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 #include <linux/highmem.h>
  41
  42 #define CREATE_TRACE_POINTS
  43 #include <trace/events/spi.h>
  44
  45 static void spidev_release(struct device *dev)
  46 {
  47         struct spi_device       *spi = to_spi_device(dev);
  48
  49         /* spi masters may cleanup for released devices */
  50         if (spi->master->cleanup)
  51                 spi->master->cleanup(spi);
  52
  53         spi_master_put(spi->master);
  54         kfree(spi);
  55 }
  56
  57 static ssize_t
  58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  59 {
  60         const struct spi_device *spi = to_spi_device(dev);
  61         int len;
  62
  63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  64         if (len != -ENODEV)
  65                 return len;
  66
  67         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  68 }
  69 static DEVICE_ATTR_RO(modalias);
  70
  71 #define SPI_STATISTICS_ATTRS(field, file)                               \
  72 static ssize_t spi_master_##field##_show(struct device *dev,            \
  73                                          struct device_attribute *attr, \
  74                                          char *buf)                     \
  75 {                                                                       \
  76         struct spi_master *master = container_of(dev,                   \
  77                                                  struct spi_master, dev); \
  78         return spi_statistics_##field##_show(&master->statistics, buf); \
  79 }                                                                       \
  80 static struct device_attribute dev_attr_spi_master_##field = {          \
  81         .attr = { .name = file, .mode = S_IRUGO },                      \
  82         .show = spi_master_##field##_show,                              \
  83 };                                                                      \
  84 static ssize_t spi_device_##field##_show(struct device *dev,            \
  85                                          struct device_attribute *attr, \
  86                                         char *buf)                      \
  87 {                                                                       \
  88         struct spi_device *spi = to_spi_device(dev);                    \
  89         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  90 }                                                                       \
  91 static struct device_attribute dev_attr_spi_device_##field = {          \
  92         .attr = { .name = file, .mode = S_IRUGO },                      \
  93         .show = spi_device_##field##_show,                              \
  94 }
  95
  96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  98                                             char *buf)                  \
  99 {                                                                       \
 100         unsigned long flags;                                            \
 101         ssize_t len;                                                    \
 102         spin_lock_irqsave(&stat->lock, flags);                          \
 103         len = sprintf(buf, format_string, stat->field);                 \
 104         spin_unlock_irqrestore(&stat->lock, flags);                     \
 105         return len;                                                     \
 106 }                                                                       \
 107 SPI_STATISTICS_ATTRS(name, file)
 108
 109 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 110         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 111                                  field, format_string)
 112
 113 SPI_STATISTICS_SHOW(messages, "%lu");
 114 SPI_STATISTICS_SHOW(transfers, "%lu");
 115 SPI_STATISTICS_SHOW(errors, "%lu");
 116 SPI_STATISTICS_SHOW(timedout, "%lu");
 117
 118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 120 SPI_STATISTICS_SHOW(spi_async, "%lu");
 121
 122 SPI_STATISTICS_SHOW(bytes, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 125
 126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 127         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 128                                  "transfer_bytes_histo_" number,        \
 129                                  transfer_bytes_histo[index],  "%lu")
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 147
 148 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 149
 150 static struct attribute *spi_dev_attrs[] = {
 151         &dev_attr_modalias.attr,
 152         NULL,
 153 };
 154
 155 static const struct attribute_group spi_dev_group = {
 156         .attrs  = spi_dev_attrs,
 157 };
 158
 159 static struct attribute *spi_device_statistics_attrs[] = {
 160         &dev_attr_spi_device_messages.attr,
 161         &dev_attr_spi_device_transfers.attr,
 162         &dev_attr_spi_device_errors.attr,
 163         &dev_attr_spi_device_timedout.attr,
 164         &dev_attr_spi_device_spi_sync.attr,
 165         &dev_attr_spi_device_spi_sync_immediate.attr,
 166         &dev_attr_spi_device_spi_async.attr,
 167         &dev_attr_spi_device_bytes.attr,
 168         &dev_attr_spi_device_bytes_rx.attr,
 169         &dev_attr_spi_device_bytes_tx.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 186         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 187         &dev_attr_spi_device_transfers_split_maxsize.attr,
 188         NULL,
 189 };
 190
 191 static const struct attribute_group spi_device_statistics_group = {
 192         .name  = "statistics",
 193         .attrs  = spi_device_statistics_attrs,
 194 };
 195
 196 static const struct attribute_group *spi_dev_groups[] = {
 197         &spi_dev_group,
 198         &spi_device_statistics_group,
 199         NULL,
 200 };
 201
 202 static struct attribute *spi_master_statistics_attrs[] = {
 203         &dev_attr_spi_master_messages.attr,
 204         &dev_attr_spi_master_transfers.attr,
 205         &dev_attr_spi_master_errors.attr,
 206         &dev_attr_spi_master_timedout.attr,
 207         &dev_attr_spi_master_spi_sync.attr,
 208         &dev_attr_spi_master_spi_sync_immediate.attr,
 209         &dev_attr_spi_master_spi_async.attr,
 210         &dev_attr_spi_master_bytes.attr,
 211         &dev_attr_spi_master_bytes_rx.attr,
 212         &dev_attr_spi_master_bytes_tx.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 226         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 227         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 228         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 229         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 230         &dev_attr_spi_master_transfers_split_maxsize.attr,
 231         NULL,
 232 };
 233
 234 static const struct attribute_group spi_master_statistics_group = {
 235         .name  = "statistics",
 236         .attrs  = spi_master_statistics_attrs,
 237 };
 238
 239 static const struct attribute_group *spi_master_groups[] = {
 240         &spi_master_statistics_group,
 241         NULL,
 242 };
 243
 244 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 245                                        struct spi_transfer *xfer,
 246                                        struct spi_master *master)
 247 {
 248         unsigned long flags;
 249         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 250
 251         if (l2len < 0)
 252                 l2len = 0;
 253
 254         spin_lock_irqsave(&stats->lock, flags);
 255
 256         stats->transfers++;
 257         stats->transfer_bytes_histo[l2len]++;
 258
 259         stats->bytes += xfer->len;
 260         if ((xfer->tx_buf) &&
 261             (xfer->tx_buf != master->dummy_tx))
 262                 stats->bytes_tx += xfer->len;
 263         if ((xfer->rx_buf) &&
 264             (xfer->rx_buf != master->dummy_rx))
 265                 stats->bytes_rx += xfer->len;
 266
 267         spin_unlock_irqrestore(&stats->lock, flags);
 268 }
 269 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 270
 271 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 272  * and the sysfs version makes coldplug work too.
 273  */
 274
 275 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 276                                                 const struct spi_device *sdev)
 277 {
 278         while (id->name[0]) {
 279                 if (!strcmp(sdev->modalias, id->name))
 280                         return id;
 281                 id++;
 282         }
 283         return NULL;
 284 }
 285
 286 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 287 {
 288         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 289
 290         return spi_match_id(sdrv->id_table, sdev);
 291 }
 292 EXPORT_SYMBOL_GPL(spi_get_device_id);
 293
 294 static int spi_match_device(struct device *dev, struct device_driver *drv)
 295 {
 296         const struct spi_device *spi = to_spi_device(dev);
 297         const struct spi_driver *sdrv = to_spi_driver(drv);
 298
 299         /* Attempt an OF style match */
 300         if (of_driver_match_device(dev, drv))
 301                 return 1;
 302
 303         /* Then try ACPI */
 304         if (acpi_driver_match_device(dev, drv))
 305                 return 1;
 306
 307         if (sdrv->id_table)
 308                 return !!spi_match_id(sdrv->id_table, spi);
 309
 310         return strcmp(spi->modalias, drv->name) == 0;
 311 }
 312
 313 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 314 {
 315         const struct spi_device         *spi = to_spi_device(dev);
 316         int rc;
 317
 318         rc = acpi_device_uevent_modalias(dev, env);
 319         if (rc != -ENODEV)
 320                 return rc;
 321
 322         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 323         return 0;
 324 }
 325
 326 struct bus_type spi_bus_type = {
 327         .name           = "spi",
 328         .dev_groups     = spi_dev_groups,
 329         .match          = spi_match_device,
 330         .uevent         = spi_uevent,
 331 };
 332 EXPORT_SYMBOL_GPL(spi_bus_type);
 333
 334
 335 static int spi_drv_probe(struct device *dev)
 336 {
 337         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 338         struct spi_device               *spi = to_spi_device(dev);
 339         int ret;
 340
 341         ret = of_clk_set_defaults(dev->of_node, false);
 342         if (ret)
 343                 return ret;
 344
 345         if (dev->of_node) {
 346                 spi->irq = of_irq_get(dev->of_node, 0);
 347                 if (spi->irq == -EPROBE_DEFER)
 348                         return -EPROBE_DEFER;
 349                 if (spi->irq < 0)
 350                         spi->irq = 0;
 351         }
 352
 353         ret = dev_pm_domain_attach(dev, true);
 354         if (ret != -EPROBE_DEFER) {
 355                 ret = sdrv->probe(spi);
 356                 if (ret)
 357                         dev_pm_domain_detach(dev, true);
 358         }
 359
 360         return ret;
 361 }
 362
 363 static int spi_drv_remove(struct device *dev)
 364 {
 365         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 366         int ret;
 367
 368         ret = sdrv->remove(to_spi_device(dev));
 369         dev_pm_domain_detach(dev, true);
 370
 371         return ret;
 372 }
 373
 374 static void spi_drv_shutdown(struct device *dev)
 375 {
 376         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 377
 378         sdrv->shutdown(to_spi_device(dev));
 379 }
 380
 381 /**
 382  * __spi_register_driver - register a SPI driver
 383  * @owner: owner module of the driver to register
 384  * @sdrv: the driver to register
 385  * Context: can sleep
 386  *
 387  * Return: zero on success, else a negative error code.
 388  */
 389 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 390 {
 391         sdrv->driver.owner = owner;
 392         sdrv->driver.bus = &spi_bus_type;
 393         if (sdrv->probe)
 394                 sdrv->driver.probe = spi_drv_probe;
 395         if (sdrv->remove)
 396                 sdrv->driver.remove = spi_drv_remove;
 397         if (sdrv->shutdown)
 398                 sdrv->driver.shutdown = spi_drv_shutdown;
 399         return driver_register(&sdrv->driver);
 400 }
 401 EXPORT_SYMBOL_GPL(__spi_register_driver);
 402
 403 /*-------------------------------------------------------------------------*/
 404
 405 /* SPI devices should normally not be created by SPI device drivers; that
 406  * would make them board-specific.  Similarly with SPI master drivers.
 407  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 408  * with other readonly (flashable) information about mainboard devices.
 409  */
 410
 411 struct boardinfo {
 412         struct list_head        list;
 413         struct spi_board_info   board_info;
 414 };
 415
 416 static LIST_HEAD(board_list);
 417 static LIST_HEAD(spi_master_list);
 418
 419 /*
 420  * Used to protect add/del opertion for board_info list and
 421  * spi_master list, and their matching process
 422  */
 423 static DEFINE_MUTEX(board_lock);
 424
 425 /**
 426  * spi_alloc_device - Allocate a new SPI device
 427  * @master: Controller to which device is connected
 428  * Context: can sleep
 429  *
 430  * Allows a driver to allocate and initialize a spi_device without
 431  * registering it immediately.  This allows a driver to directly
 432  * fill the spi_device with device parameters before calling
 433  * spi_add_device() on it.
 434  *
 435  * Caller is responsible to call spi_add_device() on the returned
 436  * spi_device structure to add it to the SPI master.  If the caller
 437  * needs to discard the spi_device without adding it, then it should
 438  * call spi_dev_put() on it.
 439  *
 440  * Return: a pointer to the new device, or NULL.
 441  */
 442 struct spi_device *spi_alloc_device(struct spi_master *master)
 443 {
 444         struct spi_device       *spi;
 445
 446         if (!spi_master_get(master))
 447                 return NULL;
 448
 449         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 450         if (!spi) {
 451                 spi_master_put(master);
 452                 return NULL;
 453         }
 454
 455         spi->master = master;
 456         spi->dev.parent = &master->dev;
 457         spi->dev.bus = &spi_bus_type;
 458         spi->dev.release = spidev_release;
 459         spi->cs_gpio = -ENOENT;
 460
 461         spin_lock_init(&spi->statistics.lock);
 462
 463         device_initialize(&spi->dev);
 464         return spi;
 465 }
 466 EXPORT_SYMBOL_GPL(spi_alloc_device);
 467
 468 static void spi_dev_set_name(struct spi_device *spi)
 469 {
 470         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 471
 472         if (adev) {
 473                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 474                 return;
 475         }
 476
 477         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 478                      spi->chip_select);
 479 }
 480
 481 static int spi_dev_check(struct device *dev, void *data)
 482 {
 483         struct spi_device *spi = to_spi_device(dev);
 484         struct spi_device *new_spi = data;
 485
 486         if (spi->master == new_spi->master &&
 487             spi->chip_select == new_spi->chip_select)
 488                 return -EBUSY;
 489         return 0;
 490 }
 491
 492 /**
 493  * spi_add_device - Add spi_device allocated with spi_alloc_device
 494  * @spi: spi_device to register
 495  *
 496  * Companion function to spi_alloc_device.  Devices allocated with
 497  * spi_alloc_device can be added onto the spi bus with this function.
 498  *
 499  * Return: 0 on success; negative errno on failure
 500  */
 501 int spi_add_device(struct spi_device *spi)
 502 {
 503         static DEFINE_MUTEX(spi_add_lock);
 504         struct spi_master *master = spi->master;
 505         struct device *dev = master->dev.parent;
 506         int status;
 507
 508         /* Chipselects are numbered 0..max; validate. */
 509         if (spi->chip_select >= master->num_chipselect) {
 510                 dev_err(dev, "cs%d >= max %d\n",
 511                         spi->chip_select,
 512                         master->num_chipselect);
 513                 return -EINVAL;
 514         }
 515
 516         /* Set the bus ID string */
 517         spi_dev_set_name(spi);
 518
 519         /* We need to make sure there's no other device with this
 520          * chipselect **BEFORE** we call setup(), else we'll trash
 521          * its configuration.  Lock against concurrent add() calls.
 522          */
 523         mutex_lock(&spi_add_lock);
 524
 525         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 526         if (status) {
 527                 dev_err(dev, "chipselect %d already in use\n",
 528                                 spi->chip_select);
 529                 goto done;
 530         }
 531
 532         if (master->cs_gpios)
 533                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 534
 535         /* Drivers may modify this initial i/o setup, but will
 536          * normally rely on the device being setup.  Devices
 537          * using SPI_CS_HIGH can't coexist well otherwise...
 538          */
 539         status = spi_setup(spi);
 540         if (status < 0) {
 541                 dev_err(dev, "can't setup %s, status %d\n",
 542                                 dev_name(&spi->dev), status);
 543                 goto done;
 544         }
 545
 546         /* Device may be bound to an active driver when this returns */
 547         status = device_add(&spi->dev);
 548         if (status < 0)
 549                 dev_err(dev, "can't add %s, status %d\n",
 550                                 dev_name(&spi->dev), status);
 551         else
 552                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 553
 554 done:
 555         mutex_unlock(&spi_add_lock);
 556         return status;
 557 }
 558 EXPORT_SYMBOL_GPL(spi_add_device);
 559
 560 /**
 561  * spi_new_device - instantiate one new SPI device
 562  * @master: Controller to which device is connected
 563  * @chip: Describes the SPI device
 564  * Context: can sleep
 565  *
 566  * On typical mainboards, this is purely internal; and it's not needed
 567  * after board init creates the hard-wired devices.  Some development
 568  * platforms may not be able to use spi_register_board_info though, and
 569  * this is exported so that for example a USB or parport based adapter
 570  * driver could add devices (which it would learn about out-of-band).
 571  *
 572  * Return: the new device, or NULL.
 573  */
 574 struct spi_device *spi_new_device(struct spi_master *master,
 575                                   struct spi_board_info *chip)
 576 {
 577         struct spi_device       *proxy;
 578         int                     status;
 579
 580         /* NOTE:  caller did any chip->bus_num checks necessary.
 581          *
 582          * Also, unless we change the return value convention to use
 583          * error-or-pointer (not NULL-or-pointer), troubleshootability
 584          * suggests syslogged diagnostics are best here (ugh).
 585          */
 586
 587         proxy = spi_alloc_device(master);
 588         if (!proxy)
 589                 return NULL;
 590
 591         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 592
 593         proxy->chip_select = chip->chip_select;
 594         proxy->max_speed_hz = chip->max_speed_hz;
 595         proxy->mode = chip->mode;
 596         proxy->irq = chip->irq;
 597         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 598         proxy->dev.platform_data = (void *) chip->platform_data;
 599         proxy->controller_data = chip->controller_data;
 600         proxy->controller_state = NULL;
 601
 602         status = spi_add_device(proxy);
 603         if (status < 0) {
 604                 spi_dev_put(proxy);
 605                 return NULL;
 606         }
 607
 608         return proxy;
 609 }
 610 EXPORT_SYMBOL_GPL(spi_new_device);
 611
 612 /**
 613  * spi_unregister_device - unregister a single SPI device
 614  * @spi: spi_device to unregister
 615  *
 616  * Start making the passed SPI device vanish. Normally this would be handled
 617  * by spi_unregister_master().
 618  */
 619 void spi_unregister_device(struct spi_device *spi)
 620 {
 621         if (!spi)
 622                 return;
 623
 624         if (spi->dev.of_node)
 625                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 626         if (ACPI_COMPANION(&spi->dev))
 627                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 628         device_unregister(&spi->dev);
 629 }
 630 EXPORT_SYMBOL_GPL(spi_unregister_device);
 631
 632 static void spi_match_master_to_boardinfo(struct spi_master *master,
 633                                 struct spi_board_info *bi)
 634 {
 635         struct spi_device *dev;
 636
 637         if (master->bus_num != bi->bus_num)
 638                 return;
 639
 640         dev = spi_new_device(master, bi);
 641         if (!dev)
 642                 dev_err(master->dev.parent, "can't create new device for %s\n",
 643                         bi->modalias);
 644 }
 645
 646 /**
 647  * spi_register_board_info - register SPI devices for a given board
 648  * @info: array of chip descriptors
 649  * @n: how many descriptors are provided
 650  * Context: can sleep
 651  *
 652  * Board-specific early init code calls this (probably during arch_initcall)
 653  * with segments of the SPI device table.  Any device nodes are created later,
 654  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 655  * this table of devices forever, so that reloading a controller driver will
 656  * not make Linux forget about these hard-wired devices.
 657  *
 658  * Other code can also call this, e.g. a particular add-on board might provide
 659  * SPI devices through its expansion connector, so code initializing that board
 660  * would naturally declare its SPI devices.
 661  *
 662  * The board info passed can safely be __initdata ... but be careful of
 663  * any embedded pointers (platform_data, etc), they're copied as-is.
 664  *
 665  * Return: zero on success, else a negative error code.
 666  */
 667 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 668 {
 669         struct boardinfo *bi;
 670         int i;
 671
 672         if (!n)
 673                 return -EINVAL;
 674
 675         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 676         if (!bi)
 677                 return -ENOMEM;
 678
 679         for (i = 0; i < n; i++, bi++, info++) {
 680                 struct spi_master *master;
 681
 682                 memcpy(&bi->board_info, info, sizeof(*info));
 683                 mutex_lock(&board_lock);
 684                 list_add_tail(&bi->list, &board_list);
 685                 list_for_each_entry(master, &spi_master_list, list)
 686                         spi_match_master_to_boardinfo(master, &bi->board_info);
 687                 mutex_unlock(&board_lock);
 688         }
 689
 690         return 0;
 691 }
 692
 693 /*-------------------------------------------------------------------------*/
 694
 695 static void spi_set_cs(struct spi_device *spi, bool enable)
 696 {
 697         if (spi->mode & SPI_CS_HIGH)
 698                 enable = !enable;
 699
 700         if (gpio_is_valid(spi->cs_gpio)) {
 701                 gpio_set_value(spi->cs_gpio, !enable);
 702                 /* Some SPI masters need both GPIO CS & slave_select */
 703                 if ((spi->master->flags & SPI_MASTER_GPIO_SS) &&
 704                     spi->master->set_cs)
 705                         spi->master->set_cs(spi, !enable);
 706         } else if (spi->master->set_cs) {
 707                 spi->master->set_cs(spi, !enable);
 708         }
 709 }
 710
 711 #ifdef CONFIG_HAS_DMA
 712 static int spi_map_buf(struct spi_master *master, struct device *dev,
 713                        struct sg_table *sgt, void *buf, size_t len,
 714                        enum dma_data_direction dir)
 715 {
 716         const bool vmalloced_buf = is_vmalloc_addr(buf);
 717         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 718 #ifdef CONFIG_HIGHMEM
 719         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 720                                 (unsigned long)buf < (PKMAP_BASE +
 721                                         (LAST_PKMAP * PAGE_SIZE)));
 722 #else
 723         const bool kmap_buf = false;
 724 #endif
 725         int desc_len;
 726         int sgs;
 727         struct page *vm_page;
 728         struct scatterlist *sg;
 729         void *sg_buf;
 730         size_t min;
 731         int i, ret;
 732
 733         if (vmalloced_buf || kmap_buf) {
 734                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 735                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 736         } else if (virt_addr_valid(buf)) {
 737                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
 738                 sgs = DIV_ROUND_UP(len, desc_len);
 739         } else {
 740                 return -EINVAL;
 741         }
 742
 743         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 744         if (ret != 0)
 745                 return ret;
 746
 747         sg = &sgt->sgl[0];
 748         for (i = 0; i < sgs; i++) {
 749
 750                 if (vmalloced_buf || kmap_buf) {
 751                         min = min_t(size_t,
 752                                     len, desc_len - offset_in_page(buf));
 753                         if (vmalloced_buf)
 754                                 vm_page = vmalloc_to_page(buf);
 755                         else
 756                                 vm_page = kmap_to_page(buf);
 757                         if (!vm_page) {
 758                                 sg_free_table(sgt);
 759                                 return -ENOMEM;
 760                         }
 761                         sg_set_page(sg, vm_page,
 762                                     min, offset_in_page(buf));
 763                 } else {
 764                         min = min_t(size_t, len, desc_len);
 765                         sg_buf = buf;
 766                         sg_set_buf(sg, sg_buf, min);
 767                 }
 768
 769                 buf += min;
 770                 len -= min;
 771                 sg = sg_next(sg);
 772         }
 773
 774         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 775         if (!ret)
 776                 ret = -ENOMEM;
 777         if (ret < 0) {
 778                 sg_free_table(sgt);
 779                 return ret;
 780         }
 781
 782         sgt->nents = ret;
 783
 784         return 0;
 785 }
 786
 787 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 788                           struct sg_table *sgt, enum dma_data_direction dir)
 789 {
 790         if (sgt->orig_nents) {
 791                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 792                 sg_free_table(sgt);
 793         }
 794 }
 795
 796 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 797 {
 798         struct device *tx_dev, *rx_dev;
 799         struct spi_transfer *xfer;
 800         int ret;
 801
 802         if (!master->can_dma)
 803                 return 0;
 804
 805         if (master->dma_tx)
 806                 tx_dev = master->dma_tx->device->dev;
 807         else
 808                 tx_dev = &master->dev;
 809
 810         if (master->dma_rx)
 811                 rx_dev = master->dma_rx->device->dev;
 812         else
 813                 rx_dev = &master->dev;
 814
 815         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 816                 if (!master->can_dma(master, msg->spi, xfer))
 817                         continue;
 818
 819                 if (xfer->tx_buf != NULL) {
 820                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 821                                           (void *)xfer->tx_buf, xfer->len,
 822                                           DMA_TO_DEVICE);
 823                         if (ret != 0)
 824                                 return ret;
 825                 }
 826
 827                 if (xfer->rx_buf != NULL) {
 828                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 829                                           xfer->rx_buf, xfer->len,
 830                                           DMA_FROM_DEVICE);
 831                         if (ret != 0) {
 832                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 833                                               DMA_TO_DEVICE);
 834                                 return ret;
 835                         }
 836                 }
 837         }
 838
 839         master->cur_msg_mapped = true;
 840
 841         return 0;
 842 }
 843
 844 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 845 {
 846         struct spi_transfer *xfer;
 847         struct device *tx_dev, *rx_dev;
 848
 849         if (!master->cur_msg_mapped || !master->can_dma)
 850                 return 0;
 851
 852         if (master->dma_tx)
 853                 tx_dev = master->dma_tx->device->dev;
 854         else
 855                 tx_dev = &master->dev;
 856
 857         if (master->dma_rx)
 858                 rx_dev = master->dma_rx->device->dev;
 859         else
 860                 rx_dev = &master->dev;
 861
 862         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 863                 if (!master->can_dma(master, msg->spi, xfer))
 864                         continue;
 865
 866                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 867                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 868         }
 869
 870         return 0;
 871 }
 872 #else /* !CONFIG_HAS_DMA */
 873 static inline int spi_map_buf(struct spi_master *master,
 874                               struct device *dev, struct sg_table *sgt,
 875                               void *buf, size_t len,
 876                               enum dma_data_direction dir)
 877 {
 878         return -EINVAL;
 879 }
 880
 881 static inline void spi_unmap_buf(struct spi_master *master,
 882                                  struct device *dev, struct sg_table *sgt,
 883                                  enum dma_data_direction dir)
 884 {
 885 }
 886
 887 static inline int __spi_map_msg(struct spi_master *master,
 888                                 struct spi_message *msg)
 889 {
 890         return 0;
 891 }
 892
 893 static inline int __spi_unmap_msg(struct spi_master *master,
 894                                   struct spi_message *msg)
 895 {
 896         return 0;
 897 }
 898 #endif /* !CONFIG_HAS_DMA */
 899
 900 static inline int spi_unmap_msg(struct spi_master *master,
 901                                 struct spi_message *msg)
 902 {
 903         struct spi_transfer *xfer;
 904
 905         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 906                 /*
 907                  * Restore the original value of tx_buf or rx_buf if they are
 908                  * NULL.
 909                  */
 910                 if (xfer->tx_buf == master->dummy_tx)
 911                         xfer->tx_buf = NULL;
 912                 if (xfer->rx_buf == master->dummy_rx)
 913                         xfer->rx_buf = NULL;
 914         }
 915
 916         return __spi_unmap_msg(master, msg);
 917 }
 918
 919 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 920 {
 921         struct spi_transfer *xfer;
 922         void *tmp;
 923         unsigned int max_tx, max_rx;
 924
 925         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 926                 max_tx = 0;
 927                 max_rx = 0;
 928
 929                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 930                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 931                             !xfer->tx_buf)
 932                                 max_tx = max(xfer->len, max_tx);
 933                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 934                             !xfer->rx_buf)
 935                                 max_rx = max(xfer->len, max_rx);
 936                 }
 937
 938                 if (max_tx) {
 939                         tmp = krealloc(master->dummy_tx, max_tx,
 940                                        GFP_KERNEL | GFP_DMA);
 941                         if (!tmp)
 942                                 return -ENOMEM;
 943                         master->dummy_tx = tmp;
 944                         memset(tmp, 0, max_tx);
 945                 }
 946
 947                 if (max_rx) {
 948                         tmp = krealloc(master->dummy_rx, max_rx,
 949                                        GFP_KERNEL | GFP_DMA);
 950                         if (!tmp)
 951                                 return -ENOMEM;
 952                         master->dummy_rx = tmp;
 953                 }
 954
 955                 if (max_tx || max_rx) {
 956                         list_for_each_entry(xfer, &msg->transfers,
 957                                             transfer_list) {
 958                                 if (!xfer->tx_buf)
 959                                         xfer->tx_buf = master->dummy_tx;
 960                                 if (!xfer->rx_buf)
 961                                         xfer->rx_buf = master->dummy_rx;
 962                         }
 963                 }
 964         }
 965
 966         return __spi_map_msg(master, msg);
 967 }
 968
 969 /*
 970  * spi_transfer_one_message - Default implementation of transfer_one_message()
 971  *
 972  * This is a standard implementation of transfer_one_message() for
 973  * drivers which implement a transfer_one() operation.  It provides
 974  * standard handling of delays and chip select management.
 975  */
 976 static int spi_transfer_one_message(struct spi_master *master,
 977                                     struct spi_message *msg)
 978 {
 979         struct spi_transfer *xfer;
 980         bool keep_cs = false;
 981         int ret = 0;
 982         unsigned long long ms = 1;
 983         struct spi_statistics *statm = &master->statistics;
 984         struct spi_statistics *stats = &msg->spi->statistics;
 985
 986         spi_set_cs(msg->spi, true);
 987
 988         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 989         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 990
 991         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 992                 trace_spi_transfer_start(msg, xfer);
 993
 994                 spi_statistics_add_transfer_stats(statm, xfer, master);
 995                 spi_statistics_add_transfer_stats(stats, xfer, master);
 996
 997                 if (xfer->tx_buf || xfer->rx_buf) {
 998                         reinit_completion(&master->xfer_completion);
 999
1000                         ret = master->transfer_one(master, msg->spi, xfer);
1001                         if (ret < 0) {
1002                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1003                                                                errors);
1004                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1005                                                                errors);
1006                                 dev_err(&msg->spi->dev,
1007                                         "SPI transfer failed: %d\n", ret);
1008                                 goto out;
1009                         }
1010
1011                         if (ret > 0) {
1012                                 ret = 0;
1013                                 ms = 8LL * 1000LL * xfer->len;
1014                                 do_div(ms, xfer->speed_hz);
1015                                 ms += ms + 100; /* some tolerance */
1016
1017                                 if (ms > UINT_MAX)
1018                                         ms = UINT_MAX;
1019
1020                                 ms = wait_for_completion_timeout(&master->xfer_completion,
1021                                                                  msecs_to_jiffies(ms));
1022                         }
1023
1024                         if (ms == 0) {
1025                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1026                                                                timedout);
1027                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1028                                                                timedout);
1029                                 dev_err(&msg->spi->dev,
1030                                         "SPI transfer timed out\n");
1031                                 msg->status = -ETIMEDOUT;
1032                         }
1033                 } else {
1034                         if (xfer->len)
1035                                 dev_err(&msg->spi->dev,
1036                                         "Bufferless transfer has length %u\n",
1037                                         xfer->len);
1038                 }
1039
1040                 trace_spi_transfer_stop(msg, xfer);
1041
1042                 if (msg->status != -EINPROGRESS)
1043                         goto out;
1044
1045                 if (xfer->delay_usecs) {
1046                         u16 us = xfer->delay_usecs;
1047
1048                         if (us <= 10)
1049                                 udelay(us);
1050                         else
1051                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1052                 }
1053
1054                 if (xfer->cs_change) {
1055                         if (list_is_last(&xfer->transfer_list,
1056                                          &msg->transfers)) {
1057                                 keep_cs = true;
1058                         } else {
1059                                 spi_set_cs(msg->spi, false);
1060                                 udelay(10);
1061                                 spi_set_cs(msg->spi, true);
1062                         }
1063                 }
1064
1065                 msg->actual_length += xfer->len;
1066         }
1067
1068 out:
1069         if (ret != 0 || !keep_cs)
1070                 spi_set_cs(msg->spi, false);
1071
1072         if (msg->status == -EINPROGRESS)
1073                 msg->status = ret;
1074
1075         if (msg->status && master->handle_err)
1076                 master->handle_err(master, msg);
1077
1078         spi_res_release(master, msg);
1079
1080         spi_finalize_current_message(master);
1081
1082         return ret;
1083 }
1084
1085 /**
1086  * spi_finalize_current_transfer - report completion of a transfer
1087  * @master: the master reporting completion
1088  *
1089  * Called by SPI drivers using the core transfer_one_message()
1090  * implementation to notify it that the current interrupt driven
1091  * transfer has finished and the next one may be scheduled.
1092  */
1093 void spi_finalize_current_transfer(struct spi_master *master)
1094 {
1095         complete(&master->xfer_completion);
1096 }
1097 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1098
1099 /**
1100  * __spi_pump_messages - function which processes spi message queue
1101  * @master: master to process queue for
1102  * @in_kthread: true if we are in the context of the message pump thread
1103  *
1104  * This function checks if there is any spi message in the queue that
1105  * needs processing and if so call out to the driver to initialize hardware
1106  * and transfer each message.
1107  *
1108  * Note that it is called both from the kthread itself and also from
1109  * inside spi_sync(); the queue extraction handling at the top of the
1110  * function should deal with this safely.
1111  */
1112 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1113 {
1114         unsigned long flags;
1115         bool was_busy = false;
1116         int ret;
1117
1118         /* Lock queue */
1119         spin_lock_irqsave(&master->queue_lock, flags);
1120
1121         /* Make sure we are not already running a message */
1122         if (master->cur_msg) {
1123                 spin_unlock_irqrestore(&master->queue_lock, flags);
1124                 return;
1125         }
1126
1127         /* If another context is idling the device then defer */
1128         if (master->idling) {
1129                 kthread_queue_work(&master->kworker, &master->pump_messages);
1130                 spin_unlock_irqrestore(&master->queue_lock, flags);
1131                 return;
1132         }
1133
1134         /* Check if the queue is idle */
1135         if (list_empty(&master->queue) || !master->running) {
1136                 if (!master->busy) {
1137                         spin_unlock_irqrestore(&master->queue_lock, flags);
1138                         return;
1139                 }
1140
1141                 /* Only do teardown in the thread */
1142                 if (!in_kthread) {
1143                         kthread_queue_work(&master->kworker,
1144                                            &master->pump_messages);
1145                         spin_unlock_irqrestore(&master->queue_lock, flags);
1146                         return;
1147                 }
1148
1149                 master->busy = false;
1150                 master->idling = true;
1151                 spin_unlock_irqrestore(&master->queue_lock, flags);
1152
1153                 kfree(master->dummy_rx);
1154                 master->dummy_rx = NULL;
1155                 kfree(master->dummy_tx);
1156                 master->dummy_tx = NULL;
1157                 if (master->unprepare_transfer_hardware &&
1158                     master->unprepare_transfer_hardware(master))
1159                         dev_err(&master->dev,
1160                                 "failed to unprepare transfer hardware\n");
1161                 if (master->auto_runtime_pm) {
1162                         pm_runtime_mark_last_busy(master->dev.parent);
1163                         pm_runtime_put_autosuspend(master->dev.parent);
1164                 }
1165                 trace_spi_master_idle(master);
1166
1167                 spin_lock_irqsave(&master->queue_lock, flags);
1168                 master->idling = false;
1169                 spin_unlock_irqrestore(&master->queue_lock, flags);
1170                 return;
1171         }
1172
1173         /* Extract head of queue */
1174         master->cur_msg =
1175                 list_first_entry(&master->queue, struct spi_message, queue);
1176
1177         list_del_init(&master->cur_msg->queue);
1178         if (master->busy)
1179                 was_busy = true;
1180         else
1181                 master->busy = true;
1182         spin_unlock_irqrestore(&master->queue_lock, flags);
1183
1184         mutex_lock(&master->io_mutex);
1185
1186         if (!was_busy && master->auto_runtime_pm) {
1187                 ret = pm_runtime_get_sync(master->dev.parent);
1188                 if (ret < 0) {
1189                         dev_err(&master->dev, "Failed to power device: %d\n",
1190                                 ret);
1191                         mutex_unlock(&master->io_mutex);
1192                         return;
1193                 }
1194         }
1195
1196         if (!was_busy)
1197                 trace_spi_master_busy(master);
1198
1199         if (!was_busy && master->prepare_transfer_hardware) {
1200                 ret = master->prepare_transfer_hardware(master);
1201                 if (ret) {
1202                         dev_err(&master->dev,
1203                                 "failed to prepare transfer hardware\n");
1204
1205                         if (master->auto_runtime_pm)
1206                                 pm_runtime_put(master->dev.parent);
1207                         mutex_unlock(&master->io_mutex);
1208                         return;
1209                 }
1210         }
1211
1212         trace_spi_message_start(master->cur_msg);
1213
1214         if (master->prepare_message) {
1215                 ret = master->prepare_message(master, master->cur_msg);
1216                 if (ret) {
1217                         dev_err(&master->dev,
1218                                 "failed to prepare message: %d\n", ret);
1219                         master->cur_msg->status = ret;
1220                         spi_finalize_current_message(master);
1221                         goto out;
1222                 }
1223                 master->cur_msg_prepared = true;
1224         }
1225
1226         ret = spi_map_msg(master, master->cur_msg);
1227         if (ret) {
1228                 master->cur_msg->status = ret;
1229                 spi_finalize_current_message(master);
1230                 goto out;
1231         }
1232
1233         ret = master->transfer_one_message(master, master->cur_msg);
1234         if (ret) {
1235                 dev_err(&master->dev,
1236                         "failed to transfer one message from queue\n");
1237                 goto out;
1238         }
1239
1240 out:
1241         mutex_unlock(&master->io_mutex);
1242
1243         /* Prod the scheduler in case transfer_one() was busy waiting */
1244         if (!ret)
1245                 cond_resched();
1246 }
1247
1248 /**
1249  * spi_pump_messages - kthread work function which processes spi message queue
1250  * @work: pointer to kthread work struct contained in the master struct
1251  */
1252 static void spi_pump_messages(struct kthread_work *work)
1253 {
1254         struct spi_master *master =
1255                 container_of(work, struct spi_master, pump_messages);
1256
1257         __spi_pump_messages(master, true);
1258 }
1259
1260 static int spi_init_queue(struct spi_master *master)
1261 {
1262         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1263
1264         master->running = false;
1265         master->busy = false;
1266
1267         kthread_init_worker(&master->kworker);
1268         master->kworker_task = kthread_run(kthread_worker_fn,
1269                                            &master->kworker, "%s",
1270                                            dev_name(&master->dev));
1271         if (IS_ERR(master->kworker_task)) {
1272                 dev_err(&master->dev, "failed to create message pump task\n");
1273                 return PTR_ERR(master->kworker_task);
1274         }
1275         kthread_init_work(&master->pump_messages, spi_pump_messages);
1276
1277         /*
1278          * Master config will indicate if this controller should run the
1279          * message pump with high (realtime) priority to reduce the transfer
1280          * latency on the bus by minimising the delay between a transfer
1281          * request and the scheduling of the message pump thread. Without this
1282          * setting the message pump thread will remain at default priority.
1283          */
1284         if (master->rt) {
1285                 dev_info(&master->dev,
1286                         "will run message pump with realtime priority\n");
1287                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1288         }
1289
1290         return 0;
1291 }
1292
1293 /**
1294  * spi_get_next_queued_message() - called by driver to check for queued
1295  * messages
1296  * @master: the master to check for queued messages
1297  *
1298  * If there are more messages in the queue, the next message is returned from
1299  * this call.
1300  *
1301  * Return: the next message in the queue, else NULL if the queue is empty.
1302  */
1303 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1304 {
1305         struct spi_message *next;
1306         unsigned long flags;
1307
1308         /* get a pointer to the next message, if any */
1309         spin_lock_irqsave(&master->queue_lock, flags);
1310         next = list_first_entry_or_null(&master->queue, struct spi_message,
1311                                         queue);
1312         spin_unlock_irqrestore(&master->queue_lock, flags);
1313
1314         return next;
1315 }
1316 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1317
1318 /**
1319  * spi_finalize_current_message() - the current message is complete
1320  * @master: the master to return the message to
1321  *
1322  * Called by the driver to notify the core that the message in the front of the
1323  * queue is complete and can be removed from the queue.
1324  */
1325 void spi_finalize_current_message(struct spi_master *master)
1326 {
1327         struct spi_message *mesg;
1328         unsigned long flags;
1329         int ret;
1330
1331         spin_lock_irqsave(&master->queue_lock, flags);
1332         mesg = master->cur_msg;
1333         spin_unlock_irqrestore(&master->queue_lock, flags);
1334
1335         spi_unmap_msg(master, mesg);
1336
1337         if (master->cur_msg_prepared && master->unprepare_message) {
1338                 ret = master->unprepare_message(master, mesg);
1339                 if (ret) {
1340                         dev_err(&master->dev,
1341                                 "failed to unprepare message: %d\n", ret);
1342                 }
1343         }
1344
1345         spin_lock_irqsave(&master->queue_lock, flags);
1346         master->cur_msg = NULL;
1347         master->cur_msg_prepared = false;
1348         kthread_queue_work(&master->kworker, &master->pump_messages);
1349         spin_unlock_irqrestore(&master->queue_lock, flags);
1350
1351         trace_spi_message_done(mesg);
1352
1353         mesg->state = NULL;
1354         if (mesg->complete)
1355                 mesg->complete(mesg->context);
1356 }
1357 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1358
1359 static int spi_start_queue(struct spi_master *master)
1360 {
1361         unsigned long flags;
1362
1363         spin_lock_irqsave(&master->queue_lock, flags);
1364
1365         if (master->running || master->busy) {
1366                 spin_unlock_irqrestore(&master->queue_lock, flags);
1367                 return -EBUSY;
1368         }
1369
1370         master->running = true;
1371         master->cur_msg = NULL;
1372         spin_unlock_irqrestore(&master->queue_lock, flags);
1373
1374         kthread_queue_work(&master->kworker, &master->pump_messages);
1375
1376         return 0;
1377 }
1378
1379 static int spi_stop_queue(struct spi_master *master)
1380 {
1381         unsigned long flags;
1382         unsigned limit = 500;
1383         int ret = 0;
1384
1385         spin_lock_irqsave(&master->queue_lock, flags);
1386
1387         /*
1388          * This is a bit lame, but is optimized for the common execution path.
1389          * A wait_queue on the master->busy could be used, but then the common
1390          * execution path (pump_messages) would be required to call wake_up or
1391          * friends on every SPI message. Do this instead.
1392          */
1393         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1394                 spin_unlock_irqrestore(&master->queue_lock, flags);
1395                 usleep_range(10000, 11000);
1396                 spin_lock_irqsave(&master->queue_lock, flags);
1397         }
1398
1399         if (!list_empty(&master->queue) || master->busy)
1400                 ret = -EBUSY;
1401         else
1402                 master->running = false;
1403
1404         spin_unlock_irqrestore(&master->queue_lock, flags);
1405
1406         if (ret) {
1407                 dev_warn(&master->dev,
1408                          "could not stop message queue\n");
1409                 return ret;
1410         }
1411         return ret;
1412 }
1413
1414 static int spi_destroy_queue(struct spi_master *master)
1415 {
1416         int ret;
1417
1418         ret = spi_stop_queue(master);
1419
1420         /*
1421          * kthread_flush_worker will block until all work is done.
1422          * If the reason that stop_queue timed out is that the work will never
1423          * finish, then it does no good to call flush/stop thread, so
1424          * return anyway.
1425          */
1426         if (ret) {
1427                 dev_err(&master->dev, "problem destroying queue\n");
1428                 return ret;
1429         }
1430
1431         kthread_flush_worker(&master->kworker);
1432         kthread_stop(master->kworker_task);
1433
1434         return 0;
1435 }
1436
1437 static int __spi_queued_transfer(struct spi_device *spi,
1438                                  struct spi_message *msg,
1439                                  bool need_pump)
1440 {
1441         struct spi_master *master = spi->master;
1442         unsigned long flags;
1443
1444         spin_lock_irqsave(&master->queue_lock, flags);
1445
1446         if (!master->running) {
1447                 spin_unlock_irqrestore(&master->queue_lock, flags);
1448                 return -ESHUTDOWN;
1449         }
1450         msg->actual_length = 0;
1451         msg->status = -EINPROGRESS;
1452
1453         list_add_tail(&msg->queue, &master->queue);
1454         if (!master->busy && need_pump)
1455                 kthread_queue_work(&master->kworker, &master->pump_messages);
1456
1457         spin_unlock_irqrestore(&master->queue_lock, flags);
1458         return 0;
1459 }
1460
1461 /**
1462  * spi_queued_transfer - transfer function for queued transfers
1463  * @spi: spi device which is requesting transfer
1464  * @msg: spi message which is to handled is queued to driver queue
1465  *
1466  * Return: zero on success, else a negative error code.
1467  */
1468 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1469 {
1470         return __spi_queued_transfer(spi, msg, true);
1471 }
1472
1473 static int spi_master_initialize_queue(struct spi_master *master)
1474 {
1475         int ret;
1476
1477         master->transfer = spi_queued_transfer;
1478         if (!master->transfer_one_message)
1479                 master->transfer_one_message = spi_transfer_one_message;
1480
1481         /* Initialize and start queue */
1482         ret = spi_init_queue(master);
1483         if (ret) {
1484                 dev_err(&master->dev, "problem initializing queue\n");
1485                 goto err_init_queue;
1486         }
1487         master->queued = true;
1488         ret = spi_start_queue(master);
1489         if (ret) {
1490                 dev_err(&master->dev, "problem starting queue\n");
1491                 goto err_start_queue;
1492         }
1493
1494         return 0;
1495
1496 err_start_queue:
1497         spi_destroy_queue(master);
1498 err_init_queue:
1499         return ret;
1500 }
1501
1502 /*-------------------------------------------------------------------------*/
1503
1504 #if defined(CONFIG_OF)
1505 static struct spi_device *
1506 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1507 {
1508         struct spi_device *spi;
1509         int rc;
1510         u32 value;
1511
1512         /* Alloc an spi_device */
1513         spi = spi_alloc_device(master);
1514         if (!spi) {
1515                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1516                         nc->full_name);
1517                 rc = -ENOMEM;
1518                 goto err_out;
1519         }
1520
1521         /* Select device driver */
1522         rc = of_modalias_node(nc, spi->modalias,
1523                                 sizeof(spi->modalias));
1524         if (rc < 0) {
1525                 dev_err(&master->dev, "cannot find modalias for %s\n",
1526                         nc->full_name);
1527                 goto err_out;
1528         }
1529
1530         /* Device address */
1531         rc = of_property_read_u32(nc, "reg", &value);
1532         if (rc) {
1533                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1534                         nc->full_name, rc);
1535                 goto err_out;
1536         }
1537         spi->chip_select = value;
1538
1539         /* Mode (clock phase/polarity/etc.) */
1540         if (of_find_property(nc, "spi-cpha", NULL))
1541                 spi->mode |= SPI_CPHA;
1542         if (of_find_property(nc, "spi-cpol", NULL))
1543                 spi->mode |= SPI_CPOL;
1544         if (of_find_property(nc, "spi-cs-high", NULL))
1545                 spi->mode |= SPI_CS_HIGH;
1546         if (of_find_property(nc, "spi-3wire", NULL))
1547                 spi->mode |= SPI_3WIRE;
1548         if (of_find_property(nc, "spi-lsb-first", NULL))
1549                 spi->mode |= SPI_LSB_FIRST;
1550
1551         /* Device DUAL/QUAD mode */
1552         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1553                 switch (value) {
1554                 case 1:
1555                         break;
1556                 case 2:
1557                         spi->mode |= SPI_TX_DUAL;
1558                         break;
1559                 case 4:
1560                         spi->mode |= SPI_TX_QUAD;
1561                         break;
1562                 default:
1563                         dev_warn(&master->dev,
1564                                 "spi-tx-bus-width %d not supported\n",
1565                                 value);
1566                         break;
1567                 }
1568         }
1569
1570         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1571                 switch (value) {
1572                 case 1:
1573                         break;
1574                 case 2:
1575                         spi->mode |= SPI_RX_DUAL;
1576                         break;
1577                 case 4:
1578                         spi->mode |= SPI_RX_QUAD;
1579                         break;
1580                 default:
1581                         dev_warn(&master->dev,
1582                                 "spi-rx-bus-width %d not supported\n",
1583                                 value);
1584                         break;
1585                 }
1586         }
1587
1588         /* Device speed */
1589         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1590         if (rc) {
1591                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1592                         nc->full_name, rc);
1593                 goto err_out;
1594         }
1595         spi->max_speed_hz = value;
1596
1597         /* Store a pointer to the node in the device structure */
1598         of_node_get(nc);
1599         spi->dev.of_node = nc;
1600
1601         /* Register the new device */
1602         rc = spi_add_device(spi);
1603         if (rc) {
1604                 dev_err(&master->dev, "spi_device register error %s\n",
1605                         nc->full_name);
1606                 goto err_out;
1607         }
1608
1609         return spi;
1610
1611 err_out:
1612         spi_dev_put(spi);
1613         return ERR_PTR(rc);
1614 }
1615
1616 /**
1617  * of_register_spi_devices() - Register child devices onto the SPI bus
1618  * @master:     Pointer to spi_master device
1619  *
1620  * Registers an spi_device for each child node of master node which has a 'reg'
1621  * property.
1622  */
1623 static void of_register_spi_devices(struct spi_master *master)
1624 {
1625         struct spi_device *spi;
1626         struct device_node *nc;
1627
1628         if (!master->dev.of_node)
1629                 return;
1630
1631         for_each_available_child_of_node(master->dev.of_node, nc) {
1632                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1633                         continue;
1634                 spi = of_register_spi_device(master, nc);
1635                 if (IS_ERR(spi)) {
1636                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1637                                 nc->full_name);
1638                         of_node_clear_flag(nc, OF_POPULATED);
1639                 }
1640         }
1641 }
1642 #else
1643 static void of_register_spi_devices(struct spi_master *master) { }
1644 #endif
1645
1646 #ifdef CONFIG_ACPI
1647 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1648 {
1649         struct spi_device *spi = data;
1650         struct spi_master *master = spi->master;
1651
1652         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1653                 struct acpi_resource_spi_serialbus *sb;
1654
1655                 sb = &ares->data.spi_serial_bus;
1656                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1657                         /*
1658                          * ACPI DeviceSelection numbering is handled by the
1659                          * host controller driver in Windows and can vary
1660                          * from driver to driver. In Linux we always expect
1661                          * 0 .. max - 1 so we need to ask the driver to
1662                          * translate between the two schemes.
1663                          */
1664                         if (master->fw_translate_cs) {
1665                                 int cs = master->fw_translate_cs(master,
1666                                                 sb->device_selection);
1667                                 if (cs < 0)
1668                                         return cs;
1669                                 spi->chip_select = cs;
1670                         } else {
1671                                 spi->chip_select = sb->device_selection;
1672                         }
1673
1674                         spi->max_speed_hz = sb->connection_speed;
1675
1676                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1677                                 spi->mode |= SPI_CPHA;
1678                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1679                                 spi->mode |= SPI_CPOL;
1680                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1681                                 spi->mode |= SPI_CS_HIGH;
1682                 }
1683         } else if (spi->irq < 0) {
1684                 struct resource r;
1685
1686                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1687                         spi->irq = r.start;
1688         }
1689
1690         /* Always tell the ACPI core to skip this resource */
1691         return 1;
1692 }
1693
1694 static acpi_status acpi_register_spi_device(struct spi_master *master,
1695                                             struct acpi_device *adev)
1696 {
1697         struct list_head resource_list;
1698         struct spi_device *spi;
1699         int ret;
1700
1701         if (acpi_bus_get_status(adev) || !adev->status.present ||
1702             acpi_device_enumerated(adev))
1703                 return AE_OK;
1704
1705         spi = spi_alloc_device(master);
1706         if (!spi) {
1707                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1708                         dev_name(&adev->dev));
1709                 return AE_NO_MEMORY;
1710         }
1711
1712         ACPI_COMPANION_SET(&spi->dev, adev);
1713         spi->irq = -1;
1714
1715         INIT_LIST_HEAD(&resource_list);
1716         ret = acpi_dev_get_resources(adev, &resource_list,
1717                                      acpi_spi_add_resource, spi);
1718         acpi_dev_free_resource_list(&resource_list);
1719
1720         if (ret < 0 || !spi->max_speed_hz) {
1721                 spi_dev_put(spi);
1722                 return AE_OK;
1723         }
1724
1725         if (spi->irq < 0)
1726                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1727
1728         acpi_device_set_enumerated(adev);
1729
1730         adev->power.flags.ignore_parent = true;
1731         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1732         if (spi_add_device(spi)) {
1733                 adev->power.flags.ignore_parent = false;
1734                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1735                         dev_name(&adev->dev));
1736                 spi_dev_put(spi);
1737         }
1738
1739         return AE_OK;
1740 }
1741
1742 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1743                                        void *data, void **return_value)
1744 {
1745         struct spi_master *master = data;
1746         struct acpi_device *adev;
1747
1748         if (acpi_bus_get_device(handle, &adev))
1749                 return AE_OK;
1750
1751         return acpi_register_spi_device(master, adev);
1752 }
1753
1754 static void acpi_register_spi_devices(struct spi_master *master)
1755 {
1756         acpi_status status;
1757         acpi_handle handle;
1758
1759         handle = ACPI_HANDLE(master->dev.parent);
1760         if (!handle)
1761                 return;
1762
1763         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1764                                      acpi_spi_add_device, NULL,
1765                                      master, NULL);
1766         if (ACPI_FAILURE(status))
1767                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1768 }
1769 #else
1770 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1771 #endif /* CONFIG_ACPI */
1772
1773 static void spi_master_release(struct device *dev)
1774 {
1775         struct spi_master *master;
1776
1777         master = container_of(dev, struct spi_master, dev);
1778         kfree(master);
1779 }
1780
1781 static struct class spi_master_class = {
1782         .name           = "spi_master",
1783         .owner          = THIS_MODULE,
1784         .dev_release    = spi_master_release,
1785         .dev_groups     = spi_master_groups,
1786 };
1787
1788
1789 /**
1790  * spi_alloc_master - allocate SPI master controller
1791  * @dev: the controller, possibly using the platform_bus
1792  * @size: how much zeroed driver-private data to allocate; the pointer to this
1793  *      memory is in the driver_data field of the returned device,
1794  *      accessible with spi_master_get_devdata().
1795  * Context: can sleep
1796  *
1797  * This call is used only by SPI master controller drivers, which are the
1798  * only ones directly touching chip registers.  It's how they allocate
1799  * an spi_master structure, prior to calling spi_register_master().
1800  *
1801  * This must be called from context that can sleep.
1802  *
1803  * The caller is responsible for assigning the bus number and initializing
1804  * the master's methods before calling spi_register_master(); and (after errors
1805  * adding the device) calling spi_master_put() to prevent a memory leak.
1806  *
1807  * Return: the SPI master structure on success, else NULL.
1808  */
1809 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1810 {
1811         struct spi_master       *master;
1812
1813         if (!dev)
1814                 return NULL;
1815
1816         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1817         if (!master)
1818                 return NULL;
1819
1820         device_initialize(&master->dev);
1821         master->bus_num = -1;
1822         master->num_chipselect = 1;
1823         master->dev.class = &spi_master_class;
1824         master->dev.parent = dev;
1825         pm_suspend_ignore_children(&master->dev, true);
1826         spi_master_set_devdata(master, &master[1]);
1827
1828         return master;
1829 }
1830 EXPORT_SYMBOL_GPL(spi_alloc_master);
1831
1832 #ifdef CONFIG_OF
1833 static int of_spi_register_master(struct spi_master *master)
1834 {
1835         int nb, i, *cs;
1836         struct device_node *np = master->dev.of_node;
1837
1838         if (!np)
1839                 return 0;
1840
1841         nb = of_gpio_named_count(np, "cs-gpios");
1842         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1843
1844         /* Return error only for an incorrectly formed cs-gpios property */
1845         if (nb == 0 || nb == -ENOENT)
1846                 return 0;
1847         else if (nb < 0)
1848                 return nb;
1849
1850         cs = devm_kzalloc(&master->dev,
1851                           sizeof(int) * master->num_chipselect,
1852                           GFP_KERNEL);
1853         master->cs_gpios = cs;
1854
1855         if (!master->cs_gpios)
1856                 return -ENOMEM;
1857
1858         for (i = 0; i < master->num_chipselect; i++)
1859                 cs[i] = -ENOENT;
1860
1861         for (i = 0; i < nb; i++)
1862                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1863
1864         return 0;
1865 }
1866 #else
1867 static int of_spi_register_master(struct spi_master *master)
1868 {
1869         return 0;
1870 }
1871 #endif
1872
1873 /**
1874  * spi_register_master - register SPI master controller
1875  * @master: initialized master, originally from spi_alloc_master()
1876  * Context: can sleep
1877  *
1878  * SPI master controllers connect to their drivers using some non-SPI bus,
1879  * such as the platform bus.  The final stage of probe() in that code
1880  * includes calling spi_register_master() to hook up to this SPI bus glue.
1881  *
1882  * SPI controllers use board specific (often SOC specific) bus numbers,
1883  * and board-specific addressing for SPI devices combines those numbers
1884  * with chip select numbers.  Since SPI does not directly support dynamic
1885  * device identification, boards need configuration tables telling which
1886  * chip is at which address.
1887  *
1888  * This must be called from context that can sleep.  It returns zero on
1889  * success, else a negative error code (dropping the master's refcount).
1890  * After a successful return, the caller is responsible for calling
1891  * spi_unregister_master().
1892  *
1893  * Return: zero on success, else a negative error code.
1894  */
1895 int spi_register_master(struct spi_master *master)
1896 {
1897         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1898         struct device           *dev = master->dev.parent;
1899         struct boardinfo        *bi;
1900         int                     status = -ENODEV;
1901         int                     dynamic = 0;
1902
1903         if (!dev)
1904                 return -ENODEV;
1905
1906         status = of_spi_register_master(master);
1907         if (status)
1908                 return status;
1909
1910         /* even if it's just one always-selected device, there must
1911          * be at least one chipselect
1912          */
1913         if (master->num_chipselect == 0)
1914                 return -EINVAL;
1915
1916         if ((master->bus_num < 0) && master->dev.of_node)
1917                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1918
1919         /* convention:  dynamically assigned bus IDs count down from the max */
1920         if (master->bus_num < 0) {
1921                 /* FIXME switch to an IDR based scheme, something like
1922                  * I2C now uses, so we can't run out of "dynamic" IDs
1923                  */
1924                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1925                 dynamic = 1;
1926         }
1927
1928         INIT_LIST_HEAD(&master->queue);
1929         spin_lock_init(&master->queue_lock);
1930         spin_lock_init(&master->bus_lock_spinlock);
1931         mutex_init(&master->bus_lock_mutex);
1932         mutex_init(&master->io_mutex);
1933         master->bus_lock_flag = 0;
1934         init_completion(&master->xfer_completion);
1935         if (!master->max_dma_len)
1936                 master->max_dma_len = INT_MAX;
1937
1938         /* register the device, then userspace will see it.
1939          * registration fails if the bus ID is in use.
1940          */
1941         dev_set_name(&master->dev, "spi%u", master->bus_num);
1942         status = device_add(&master->dev);
1943         if (status < 0)
1944                 goto done;
1945         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1946                         dynamic ? " (dynamic)" : "");
1947
1948         /* If we're using a queued driver, start the queue */
1949         if (master->transfer)
1950                 dev_info(dev, "master is unqueued, this is deprecated\n");
1951         else {
1952                 status = spi_master_initialize_queue(master);
1953                 if (status) {
1954                         device_del(&master->dev);
1955                         goto done;
1956                 }
1957         }
1958         /* add statistics */
1959         spin_lock_init(&master->statistics.lock);
1960
1961         mutex_lock(&board_lock);
1962         list_add_tail(&master->list, &spi_master_list);
1963         list_for_each_entry(bi, &board_list, list)
1964                 spi_match_master_to_boardinfo(master, &bi->board_info);
1965         mutex_unlock(&board_lock);
1966
1967         /* Register devices from the device tree and ACPI */
1968         of_register_spi_devices(master);
1969         acpi_register_spi_devices(master);
1970 done:
1971         return status;
1972 }
1973 EXPORT_SYMBOL_GPL(spi_register_master);
1974
1975 static void devm_spi_unregister(struct device *dev, void *res)
1976 {
1977         spi_unregister_master(*(struct spi_master **)res);
1978 }
1979
1980 /**
1981  * dev_spi_register_master - register managed SPI master controller
1982  * @dev:    device managing SPI master
1983  * @master: initialized master, originally from spi_alloc_master()
1984  * Context: can sleep
1985  *
1986  * Register a SPI device as with spi_register_master() which will
1987  * automatically be unregister
1988  *
1989  * Return: zero on success, else a negative error code.
1990  */
1991 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1992 {
1993         struct spi_master **ptr;
1994         int ret;
1995
1996         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1997         if (!ptr)
1998                 return -ENOMEM;
1999
2000         ret = spi_register_master(master);
2001         if (!ret) {
2002                 *ptr = master;
2003                 devres_add(dev, ptr);
2004         } else {
2005                 devres_free(ptr);
2006         }
2007
2008         return ret;
2009 }
2010 EXPORT_SYMBOL_GPL(devm_spi_register_master);
2011
2012 static int __unregister(struct device *dev, void *null)
2013 {
2014         spi_unregister_device(to_spi_device(dev));
2015         return 0;
2016 }
2017
2018 /**
2019  * spi_unregister_master - unregister SPI master controller
2020  * @master: the master being unregistered
2021  * Context: can sleep
2022  *
2023  * This call is used only by SPI master controller drivers, which are the
2024  * only ones directly touching chip registers.
2025  *
2026  * This must be called from context that can sleep.
2027  */
2028 void spi_unregister_master(struct spi_master *master)
2029 {
2030         int dummy;
2031
2032         if (master->queued) {
2033                 if (spi_destroy_queue(master))
2034                         dev_err(&master->dev, "queue remove failed\n");
2035         }
2036
2037         mutex_lock(&board_lock);
2038         list_del(&master->list);
2039         mutex_unlock(&board_lock);
2040
2041         dummy = device_for_each_child(&master->dev, NULL, __unregister);
2042         device_unregister(&master->dev);
2043 }
2044 EXPORT_SYMBOL_GPL(spi_unregister_master);
2045
2046 int spi_master_suspend(struct spi_master *master)
2047 {
2048         int ret;
2049
2050         /* Basically no-ops for non-queued masters */
2051         if (!master->queued)
2052                 return 0;
2053
2054         ret = spi_stop_queue(master);
2055         if (ret)
2056                 dev_err(&master->dev, "queue stop failed\n");
2057
2058         return ret;
2059 }
2060 EXPORT_SYMBOL_GPL(spi_master_suspend);
2061
2062 int spi_master_resume(struct spi_master *master)
2063 {
2064         int ret;
2065
2066         if (!master->queued)
2067                 return 0;
2068
2069         ret = spi_start_queue(master);
2070         if (ret)
2071                 dev_err(&master->dev, "queue restart failed\n");
2072
2073         return ret;
2074 }
2075 EXPORT_SYMBOL_GPL(spi_master_resume);
2076
2077 static int __spi_master_match(struct device *dev, const void *data)
2078 {
2079         struct spi_master *m;
2080         const u16 *bus_num = data;
2081
2082         m = container_of(dev, struct spi_master, dev);
2083         return m->bus_num == *bus_num;
2084 }
2085
2086 /**
2087  * spi_busnum_to_master - look up master associated with bus_num
2088  * @bus_num: the master's bus number
2089  * Context: can sleep
2090  *
2091  * This call may be used with devices that are registered after
2092  * arch init time.  It returns a refcounted pointer to the relevant
2093  * spi_master (which the caller must release), or NULL if there is
2094  * no such master registered.
2095  *
2096  * Return: the SPI master structure on success, else NULL.
2097  */
2098 struct spi_master *spi_busnum_to_master(u16 bus_num)
2099 {
2100         struct device           *dev;
2101         struct spi_master       *master = NULL;
2102
2103         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2104                                 __spi_master_match);
2105         if (dev)
2106                 master = container_of(dev, struct spi_master, dev);
2107         /* reference got in class_find_device */
2108         return master;
2109 }
2110 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2111
2112 /*-------------------------------------------------------------------------*/
2113
2114 /* Core methods for SPI resource management */
2115
2116 /**
2117  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2118  *                 during the processing of a spi_message while using
2119  *                 spi_transfer_one
2120  * @spi:     the spi device for which we allocate memory
2121  * @release: the release code to execute for this resource
2122  * @size:    size to alloc and return
2123  * @gfp:     GFP allocation flags
2124  *
2125  * Return: the pointer to the allocated data
2126  *
2127  * This may get enhanced in the future to allocate from a memory pool
2128  * of the @spi_device or @spi_master to avoid repeated allocations.
2129  */
2130 void *spi_res_alloc(struct spi_device *spi,
2131                     spi_res_release_t release,
2132                     size_t size, gfp_t gfp)
2133 {
2134         struct spi_res *sres;
2135
2136         sres = kzalloc(sizeof(*sres) + size, gfp);
2137         if (!sres)
2138                 return NULL;
2139
2140         INIT_LIST_HEAD(&sres->entry);
2141         sres->release = release;
2142
2143         return sres->data;
2144 }
2145 EXPORT_SYMBOL_GPL(spi_res_alloc);
2146
2147 /**
2148  * spi_res_free - free an spi resource
2149  * @res: pointer to the custom data of a resource
2150  *
2151  */
2152 void spi_res_free(void *res)
2153 {
2154         struct spi_res *sres = container_of(res, struct spi_res, data);
2155
2156         if (!res)
2157                 return;
2158
2159         WARN_ON(!list_empty(&sres->entry));
2160         kfree(sres);
2161 }
2162 EXPORT_SYMBOL_GPL(spi_res_free);
2163
2164 /**
2165  * spi_res_add - add a spi_res to the spi_message
2166  * @message: the spi message
2167  * @res:     the spi_resource
2168  */
2169 void spi_res_add(struct spi_message *message, void *res)
2170 {
2171         struct spi_res *sres = container_of(res, struct spi_res, data);
2172
2173         WARN_ON(!list_empty(&sres->entry));
2174         list_add_tail(&sres->entry, &message->resources);
2175 }
2176 EXPORT_SYMBOL_GPL(spi_res_add);
2177
2178 /**
2179  * spi_res_release - release all spi resources for this message
2180  * @master:  the @spi_master
2181  * @message: the @spi_message
2182  */
2183 void spi_res_release(struct spi_master *master,
2184                      struct spi_message *message)
2185 {
2186         struct spi_res *res;
2187
2188         while (!list_empty(&message->resources)) {
2189                 res = list_last_entry(&message->resources,
2190                                       struct spi_res, entry);
2191
2192                 if (res->release)
2193                         res->release(master, message, res->data);
2194
2195                 list_del(&res->entry);
2196
2197                 kfree(res);
2198         }
2199 }
2200 EXPORT_SYMBOL_GPL(spi_res_release);
2201
2202 /*-------------------------------------------------------------------------*/
2203
2204 /* Core methods for spi_message alterations */
2205
2206 static void __spi_replace_transfers_release(struct spi_master *master,
2207                                             struct spi_message *msg,
2208                                             void *res)
2209 {
2210         struct spi_replaced_transfers *rxfer = res;
2211         size_t i;
2212
2213         /* call extra callback if requested */
2214         if (rxfer->release)
2215                 rxfer->release(master, msg, res);
2216
2217         /* insert replaced transfers back into the message */
2218         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2219
2220         /* remove the formerly inserted entries */
2221         for (i = 0; i < rxfer->inserted; i++)
2222                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2223 }
2224
2225 /**
2226  * spi_replace_transfers - replace transfers with several transfers
2227  *                         and register change with spi_message.resources
2228  * @msg:           the spi_message we work upon
2229  * @xfer_first:    the first spi_transfer we want to replace
2230  * @remove:        number of transfers to remove
2231  * @insert:        the number of transfers we want to insert instead
2232  * @release:       extra release code necessary in some circumstances
2233  * @extradatasize: extra data to allocate (with alignment guarantees
2234  *                 of struct @spi_transfer)
2235  * @gfp:           gfp flags
2236  *
2237  * Returns: pointer to @spi_replaced_transfers,
2238  *          PTR_ERR(...) in case of errors.
2239  */
2240 struct spi_replaced_transfers *spi_replace_transfers(
2241         struct spi_message *msg,
2242         struct spi_transfer *xfer_first,
2243         size_t remove,
2244         size_t insert,
2245         spi_replaced_release_t release,
2246         size_t extradatasize,
2247         gfp_t gfp)
2248 {
2249         struct spi_replaced_transfers *rxfer;
2250         struct spi_transfer *xfer;
2251         size_t i;
2252
2253         /* allocate the structure using spi_res */
2254         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2255                               insert * sizeof(struct spi_transfer)
2256                               + sizeof(struct spi_replaced_transfers)
2257                               + extradatasize,
2258                               gfp);
2259         if (!rxfer)
2260                 return ERR_PTR(-ENOMEM);
2261
2262         /* the release code to invoke before running the generic release */
2263         rxfer->release = release;
2264
2265         /* assign extradata */
2266         if (extradatasize)
2267                 rxfer->extradata =
2268                         &rxfer->inserted_transfers[insert];
2269
2270         /* init the replaced_transfers list */
2271         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2272
2273         /* assign the list_entry after which we should reinsert
2274          * the @replaced_transfers - it may be spi_message.messages!
2275          */
2276         rxfer->replaced_after = xfer_first->transfer_list.prev;
2277
2278         /* remove the requested number of transfers */
2279         for (i = 0; i < remove; i++) {
2280                 /* if the entry after replaced_after it is msg->transfers
2281                  * then we have been requested to remove more transfers
2282                  * than are in the list
2283                  */
2284                 if (rxfer->replaced_after->next == &msg->transfers) {
2285                         dev_err(&msg->spi->dev,
2286                                 "requested to remove more spi_transfers than are available\n");
2287                         /* insert replaced transfers back into the message */
2288                         list_splice(&rxfer->replaced_transfers,
2289                                     rxfer->replaced_after);
2290
2291                         /* free the spi_replace_transfer structure */
2292                         spi_res_free(rxfer);
2293
2294                         /* and return with an error */
2295                         return ERR_PTR(-EINVAL);
2296                 }
2297
2298                 /* remove the entry after replaced_after from list of
2299                  * transfers and add it to list of replaced_transfers
2300                  */
2301                 list_move_tail(rxfer->replaced_after->next,
2302                                &rxfer->replaced_transfers);
2303         }
2304
2305         /* create copy of the given xfer with identical settings
2306          * based on the first transfer to get removed
2307          */
2308         for (i = 0; i < insert; i++) {
2309                 /* we need to run in reverse order */
2310                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2311
2312                 /* copy all spi_transfer data */
2313                 memcpy(xfer, xfer_first, sizeof(*xfer));
2314
2315                 /* add to list */
2316                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2317
2318                 /* clear cs_change and delay_usecs for all but the last */
2319                 if (i) {
2320                         xfer->cs_change = false;
2321                         xfer->delay_usecs = 0;
2322                 }
2323         }
2324
2325         /* set up inserted */
2326         rxfer->inserted = insert;
2327
2328         /* and register it with spi_res/spi_message */
2329         spi_res_add(msg, rxfer);
2330
2331         return rxfer;
2332 }
2333 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2334
2335 static int __spi_split_transfer_maxsize(struct spi_master *master,
2336                                         struct spi_message *msg,
2337                                         struct spi_transfer **xferp,
2338                                         size_t maxsize,
2339                                         gfp_t gfp)
2340 {
2341         struct spi_transfer *xfer = *xferp, *xfers;
2342         struct spi_replaced_transfers *srt;
2343         size_t offset;
2344         size_t count, i;
2345
2346         /* warn once about this fact that we are splitting a transfer */
2347         dev_warn_once(&msg->spi->dev,
2348                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2349                       xfer->len, maxsize);
2350
2351         /* calculate how many we have to replace */
2352         count = DIV_ROUND_UP(xfer->len, maxsize);
2353
2354         /* create replacement */
2355         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2356         if (IS_ERR(srt))
2357                 return PTR_ERR(srt);
2358         xfers = srt->inserted_transfers;
2359
2360         /* now handle each of those newly inserted spi_transfers
2361          * note that the replacements spi_transfers all are preset
2362          * to the same values as *xferp, so tx_buf, rx_buf and len
2363          * are all identical (as well as most others)
2364          * so we just have to fix up len and the pointers.
2365          *
2366          * this also includes support for the depreciated
2367          * spi_message.is_dma_mapped interface
2368          */
2369
2370         /* the first transfer just needs the length modified, so we
2371          * run it outside the loop
2372          */
2373         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2374
2375         /* all the others need rx_buf/tx_buf also set */
2376         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2377                 /* update rx_buf, tx_buf and dma */
2378                 if (xfers[i].rx_buf)
2379                         xfers[i].rx_buf += offset;
2380                 if (xfers[i].rx_dma)
2381                         xfers[i].rx_dma += offset;
2382                 if (xfers[i].tx_buf)
2383                         xfers[i].tx_buf += offset;
2384                 if (xfers[i].tx_dma)
2385                         xfers[i].tx_dma += offset;
2386
2387                 /* update length */
2388                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2389         }
2390
2391         /* we set up xferp to the last entry we have inserted,
2392          * so that we skip those already split transfers
2393          */
2394         *xferp = &xfers[count - 1];
2395
2396         /* increment statistics counters */
2397         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2398                                        transfers_split_maxsize);
2399         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2400                                        transfers_split_maxsize);
2401
2402         return 0;
2403 }
2404
2405 /**
2406  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2407  *                              when an individual transfer exceeds a
2408  *                              certain size
2409  * @master:    the @spi_master for this transfer
2410  * @msg:   the @spi_message to transform
2411  * @maxsize:  the maximum when to apply this
2412  * @gfp: GFP allocation flags
2413  *
2414  * Return: status of transformation
2415  */
2416 int spi_split_transfers_maxsize(struct spi_master *master,
2417                                 struct spi_message *msg,
2418                                 size_t maxsize,
2419                                 gfp_t gfp)
2420 {
2421         struct spi_transfer *xfer;
2422         int ret;
2423
2424         /* iterate over the transfer_list,
2425          * but note that xfer is advanced to the last transfer inserted
2426          * to avoid checking sizes again unnecessarily (also xfer does
2427          * potentiall belong to a different list by the time the
2428          * replacement has happened
2429          */
2430         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2431                 if (xfer->len > maxsize) {
2432                         ret = __spi_split_transfer_maxsize(
2433                                 master, msg, &xfer, maxsize, gfp);
2434                         if (ret)
2435                                 return ret;
2436                 }
2437         }
2438
2439         return 0;
2440 }
2441 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2442
2443 /*-------------------------------------------------------------------------*/
2444
2445 /* Core methods for SPI master protocol drivers.  Some of the
2446  * other core methods are currently defined as inline functions.
2447  */
2448
2449 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2450 {
2451         if (master->bits_per_word_mask) {
2452                 /* Only 32 bits fit in the mask */
2453                 if (bits_per_word > 32)
2454                         return -EINVAL;
2455                 if (!(master->bits_per_word_mask &
2456                                 SPI_BPW_MASK(bits_per_word)))
2457                         return -EINVAL;
2458         }
2459
2460         return 0;
2461 }
2462
2463 /**
2464  * spi_setup - setup SPI mode and clock rate
2465  * @spi: the device whose settings are being modified
2466  * Context: can sleep, and no requests are queued to the device
2467  *
2468  * SPI protocol drivers may need to update the transfer mode if the
2469  * device doesn't work with its default.  They may likewise need
2470  * to update clock rates or word sizes from initial values.  This function
2471  * changes those settings, and must be called from a context that can sleep.
2472  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2473  * effect the next time the device is selected and data is transferred to
2474  * or from it.  When this function returns, the spi device is deselected.
2475  *
2476  * Note that this call will fail if the protocol driver specifies an option
2477  * that the underlying controller or its driver does not support.  For
2478  * example, not all hardware supports wire transfers using nine bit words,
2479  * LSB-first wire encoding, or active-high chipselects.
2480  *
2481  * Return: zero on success, else a negative error code.
2482  */
2483 int spi_setup(struct spi_device *spi)
2484 {
2485         unsigned        bad_bits, ugly_bits;
2486         int             status;
2487
2488         /* check mode to prevent that DUAL and QUAD set at the same time
2489          */
2490         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2491                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2492                 dev_err(&spi->dev,
2493                 "setup: can not select dual and quad at the same time\n");
2494                 return -EINVAL;
2495         }
2496         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2497          */
2498         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2499                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2500                 return -EINVAL;
2501         /* help drivers fail *cleanly* when they need options
2502          * that aren't supported with their current master
2503          */
2504         bad_bits = spi->mode & ~spi->master->mode_bits;
2505         ugly_bits = bad_bits &
2506                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2507         if (ugly_bits) {
2508                 dev_warn(&spi->dev,
2509                          "setup: ignoring unsupported mode bits %x\n",
2510                          ugly_bits);
2511                 spi->mode &= ~ugly_bits;
2512                 bad_bits &= ~ugly_bits;
2513         }
2514         if (bad_bits) {
2515                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2516                         bad_bits);
2517                 return -EINVAL;
2518         }
2519
2520         if (!spi->bits_per_word)
2521                 spi->bits_per_word = 8;
2522
2523         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2524         if (status)
2525                 return status;
2526
2527         if (!spi->max_speed_hz)
2528                 spi->max_speed_hz = spi->master->max_speed_hz;
2529
2530         if (spi->master->setup)
2531                 status = spi->master->setup(spi);
2532
2533         spi_set_cs(spi, false);
2534
2535         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2536                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2537                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2538                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2539                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2540                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2541                         spi->bits_per_word, spi->max_speed_hz,
2542                         status);
2543
2544         return status;
2545 }
2546 EXPORT_SYMBOL_GPL(spi_setup);
2547
2548 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2549 {
2550         struct spi_master *master = spi->master;
2551         struct spi_transfer *xfer;
2552         int w_size;
2553
2554         if (list_empty(&message->transfers))
2555                 return -EINVAL;
2556
2557         /* Half-duplex links include original MicroWire, and ones with
2558          * only one data pin like SPI_3WIRE (switches direction) or where
2559          * either MOSI or MISO is missing.  They can also be caused by
2560          * software limitations.
2561          */
2562         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2563                         || (spi->mode & SPI_3WIRE)) {
2564                 unsigned flags = master->flags;
2565
2566                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2567                         if (xfer->rx_buf && xfer->tx_buf)
2568                                 return -EINVAL;
2569                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2570                                 return -EINVAL;
2571                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2572                                 return -EINVAL;
2573                 }
2574         }
2575
2576         /**
2577          * Set transfer bits_per_word and max speed as spi device default if
2578          * it is not set for this transfer.
2579          * Set transfer tx_nbits and rx_nbits as single transfer default
2580          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2581          */
2582         message->frame_length = 0;
2583         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2584                 message->frame_length += xfer->len;
2585                 if (!xfer->bits_per_word)
2586                         xfer->bits_per_word = spi->bits_per_word;
2587
2588                 if (!xfer->speed_hz)
2589                         xfer->speed_hz = spi->max_speed_hz;
2590                 if (!xfer->speed_hz)
2591                         xfer->speed_hz = master->max_speed_hz;
2592
2593                 if (master->max_speed_hz &&
2594                     xfer->speed_hz > master->max_speed_hz)
2595                         xfer->speed_hz = master->max_speed_hz;
2596
2597                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2598                         return -EINVAL;
2599
2600                 /*
2601                  * SPI transfer length should be multiple of SPI word size
2602                  * where SPI word size should be power-of-two multiple
2603                  */
2604                 if (xfer->bits_per_word <= 8)
2605                         w_size = 1;
2606                 else if (xfer->bits_per_word <= 16)
2607                         w_size = 2;
2608                 else
2609                         w_size = 4;
2610
2611                 /* No partial transfers accepted */
2612                 if (xfer->len % w_size)
2613                         return -EINVAL;
2614
2615                 if (xfer->speed_hz && master->min_speed_hz &&
2616                     xfer->speed_hz < master->min_speed_hz)
2617                         return -EINVAL;
2618
2619                 if (xfer->tx_buf && !xfer->tx_nbits)
2620                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2621                 if (xfer->rx_buf && !xfer->rx_nbits)
2622                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2623                 /* check transfer tx/rx_nbits:
2624                  * 1. check the value matches one of single, dual and quad
2625                  * 2. check tx/rx_nbits match the mode in spi_device
2626                  */
2627                 if (xfer->tx_buf) {
2628                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2629                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2630                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2631                                 return -EINVAL;
2632                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2633                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2634                                 return -EINVAL;
2635                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2636                                 !(spi->mode & SPI_TX_QUAD))
2637                                 return -EINVAL;
2638                 }
2639                 /* check transfer rx_nbits */
2640                 if (xfer->rx_buf) {
2641                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2642                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2643                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2644                                 return -EINVAL;
2645                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2646                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2647                                 return -EINVAL;
2648                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2649                                 !(spi->mode & SPI_RX_QUAD))
2650                                 return -EINVAL;
2651                 }
2652         }
2653
2654         message->status = -EINPROGRESS;
2655
2656         return 0;
2657 }
2658
2659 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2660 {
2661         struct spi_master *master = spi->master;
2662
2663         message->spi = spi;
2664
2665         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2666         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2667
2668         trace_spi_message_submit(message);
2669
2670         return master->transfer(spi, message);
2671 }
2672
2673 /**
2674  * spi_async - asynchronous SPI transfer
2675  * @spi: device with which data will be exchanged
2676  * @message: describes the data transfers, including completion callback
2677  * Context: any (irqs may be blocked, etc)
2678  *
2679  * This call may be used in_irq and other contexts which can't sleep,
2680  * as well as from task contexts which can sleep.
2681  *
2682  * The completion callback is invoked in a context which can't sleep.
2683  * Before that invocation, the value of message->status is undefined.
2684  * When the callback is issued, message->status holds either zero (to
2685  * indicate complete success) or a negative error code.  After that
2686  * callback returns, the driver which issued the transfer request may
2687  * deallocate the associated memory; it's no longer in use by any SPI
2688  * core or controller driver code.
2689  *
2690  * Note that although all messages to a spi_device are handled in
2691  * FIFO order, messages may go to different devices in other orders.
2692  * Some device might be higher priority, or have various "hard" access
2693  * time requirements, for example.
2694  *
2695  * On detection of any fault during the transfer, processing of
2696  * the entire message is aborted, and the device is deselected.
2697  * Until returning from the associated message completion callback,
2698  * no other spi_message queued to that device will be processed.
2699  * (This rule applies equally to all the synchronous transfer calls,
2700  * which are wrappers around this core asynchronous primitive.)
2701  *
2702  * Return: zero on success, else a negative error code.
2703  */
2704 int spi_async(struct spi_device *spi, struct spi_message *message)
2705 {
2706         struct spi_master *master = spi->master;
2707         int ret;
2708         unsigned long flags;
2709
2710         ret = __spi_validate(spi, message);
2711         if (ret != 0)
2712                 return ret;
2713
2714         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2715
2716         if (master->bus_lock_flag)
2717                 ret = -EBUSY;
2718         else
2719                 ret = __spi_async(spi, message);
2720
2721         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2722
2723         return ret;
2724 }
2725 EXPORT_SYMBOL_GPL(spi_async);
2726
2727 /**
2728  * spi_async_locked - version of spi_async with exclusive bus usage
2729  * @spi: device with which data will be exchanged
2730  * @message: describes the data transfers, including completion callback
2731  * Context: any (irqs may be blocked, etc)
2732  *
2733  * This call may be used in_irq and other contexts which can't sleep,
2734  * as well as from task contexts which can sleep.
2735  *
2736  * The completion callback is invoked in a context which can't sleep.
2737  * Before that invocation, the value of message->status is undefined.
2738  * When the callback is issued, message->status holds either zero (to
2739  * indicate complete success) or a negative error code.  After that
2740  * callback returns, the driver which issued the transfer request may
2741  * deallocate the associated memory; it's no longer in use by any SPI
2742  * core or controller driver code.
2743  *
2744  * Note that although all messages to a spi_device are handled in
2745  * FIFO order, messages may go to different devices in other orders.
2746  * Some device might be higher priority, or have various "hard" access
2747  * time requirements, for example.
2748  *
2749  * On detection of any fault during the transfer, processing of
2750  * the entire message is aborted, and the device is deselected.
2751  * Until returning from the associated message completion callback,
2752  * no other spi_message queued to that device will be processed.
2753  * (This rule applies equally to all the synchronous transfer calls,
2754  * which are wrappers around this core asynchronous primitive.)
2755  *
2756  * Return: zero on success, else a negative error code.
2757  */
2758 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2759 {
2760         struct spi_master *master = spi->master;
2761         int ret;
2762         unsigned long flags;
2763
2764         ret = __spi_validate(spi, message);
2765         if (ret != 0)
2766                 return ret;
2767
2768         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2769
2770         ret = __spi_async(spi, message);
2771
2772         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2773
2774         return ret;
2775
2776 }
2777 EXPORT_SYMBOL_GPL(spi_async_locked);
2778
2779
2780 int spi_flash_read(struct spi_device *spi,
2781                    struct spi_flash_read_message *msg)
2782
2783 {
2784         struct spi_master *master = spi->master;
2785         struct device *rx_dev = NULL;
2786         int ret;
2787
2788         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2789              msg->addr_nbits == SPI_NBITS_DUAL) &&
2790             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2791                 return -EINVAL;
2792         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2793              msg->addr_nbits == SPI_NBITS_QUAD) &&
2794             !(spi->mode & SPI_TX_QUAD))
2795                 return -EINVAL;
2796         if (msg->data_nbits == SPI_NBITS_DUAL &&
2797             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2798                 return -EINVAL;
2799         if (msg->data_nbits == SPI_NBITS_QUAD &&
2800             !(spi->mode &  SPI_RX_QUAD))
2801                 return -EINVAL;
2802
2803         if (master->auto_runtime_pm) {
2804                 ret = pm_runtime_get_sync(master->dev.parent);
2805                 if (ret < 0) {
2806                         dev_err(&master->dev, "Failed to power device: %d\n",
2807                                 ret);
2808                         return ret;
2809                 }
2810         }
2811
2812         mutex_lock(&master->bus_lock_mutex);
2813         mutex_lock(&master->io_mutex);
2814         if (master->dma_rx) {
2815                 rx_dev = master->dma_rx->device->dev;
2816                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2817                                   msg->buf, msg->len,
2818                                   DMA_FROM_DEVICE);
2819                 if (!ret)
2820                         msg->cur_msg_mapped = true;
2821         }
2822         ret = master->spi_flash_read(spi, msg);
2823         if (msg->cur_msg_mapped)
2824                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2825                               DMA_FROM_DEVICE);
2826         mutex_unlock(&master->io_mutex);
2827         mutex_unlock(&master->bus_lock_mutex);
2828
2829         if (master->auto_runtime_pm)
2830                 pm_runtime_put(master->dev.parent);
2831
2832         return ret;
2833 }
2834 EXPORT_SYMBOL_GPL(spi_flash_read);
2835
2836 /*-------------------------------------------------------------------------*/
2837
2838 /* Utility methods for SPI master protocol drivers, layered on
2839  * top of the core.  Some other utility methods are defined as
2840  * inline functions.
2841  */
2842
2843 static void spi_complete(void *arg)
2844 {
2845         complete(arg);
2846 }
2847
2848 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2849 {
2850         DECLARE_COMPLETION_ONSTACK(done);
2851         int status;
2852         struct spi_master *master = spi->master;
2853         unsigned long flags;
2854
2855         status = __spi_validate(spi, message);
2856         if (status != 0)
2857                 return status;
2858
2859         message->complete = spi_complete;
2860         message->context = &done;
2861         message->spi = spi;
2862
2863         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2864         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2865
2866         /* If we're not using the legacy transfer method then we will
2867          * try to transfer in the calling context so special case.
2868          * This code would be less tricky if we could remove the
2869          * support for driver implemented message queues.
2870          */
2871         if (master->transfer == spi_queued_transfer) {
2872                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2873
2874                 trace_spi_message_submit(message);
2875
2876                 status = __spi_queued_transfer(spi, message, false);
2877
2878                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2879         } else {
2880                 status = spi_async_locked(spi, message);
2881         }
2882
2883         if (status == 0) {
2884                 /* Push out the messages in the calling context if we
2885                  * can.
2886                  */
2887                 if (master->transfer == spi_queued_transfer) {
2888                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2889                                                        spi_sync_immediate);
2890                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2891                                                        spi_sync_immediate);
2892                         __spi_pump_messages(master, false);
2893                 }
2894
2895                 wait_for_completion(&done);
2896                 status = message->status;
2897         }
2898         message->context = NULL;
2899         return status;
2900 }
2901
2902 /**
2903  * spi_sync - blocking/synchronous SPI data transfers
2904  * @spi: device with which data will be exchanged
2905  * @message: describes the data transfers
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.  Low-overhead controller
2910  * drivers may DMA directly into and out of the message buffers.
2911  *
2912  * Note that the SPI device's chip select is active during the message,
2913  * and then is normally disabled between messages.  Drivers for some
2914  * frequently-used devices may want to minimize costs of selecting a chip,
2915  * by leaving it selected in anticipation that the next message will go
2916  * to the same chip.  (That may increase power usage.)
2917  *
2918  * Also, the caller is guaranteeing that the memory associated with the
2919  * message will not be freed before this call returns.
2920  *
2921  * Return: zero on success, else a negative error code.
2922  */
2923 int spi_sync(struct spi_device *spi, struct spi_message *message)
2924 {
2925         int ret;
2926
2927         mutex_lock(&spi->master->bus_lock_mutex);
2928         ret = __spi_sync(spi, message);
2929         mutex_unlock(&spi->master->bus_lock_mutex);
2930
2931         return ret;
2932 }
2933 EXPORT_SYMBOL_GPL(spi_sync);
2934
2935 /**
2936  * spi_sync_locked - version of spi_sync with exclusive bus usage
2937  * @spi: device with which data will be exchanged
2938  * @message: describes the data transfers
2939  * Context: can sleep
2940  *
2941  * This call may only be used from a context that may sleep.  The sleep
2942  * is non-interruptible, and has no timeout.  Low-overhead controller
2943  * drivers may DMA directly into and out of the message buffers.
2944  *
2945  * This call should be used by drivers that require exclusive access to the
2946  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2947  * be released by a spi_bus_unlock call when the exclusive access is over.
2948  *
2949  * Return: zero on success, else a negative error code.
2950  */
2951 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2952 {
2953         return __spi_sync(spi, message);
2954 }
2955 EXPORT_SYMBOL_GPL(spi_sync_locked);
2956
2957 /**
2958  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2959  * @master: SPI bus master that should be locked for exclusive bus access
2960  * Context: can sleep
2961  *
2962  * This call may only be used from a context that may sleep.  The sleep
2963  * is non-interruptible, and has no timeout.
2964  *
2965  * This call should be used by drivers that require exclusive access to the
2966  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2967  * exclusive access is over. Data transfer must be done by spi_sync_locked
2968  * and spi_async_locked calls when the SPI bus lock is held.
2969  *
2970  * Return: always zero.
2971  */
2972 int spi_bus_lock(struct spi_master *master)
2973 {
2974         unsigned long flags;
2975
2976         mutex_lock(&master->bus_lock_mutex);
2977
2978         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2979         master->bus_lock_flag = 1;
2980         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2981
2982         /* mutex remains locked until spi_bus_unlock is called */
2983
2984         return 0;
2985 }
2986 EXPORT_SYMBOL_GPL(spi_bus_lock);
2987
2988 /**
2989  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2990  * @master: SPI bus master that was locked for exclusive bus access
2991  * Context: can sleep
2992  *
2993  * This call may only be used from a context that may sleep.  The sleep
2994  * is non-interruptible, and has no timeout.
2995  *
2996  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2997  * call.
2998  *
2999  * Return: always zero.
3000  */
3001 int spi_bus_unlock(struct spi_master *master)
3002 {
3003         master->bus_lock_flag = 0;
3004
3005         mutex_unlock(&master->bus_lock_mutex);
3006
3007         return 0;
3008 }
3009 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3010
3011 /* portable code must never pass more than 32 bytes */
3012 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3013
3014 static u8       *buf;
3015
3016 /**
3017  * spi_write_then_read - SPI synchronous write followed by read
3018  * @spi: device with which data will be exchanged
3019  * @txbuf: data to be written (need not be dma-safe)
3020  * @n_tx: size of txbuf, in bytes
3021  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3022  * @n_rx: size of rxbuf, in bytes
3023  * Context: can sleep
3024  *
3025  * This performs a half duplex MicroWire style transaction with the
3026  * device, sending txbuf and then reading rxbuf.  The return value
3027  * is zero for success, else a negative errno status code.
3028  * This call may only be used from a context that may sleep.
3029  *
3030  * Parameters to this routine are always copied using a small buffer;
3031  * portable code should never use this for more than 32 bytes.
3032  * Performance-sensitive or bulk transfer code should instead use
3033  * spi_{async,sync}() calls with dma-safe buffers.
3034  *
3035  * Return: zero on success, else a negative error code.
3036  */
3037 int spi_write_then_read(struct spi_device *spi,
3038                 const void *txbuf, unsigned n_tx,
3039                 void *rxbuf, unsigned n_rx)
3040 {
3041         static DEFINE_MUTEX(lock);
3042
3043         int                     status;
3044         struct spi_message      message;
3045         struct spi_transfer     x[2];
3046         u8                      *local_buf;
3047
3048         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3049          * copying here, (as a pure convenience thing), but we can
3050          * keep heap costs out of the hot path unless someone else is
3051          * using the pre-allocated buffer or the transfer is too large.
3052          */
3053         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3054                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3055                                     GFP_KERNEL | GFP_DMA);
3056                 if (!local_buf)
3057                         return -ENOMEM;
3058         } else {
3059                 local_buf = buf;
3060         }
3061
3062         spi_message_init(&message);
3063         memset(x, 0, sizeof(x));
3064         if (n_tx) {
3065                 x[0].len = n_tx;
3066                 spi_message_add_tail(&x[0], &message);
3067         }
3068         if (n_rx) {
3069                 x[1].len = n_rx;
3070                 spi_message_add_tail(&x[1], &message);
3071         }
3072
3073         memcpy(local_buf, txbuf, n_tx);
3074         x[0].tx_buf = local_buf;
3075         x[1].rx_buf = local_buf + n_tx;
3076
3077         /* do the i/o */
3078         status = spi_sync(spi, &message);
3079         if (status == 0)
3080                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3081
3082         if (x[0].tx_buf == buf)
3083                 mutex_unlock(&lock);
3084         else
3085                 kfree(local_buf);
3086
3087         return status;
3088 }
3089 EXPORT_SYMBOL_GPL(spi_write_then_read);
3090
3091 /*-------------------------------------------------------------------------*/
3092
3093 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3094 static int __spi_of_device_match(struct device *dev, void *data)
3095 {
3096         return dev->of_node == data;
3097 }
3098
3099 /* must call put_device() when done with returned spi_device device */
3100 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3101 {
3102         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3103                                                 __spi_of_device_match);
3104         return dev ? to_spi_device(dev) : NULL;
3105 }
3106
3107 static int __spi_of_master_match(struct device *dev, const void *data)
3108 {
3109         return dev->of_node == data;
3110 }
3111
3112 /* the spi masters are not using spi_bus, so we find it with another way */
3113 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3114 {
3115         struct device *dev;
3116
3117         dev = class_find_device(&spi_master_class, NULL, node,
3118                                 __spi_of_master_match);
3119         if (!dev)
3120                 return NULL;
3121
3122         /* reference got in class_find_device */
3123         return container_of(dev, struct spi_master, dev);
3124 }
3125
3126 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3127                          void *arg)
3128 {
3129         struct of_reconfig_data *rd = arg;
3130         struct spi_master *master;
3131         struct spi_device *spi;
3132
3133         switch (of_reconfig_get_state_change(action, arg)) {
3134         case OF_RECONFIG_CHANGE_ADD:
3135                 master = of_find_spi_master_by_node(rd->dn->parent);
3136                 if (master == NULL)
3137                         return NOTIFY_OK;       /* not for us */
3138
3139                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3140                         put_device(&master->dev);
3141                         return NOTIFY_OK;
3142                 }
3143
3144                 spi = of_register_spi_device(master, rd->dn);
3145                 put_device(&master->dev);
3146
3147                 if (IS_ERR(spi)) {
3148                         pr_err("%s: failed to create for '%s'\n",
3149                                         __func__, rd->dn->full_name);
3150                         of_node_clear_flag(rd->dn, OF_POPULATED);
3151                         return notifier_from_errno(PTR_ERR(spi));
3152                 }
3153                 break;
3154
3155         case OF_RECONFIG_CHANGE_REMOVE:
3156                 /* already depopulated? */
3157                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3158                         return NOTIFY_OK;
3159
3160                 /* find our device by node */
3161                 spi = of_find_spi_device_by_node(rd->dn);
3162                 if (spi == NULL)
3163                         return NOTIFY_OK;       /* no? not meant for us */
3164
3165                 /* unregister takes one ref away */
3166                 spi_unregister_device(spi);
3167
3168                 /* and put the reference of the find */
3169                 put_device(&spi->dev);
3170                 break;
3171         }
3172
3173         return NOTIFY_OK;
3174 }
3175
3176 static struct notifier_block spi_of_notifier = {
3177         .notifier_call = of_spi_notify,
3178 };
3179 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3180 extern struct notifier_block spi_of_notifier;
3181 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3182
3183 #if IS_ENABLED(CONFIG_ACPI)
3184 static int spi_acpi_master_match(struct device *dev, const void *data)
3185 {
3186         return ACPI_COMPANION(dev->parent) == data;
3187 }
3188
3189 static int spi_acpi_device_match(struct device *dev, void *data)
3190 {
3191         return ACPI_COMPANION(dev) == data;
3192 }
3193
3194 static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3195 {
3196         struct device *dev;
3197
3198         dev = class_find_device(&spi_master_class, NULL, adev,
3199                                 spi_acpi_master_match);
3200         if (!dev)
3201                 return NULL;
3202
3203         return container_of(dev, struct spi_master, dev);
3204 }
3205
3206 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3207 {
3208         struct device *dev;
3209
3210         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3211
3212         return dev ? to_spi_device(dev) : NULL;
3213 }
3214
3215 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3216                            void *arg)
3217 {
3218         struct acpi_device *adev = arg;
3219         struct spi_master *master;
3220         struct spi_device *spi;
3221
3222         switch (value) {
3223         case ACPI_RECONFIG_DEVICE_ADD:
3224                 master = acpi_spi_find_master_by_adev(adev->parent);
3225                 if (!master)
3226                         break;
3227
3228                 acpi_register_spi_device(master, adev);
3229                 put_device(&master->dev);
3230                 break;
3231         case ACPI_RECONFIG_DEVICE_REMOVE:
3232                 if (!acpi_device_enumerated(adev))
3233                         break;
3234
3235                 spi = acpi_spi_find_device_by_adev(adev);
3236                 if (!spi)
3237                         break;
3238
3239                 spi_unregister_device(spi);
3240                 put_device(&spi->dev);
3241                 break;
3242         }
3243
3244         return NOTIFY_OK;
3245 }
3246
3247 static struct notifier_block spi_acpi_notifier = {
3248         .notifier_call = acpi_spi_notify,
3249 };
3250 #else
3251 extern struct notifier_block spi_acpi_notifier;
3252 #endif
3253
3254 static int __init spi_init(void)
3255 {
3256         int     status;
3257
3258         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3259         if (!buf) {
3260                 status = -ENOMEM;
3261                 goto err0;
3262         }
3263
3264         status = bus_register(&spi_bus_type);
3265         if (status < 0)
3266                 goto err1;
3267
3268         status = class_register(&spi_master_class);
3269         if (status < 0)
3270                 goto err2;
3271
3272         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3273                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3274         if (IS_ENABLED(CONFIG_ACPI))
3275                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3276
3277         return 0;
3278
3279 err2:
3280         bus_unregister(&spi_bus_type);
3281 err1:
3282         kfree(buf);
3283         buf = NULL;
3284 err0:
3285         return status;
3286 }
3287
3288 /* board_info is normally registered in arch_initcall(),
3289  * but even essential drivers wait till later
3290  *
3291  * REVISIT only boardinfo really needs static linking. the rest (device and
3292  * driver registration) _could_ be dynamically linked (modular) ... costs
3293  * include needing to have boardinfo data structures be much more public.
3294  */
3295 postcore_initcall(spi_init);
3296