spi_master_##field##_show,                              \
  82 };                                                                      \
  83 static ssize_t spi_device_##field##_show(struct device *dev,            \
  84                                          struct device_attribute *attr, \
  85                                         char *buf)                      \
  86 {                                                                       \
  87         struct spi_device *spi = to_spi_device(dev);                    \
  88         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  89 }                                                                       \
  90 static struct device_attribute dev_attr_spi_device_##field = {          \
  91         .attr = { .name = file, .mode = S_IRUGO },                      \
  92         .show = spi_device_##field##_show,                              \
  93 }
  94
  95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  97                                             char *buf)                  \
  98 {                                                                       \
  99         unsigned long flags;                                            \
 100         ssize_t len;                                                    \
 101         spin_lock_irqsave(&stat->lock, flags);                          \
 102         len = sprintf(buf, format_string, stat->field);                 \
 103         spin_unlock_irqrestore(&stat->lock, flags);                     \
 104         return len;                                                     \
 105 }                                                                       \
 106 SPI_STATISTICS_ATTRS(name, file)
 107
 108 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 109         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 110                                  field, format_string)
 111
 112 SPI_STATISTICS_SHOW(messages, "%lu");
 113 SPI_STATISTICS_SHOW(transfers, "%lu");
 114 SPI_STATISTICS_SHOW(errors, "%lu");
 115 SPI_STATISTICS_SHOW(timedout, "%lu");
 116
 117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 119 SPI_STATISTICS_SHOW(spi_async, "%lu");
 120
 121 SPI_STATISTICS_SHOW(bytes, "%llu");
 122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 124
 125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 126         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 127                                  "transfer_bytes_histo_" number,        \
 128                                  transfer_bytes_histo[index],  "%lu")
 129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 146
 147 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 148
 149 static struct attribute *spi_dev_attrs[] = {
 150         &dev_attr_modalias.attr,
 151         NULL,
 152 };
 153
 154 static const struct attribute_group spi_dev_group = {
 155         .attrs  = spi_dev_attrs,
 156 };
 157
 158 static struct attribute *spi_device_statistics_attrs[] = {
 159         &dev_attr_spi_device_messages.attr,
 160         &dev_attr_spi_device_transfers.attr,
 161         &dev_attr_spi_device_errors.attr,
 162         &dev_attr_spi_device_timedout.attr,
 163         &dev_attr_spi_device_spi_sync.attr,
 164         &dev_attr_spi_device_spi_sync_immediate.attr,
 165         &dev_attr_spi_device_spi_async.attr,
 166         &dev_attr_spi_device_bytes.attr,
 167         &dev_attr_spi_device_bytes_rx.attr,
 168         &dev_attr_spi_device_bytes_tx.attr,
 169         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 186         &dev_attr_spi_device_transfers_split_maxsize.attr,
 187         NULL,
 188 };
 189
 190 static const struct attribute_group spi_device_statistics_group = {
 191         .name  = "statistics",
 192         .attrs  = spi_device_statistics_attrs,
 193 };
 194
 195 static const struct attribute_group *spi_dev_groups[] = {
 196         &spi_dev_group,
 197         &spi_device_statistics_group,
 198         NULL,
 199 };
 200
 201 static struct attribute *spi_master_statistics_attrs[] = {
 202         &dev_attr_spi_master_messages.attr,
 203         &dev_attr_spi_master_transfers.attr,
 204         &dev_attr_spi_master_errors.attr,
 205         &dev_attr_spi_master_timedout.attr,
 206         &dev_attr_spi_master_spi_sync.attr,
 207         &dev_attr_spi_master_spi_sync_immediate.attr,
 208         &dev_attr_spi_master_spi_async.attr,
 209         &dev_attr_spi_master_bytes.attr,
 210         &dev_attr_spi_master_bytes_rx.attr,
 211         &dev_attr_spi_master_bytes_tx.attr,
 212         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 226         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 227         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 228         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 229         &dev_attr_spi_master_transfers_split_maxsize.attr,
 230         NULL,
 231 };
 232
 233 static const struct attribute_group spi_master_statistics_group = {
 234         .name  = "statistics",
 235         .attrs  = spi_master_statistics_attrs,
 236 };
 237
 238 static const struct attribute_group *spi_master_groups[] = {
 239         &spi_master_statistics_group,
 240         NULL,
 241 };
 242
 243 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 244                                        struct spi_transfer *xfer,
 245                                        struct spi_master *master)
 246 {
 247         unsigned long flags;
 248         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 249
 250         if (l2len < 0)
 251                 l2len = 0;
 252
 253         spin_lock_irqsave(&stats->lock, flags);
 254
 255         stats->transfers++;
 256         stats->transfer_bytes_histo[l2len]++;
 257
 258         stats->bytes += xfer->len;
 259         if ((xfer->tx_buf) &&
 260             (xfer->tx_buf != master->dummy_tx))
 261                 stats->bytes_tx += xfer->len;
 262         if ((xfer->rx_buf) &&
 263             (xfer->rx_buf != master->dummy_rx))
 264                 stats->bytes_rx += xfer->len;
 265
 266         spin_unlock_irqrestore(&stats->lock, flags);
 267 }
 268 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 269
 270 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 271  * and the sysfs version makes coldplug work too.
 272  */
 273
 274 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 275                                                 const struct spi_device *sdev)
 276 {
 277         while (id->name[0]) {
 278                 if (!strcmp(sdev->modalias, id->name))
 279                         return id;
 280                 id++;
 281         }
 282         return NULL;
 283 }
 284
 285 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 286 {
 287         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 288
 289         return spi_match_id(sdrv->id_table, sdev);
 290 }
 291 EXPORT_SYMBOL_GPL(spi_get_device_id);
 292
 293 static int spi_match_device(struct device *dev, struct device_driver *drv)
 294 {
 295         const struct spi_device *spi = to_spi_device(dev);
 296         const struct spi_driver *sdrv = to_spi_driver(drv);
 297
 298         /* Attempt an OF style match */
 299         if (of_driver_match_device(dev, drv))
 300                 return 1;
 301
 302         /* Then try ACPI */
 303         if (acpi_driver_match_device(dev, drv))
 304                 return 1;
 305
 306         if (sdrv->id_table)
 307                 return !!spi_match_id(sdrv->id_table, spi);
 308
 309         return strcmp(spi->modalias, drv->name) == 0;
 310 }
 311
 312 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 313 {
 314         const struct spi_device         *spi = to_spi_device(dev);
 315         int rc;
 316
 317         rc = acpi_device_uevent_modalias(dev, env);
 318         if (rc != -ENODEV)
 319                 return rc;
 320
 321         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 322         return 0;
 323 }
 324
 325 struct bus_type spi_bus_type = {
 326         .name           = "spi",
 327         .dev_groups     = spi_dev_groups,
 328         .match          = spi_match_device,
 329         .uevent         = spi_uevent,
 330 };
 331 EXPORT_SYMBOL_GPL(spi_bus_type);
 332
 333
 334 static int spi_drv_probe(struct device *dev)
 335 {
 336         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 337         struct spi_device               *spi = to_spi_device(dev);
 338         int ret;
 339
 340         ret = of_clk_set_defaults(dev->of_node, false);
 341         if (ret)
 342                 return ret;
 343
 344         if (dev->of_node) {
 345                 spi->irq = of_irq_get(dev->of_node, 0);
 346                 if (spi->irq == -EPROBE_DEFER)
 347                         return -EPROBE_DEFER;
 348                 if (spi->irq < 0)
 349                         spi->irq = 0;
 350         }
 351
 352         ret = dev_pm_domain_attach(dev, true);
 353         if (ret != -EPROBE_DEFER) {
 354                 ret = sdrv->probe(spi);
 355                 if (ret)
 356                         dev_pm_domain_detach(dev, true);
 357         }
 358
 359         return ret;
 360 }
 361
 362 static int spi_drv_remove(struct device *dev)
 363 {
 364         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 365         int ret;
 366
 367         ret = sdrv->remove(to_spi_device(dev));
 368         dev_pm_domain_detach(dev, true);
 369
 370         return ret;
 371 }
 372
 373 static void spi_drv_shutdown(struct device *dev)
 374 {
 375         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 376
 377         sdrv->shutdown(to_spi_device(dev));
 378 }
 379
 380 /**
 381  * __spi_register_driver - register a SPI driver
 382  * @owner: owner module of the driver to register
 383  * @sdrv: the driver to register
 384  * Context: can sleep
 385  *
 386  * Return: zero on success, else a negative error code.
 387  */
 388 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 389 {
 390         sdrv->driver.owner = owner;
 391         sdrv->driver.bus = &spi_bus_type;
 392         if (sdrv->probe)
 393                 sdrv->driver.probe = spi_drv_probe;
 394         if (sdrv->remove)
 395                 sdrv->driver.remove = spi_drv_remove;
 396         if (sdrv->shutdown)
 397                 sdrv->driver.shutdown = spi_drv_shutdown;
 398         return driver_register(&sdrv->driver);
 399 }
 400 EXPORT_SYMBOL_GPL(__spi_register_driver);
 401
 402 /*-------------------------------------------------------------------------*/
 403
 404 /* SPI devices should normally not be created by SPI device drivers; that
 405  * would make them board-specific.  Similarly with SPI master drivers.
 406  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 407  * with other readonly (flashable) information about mainboard devices.
 408  */
 409
 410 struct boardinfo {
 411         struct list_head        list;
 412         struct spi_board_info   board_info;
 413 };
 414
 415 static LIST_HEAD(board_list);
 416 static LIST_HEAD(spi_master_list);
 417
 418 /*
 419  * Used to protect add/del opertion for board_info list and
 420  * spi_master list, and their matching process
 421  */
 422 static DEFINE_MUTEX(board_lock);
 423
 424 /**
 425  * spi_alloc_device - Allocate a new SPI device
 426  * @master: Controller to which device is connected
 427  * Context: can sleep
 428  *
 429  * Allows a driver to allocate and initialize a spi_device without
 430  * registering it immediately.  This allows a driver to directly
 431  * fill the spi_device with device parameters before calling
 432  * spi_add_device() on it.
 433  *
 434  * Caller is responsible to call spi_add_device() on the returned
 435  * spi_device structure to add it to the SPI master.  If the caller
 436  * needs to discard the spi_device without adding it, then it should
 437  * call spi_dev_put() on it.
 438  *
 439  * Return: a pointer to the new device, or NULL.
 440  */
 441 struct spi_device *spi_alloc_device(struct spi_master *master)
 442 {
 443         struct spi_device       *spi;
 444
 445         if (!spi_master_get(master))
 446                 return NULL;
 447
 448         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 449         if (!spi) {
 450                 spi_master_put(master);
 451                 return NULL;
 452         }
 453
 454         spi->master = master;
 455         spi->dev.parent = &master->dev;
 456         spi->dev.bus = &spi_bus_type;
 457         spi->dev.release = spidev_release;
 458         spi->cs_gpio = -ENOENT;
 459
 460         spin_lock_init(&spi->statistics.lock);
 461
 462         device_initialize(&spi->dev);
 463         return spi;
 464 }
 465 EXPORT_SYMBOL_GPL(spi_alloc_device);
 466
 467 static void spi_dev_set_name(struct spi_device *spi)
 468 {
 469         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 470
 471         if (adev) {
 472                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 473                 return;
 474         }
 475
 476         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 477                      spi->chip_select);
 478 }
 479
 480 static int spi_dev_check(struct device *dev, void *data)
 481 {
 482         struct spi_device *spi = to_spi_device(dev);
 483         struct spi_device *new_spi = data;
 484
 485         if (spi->master == new_spi->master &&
 486             spi->chip_select == new_spi->chip_select)
 487                 return -EBUSY;
 488         return 0;
 489 }
 490
 491 /**
 492  * spi_add_device - Add spi_device allocated with spi_alloc_device
 493  * @spi: spi_device to register
 494  *
 495  * Companion function to spi_alloc_device.  Devices allocated with
 496  * spi_alloc_device can be added onto the spi bus with this function.
 497  *
 498  * Return: 0 on success; negative errno on failure
 499  */
 500 int spi_add_device(struct spi_device *spi)
 501 {
 502         static DEFINE_MUTEX(spi_add_lock);
 503         struct spi_master *master = spi->master;
 504         struct device *dev = master->dev.parent;
 505         int status;
 506
 507         /* Chipselects are numbered 0..max; validate. */
 508         if (spi->chip_select >= master->num_chipselect) {
 509                 dev_err(dev, "cs%d >= max %d\n",
 510                         spi->chip_select,
 511                         master->num_chipselect);
 512                 return -EINVAL;
 513         }
 514
 515         /* Set the bus ID string */
 516         spi_dev_set_name(spi);
 517
 518         /* We need to make sure there's no other device with this
 519          * chipselect **BEFORE** we call setup(), else we'll trash
 520          * its configuration.  Lock against concurrent add() calls.
 521          */
 522         mutex_lock(&spi_add_lock);
 523
 524         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 525         if (status) {
 526                 dev_err(dev, "chipselect %d already in use\n",
 527                                 spi->chip_select);
 528                 goto done;
 529         }
 530
 531         if (master->cs_gpios)
 532                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 533
 534         /* Drivers may modify this initial i/o setup, but will
 535          * normally rely on the device being setup.  Devices
 536          * using SPI_CS_HIGH can't coexist well otherwise...
 537          */
 538         status = spi_setup(spi);
 539         if (status < 0) {
 540                 dev_err(dev, "can't setup %s, status %d\n",
 541                                 dev_name(&spi->dev), status);
 542                 goto done;
 543         }
 544
 545         /* Device may be bound to an active driver when this returns */
 546         status = device_add(&spi->dev);
 547         if (status < 0)
 548                 dev_err(dev, "can't add %s, status %d\n",
 549                                 dev_name(&spi->dev), status);
 550         else
 551                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 552
 553 done:
 554         mutex_unlock(&spi_add_lock);
 555         return status;
 556 }
 557 EXPORT_SYMBOL_GPL(spi_add_device);
 558
 559 /**
 560  * spi_new_device - instantiate one new SPI device
 561  * @master: Controller to which device is connected
 562  * @chip: Describes the SPI device
 563  * Context: can sleep
 564  *
 565  * On typical mainboards, this is purely internal; and it's not needed
 566  * after board init creates the hard-wired devices.  Some development
 567  * platforms may not be able to use spi_register_board_info though, and
 568  * this is exported so that for example a USB or parport based adapter
 569  * driver could add devices (which it would learn about out-of-band).
 570  *
 571  * Return: the new device, or NULL.
 572  */
 573 struct spi_device *spi_new_device(struct spi_master *master,
 574                                   struct spi_board_info *chip)
 575 {
 576         struct spi_device       *proxy;
 577         int                     status;
 578
 579         /* NOTE:  caller did any chip->bus_num checks necessary.
 580          *
 581          * Also, unless we change the return value convention to use
 582          * error-or-pointer (not NULL-or-pointer), troubleshootability
 583          * suggests syslogged diagnostics are best here (ugh).
 584          */
 585
 586         proxy = spi_alloc_device(master);
 587         if (!proxy)
 588                 return NULL;
 589
 590         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 591
 592         proxy->chip_select = chip->chip_select;
 593         proxy->max_speed_hz = chip->max_speed_hz;
 594         proxy->mode = chip->mode;
 595         proxy->irq = chip->irq;
 596         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 597         proxy->dev.platform_data = (void *) chip->platform_data;
 598         proxy->controller_data = chip->controller_data;
 599         proxy->controller_state = NULL;
 600
 601         status = spi_add_device(proxy);
 602         if (status < 0) {
 603                 spi_dev_put(proxy);
 604                 return NULL;
 605         }
 606
 607         return proxy;
 608 }
 609 EXPORT_SYMBOL_GPL(spi_new_device);
 610
 611 /**
 612  * spi_unregister_device - unregister a single SPI device
 613  * @spi: spi_device to unregister
 614  *
 615  * Start making the passed SPI device vanish. Normally this would be handled
 616  * by spi_unregister_master().
 617  */
 618 void spi_unregister_device(struct spi_device *spi)
 619 {
 620         if (!spi)
 621                 return;
 622
 623         if (spi->dev.of_node)
 624                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 625         device_unregister(&spi->dev);
 626 }
 627 EXPORT_SYMBOL_GPL(spi_unregister_device);
 628
 629 static void spi_match_master_to_boardinfo(struct spi_master *master,
 630                                 struct spi_board_info *bi)
 631 {
 632         struct spi_device *dev;
 633
 634         if (master->bus_num != bi->bus_num)
 635                 return;
 636
 637         dev = spi_new_device(master, bi);
 638         if (!dev)
 639                 dev_err(master->dev.parent, "can't create new device for %s\n",
 640                         bi->modalias);
 641 }
 642
 643 /**
 644  * spi_register_board_info - register SPI devices for a given board
 645  * @info: array of chip descriptors
 646  * @n: how many descriptors are provided
 647  * Context: can sleep
 648  *
 649  * Board-specific early init code calls this (probably during arch_initcall)
 650  * with segments of the SPI device table.  Any device nodes are created later,
 651  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 652  * this table of devices forever, so that reloading a controller driver will
 653  * not make Linux forget about these hard-wired devices.
 654  *
 655  * Other code can also call this, e.g. a particular add-on board might provide
 656  * SPI devices through its expansion connector, so code initializing that board
 657  * would naturally declare its SPI devices.
 658  *
 659  * The board info passed can safely be __initdata ... but be careful of
 660  * any embedded pointers (platform_data, etc), they're copied as-is.
 661  *
 662  * Return: zero on success, else a negative error code.
 663  */
 664 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 665 {
 666         struct boardinfo *bi;
 667         int i;
 668
 669         if (!n)
 670                 return -EINVAL;
 671
 672         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 673         if (!bi)
 674                 return -ENOMEM;
 675
 676         for (i = 0; i < n; i++, bi++, info++) {
 677                 struct spi_master *master;
 678
 679                 memcpy(&bi->board_info, info, sizeof(*info));
 680                 mutex_lock(&board_lock);
 681                 list_add_tail(&bi->list, &board_list);
 682                 list_for_each_entry(master, &spi_master_list, list)
 683                         spi_match_master_to_boardinfo(master, &bi->board_info);
 684                 mutex_unlock(&board_lock);
 685         }
 686
 687         return 0;
 688 }
 689
 690 /*-------------------------------------------------------------------------*/
 691
 692 static void spi_set_cs(struct spi_device *spi, bool enable)
 693 {
 694         if (spi->mode & SPI_CS_HIGH)
 695                 enable = !enable;
 696
 697         if (gpio_is_valid(spi->cs_gpio))
 698                 gpio_set_value(spi->cs_gpio, !enable);
 699         else if (spi->master->set_cs)
 700                 spi->master->set_cs(spi, !enable);
 701 }
 702
 703 #ifdef CONFIG_HAS_DMA
 704 static int spi_map_buf(struct spi_master *master, struct device *dev,
 705                        struct sg_table *sgt, void *buf, size_t len,
 706                        enum dma_data_direction dir)
 707 {
 708         const bool vmalloced_buf = is_vmalloc_addr(buf);
 709         int desc_len;
 710         int sgs;
 711         struct page *vm_page;
 712         void *sg_buf;
 713         size_t min;
 714         int i, ret;
 715
 716         if (vmalloced_buf) {
 717                 desc_len = PAGE_SIZE;
 718                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 719         } else {
 720                 desc_len = master->max_dma_len;
 721                 sgs = DIV_ROUND_UP(len, desc_len);
 722         }
 723
 724         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 725         if (ret != 0)
 726                 return ret;
 727
 728         for (i = 0; i < sgs; i++) {
 729
 730                 if (vmalloced_buf) {
 731                         min = min_t(size_t,
 732                                     len, desc_len - offset_in_page(buf));
 733                         vm_page = vmalloc_to_page(buf);
 734                         if (!vm_page) {
 735                                 sg_free_table(sgt);
 736                                 return -ENOMEM;
 737                         }
 738                         sg_set_page(&sgt->sgl[i], vm_page,
 739                                     min, offset_in_page(buf));
 740                 } else {
 741                         min = min_t(size_t, len, desc_len);
 742                         sg_buf = buf;
 743                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
 744                 }
 745
 746
 747                 buf += min;
 748                 len -= min;
 749         }
 750
 751         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 752         if (!ret)
 753                 ret = -ENOMEM;
 754         if (ret < 0) {
 755                 sg_free_table(sgt);
 756                 return ret;
 757         }
 758
 759         sgt->nents = ret;
 760
 761         return 0;
 762 }
 763
 764 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 765                           struct sg_table *sgt, enum dma_data_direction dir)
 766 {
 767         if (sgt->orig_nents) {
 768                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 769                 sg_free_table(sgt);
 770         }
 771 }
 772
 773 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 774 {
 775         struct device *tx_dev, *rx_dev;
 776         struct spi_transfer *xfer;
 777         int ret;
 778
 779         if (!master->can_dma)
 780                 return 0;
 781
 782         if (master->dma_tx)
 783                 tx_dev = master->dma_tx->device->dev;
 784         else
 785                 tx_dev = &master->dev;
 786
 787         if (master->dma_rx)
 788                 rx_dev = master->dma_rx->device->dev;
 789         else
 790                 rx_dev = &master->dev;
 791
 792         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 793                 if (!master->can_dma(master, msg->spi, xfer))
 794                         continue;
 795
 796                 if (xfer->tx_buf != NULL) {
 797                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 798                                           (void *)xfer->tx_buf, xfer->len,
 799                                           DMA_TO_DEVICE);
 800                         if (ret != 0)
 801                                 return ret;
 802                 }
 803
 804                 if (xfer->rx_buf != NULL) {
 805                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 806                                           xfer->rx_buf, xfer->len,
 807                                           DMA_FROM_DEVICE);
 808                         if (ret != 0) {
 809                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 810                                               DMA_TO_DEVICE);
 811                                 return ret;
 812                         }
 813                 }
 814         }
 815
 816         master->cur_msg_mapped = true;
 817
 818         return 0;
 819 }
 820
 821 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 822 {
 823         struct spi_transfer *xfer;
 824         struct device *tx_dev, *rx_dev;
 825
 826         if (!master->cur_msg_mapped || !master->can_dma)
 827                 return 0;
 828
 829         if (master->dma_tx)
 830                 tx_dev = master->dma_tx->device->dev;
 831         else
 832                 tx_dev = &master->dev;
 833
 834         if (master->dma_rx)
 835                 rx_dev = master->dma_rx->device->dev;
 836         else
 837                 rx_dev = &master->dev;
 838
 839         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 840                 if (!master->can_dma(master, msg->spi, xfer))
 841                         continue;
 842
 843                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 844                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 845         }
 846
 847         return 0;
 848 }
 849 #else /* !CONFIG_HAS_DMA */
 850 static inline int __spi_map_msg(struct spi_master *master,
 851                                 struct spi_message *msg)
 852 {
 853         return 0;
 854 }
 855
 856 static inline int __spi_unmap_msg(struct spi_master *master,
 857                                   struct spi_message *msg)
 858 {
 859         return 0;
 860 }
 861 #endif /* !CONFIG_HAS_DMA */
 862
 863 static inline int spi_unmap_msg(struct spi_master *master,
 864                                 struct spi_message *msg)
 865 {
 866         struct spi_transfer *xfer;
 867
 868         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 869                 /*
 870                  * Restore the original value of tx_buf or rx_buf if they are
 871                  * NULL.
 872                  */
 873                 if (xfer->tx_buf == master->dummy_tx)
 874                         xfer->tx_buf = NULL;
 875                 if (xfer->rx_buf == master->dummy_rx)
 876                         xfer->rx_buf = NULL;
 877         }
 878
 879         return __spi_unmap_msg(master, msg);
 880 }
 881
 882 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 883 {
 884         struct spi_transfer *xfer;
 885         void *tmp;
 886         unsigned int max_tx, max_rx;
 887
 888         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 889                 max_tx = 0;
 890                 max_rx = 0;
 891
 892                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 893                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 894                             !xfer->tx_buf)
 895                                 max_tx = max(xfer->len, max_tx);
 896                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 897                             !xfer->rx_buf)
 898                                 max_rx = max(xfer->len, max_rx);
 899                 }
 900
 901                 if (max_tx) {
 902                         tmp = krealloc(master->dummy_tx, max_tx,
 903                                        GFP_KERNEL | GFP_DMA);
 904                         if (!tmp)
 905                                 return -ENOMEM;
 906                         master->dummy_tx = tmp;
 907                         memset(tmp, 0, max_tx);
 908                 }
 909
 910                 if (max_rx) {
 911                         tmp = krealloc(master->dummy_rx, max_rx,
 912                                        GFP_KERNEL | GFP_DMA);
 913                         if (!tmp)
 914                                 return -ENOMEM;
 915                         master->dummy_rx = tmp;
 916                 }
 917
 918                 if (max_tx || max_rx) {
 919                         list_for_each_entry(xfer, &msg->transfers,
 920                                             transfer_list) {
 921                                 if (!xfer->tx_buf)
 922                                         xfer->tx_buf = master->dummy_tx;
 923                                 if (!xfer->rx_buf)
 924                                         xfer->rx_buf = master->dummy_rx;
 925                         }
 926                 }
 927         }
 928
 929         return __spi_map_msg(master, msg);
 930 }
 931
 932 /*
 933  * spi_transfer_one_message - Default implementation of transfer_one_message()
 934  *
 935  * This is a standard implementation of transfer_one_message() for
 936  * drivers which impelment a transfer_one() operation.  It provides
 937  * standard handling of delays and chip select management.
 938  */
 939 static int spi_transfer_one_message(struct spi_master *master,
 940                                     struct spi_message *msg)
 941 {
 942         struct spi_transfer *xfer;
 943         bool keep_cs = false;
 944         int ret = 0;
 945         unsigned long ms = 1;
 946         struct spi_statistics *statm = &master->statistics;
 947         struct spi_statistics *stats = &msg->spi->statistics;
 948
 949         spi_set_cs(msg->spi, true);
 950
 951         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 952         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 953
 954         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 955                 trace_spi_transfer_start(msg, xfer);
 956
 957                 spi_statistics_add_transfer_stats(statm, xfer, master);
 958                 spi_statistics_add_transfer_stats(stats, xfer, master);
 959
 960                 if (xfer->tx_buf || xfer->rx_buf) {
 961                         reinit_completion(&master->xfer_completion);
 962
 963                         ret = master->transfer_one(master, msg->spi, xfer);
 964                         if (ret < 0) {
 965                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 966                                                                errors);
 967                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 968                                                                errors);
 969                                 dev_err(&msg->spi->dev,
 970                                         "SPI transfer failed: %d\n", ret);
 971                                 goto out;
 972                         }
 973
 974                         if (ret > 0) {
 975                                 ret = 0;
 976                                 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
 977                                 ms += ms + 100; /* some tolerance */
 978
 979                                 ms = wait_for_completion_timeout(&master->xfer_completion,
 980                                                                  msecs_to_jiffies(ms));
 981                         }
 982
 983                         if (ms == 0) {
 984                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 985                                                                timedout);
 986                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 987                                                                timedout);
 988                                 dev_err(&msg->spi->dev,
 989                                         "SPI transfer timed out\n");
 990                                 msg->status = -ETIMEDOUT;
 991                         }
 992                 } else {
 993                         if (xfer->len)
 994                                 dev_err(&msg->spi->dev,
 995                                         "Bufferless transfer has length %u\n",
 996                                         xfer->len);
 997                 }
 998
 999                 trace_spi_transfer_stop(msg, xfer);
1000
1001                 if (msg->status != -EINPROGRESS)
1002                         goto out;
1003
1004                 if (xfer->delay_usecs)
1005                         udelay(xfer->delay_usecs);
1006
1007                 if (xfer->cs_change) {
1008                         if (list_is_last(&xfer->transfer_list,
1009                                          &msg->transfers)) {
1010                                 keep_cs = true;
1011                         } else {
1012                                 spi_set_cs(msg->spi, false);
1013                                 udelay(10);
1014                                 spi_set_cs(msg->spi, true);
1015                         }
1016                 }
1017
1018                 msg->actual_length += xfer->len;
1019         }
1020
1021 out:
1022         if (ret != 0 || !keep_cs)
1023                 spi_set_cs(msg->spi, false);
1024
1025         if (msg->status == -EINPROGRESS)
1026                 msg->status = ret;
1027
1028         if (msg->status && master->handle_err)
1029                 master->handle_err(master, msg);
1030
1031         spi_res_release(master, msg);
1032
1033         spi_finalize_current_message(master);
1034
1035         return ret;
1036 }
1037
1038 /**
1039  * spi_finalize_current_transfer - report completion of a transfer
1040  * @master: the master reporting completion
1041  *
1042  * Called by SPI drivers using the core transfer_one_message()
1043  * implementation to notify it that the current interrupt driven
1044  * transfer has finished and the next one may be scheduled.
1045  */
1046 void spi_finalize_current_transfer(struct spi_master *master)
1047 {
1048         complete(&master->xfer_completion);
1049 }
1050 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1051
1052 /**
1053  * __spi_pump_messages - function which processes spi message queue
1054  * @master: master to process queue for
1055  * @in_kthread: true if we are in the context of the message pump thread
1056  *
1057  * This function checks if there is any spi message in the queue that
1058  * needs processing and if so call out to the driver to initialize hardware
1059  * and transfer each message.
1060  *
1061  * Note that it is called both from the kthread itself and also from
1062  * inside spi_sync(); the queue extraction handling at the top of the
1063  * function should deal with this safely.
1064  */
1065 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1066 {
1067         unsigned long flags;
1068         bool was_busy = false;
1069         int ret;
1070
1071         /* Lock queue */
1072         spin_lock_irqsave(&master->queue_lock, flags);
1073
1074         /* Make sure we are not already running a message */
1075         if (master->cur_msg) {
1076                 spin_unlock_irqrestore(&master->queue_lock, flags);
1077                 return;
1078         }
1079
1080         /* If another context is idling the device then defer */
1081         if (master->idling) {
1082                 queue_kthread_work(&master->kworker, &master->pump_messages);
1083                 spin_unlock_irqrestore(&master->queue_lock, flags);
1084                 return;
1085         }
1086
1087         /* Check if the queue is idle */
1088         if (list_empty(&master->queue) || !master->running) {
1089                 if (!master->busy) {
1090                         spin_unlock_irqrestore(&master->queue_lock, flags);
1091                         return;
1092                 }
1093
1094                 /* Only do teardown in the thread */
1095                 if (!in_kthread) {
1096                         queue_kthread_work(&master->kworker,
1097                                            &master->pump_messages);
1098                         spin_unlock_irqrestore(&master->queue_lock, flags);
1099                         return;
1100                 }
1101
1102                 master->busy = false;
1103                 master->idling = true;
1104                 spin_unlock_irqrestore(&master->queue_lock, flags);
1105
1106                 kfree(master->dummy_rx);
1107                 master->dummy_rx = NULL;
1108                 kfree(master->dummy_tx);
1109                 master->dummy_tx = NULL;
1110                 if (master->unprepare_transfer_hardware &&
1111                     master->unprepare_transfer_hardware(master))
1112                         dev_err(&master->dev,
1113                                 "failed to unprepare transfer hardware\n");
1114                 if (master->auto_runtime_pm) {
1115                         pm_runtime_mark_last_busy(master->dev.parent);
1116                         pm_runtime_put_autosuspend(master->dev.parent);
1117                 }
1118                 trace_spi_master_idle(master);
1119
1120                 spin_lock_irqsave(&master->queue_lock, flags);
1121                 master->idling = false;
1122                 spin_unlock_irqrestore(&master->queue_lock, flags);
1123                 return;
1124         }
1125
1126         /* Extract head of queue */
1127         master->cur_msg =
1128                 list_first_entry(&master->queue, struct spi_message, queue);
1129
1130         list_del_init(&master->cur_msg->queue);
1131         if (master->busy)
1132                 was_busy = true;
1133         else
1134                 master->busy = true;
1135         spin_unlock_irqrestore(&master->queue_lock, flags);
1136
1137         if (!was_busy && master->auto_runtime_pm) {
1138                 ret = pm_runtime_get_sync(master->dev.parent);
1139                 if (ret < 0) {
1140                         dev_err(&master->dev, "Failed to power device: %d\n",
1141                                 ret);
1142                         return;
1143                 }
1144         }
1145
1146         if (!was_busy)
1147                 trace_spi_master_busy(master);
1148
1149         if (!was_busy && master->prepare_transfer_hardware) {
1150                 ret = master->prepare_transfer_hardware(master);
1151                 if (ret) {
1152                         dev_err(&master->dev,
1153                                 "failed to prepare transfer hardware\n");
1154
1155                         if (master->auto_runtime_pm)
1156                                 pm_runtime_put(master->dev.parent);
1157                         return;
1158                 }
1159         }
1160
1161         mutex_lock(&master->bus_lock_mutex);
1162         trace_spi_message_start(master->cur_msg);
1163
1164         if (master->prepare_message) {
1165                 ret = master->prepare_message(master, master->cur_msg);
1166                 if (ret) {
1167                         dev_err(&master->dev,
1168                                 "failed to prepare message: %d\n", ret);
1169                         master->cur_msg->status = ret;
1170                         spi_finalize_current_message(master);
1171                         mutex_unlock(&master->bus_lock_mutex);
1172                         return;
1173                 }
1174                 master->cur_msg_prepared = true;
1175         }
1176
1177         ret = spi_map_msg(master, master->cur_msg);
1178         if (ret) {
1179                 master->cur_msg->status = ret;
1180                 spi_finalize_current_message(master);
1181                 mutex_unlock(&master->bus_lock_mutex);
1182                 return;
1183         }
1184
1185         ret = master->transfer_one_message(master, master->cur_msg);
1186         if (ret) {
1187                 dev_err(&master->dev,
1188                         "failed to transfer one message from queue\n");
1189                 mutex_unlock(&master->bus_lock_mutex);
1190                 return;
1191         }
1192         mutex_unlock(&master->bus_lock_mutex);
1193 }
1194
1195 /**
1196  * spi_pump_messages - kthread work function which processes spi message queue
1197  * @work: pointer to kthread work struct contained in the master struct
1198  */
1199 static void spi_pump_messages(struct kthread_work *work)
1200 {
1201         struct spi_master *master =
1202                 container_of(work, struct spi_master, pump_messages);
1203
1204         __spi_pump_messages(master, true);
1205 }
1206
1207 static int spi_init_queue(struct spi_master *master)
1208 {
1209         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1210
1211         master->running = false;
1212         master->busy = false;
1213
1214         init_kthread_worker(&master->kworker);
1215         master->kworker_task = kthread_run(kthread_worker_fn,
1216                                            &master->kworker, "%s",
1217                                            dev_name(&master->dev));
1218         if (IS_ERR(master->kworker_task)) {
1219                 dev_err(&master->dev, "failed to create message pump task\n");
1220                 return PTR_ERR(master->kworker_task);
1221         }
1222         init_kthread_work(&master->pump_messages, spi_pump_messages);
1223
1224         /*
1225          * Master config will indicate if this controller should run the
1226          * message pump with high (realtime) priority to reduce the transfer
1227          * latency on the bus by minimising the delay between a transfer
1228          * request and the scheduling of the message pump thread. Without this
1229          * setting the message pump thread will remain at default priority.
1230          */
1231         if (master->rt) {
1232                 dev_info(&master->dev,
1233                         "will run message pump with realtime priority\n");
1234                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1235         }
1236
1237         return 0;
1238 }
1239
1240 /**
1241  * spi_get_next_queued_message() - called by driver to check for queued
1242  * messages
1243  * @master: the master to check for queued messages
1244  *
1245  * If there are more messages in the queue, the next message is returned from
1246  * this call.
1247  *
1248  * Return: the next message in the queue, else NULL if the queue is empty.
1249  */
1250 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1251 {
1252         struct spi_message *next;
1253         unsigned long flags;
1254
1255         /* get a pointer to the next message, if any */
1256         spin_lock_irqsave(&master->queue_lock, flags);
1257         next = list_first_entry_or_null(&master->queue, struct spi_message,
1258                                         queue);
1259         spin_unlock_irqrestore(&master->queue_lock, flags);
1260
1261         return next;
1262 }
1263 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1264
1265 /**
1266  * spi_finalize_current_message() - the current message is complete
1267  * @master: the master to return the message to
1268  *
1269  * Called by the driver to notify the core that the message in the front of the
1270  * queue is complete and can be removed from the queue.
1271  */
1272 void spi_finalize_current_message(struct spi_master *master)
1273 {
1274         struct spi_message *mesg;
1275         unsigned long flags;
1276         int ret;
1277
1278         spin_lock_irqsave(&master->queue_lock, flags);
1279         mesg = master->cur_msg;
1280         spin_unlock_irqrestore(&master->queue_lock, flags);
1281
1282         spi_unmap_msg(master, mesg);
1283
1284         if (master->cur_msg_prepared && master->unprepare_message) {
1285                 ret = master->unprepare_message(master, mesg);
1286                 if (ret) {
1287                         dev_err(&master->dev,
1288                                 "failed to unprepare message: %d\n", ret);
1289                 }
1290         }
1291
1292         spin_lock_irqsave(&master->queue_lock, flags);
1293         master->cur_msg = NULL;
1294         master->cur_msg_prepared = false;
1295         queue_kthread_work(&master->kworker, &master->pump_messages);
1296         spin_unlock_irqrestore(&master->queue_lock, flags);
1297
1298         trace_spi_message_done(mesg);
1299
1300         mesg->state = NULL;
1301         if (mesg->complete)
1302                 mesg->complete(mesg->context);
1303 }
1304 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1305
1306 static int spi_start_queue(struct spi_master *master)
1307 {
1308         unsigned long flags;
1309
1310         spin_lock_irqsave(&master->queue_lock, flags);
1311
1312         if (master->running || master->busy) {
1313                 spin_unlock_irqrestore(&master->queue_lock, flags);
1314                 return -EBUSY;
1315         }
1316
1317         master->running = true;
1318         master->cur_msg = NULL;
1319         spin_unlock_irqrestore(&master->queue_lock, flags);
1320
1321         queue_kthread_work(&master->kworker, &master->pump_messages);
1322
1323         return 0;
1324 }
1325
1326 static int spi_stop_queue(struct spi_master *master)
1327 {
1328         unsigned long flags;
1329         unsigned limit = 500;
1330         int ret = 0;
1331
1332         spin_lock_irqsave(&master->queue_lock, flags);
1333
1334         /*
1335          * This is a bit lame, but is optimized for the common execution path.
1336          * A wait_queue on the master->busy could be used, but then the common
1337          * execution path (pump_messages) would be required to call wake_up or
1338          * friends on every SPI message. Do this instead.
1339          */
1340         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1341                 spin_unlock_irqrestore(&master->queue_lock, flags);
1342                 usleep_range(10000, 11000);
1343                 spin_lock_irqsave(&master->queue_lock, flags);
1344         }
1345
1346         if (!list_empty(&master->queue) || master->busy)
1347                 ret = -EBUSY;
1348         else
1349                 master->running = false;
1350
1351         spin_unlock_irqrestore(&master->queue_lock, flags);
1352
1353         if (ret) {
1354                 dev_warn(&master->dev,
1355                          "could not stop message queue\n");
1356                 return ret;
1357         }
1358         return ret;
1359 }
1360
1361 static int spi_destroy_queue(struct spi_master *master)
1362 {
1363         int ret;
1364
1365         ret = spi_stop_queue(master);
1366
1367         /*
1368          * flush_kthread_worker will block until all work is done.
1369          * If the reason that stop_queue timed out is that the work will never
1370          * finish, then it does no good to call flush/stop thread, so
1371          * return anyway.
1372          */
1373         if (ret) {
1374                 dev_err(&master->dev, "problem destroying queue\n");
1375                 return ret;
1376         }
1377
1378         flush_kthread_worker(&master->kworker);
1379         kthread_stop(master->kworker_task);
1380
1381         return 0;
1382 }
1383
1384 static int __spi_queued_transfer(struct spi_device *spi,
1385                                  struct spi_message *msg,
1386                                  bool need_pump)
1387 {
1388         struct spi_master *master = spi->master;
1389         unsigned long flags;
1390
1391         spin_lock_irqsave(&master->queue_lock, flags);
1392
1393         if (!master->running) {
1394                 spin_unlock_irqrestore(&master->queue_lock, flags);
1395                 return -ESHUTDOWN;
1396         }
1397         msg->actual_length = 0;
1398         msg->status = -EINPROGRESS;
1399
1400         list_add_tail(&msg->queue, &master->queue);
1401         if (!master->busy && need_pump)
1402                 queue_kthread_work(&master->kworker, &master->pump_messages);
1403
1404         spin_unlock_irqrestore(&master->queue_lock, flags);
1405         return 0;
1406 }
1407
1408 /**
1409  * spi_queued_transfer - transfer function for queued transfers
1410  * @spi: spi device which is requesting transfer
1411  * @msg: spi message which is to handled is queued to driver queue
1412  *
1413  * Return: zero on success, else a negative error code.
1414  */
1415 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1416 {
1417         return __spi_queued_transfer(spi, msg, true);
1418 }
1419
1420 static int spi_master_initialize_queue(struct spi_master *master)
1421 {
1422         int ret;
1423
1424         master->transfer = spi_queued_transfer;
1425         if (!master->transfer_one_message)
1426                 master->transfer_one_message = spi_transfer_one_message;
1427
1428         /* Initialize and start queue */
1429         ret = spi_init_queue(master);
1430         if (ret) {
1431                 dev_err(&master->dev, "problem initializing queue\n");
1432                 goto err_init_queue;
1433         }
1434         master->queued = true;
1435         ret = spi_start_queue(master);
1436         if (ret) {
1437                 dev_err(&master->dev, "problem starting queue\n");
1438                 goto err_start_queue;
1439         }
1440
1441         return 0;
1442
1443 err_start_queue:
1444         spi_destroy_queue(master);
1445 err_init_queue:
1446         return ret;
1447 }
1448
1449 /*-------------------------------------------------------------------------*/
1450
1451 #if defined(CONFIG_OF)
1452 static struct spi_device *
1453 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1454 {
1455         struct spi_device *spi;
1456         int rc;
1457         u32 value;
1458
1459         /* Alloc an spi_device */
1460         spi = spi_alloc_device(master);
1461         if (!spi) {
1462                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1463                         nc->full_name);
1464                 rc = -ENOMEM;
1465                 goto err_out;
1466         }
1467
1468         /* Select device driver */
1469         rc = of_modalias_node(nc, spi->modalias,
1470                                 sizeof(spi->modalias));
1471         if (rc < 0) {
1472                 dev_err(&master->dev, "cannot find modalias for %s\n",
1473                         nc->full_name);
1474                 goto err_out;
1475         }
1476
1477         /* Device address */
1478         rc = of_property_read_u32(nc, "reg", &value);
1479         if (rc) {
1480                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1481                         nc->full_name, rc);
1482                 goto err_out;
1483         }
1484         spi->chip_select = value;
1485
1486         /* Mode (clock phase/polarity/etc.) */
1487         if (of_find_property(nc, "spi-cpha", NULL))
1488                 spi->mode |= SPI_CPHA;
1489         if (of_find_property(nc, "spi-cpol", NULL))
1490                 spi->mode |= SPI_CPOL;
1491         if (of_find_property(nc, "spi-cs-high", NULL))
1492                 spi->mode |= SPI_CS_HIGH;
1493         if (of_find_property(nc, "spi-3wire", NULL))
1494                 spi->mode |= SPI_3WIRE;
1495         if (of_find_property(nc, "spi-lsb-first", NULL))
1496                 spi->mode |= SPI_LSB_FIRST;
1497
1498         /* Device DUAL/QUAD mode */
1499         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1500                 switch (value) {
1501                 case 1:
1502                         break;
1503                 case 2:
1504                         spi->mode |= SPI_TX_DUAL;
1505                         break;
1506                 case 4:
1507                         spi->mode |= SPI_TX_QUAD;
1508                         break;
1509                 default:
1510                         dev_warn(&master->dev,
1511                                 "spi-tx-bus-width %d not supported\n",
1512                                 value);
1513                         break;
1514                 }
1515         }
1516
1517         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1518                 switch (value) {
1519                 case 1:
1520                         break;
1521                 case 2:
1522                         spi->mode |= SPI_RX_DUAL;
1523                         break;
1524                 case 4:
1525                         spi->mode |= SPI_RX_QUAD;
1526                         break;
1527                 default:
1528                         dev_warn(&master->dev,
1529                                 "spi-rx-bus-width %d not supported\n",
1530                                 value);
1531                         break;
1532                 }
1533         }
1534
1535         /* Device speed */
1536         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1537         if (rc) {
1538                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1539                         nc->full_name, rc);
1540                 goto err_out;
1541         }
1542         spi->max_speed_hz = value;
1543
1544         /* Store a pointer to the node in the device structure */
1545         of_node_get(nc);
1546         spi->dev.of_node = nc;
1547
1548         /* Register the new device */
1549         rc = spi_add_device(spi);
1550         if (rc) {
1551                 dev_err(&master->dev, "spi_device register error %s\n",
1552                         nc->full_name);
1553                 goto err_out;
1554         }
1555
1556         return spi;
1557
1558 err_out:
1559         spi_dev_put(spi);
1560         return ERR_PTR(rc);
1561 }
1562
1563 /**
1564  * of_register_spi_devices() - Register child devices onto the SPI bus
1565  * @master:     Pointer to spi_master device
1566  *
1567  * Registers an spi_device for each child node of master node which has a 'reg'
1568  * property.
1569  */
1570 static void of_register_spi_devices(struct spi_master *master)
1571 {
1572         struct spi_device *spi;
1573         struct device_node *nc;
1574
1575         if (!master->dev.of_node)
1576                 return;
1577
1578         for_each_available_child_of_node(master->dev.of_node, nc) {
1579                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1580                         continue;
1581                 spi = of_register_spi_device(master, nc);
1582                 if (IS_ERR(spi))
1583                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1584                                 nc->full_name);
1585         }
1586 }
1587 #else
1588 static void of_register_spi_devices(struct spi_master *master) { }
1589 #endif
1590
1591 #ifdef CONFIG_ACPI
1592 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1593 {
1594         struct spi_device *spi = data;
1595         struct spi_master *master = spi->master;
1596
1597         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1598                 struct acpi_resource_spi_serialbus *sb;
1599
1600                 sb = &ares->data.spi_serial_bus;
1601                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1602                         /*
1603                          * ACPI DeviceSelection numbering is handled by the
1604                          * host controller driver in Windows and can vary
1605                          * from driver to driver. In Linux we always expect
1606                          * 0 .. max - 1 so we need to ask the driver to
1607                          * translate between the two schemes.
1608                          */
1609                         if (master->fw_translate_cs) {
1610                                 int cs = master->fw_translate_cs(master,
1611                                                 sb->device_selection);
1612                                 if (cs < 0)
1613                                         return cs;
1614                                 spi->chip_select = cs;
1615                         } else {
1616                                 spi->chip_select = sb->device_selection;
1617                         }
1618
1619                         spi->max_speed_hz = sb->connection_speed;
1620
1621                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1622                                 spi->mode |= SPI_CPHA;
1623                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1624                                 spi->mode |= SPI_CPOL;
1625                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1626                                 spi->mode |= SPI_CS_HIGH;
1627                 }
1628         } else if (spi->irq < 0) {
1629                 struct resource r;
1630
1631                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1632                         spi->irq = r.start;
1633         }
1634
1635         /* Always tell the ACPI core to skip this resource */
1636         return 1;
1637 }
1638
1639 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1640                                        void *data, void **return_value)
1641 {
1642         struct spi_master *master = data;
1643         struct list_head resource_list;
1644         struct acpi_device *adev;
1645         struct spi_device *spi;
1646         int ret;
1647
1648         if (acpi_bus_get_device(handle, &adev))
1649                 return AE_OK;
1650         if (acpi_bus_get_status(adev) || !adev->status.present)
1651                 return AE_OK;
1652
1653         spi = spi_alloc_device(master);
1654         if (!spi) {
1655                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1656                         dev_name(&adev->dev));
1657                 return AE_NO_MEMORY;
1658         }
1659
1660         ACPI_COMPANION_SET(&spi->dev, adev);
1661         spi->irq = -1;
1662
1663         INIT_LIST_HEAD(&resource_list);
1664         ret = acpi_dev_get_resources(adev, &resource_list,
1665                                      acpi_spi_add_resource, spi);
1666         acpi_dev_free_resource_list(&resource_list);
1667
1668         if (ret < 0 || !spi->max_speed_hz) {
1669                 spi_dev_put(spi);
1670                 return AE_OK;
1671         }
1672
1673         if (spi->irq < 0)
1674                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1675
1676         adev->power.flags.ignore_parent = true;
1677         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1678         if (spi_add_device(spi)) {
1679                 adev->power.flags.ignore_parent = false;
1680                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1681                         dev_name(&adev->dev));
1682                 spi_dev_put(spi);
1683         }
1684
1685         return AE_OK;
1686 }
1687
1688 static void acpi_register_spi_devices(struct spi_master *master)
1689 {
1690         acpi_status status;
1691         acpi_handle handle;
1692
1693         handle = ACPI_HANDLE(master->dev.parent);
1694         if (!handle)
1695                 return;
1696
1697         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1698                                      acpi_spi_add_device, NULL,
1699                                      master, NULL);
1700         if (ACPI_FAILURE(status))
1701                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1702 }
1703 #else
1704 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1705 #endif /* CONFIG_ACPI */
1706
1707 static void spi_master_release(struct device *dev)
1708 {
1709         struct spi_master *master;
1710
1711         master = container_of(dev, struct spi_master, dev);
1712         kfree(master);
1713 }
1714
1715 static struct class spi_master_class = {
1716         .name           = "spi_master",
1717         .owner          = THIS_MODULE,
1718         .dev_release    = spi_master_release,
1719         .dev_groups     = spi_master_groups,
1720 };
1721
1722
1723 /**
1724  * spi_alloc_master - allocate SPI master controller
1725  * @dev: the controller, possibly using the platform_bus
1726  * @size: how much zeroed driver-private data to allocate; the pointer to this
1727  *      memory is in the driver_data field of the returned device,
1728  *      accessible with spi_master_get_devdata().
1729  * Context: can sleep
1730  *
1731  * This call is used only by SPI master controller drivers, which are the
1732  * only ones directly touching chip registers.  It's how they allocate
1733  * an spi_master structure, prior to calling spi_register_master().
1734  *
1735  * This must be called from context that can sleep.
1736  *
1737  * The caller is responsible for assigning the bus number and initializing
1738  * the master's methods before calling spi_register_master(); and (after errors
1739  * adding the device) calling spi_master_put() to prevent a memory leak.
1740  *
1741  * Return: the SPI master structure on success, else NULL.
1742  */
1743 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1744 {
1745         struct spi_master       *master;
1746
1747         if (!dev)
1748                 return NULL;
1749
1750         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1751         if (!master)
1752                 return NULL;
1753
1754         device_initialize(&master->dev);
1755         master->bus_num = -1;
1756         master->num_chipselect = 1;
1757         master->dev.class = &spi_master_class;
1758         master->dev.parent = dev;
1759         spi_master_set_devdata(master, &master[1]);
1760
1761         return master;
1762 }
1763 EXPORT_SYMBOL_GPL(spi_alloc_master);
1764
1765 #ifdef CONFIG_OF
1766 static int of_spi_register_master(struct spi_master *master)
1767 {
1768         int nb, i, *cs;
1769         struct device_node *np = master->dev.of_node;
1770
1771         if (!np)
1772                 return 0;
1773
1774         nb = of_gpio_named_count(np, "cs-gpios");
1775         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1776
1777         /* Return error only for an incorrectly formed cs-gpios property */
1778         if (nb == 0 || nb == -ENOENT)
1779                 return 0;
1780         else if (nb < 0)
1781                 return nb;
1782
1783         cs = devm_kzalloc(&master->dev,
1784                           sizeof(int) * master->num_chipselect,
1785                           GFP_KERNEL);
1786         master->cs_gpios = cs;
1787
1788         if (!master->cs_gpios)
1789                 return -ENOMEM;
1790
1791         for (i = 0; i < master->num_chipselect; i++)
1792                 cs[i] = -ENOENT;
1793
1794         for (i = 0; i < nb; i++)
1795                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1796
1797         return 0;
1798 }
1799 #else
1800 static int of_spi_register_master(struct spi_master *master)
1801 {
1802         return 0;
1803 }
1804 #endif
1805
1806 /**
1807  * spi_register_master - register SPI master controller
1808  * @master: initialized master, originally from spi_alloc_master()
1809  * Context: can sleep
1810  *
1811  * SPI master controllers connect to their drivers using some non-SPI bus,
1812  * such as the platform bus.  The final stage of probe() in that code
1813  * includes calling spi_register_master() to hook up to this SPI bus glue.
1814  *
1815  * SPI controllers use board specific (often SOC specific) bus numbers,
1816  * and board-specific addressing for SPI devices combines those numbers
1817  * with chip select numbers.  Since SPI does not directly support dynamic
1818  * device identification, boards need configuration tables telling which
1819  * chip is at which address.
1820  *
1821  * This must be called from context that can sleep.  It returns zero on
1822  * success, else a negative error code (dropping the master's refcount).
1823  * After a successful return, the caller is responsible for calling
1824  * spi_unregister_master().
1825  *
1826  * Return: zero on success, else a negative error code.
1827  */
1828 int spi_register_master(struct spi_master *master)
1829 {
1830         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1831         struct device           *dev = master->dev.parent;
1832         struct boardinfo        *bi;
1833         int                     status = -ENODEV;
1834         int                     dynamic = 0;
1835
1836         if (!dev)
1837                 return -ENODEV;
1838
1839         status = of_spi_register_master(master);
1840         if (status)
1841                 return status;
1842
1843         /* even if it's just one always-selected device, there must
1844          * be at least one chipselect
1845          */
1846         if (master->num_chipselect == 0)
1847                 return -EINVAL;
1848
1849         if ((master->bus_num < 0) && master->dev.of_node)
1850                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1851
1852         /* convention:  dynamically assigned bus IDs count down from the max */
1853         if (master->bus_num < 0) {
1854                 /* FIXME switch to an IDR based scheme, something like
1855                  * I2C now uses, so we can't run out of "dynamic" IDs
1856                  */
1857                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1858                 dynamic = 1;
1859         }
1860
1861         INIT_LIST_HEAD(&master->queue);
1862         spin_lock_init(&master->queue_lock);
1863         spin_lock_init(&master->bus_lock_spinlock);
1864         mutex_init(&master->bus_lock_mutex);
1865         master->bus_lock_flag = 0;
1866         init_completion(&master->xfer_completion);
1867         if (!master->max_dma_len)
1868                 master->max_dma_len = INT_MAX;
1869
1870         /* register the device, then userspace will see it.
1871          * registration fails if the bus ID is in use.
1872          */
1873         dev_set_name(&master->dev, "spi%u", master->bus_num);
1874         status = device_add(&master->dev);
1875         if (status < 0)
1876                 goto done;
1877         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1878                         dynamic ? " (dynamic)" : "");
1879
1880         /* If we're using a queued driver, start the queue */
1881         if (master->transfer)
1882                 dev_info(dev, "master is unqueued, this is deprecated\n");
1883         else {
1884                 status = spi_master_initialize_queue(master);
1885                 if (status) {
1886                         device_del(&master->dev);
1887                         goto done;
1888                 }
1889         }
1890         /* add statistics */
1891         spin_lock_init(&master->statistics.lock);
1892
1893         mutex_lock(&board_lock);
1894         list_add_tail(&master->list, &spi_master_list);
1895         list_for_each_entry(bi, &board_list, list)
1896                 spi_match_master_to_boardinfo(master, &bi->board_info);
1897         mutex_unlock(&board_lock);
1898
1899         /* Register devices from the device tree and ACPI */
1900         of_register_spi_devices(master);
1901         acpi_register_spi_devices(master);
1902 done:
1903         return status;
1904 }
1905 EXPORT_SYMBOL_GPL(spi_register_master);
1906
1907 static void devm_spi_unregister(struct device *dev, void *res)
1908 {
1909         spi_unregister_master(*(struct spi_master **)res);
1910 }
1911
1912 /**
1913  * dev_spi_register_master - register managed SPI master controller
1914  * @dev:    device managing SPI master
1915  * @master: initialized master, originally from spi_alloc_master()
1916  * Context: can sleep
1917  *
1918  * Register a SPI device as with spi_register_master() which will
1919  * automatically be unregister
1920  *
1921  * Return: zero on success, else a negative error code.
1922  */
1923 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1924 {
1925         struct spi_master **ptr;
1926         int ret;
1927
1928         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1929         if (!ptr)
1930                 return -ENOMEM;
1931
1932         ret = spi_register_master(master);
1933         if (!ret) {
1934                 *ptr = master;
1935                 devres_add(dev, ptr);
1936         } else {
1937                 devres_free(ptr);
1938         }
1939
1940         return ret;
1941 }
1942 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1943
1944 static int __unregister(struct device *dev, void *null)
1945 {
1946         spi_unregister_device(to_spi_device(dev));
1947         return 0;
1948 }
1949
1950 /**
1951  * spi_unregister_master - unregister SPI master controller
1952  * @master: the master being unregistered
1953  * Context: can sleep
1954  *
1955  * This call is used only by SPI master controller drivers, which are the
1956  * only ones directly touching chip registers.
1957  *
1958  * This must be called from context that can sleep.
1959  */
1960 void spi_unregister_master(struct spi_master *master)
1961 {
1962         int dummy;
1963
1964         if (master->queued) {
1965                 if (spi_destroy_queue(master))
1966                         dev_err(&master->dev, "queue remove failed\n");
1967         }
1968
1969         mutex_lock(&board_lock);
1970         list_del(&master->list);
1971         mutex_unlock(&board_lock);
1972
1973         dummy = device_for_each_child(&master->dev, NULL, __unregister);
1974         device_unregister(&master->dev);
1975 }
1976 EXPORT_SYMBOL_GPL(spi_unregister_master);
1977
1978 int spi_master_suspend(struct spi_master *master)
1979 {
1980         int ret;
1981
1982         /* Basically no-ops for non-queued masters */
1983         if (!master->queued)
1984                 return 0;
1985
1986         ret = spi_stop_queue(master);
1987         if (ret)
1988                 dev_err(&master->dev, "queue stop failed\n");
1989
1990         return ret;
1991 }
1992 EXPORT_SYMBOL_GPL(spi_master_suspend);
1993
1994 int spi_master_resume(struct spi_master *master)
1995 {
1996         int ret;
1997
1998         if (!master->queued)
1999                 return 0;
2000
2001         ret = spi_start_queue(master);
2002         if (ret)
2003                 dev_err(&master->dev, "queue restart failed\n");
2004
2005         return ret;
2006 }
2007 EXPORT_SYMBOL_GPL(spi_master_resume);
2008
2009 static int __spi_master_match(struct device *dev, const void *data)
2010 {
2011         struct spi_master *m;
2012         const u16 *bus_num = data;
2013
2014         m = container_of(dev, struct spi_master, dev);
2015         return m->bus_num == *bus_num;
2016 }
2017
2018 /**
2019  * spi_busnum_to_master - look up master associated with bus_num
2020  * @bus_num: the master's bus number
2021  * Context: can sleep
2022  *
2023  * This call may be used with devices that are registered after
2024  * arch init time.  It returns a refcounted pointer to the relevant
2025  * spi_master (which the caller must release), or NULL if there is
2026  * no such master registered.
2027  *
2028  * Return: the SPI master structure on success, else NULL.
2029  */
2030 struct spi_master *spi_busnum_to_master(u16 bus_num)
2031 {
2032         struct device           *dev;
2033         struct spi_master       *master = NULL;
2034
2035         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2036                                 __spi_master_match);
2037         if (dev)
2038                 master = container_of(dev, struct spi_master, dev);
2039         /* reference got in class_find_device */
2040         return master;
2041 }
2042 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2043
2044 /*-------------------------------------------------------------------------*/
2045
2046 /* Core methods for SPI resource management */
2047
2048 /**
2049  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2050  *                 during the processing of a spi_message while using
2051  *                 spi_transfer_one
2052  * @spi:     the spi device for which we allocate memory
2053  * @release: the release code to execute for this resource
2054  * @size:    size to alloc and return
2055  * @gfp:     GFP allocation flags
2056  *
2057  * Return: the pointer to the allocated data
2058  *
2059  * This may get enhanced in the future to allocate from a memory pool
2060  * of the @spi_device or @spi_master to avoid repeated allocations.
2061  */
2062 void *spi_res_alloc(struct spi_device *spi,
2063                     spi_res_release_t release,
2064                     size_t size, gfp_t gfp)
2065 {
2066         struct spi_res *sres;
2067
2068         sres = kzalloc(sizeof(*sres) + size, gfp);
2069         if (!sres)
2070                 return NULL;
2071
2072         INIT_LIST_HEAD(&sres->entry);
2073         sres->release = release;
2074
2075         return sres->data;
2076 }
2077 EXPORT_SYMBOL_GPL(spi_res_alloc);
2078
2079 /**
2080  * spi_res_free - free an spi resource
2081  * @res: pointer to the custom data of a resource
2082  *
2083  */
2084 void spi_res_free(void *res)
2085 {
2086         struct spi_res *sres = container_of(res, struct spi_res, data);
2087
2088         if (!res)
2089                 return;
2090
2091         WARN_ON(!list_empty(&sres->entry));
2092         kfree(sres);
2093 }
2094 EXPORT_SYMBOL_GPL(spi_res_free);
2095
2096 /**
2097  * spi_res_add - add a spi_res to the spi_message
2098  * @message: the spi message
2099  * @res:     the spi_resource
2100  */
2101 void spi_res_add(struct spi_message *message, void *res)
2102 {
2103         struct spi_res *sres = container_of(res, struct spi_res, data);
2104
2105         WARN_ON(!list_empty(&sres->entry));
2106         list_add_tail(&sres->entry, &message->resources);
2107 }
2108 EXPORT_SYMBOL_GPL(spi_res_add);
2109
2110 /**
2111  * spi_res_release - release all spi resources for this message
2112  * @master:  the @spi_master
2113  * @message: the @spi_message
2114  */
2115 void spi_res_release(struct spi_master *master,
2116                      struct spi_message *message)
2117 {
2118         struct spi_res *res;
2119
2120         while (!list_empty(&message->resources)) {
2121                 res = list_last_entry(&message->resources,
2122                                       struct spi_res, entry);
2123
2124                 if (res->release)
2125                         res->release(master, message, res->data);
2126
2127                 list_del(&res->entry);
2128
2129                 kfree(res);
2130         }
2131 }
2132 EXPORT_SYMBOL_GPL(spi_res_release);
2133
2134 /*-------------------------------------------------------------------------*/
2135
2136 /* Core methods for spi_message alterations */
2137
2138 static void __spi_replace_transfers_release(struct spi_master *master,
2139                                             struct spi_message *msg,
2140                                             void *res)
2141 {
2142         struct spi_replaced_transfers *rxfer = res;
2143         size_t i;
2144
2145         /* call extra callback if requested */
2146         if (rxfer->release)
2147                 rxfer->release(master, msg, res);
2148
2149         /* insert replaced transfers back into the message */
2150         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2151
2152         /* remove the formerly inserted entries */
2153         for (i = 0; i < rxfer->inserted; i++)
2154                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2155 }
2156
2157 /**
2158  * spi_replace_transfers - replace transfers with several transfers
2159  *                         and register change with spi_message.resources
2160  * @msg:           the spi_message we work upon
2161  * @xfer_first:    the first spi_transfer we want to replace
2162  * @remove:        number of transfers to remove
2163  * @insert:        the number of transfers we want to insert instead
2164  * @release:       extra release code necessary in some circumstances
2165  * @extradatasize: extra data to allocate (with alignment guarantees
2166  *                 of struct @spi_transfer)
2167  *
2168  * Returns: pointer to @spi_replaced_transfers,
2169  *          PTR_ERR(...) in case of errors.
2170  */
2171 struct spi_replaced_transfers *spi_replace_transfers(
2172         struct spi_message *msg,
2173         struct spi_transfer *xfer_first,
2174         size_t remove,
2175         size_t insert,
2176         spi_replaced_release_t release,
2177         size_t extradatasize,
2178         gfp_t gfp)
2179 {
2180         struct spi_replaced_transfers *rxfer;
2181         struct spi_transfer *xfer;
2182         size_t i;
2183
2184         /* allocate the structure using spi_res */
2185         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2186                               insert * sizeof(struct spi_transfer)
2187                               + sizeof(struct spi_replaced_transfers)
2188                               + extradatasize,
2189                               gfp);
2190         if (!rxfer)
2191                 return ERR_PTR(-ENOMEM);
2192
2193         /* the release code to invoke before running the generic release */
2194         rxfer->release = release;
2195
2196         /* assign extradata */
2197         if (extradatasize)
2198                 rxfer->extradata =
2199                         &rxfer->inserted_transfers[insert];
2200
2201         /* init the replaced_transfers list */
2202         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2203
2204         /* assign the list_entry after which we should reinsert
2205          * the @replaced_transfers - it may be spi_message.messages!
2206          */
2207         rxfer->replaced_after = xfer_first->transfer_list.prev;
2208
2209         /* remove the requested number of transfers */
2210         for (i = 0; i < remove; i++) {
2211                 /* if the entry after replaced_after it is msg->transfers
2212                  * then we have been requested to remove more transfers
2213                  * than are in the list
2214                  */
2215                 if (rxfer->replaced_after->next == &msg->transfers) {
2216                         dev_err(&msg->spi->dev,
2217                                 "requested to remove more spi_transfers than are available\n");
2218                         /* insert replaced transfers back into the message */
2219                         list_splice(&rxfer->replaced_transfers,
2220                                     rxfer->replaced_after);
2221
2222                         /* free the spi_replace_transfer structure */
2223                         spi_res_free(rxfer);
2224
2225                         /* and return with an error */
2226                         return ERR_PTR(-EINVAL);
2227                 }
2228
2229                 /* remove the entry after replaced_after from list of
2230                  * transfers and add it to list of replaced_transfers
2231                  */
2232                 list_move_tail(rxfer->replaced_after->next,
2233                                &rxfer->replaced_transfers);
2234         }
2235
2236         /* create copy of the given xfer with identical settings
2237          * based on the first transfer to get removed
2238          */
2239         for (i = 0; i < insert; i++) {
2240                 /* we need to run in reverse order */
2241                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2242
2243                 /* copy all spi_transfer data */
2244                 memcpy(xfer, xfer_first, sizeof(*xfer));
2245
2246                 /* add to list */
2247                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2248
2249                 /* clear cs_change and delay_usecs for all but the last */
2250                 if (i) {
2251                         xfer->cs_change = false;
2252                         xfer->delay_usecs = 0;
2253                 }
2254         }
2255
2256         /* set up inserted */
2257         rxfer->inserted = insert;
2258
2259         /* and register it with spi_res/spi_message */
2260         spi_res_add(msg, rxfer);
2261
2262         return rxfer;
2263 }
2264 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2265
2266 int __spi_split_transfer_maxsize(struct spi_master *master,
2267                                  struct spi_message *msg,
2268                                  struct spi_transfer **xferp,
2269                                  size_t maxsize,
2270                                  gfp_t gfp)
2271 {
2272         struct spi_transfer *xfer = *xferp, *xfers;
2273         struct spi_replaced_transfers *srt;
2274         size_t offset;
2275         size_t count, i;
2276
2277         /* warn once about this fact that we are splitting a transfer */
2278         dev_warn_once(&msg->spi->dev,
2279                       "spi_transfer of length %i exceed max length of %i - needed to split transfers\n",
2280                       xfer->len, maxsize);
2281
2282         /* calculate how many we have to replace */
2283         count = DIV_ROUND_UP(xfer->len, maxsize);
2284
2285         /* create replacement */
2286         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2287         if (!srt)
2288                 return -ENOMEM;
2289         xfers = srt->inserted_transfers;
2290
2291         /* now handle each of those newly inserted spi_transfers
2292          * note that the replacements spi_transfers all are preset
2293          * to the same values as *xferp, so tx_buf, rx_buf and len
2294          * are all identical (as well as most others)
2295          * so we just have to fix up len and the pointers.
2296          *
2297          * this also includes support for the depreciated
2298          * spi_message.is_dma_mapped interface
2299          */
2300
2301         /* the first transfer just needs the length modified, so we
2302          * run it outside the loop
2303          */
2304         xfers[0].len = min(maxsize, xfer[0].len);
2305
2306         /* all the others need rx_buf/tx_buf also set */
2307         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2308                 /* update rx_buf, tx_buf and dma */
2309                 if (xfers[i].rx_buf)
2310                         xfers[i].rx_buf += offset;
2311                 if (xfers[i].rx_dma)
2312                         xfers[i].rx_dma += offset;
2313                 if (xfers[i].tx_buf)
2314                         xfers[i].tx_buf += offset;
2315                 if (xfers[i].tx_dma)
2316                         xfers[i].tx_dma += offset;
2317
2318                 /* update length */
2319                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2320         }
2321
2322         /* we set up xferp to the last entry we have inserted,
2323          * so that we skip those already split transfers
2324          */
2325         *xferp = &xfers[count - 1];
2326
2327         /* increment statistics counters */
2328         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2329                                        transfers_split_maxsize);
2330         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2331                                        transfers_split_maxsize);
2332
2333         return 0;
2334 }
2335
2336 /**
2337  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2338  *                              when an individual transfer exceeds a
2339  *                              certain size
2340  * @master:    the @spi_master for this transfer
2341  * @message:   the @spi_message to transform
2342  * @max_size:  the maximum when to apply this
2343  *
2344  * Return: status of transformation
2345  */
2346 int spi_split_transfers_maxsize(struct spi_master *master,
2347                                 struct spi_message *msg,
2348                                 size_t maxsize,
2349                                 gfp_t gfp)
2350 {
2351         struct spi_transfer *xfer;
2352         int ret;
2353
2354         /* iterate over the transfer_list,
2355          * but note that xfer is advanced to the last transfer inserted
2356          * to avoid checking sizes again unnecessarily (also xfer does
2357          * potentiall belong to a different list by the time the
2358          * replacement has happened
2359          */
2360         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2361                 if (xfer->len > maxsize) {
2362                         ret = __spi_split_transfer_maxsize(
2363                                 master, msg, &xfer, maxsize, gfp);
2364                         if (ret)
2365                                 return ret;
2366                 }
2367         }
2368
2369         return 0;
2370 }
2371 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2372
2373 /*-------------------------------------------------------------------------*/
2374
2375 /* Core methods for SPI master protocol drivers.  Some of the
2376  * other core methods are currently defined as inline functions.
2377  */
2378
2379 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2380 {
2381         if (master->bits_per_word_mask) {
2382                 /* Only 32 bits fit in the mask */
2383                 if (bits_per_word > 32)
2384                         return -EINVAL;
2385                 if (!(master->bits_per_word_mask &
2386                                 SPI_BPW_MASK(bits_per_word)))
2387                         return -EINVAL;
2388         }
2389
2390         return 0;
2391 }
2392
2393 /**
2394  * spi_setup - setup SPI mode and clock rate
2395  * @spi: the device whose settings are being modified
2396  * Context: can sleep, and no requests are queued to the device
2397  *
2398  * SPI protocol drivers may need to update the transfer mode if the
2399  * device doesn't work with its default.  They may likewise need
2400  * to update clock rates or word sizes from initial values.  This function
2401  * changes those settings, and must be called from a context that can sleep.
2402  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2403  * effect the next time the device is selected and data is transferred to
2404  * or from it.  When this function returns, the spi device is deselected.
2405  *
2406  * Note that this call will fail if the protocol driver specifies an option
2407  * that the underlying controller or its driver does not support.  For
2408  * example, not all hardware supports wire transfers using nine bit words,
2409  * LSB-first wire encoding, or active-high chipselects.
2410  *
2411  * Return: zero on success, else a negative error code.
2412  */
2413 int spi_setup(struct spi_device *spi)
2414 {
2415         unsigned        bad_bits, ugly_bits;
2416         int             status;
2417
2418         /* check mode to prevent that DUAL and QUAD set at the same time
2419          */
2420         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2421                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2422                 dev_err(&spi->dev,
2423                 "setup: can not select dual and quad at the same time\n");
2424                 return -EINVAL;
2425         }
2426         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2427          */
2428         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2429                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2430                 return -EINVAL;
2431         /* help drivers fail *cleanly* when they need options
2432          * that aren't supported with their current master
2433          */
2434         bad_bits = spi->mode & ~spi->master->mode_bits;
2435         ugly_bits = bad_bits &
2436                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2437         if (ugly_bits) {
2438                 dev_warn(&spi->dev,
2439                          "setup: ignoring unsupported mode bits %x\n",
2440                          ugly_bits);
2441                 spi->mode &= ~ugly_bits;
2442                 bad_bits &= ~ugly_bits;
2443         }
2444         if (bad_bits) {
2445                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2446                         bad_bits);
2447                 return -EINVAL;
2448         }
2449
2450         if (!spi->bits_per_word)
2451                 spi->bits_per_word = 8;
2452
2453         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2454         if (status)
2455                 return status;
2456
2457         if (!spi->max_speed_hz)
2458                 spi->max_speed_hz = spi->master->max_speed_hz;
2459
2460         if (spi->master->setup)
2461                 status = spi->master->setup(spi);
2462
2463         spi_set_cs(spi, false);
2464
2465         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2466                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2467                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2468                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2469                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2470                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2471                         spi->bits_per_word, spi->max_speed_hz,
2472                         status);
2473
2474         return status;
2475 }
2476 EXPORT_SYMBOL_GPL(spi_setup);
2477
2478 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2479 {
2480         struct spi_master *master = spi->master;
2481         struct spi_transfer *xfer;
2482         int w_size;
2483
2484         if (list_empty(&message->transfers))
2485                 return -EINVAL;
2486
2487         /* Half-duplex links include original MicroWire, and ones with
2488          * only one data pin like SPI_3WIRE (switches direction) or where
2489          * either MOSI or MISO is missing.  They can also be caused by
2490          * software limitations.
2491          */
2492         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2493                         || (spi->mode & SPI_3WIRE)) {
2494                 unsigned flags = master->flags;
2495
2496                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2497                         if (xfer->rx_buf && xfer->tx_buf)
2498                                 return -EINVAL;
2499                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2500                                 return -EINVAL;
2501                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2502                                 return -EINVAL;
2503                 }
2504         }
2505
2506         /**
2507          * Set transfer bits_per_word and max speed as spi device default if
2508          * it is not set for this transfer.
2509          * Set transfer tx_nbits and rx_nbits as single transfer default
2510          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2511          */
2512         message->frame_length = 0;
2513         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2514                 message->frame_length += xfer->len;
2515                 if (!xfer->bits_per_word)
2516                         xfer->bits_per_word = spi->bits_per_word;
2517
2518                 if (!xfer->speed_hz)
2519                         xfer->speed_hz = spi->max_speed_hz;
2520                 if (!xfer->speed_hz)
2521                         xfer->speed_hz = master->max_speed_hz;
2522
2523                 if (master->max_speed_hz &&
2524                     xfer->speed_hz > master->max_speed_hz)
2525                         xfer->speed_hz = master->max_speed_hz;
2526
2527                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2528                         return -EINVAL;
2529
2530                 /*
2531                  * SPI transfer length should be multiple of SPI word size
2532                  * where SPI word size should be power-of-two multiple
2533                  */
2534                 if (xfer->bits_per_word <= 8)
2535                         w_size = 1;
2536                 else if (xfer->bits_per_word <= 16)
2537                         w_size = 2;
2538                 else
2539                         w_size = 4;
2540
2541                 /* No partial transfers accepted */
2542                 if (xfer->len % w_size)
2543                         return -EINVAL;
2544
2545                 if (xfer->speed_hz && master->min_speed_hz &&
2546                     xfer->speed_hz < master->min_speed_hz)
2547                         return -EINVAL;
2548
2549                 if (xfer->tx_buf && !xfer->tx_nbits)
2550                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2551                 if (xfer->rx_buf && !xfer->rx_nbits)
2552                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2553                 /* check transfer tx/rx_nbits:
2554                  * 1. check the value matches one of single, dual and quad
2555                  * 2. check tx/rx_nbits match the mode in spi_device
2556                  */
2557                 if (xfer->tx_buf) {
2558                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2559                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2560                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2561                                 return -EINVAL;
2562                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2563                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2564                                 return -EINVAL;
2565                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2566                                 !(spi->mode & SPI_TX_QUAD))
2567                                 return -EINVAL;
2568                 }
2569                 /* check transfer rx_nbits */
2570                 if (xfer->rx_buf) {
2571                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2572                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2573                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2574                                 return -EINVAL;
2575                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2576                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2577                                 return -EINVAL;
2578                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2579                                 !(spi->mode & SPI_RX_QUAD))
2580                                 return -EINVAL;
2581                 }
2582         }
2583
2584         message->status = -EINPROGRESS;
2585
2586         return 0;
2587 }
2588
2589 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2590 {
2591         struct spi_master *master = spi->master;
2592
2593         message->spi = spi;
2594
2595         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2596         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2597
2598         trace_spi_message_submit(message);
2599
2600         return master->transfer(spi, message);
2601 }
2602
2603 /**
2604  * spi_async - asynchronous SPI transfer
2605  * @spi: device with which data will be exchanged
2606  * @message: describes the data transfers, including completion callback
2607  * Context: any (irqs may be blocked, etc)
2608  *
2609  * This call may be used in_irq and other contexts which can't sleep,
2610  * as well as from task contexts which can sleep.
2611  *
2612  * The completion callback is invoked in a context which can't sleep.
2613  * Before that invocation, the value of message->status is undefined.
2614  * When the callback is issued, message->status holds either zero (to
2615  * indicate complete success) or a negative error code.  After that
2616  * callback returns, the driver which issued the transfer request may
2617  * deallocate the associated memory; it's no longer in use by any SPI
2618  * core or controller driver code.
2619  *
2620  * Note that although all messages to a spi_device are handled in
2621  * FIFO order, messages may go to different devices in other orders.
2622  * Some device might be higher priority, or have various "hard" access
2623  * time requirements, for example.
2624  *
2625  * On detection of any fault during the transfer, processing of
2626  * the entire message is aborted, and the device is deselected.
2627  * Until returning from the associated message completion callback,
2628  * no other spi_message queued to that device will be processed.
2629  * (This rule applies equally to all the synchronous transfer calls,
2630  * which are wrappers around this core asynchronous primitive.)
2631  *
2632  * Return: zero on success, else a negative error code.
2633  */
2634 int spi_async(struct spi_device *spi, struct spi_message *message)
2635 {
2636         struct spi_master *master = spi->master;
2637         int ret;
2638         unsigned long flags;
2639
2640         ret = __spi_validate(spi, message);
2641         if (ret != 0)
2642                 return ret;
2643
2644         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2645
2646         if (master->bus_lock_flag)
2647                 ret = -EBUSY;
2648         else
2649                 ret = __spi_async(spi, message);
2650
2651         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2652
2653         return ret;
2654 }
2655 EXPORT_SYMBOL_GPL(spi_async);
2656
2657 /**
2658  * spi_async_locked - version of spi_async with exclusive bus usage
2659  * @spi: device with which data will be exchanged
2660  * @message: describes the data transfers, including completion callback
2661  * Context: any (irqs may be blocked, etc)
2662  *
2663  * This call may be used in_irq and other contexts which can't sleep,
2664  * as well as from task contexts which can sleep.
2665  *
2666  * The completion callback is invoked in a context which can't sleep.
2667  * Before that invocation, the value of message->status is undefined.
2668  * When the callback is issued, message->status holds either zero (to
2669  * indicate complete success) or a negative error code.  After that
2670  * callback returns, the driver which issued the transfer request may
2671  * deallocate the associated memory; it's no longer in use by any SPI
2672  * core or controller driver code.
2673  *
2674  * Note that although all messages to a spi_device are handled in
2675  * FIFO order, messages may go to different devices in other orders.
2676  * Some device might be higher priority, or have various "hard" access
2677  * time requirements, for example.
2678  *
2679  * On detection of any fault during the transfer, processing of
2680  * the entire message is aborted, and the device is deselected.
2681  * Until returning from the associated message completion callback,
2682  * no other spi_message queued to that device will be processed.
2683  * (This rule applies equally to all the synchronous transfer calls,
2684  * which are wrappers around this core asynchronous primitive.)
2685  *
2686  * Return: zero on success, else a negative error code.
2687  */
2688 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2689 {
2690         struct spi_master *master = spi->master;
2691         int ret;
2692         unsigned long flags;
2693
2694         ret = __spi_validate(spi, message);
2695         if (ret != 0)
2696                 return ret;
2697
2698         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2699
2700         ret = __spi_async(spi, message);
2701
2702         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2703
2704         return ret;
2705
2706 }
2707 EXPORT_SYMBOL_GPL(spi_async_locked);
2708
2709
2710 int spi_flash_read(struct spi_device *spi,
2711                    struct spi_flash_read_message *msg)
2712
2713 {
2714         struct spi_master *master = spi->master;
2715         int ret;
2716
2717         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2718              msg->addr_nbits == SPI_NBITS_DUAL) &&
2719             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2720                 return -EINVAL;
2721         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2722              msg->addr_nbits == SPI_NBITS_QUAD) &&
2723             !(spi->mode & SPI_TX_QUAD))
2724                 return -EINVAL;
2725         if (msg->data_nbits == SPI_NBITS_DUAL &&
2726             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2727                 return -EINVAL;
2728         if (msg->data_nbits == SPI_NBITS_QUAD &&
2729             !(spi->mode &  SPI_RX_QUAD))
2730                 return -EINVAL;
2731
2732         if (master->auto_runtime_pm) {
2733                 ret = pm_runtime_get_sync(master->dev.parent);
2734                 if (ret < 0) {
2735                         dev_err(&master->dev, "Failed to power device: %d\n",
2736                                 ret);
2737                         return ret;
2738                 }
2739         }
2740         mutex_lock(&master->bus_lock_mutex);
2741         ret = master->spi_flash_read(spi, msg);
2742         mutex_unlock(&master->bus_lock_mutex);
2743         if (master->auto_runtime_pm)
2744                 pm_runtime_put(master->dev.parent);
2745
2746         return ret;
2747 }
2748 EXPORT_SYMBOL_GPL(spi_flash_read);
2749
2750 /*-------------------------------------------------------------------------*/
2751
2752 /* Utility methods for SPI master protocol drivers, layered on
2753  * top of the core.  Some other utility methods are defined as
2754  * inline functions.
2755  */
2756
2757 static void spi_complete(void *arg)
2758 {
2759         complete(arg);
2760 }
2761
2762 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2763                       int bus_locked)
2764 {
2765         DECLARE_COMPLETION_ONSTACK(done);
2766         int status;
2767         struct spi_master *master = spi->master;
2768         unsigned long flags;
2769
2770         status = __spi_validate(spi, message);
2771         if (status != 0)
2772                 return status;
2773
2774         message->complete = spi_complete;
2775         message->context = &done;
2776         message->spi = spi;
2777
2778         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2779         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2780
2781         if (!bus_locked)
2782                 mutex_lock(&master->bus_lock_mutex);
2783
2784         /* If we're not using the legacy transfer method then we will
2785          * try to transfer in the calling context so special case.
2786          * This code would be less tricky if we could remove the
2787          * support for driver implemented message queues.
2788          */
2789         if (master->transfer == spi_queued_transfer) {
2790                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2791
2792                 trace_spi_message_submit(message);
2793
2794                 status = __spi_queued_transfer(spi, message, false);
2795
2796                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2797         } else {
2798                 status = spi_async_locked(spi, message);
2799         }
2800
2801         if (!bus_locked)
2802                 mutex_unlock(&master->bus_lock_mutex);
2803
2804         if (status == 0) {
2805                 /* Push out the messages in the calling context if we
2806                  * can.
2807                  */
2808                 if (master->transfer == spi_queued_transfer) {
2809                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2810                                                        spi_sync_immediate);
2811                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2812                                                        spi_sync_immediate);
2813                         __spi_pump_messages(master, false);
2814                 }
2815
2816                 wait_for_completion(&done);
2817                 status = message->status;
2818         }
2819         message->context = NULL;
2820         return status;
2821 }
2822
2823 /**
2824  * spi_sync - blocking/synchronous SPI data transfers
2825  * @spi: device with which data will be exchanged
2826  * @message: describes the data transfers
2827  * Context: can sleep
2828  *
2829  * This call may only be used from a context that may sleep.  The sleep
2830  * is non-interruptible, and has no timeout.  Low-overhead controller
2831  * drivers may DMA directly into and out of the message buffers.
2832  *
2833  * Note that the SPI device's chip select is active during the message,
2834  * and then is normally disabled between messages.  Drivers for some
2835  * frequently-used devices may want to minimize costs of selecting a chip,
2836  * by leaving it selected in anticipation that the next message will go
2837  * to the same chip.  (That may increase power usage.)
2838  *
2839  * Also, the caller is guaranteeing that the memory associated with the
2840  * message will not be freed before this call returns.
2841  *
2842  * Return: zero on success, else a negative error code.
2843  */
2844 int spi_sync(struct spi_device *spi, struct spi_message *message)
2845 {
2846         return __spi_sync(spi, message, 0);
2847 }
2848 EXPORT_SYMBOL_GPL(spi_sync);
2849
2850 /**
2851  * spi_sync_locked - version of spi_sync with exclusive bus usage
2852  * @spi: device with which data will be exchanged
2853  * @message: describes the data transfers
2854  * Context: can sleep
2855  *
2856  * This call may only be used from a context that may sleep.  The sleep
2857  * is non-interruptible, and has no timeout.  Low-overhead controller
2858  * drivers may DMA directly into and out of the message buffers.
2859  *
2860  * This call should be used by drivers that require exclusive access to the
2861  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2862  * be released by a spi_bus_unlock call when the exclusive access is over.
2863  *
2864  * Return: zero on success, else a negative error code.
2865  */
2866 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2867 {
2868         return __spi_sync(spi, message, 1);
2869 }
2870 EXPORT_SYMBOL_GPL(spi_sync_locked);
2871
2872 /**
2873  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2874  * @master: SPI bus master that should be locked for exclusive bus access
2875  * Context: can sleep
2876  *
2877  * This call may only be used from a context that may sleep.  The sleep
2878  * is non-interruptible, and has no timeout.
2879  *
2880  * This call should be used by drivers that require exclusive access to the
2881  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2882  * exclusive access is over. Data transfer must be done by spi_sync_locked
2883  * and spi_async_locked calls when the SPI bus lock is held.
2884  *
2885  * Return: always zero.
2886  */
2887 int spi_bus_lock(struct spi_master *master)
2888 {
2889         unsigned long flags;
2890
2891         mutex_lock(&master->bus_lock_mutex);
2892
2893         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2894         master->bus_lock_flag = 1;
2895         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2896
2897         /* mutex remains locked until spi_bus_unlock is called */
2898
2899         return 0;
2900 }
2901 EXPORT_SYMBOL_GPL(spi_bus_lock);
2902
2903 /**
2904  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2905  * @master: SPI bus master that was locked for exclusive bus access
2906  * Context: can sleep
2907  *
2908  * This call may only be used from a context that may sleep.  The sleep
2909  * is non-interruptible, and has no timeout.
2910  *
2911  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2912  * call.
2913  *
2914  * Return: always zero.
2915  */
2916 int spi_bus_unlock(struct spi_master *master)
2917 {
2918         master->bus_lock_flag = 0;
2919
2920         mutex_unlock(&master->bus_lock_mutex);
2921
2922         return 0;
2923 }
2924 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2925
2926 /* portable code must never pass more than 32 bytes */
2927 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
2928
2929 static u8       *buf;
2930
2931 /**
2932  * spi_write_then_read - SPI synchronous write followed by read
2933  * @spi: device with which data will be exchanged
2934  * @txbuf: data to be written (need not be dma-safe)
2935  * @n_tx: size of txbuf, in bytes
2936  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2937  * @n_rx: size of rxbuf, in bytes
2938  * Context: can sleep
2939  *
2940  * This performs a half duplex MicroWire style transaction with the
2941  * device, sending txbuf and then reading rxbuf.  The return value
2942  * is zero for success, else a negative errno status code.
2943  * This call may only be used from a context that may sleep.
2944  *
2945  * Parameters to this routine are always copied using a small buffer;
2946  * portable code should never use this for more than 32 bytes.
2947  * Performance-sensitive or bulk transfer code should instead use
2948  * spi_{async,sync}() calls with dma-safe buffers.
2949  *
2950  * Return: zero on success, else a negative error code.
2951  */
2952 int spi_write_then_read(struct spi_device *spi,
2953                 const void *txbuf, unsigned n_tx,
2954                 void *rxbuf, unsigned n_rx)
2955 {
2956         static DEFINE_MUTEX(lock);
2957
2958         int                     status;
2959         struct spi_message      message;
2960         struct spi_transfer     x[2];
2961         u8                      *local_buf;
2962
2963         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
2964          * copying here, (as a pure convenience thing), but we can
2965          * keep heap costs out of the hot path unless someone else is
2966          * using the pre-allocated buffer or the transfer is too large.
2967          */
2968         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2969                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2970                                     GFP_KERNEL | GFP_DMA);
2971                 if (!local_buf)
2972                         return -ENOMEM;
2973         } else {
2974                 local_buf = buf;
2975         }
2976
2977         spi_message_init(&message);
2978         memset(x, 0, sizeof(x));
2979         if (n_tx) {
2980                 x[0].len = n_tx;
2981                 spi_message_add_tail(&x[0], &message);
2982         }
2983         if (n_rx) {
2984                 x[1].len = n_rx;
2985                 spi_message_add_tail(&x[1], &message);
2986         }
2987
2988         memcpy(local_buf, txbuf, n_tx);
2989         x[0].tx_buf = local_buf;
2990         x[1].rx_buf = local_buf + n_tx;
2991
2992         /* do the i/o */
2993         status = spi_sync(spi, &message);
2994         if (status == 0)
2995                 memcpy(rxbuf, x[1].rx_buf, n_rx);
2996
2997         if (x[0].tx_buf == buf)
2998                 mutex_unlock(&lock);
2999         else
3000                 kfree(local_buf);
3001
3002         return status;
3003 }
3004 EXPORT_SYMBOL_GPL(spi_write_then_read);
3005
3006 /*-------------------------------------------------------------------------*/
3007
3008 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3009 static int __spi_of_device_match(struct device *dev, void *data)
3010 {
3011         return dev->of_node == data;
3012 }
3013
3014 /* must call put_device() when done with returned spi_device device */
3015 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3016 {
3017         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3018                                                 __spi_of_device_match);
3019         return dev ? to_spi_device(dev) : NULL;
3020 }
3021
3022 static int __spi_of_master_match(struct device *dev, const void *data)
3023 {
3024         return dev->of_node == data;
3025 }
3026
3027 /* the spi masters are not using spi_bus, so we find it with another way */
3028 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3029 {
3030         struct device *dev;
3031
3032         dev = class_find_device(&spi_master_class, NULL, node,
3033                                 __spi_of_master_match);
3034         if (!dev)
3035                 return NULL;
3036
3037         /* reference got in class_find_device */
3038         return container_of(dev, struct spi_master, dev);
3039 }
3040
3041 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3042                          void *arg)
3043 {
3044         struct of_reconfig_data *rd = arg;
3045         struct spi_master *master;
3046         struct spi_device *spi;
3047
3048         switch (of_reconfig_get_state_change(action, arg)) {
3049         case OF_RECONFIG_CHANGE_ADD:
3050                 master = of_find_spi_master_by_node(rd->dn->parent);
3051                 if (master == NULL)
3052                         return NOTIFY_OK;       /* not for us */
3053
3054                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3055                         put_device(&master->dev);
3056                         return NOTIFY_OK;
3057                 }
3058
3059                 spi = of_register_spi_device(master, rd->dn);
3060                 put_device(&master->dev);
3061
3062                 if (IS_ERR(spi)) {
3063                         pr_err("%s: failed to create for '%s'\n",
3064                                         __func__, rd->dn->full_name);
3065                         return notifier_from_errno(PTR_ERR(spi));
3066                 }
3067                 break;
3068
3069         case OF_RECONFIG_CHANGE_REMOVE:
3070                 /* already depopulated? */
3071                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3072                         return NOTIFY_OK;
3073
3074                 /* find our device by node */
3075                 spi = of_find_spi_device_by_node(rd->dn);
3076                 if (spi == NULL)
3077                         return NOTIFY_OK;       /* no? not meant for us */
3078
3079                 /* unregister takes one ref away */
3080                 spi_unregister_device(spi);
3081
3082                 /* and put the reference of the find */
3083                 put_device(&spi->dev);
3084                 break;
3085         }
3086
3087         return NOTIFY_OK;
3088 }
3089
3090 static struct notifier_block spi_of_notifier = {
3091         .notifier_call = of_spi_notify,
3092 };
3093 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3094 extern struct notifier_block spi_of_notifier;
3095 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3096
3097 static int __init spi_init(void)
3098 {
3099         int     status;
3100
3101         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3102         if (!buf) {
3103                 status = -ENOMEM;
3104                 goto err0;
3105         }
3106
3107         status = bus_register(&spi_bus_type);
3108         if (status < 0)
3109                 goto err1;
3110
3111         status = class_register(&spi_master_class);
3112         if (status < 0)
3113                 goto err2;
3114
3115         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3116                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3117
3118         return 0;
3119
3120 err2:
3121         bus_unregister(&spi_bus_type);
3122 err1:
3123         kfree(buf);
3124         buf = NULL;
3125 err0:
3126         return status;
3127 }
3128
3129 /* board_info is normally registered in arch_initcall(),
3130  * but even essential drivers wait till later
3131  *
3132  * REVISIT only boardinfo really needs static linking. the rest (device and
3133  * driver registration) _could_ be dynamically linked (modular) ... costs
3134  * include needing to have boardinfo data structures be much more public.
3135  */
3136 postcore_initcall(spi_init);
3137