linux/drivers/staging/comedi/drivers.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 *  module/drivers.c
   4 *  functions for manipulating drivers
   5 *
   6 *  COMEDI - Linux Control and Measurement Device Interface
   7 *  Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
   8 *  Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
   9 */
  10
  11#include <linux/device.h>
  12#include <linux/module.h>
  13#include <linux/errno.h>
  14#include <linux/kernel.h>
  15#include <linux/ioport.h>
  16#include <linux/slab.h>
  17#include <linux/dma-direction.h>
  18#include <linux/interrupt.h>
  19#include <linux/firmware.h>
  20
  21#include "comedidev.h"
  22#include "comedi_internal.h"
  23
  24struct comedi_driver *comedi_drivers;
  25/* protects access to comedi_drivers */
  26DEFINE_MUTEX(comedi_drivers_list_lock);
  27
  28/**
  29 * comedi_set_hw_dev() - Set hardware device associated with COMEDI device
  30 * @dev: COMEDI device.
  31 * @hw_dev: Hardware device.
  32 *
  33 * For automatically configured COMEDI devices (resulting from a call to
  34 * comedi_auto_config() or one of its wrappers from the low-level COMEDI
  35 * driver), comedi_set_hw_dev() is called automatically by the COMEDI core
  36 * to associate the COMEDI device with the hardware device.  It can also be
  37 * called directly by "legacy" low-level COMEDI drivers that rely on the
  38 * %COMEDI_DEVCONFIG ioctl to configure the hardware as long as the hardware
  39 * has a &struct device.
  40 *
  41 * If @dev->hw_dev is NULL, it gets a reference to @hw_dev and sets
  42 * @dev->hw_dev, otherwise, it does nothing.  Calling it multiple times
  43 * with the same hardware device is not considered an error.  If it gets
  44 * a reference to the hardware device, it will be automatically 'put' when
  45 * the device is detached from COMEDI.
  46 *
  47 * Returns 0 if @dev->hw_dev was NULL or the same as @hw_dev, otherwise
  48 * returns -EEXIST.
  49 */
  50int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev)
  51{
  52        if (hw_dev == dev->hw_dev)
  53                return 0;
  54        if (dev->hw_dev)
  55                return -EEXIST;
  56        dev->hw_dev = get_device(hw_dev);
  57        return 0;
  58}
  59EXPORT_SYMBOL_GPL(comedi_set_hw_dev);
  60
  61static void comedi_clear_hw_dev(struct comedi_device *dev)
  62{
  63        put_device(dev->hw_dev);
  64        dev->hw_dev = NULL;
  65}
  66
  67/**
  68 * comedi_alloc_devpriv() - Allocate memory for the device private data
  69 * @dev: COMEDI device.
  70 * @size: Size of the memory to allocate.
  71 *
  72 * The allocated memory is zero-filled.  @dev->private points to it on
  73 * return.  The memory will be automatically freed when the COMEDI device is
  74 * "detached".
  75 *
  76 * Returns a pointer to the allocated memory, or NULL on failure.
  77 */
  78void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size)
  79{
  80        dev->private = kzalloc(size, GFP_KERNEL);
  81        return dev->private;
  82}
  83EXPORT_SYMBOL_GPL(comedi_alloc_devpriv);
  84
  85/**
  86 * comedi_alloc_subdevices() - Allocate subdevices for COMEDI device
  87 * @dev: COMEDI device.
  88 * @num_subdevices: Number of subdevices to allocate.
  89 *
  90 * Allocates and initializes an array of &struct comedi_subdevice for the
  91 * COMEDI device.  If successful, sets @dev->subdevices to point to the
  92 * first one and @dev->n_subdevices to the number.
  93 *
  94 * Returns 0 on success, -EINVAL if @num_subdevices is < 1, or -ENOMEM if
  95 * failed to allocate the memory.
  96 */
  97int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
  98{
  99        struct comedi_subdevice *s;
 100        int i;
 101
 102        if (num_subdevices < 1)
 103                return -EINVAL;
 104
 105        s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
 106        if (!s)
 107                return -ENOMEM;
 108        dev->subdevices = s;
 109        dev->n_subdevices = num_subdevices;
 110
 111        for (i = 0; i < num_subdevices; ++i) {
 112                s = &dev->subdevices[i];
 113                s->device = dev;
 114                s->index = i;
 115                s->async_dma_dir = DMA_NONE;
 116                spin_lock_init(&s->spin_lock);
 117                s->minor = -1;
 118        }
 119        return 0;
 120}
 121EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
 122
 123/**
 124 * comedi_alloc_subdev_readback() - Allocate memory for the subdevice readback
 125 * @s: COMEDI subdevice.
 126 *
 127 * This is called by low-level COMEDI drivers to allocate an array to record
 128 * the last values written to a subdevice's analog output channels (at least
 129 * by the %INSN_WRITE instruction), to allow them to be read back by an
 130 * %INSN_READ instruction.  It also provides a default handler for the
 131 * %INSN_READ instruction unless one has already been set.
 132 *
 133 * On success, @s->readback points to the first element of the array, which
 134 * is zero-filled.  The low-level driver is responsible for updating its
 135 * contents.  @s->insn_read will be set to comedi_readback_insn_read()
 136 * unless it is already non-NULL.
 137 *
 138 * Returns 0 on success, -EINVAL if the subdevice has no channels, or
 139 * -ENOMEM on allocation failure.
 140 */
 141int comedi_alloc_subdev_readback(struct comedi_subdevice *s)
 142{
 143        if (!s->n_chan)
 144                return -EINVAL;
 145
 146        s->readback = kcalloc(s->n_chan, sizeof(*s->readback), GFP_KERNEL);
 147        if (!s->readback)
 148                return -ENOMEM;
 149
 150        if (!s->insn_read)
 151                s->insn_read = comedi_readback_insn_read;
 152
 153        return 0;
 154}
 155EXPORT_SYMBOL_GPL(comedi_alloc_subdev_readback);
 156
 157static void comedi_device_detach_cleanup(struct comedi_device *dev)
 158{
 159        int i;
 160        struct comedi_subdevice *s;
 161
 162        lockdep_assert_held(&dev->attach_lock);
 163        lockdep_assert_held(&dev->mutex);
 164        if (dev->subdevices) {
 165                for (i = 0; i < dev->n_subdevices; i++) {
 166                        s = &dev->subdevices[i];
 167                        if (comedi_can_auto_free_spriv(s))
 168                                kfree(s->private);
 169                        comedi_free_subdevice_minor(s);
 170                        if (s->async) {
 171                                comedi_buf_alloc(dev, s, 0);
 172                                kfree(s->async);
 173                        }
 174                        kfree(s->readback);
 175                }
 176                kfree(dev->subdevices);
 177                dev->subdevices = NULL;
 178                dev->n_subdevices = 0;
 179        }
 180        kfree(dev->private);
 181        kfree(dev->pacer);
 182        dev->private = NULL;
 183        dev->pacer = NULL;
 184        dev->driver = NULL;
 185        dev->board_name = NULL;
 186        dev->board_ptr = NULL;
 187        dev->mmio = NULL;
 188        dev->iobase = 0;
 189        dev->iolen = 0;
 190        dev->ioenabled = false;
 191        dev->irq = 0;
 192        dev->read_subdev = NULL;
 193        dev->write_subdev = NULL;
 194        dev->open = NULL;
 195        dev->close = NULL;
 196        comedi_clear_hw_dev(dev);
 197}
 198
 199void comedi_device_detach(struct comedi_device *dev)
 200{
 201        lockdep_assert_held(&dev->mutex);
 202        comedi_device_cancel_all(dev);
 203        down_write(&dev->attach_lock);
 204        dev->attached = false;
 205        dev->detach_count++;
 206        if (dev->driver)
 207                dev->driver->detach(dev);
 208        comedi_device_detach_cleanup(dev);
 209        up_write(&dev->attach_lock);
 210}
 211
 212static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 213{
 214        return -EINVAL;
 215}
 216
 217static int insn_device_inval(struct comedi_device *dev,
 218                             struct comedi_insn *insn, unsigned int *data)
 219{
 220        return -EINVAL;
 221}
 222
 223static unsigned int get_zero_valid_routes(struct comedi_device *dev,
 224                                          unsigned int n_pairs,
 225                                          unsigned int *pair_data)
 226{
 227        return 0;
 228}
 229
 230int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 231               struct comedi_insn *insn, unsigned int *data)
 232{
 233        return -EINVAL;
 234}
 235
 236/**
 237 * comedi_readback_insn_read() - A generic (*insn_read) for subdevice readback.
 238 * @dev: COMEDI device.
 239 * @s: COMEDI subdevice.
 240 * @insn: COMEDI instruction.
 241 * @data: Pointer to return the readback data.
 242 *
 243 * Handles the %INSN_READ instruction for subdevices that use the readback
 244 * array allocated by comedi_alloc_subdev_readback().  It may be used
 245 * directly as the subdevice's handler (@s->insn_read) or called via a
 246 * wrapper.
 247 *
 248 * @insn->n is normally 1, which will read a single value.  If higher, the
 249 * same element of the readback array will be read multiple times.
 250 *
 251 * Returns @insn->n on success, or -EINVAL if @s->readback is NULL.
 252 */
 253int comedi_readback_insn_read(struct comedi_device *dev,
 254                              struct comedi_subdevice *s,
 255                              struct comedi_insn *insn,
 256                              unsigned int *data)
 257{
 258        unsigned int chan = CR_CHAN(insn->chanspec);
 259        int i;
 260
 261        if (!s->readback)
 262                return -EINVAL;
 263
 264        for (i = 0; i < insn->n; i++)
 265                data[i] = s->readback[chan];
 266
 267        return insn->n;
 268}
 269EXPORT_SYMBOL_GPL(comedi_readback_insn_read);
 270
 271/**
 272 * comedi_timeout() - Busy-wait for a driver condition to occur
 273 * @dev: COMEDI device.
 274 * @s: COMEDI subdevice.
 275 * @insn: COMEDI instruction.
 276 * @cb: Callback to check for the condition.
 277 * @context: Private context from the driver.
 278 *
 279 * Busy-waits for up to a second (%COMEDI_TIMEOUT_MS) for the condition or
 280 * some error (other than -EBUSY) to occur.  The parameters @dev, @s, @insn,
 281 * and @context are passed to the callback function, which returns -EBUSY to
 282 * continue waiting or some other value to stop waiting (generally 0 if the
 283 * condition occurred, or some error value).
 284 *
 285 * Returns -ETIMEDOUT if timed out, otherwise the return value from the
 286 * callback function.
 287 */
 288int comedi_timeout(struct comedi_device *dev,
 289                   struct comedi_subdevice *s,
 290                   struct comedi_insn *insn,
 291                   int (*cb)(struct comedi_device *dev,
 292                             struct comedi_subdevice *s,
 293                             struct comedi_insn *insn,
 294                             unsigned long context),
 295                   unsigned long context)
 296{
 297        unsigned long timeout = jiffies + msecs_to_jiffies(COMEDI_TIMEOUT_MS);
 298        int ret;
 299
 300        while (time_before(jiffies, timeout)) {
 301                ret = cb(dev, s, insn, context);
 302                if (ret != -EBUSY)
 303                        return ret;     /* success (0) or non EBUSY errno */
 304                cpu_relax();
 305        }
 306        return -ETIMEDOUT;
 307}
 308EXPORT_SYMBOL_GPL(comedi_timeout);
 309
 310/**
 311 * comedi_dio_insn_config() - Boilerplate (*insn_config) for DIO subdevices
 312 * @dev: COMEDI device.
 313 * @s: COMEDI subdevice.
 314 * @insn: COMEDI instruction.
 315 * @data: Instruction parameters and return data.
 316 * @mask: io_bits mask for grouped channels, or 0 for single channel.
 317 *
 318 * If @mask is 0, it is replaced with a single-bit mask corresponding to the
 319 * channel number specified by @insn->chanspec.  Otherwise, @mask
 320 * corresponds to a group of channels (which should include the specified
 321 * channel) that are always configured together as inputs or outputs.
 322 *
 323 * Partially handles the %INSN_CONFIG_DIO_INPUT, %INSN_CONFIG_DIO_OUTPUTS,
 324 * and %INSN_CONFIG_DIO_QUERY instructions.  The first two update
 325 * @s->io_bits to record the directions of the masked channels.  The last
 326 * one sets @data[1] to the current direction of the group of channels
 327 * (%COMEDI_INPUT) or %COMEDI_OUTPUT) as recorded in @s->io_bits.
 328 *
 329 * The caller is responsible for updating the DIO direction in the hardware
 330 * registers if this function returns 0.
 331 *
 332 * Returns 0 for a %INSN_CONFIG_DIO_INPUT or %INSN_CONFIG_DIO_OUTPUT
 333 * instruction, @insn->n (> 0) for a %INSN_CONFIG_DIO_QUERY instruction, or
 334 * -EINVAL for some other instruction.
 335 */
 336int comedi_dio_insn_config(struct comedi_device *dev,
 337                           struct comedi_subdevice *s,
 338                           struct comedi_insn *insn,
 339                           unsigned int *data,
 340                           unsigned int mask)
 341{
 342        unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec);
 343
 344        if (!mask)
 345                mask = chan_mask;
 346
 347        switch (data[0]) {
 348        case INSN_CONFIG_DIO_INPUT:
 349                s->io_bits &= ~mask;
 350                break;
 351
 352        case INSN_CONFIG_DIO_OUTPUT:
 353                s->io_bits |= mask;
 354                break;
 355
 356        case INSN_CONFIG_DIO_QUERY:
 357                data[1] = (s->io_bits & mask) ? COMEDI_OUTPUT : COMEDI_INPUT;
 358                return insn->n;
 359
 360        default:
 361                return -EINVAL;
 362        }
 363
 364        return 0;
 365}
 366EXPORT_SYMBOL_GPL(comedi_dio_insn_config);
 367
 368/**
 369 * comedi_dio_update_state() - Update the internal state of DIO subdevices
 370 * @s: COMEDI subdevice.
 371 * @data: The channel mask and bits to update.
 372 *
 373 * Updates @s->state which holds the internal state of the outputs for DIO
 374 * or DO subdevices (up to 32 channels).  @data[0] contains a bit-mask of
 375 * the channels to be updated.  @data[1] contains a bit-mask of those
 376 * channels to be set to '1'.  The caller is responsible for updating the
 377 * outputs in hardware according to @s->state.  As a minimum, the channels
 378 * in the returned bit-mask need to be updated.
 379 *
 380 * Returns @mask with non-existent channels removed.
 381 */
 382unsigned int comedi_dio_update_state(struct comedi_subdevice *s,
 383                                     unsigned int *data)
 384{
 385        unsigned int chanmask = (s->n_chan < 32) ? ((1 << s->n_chan) - 1)
 386                                                 : 0xffffffff;
 387        unsigned int mask = data[0] & chanmask;
 388        unsigned int bits = data[1];
 389
 390        if (mask) {
 391                s->state &= ~mask;
 392                s->state |= (bits & mask);
 393        }
 394
 395        return mask;
 396}
 397EXPORT_SYMBOL_GPL(comedi_dio_update_state);
 398
 399/**
 400 * comedi_bytes_per_scan_cmd() - Get length of asynchronous command "scan" in
 401 * bytes
 402 * @s: COMEDI subdevice.
 403 * @cmd: COMEDI command.
 404 *
 405 * Determines the overall scan length according to the subdevice type and the
 406 * number of channels in the scan for the specified command.
 407 *
 408 * For digital input, output or input/output subdevices, samples for
 409 * multiple channels are assumed to be packed into one or more unsigned
 410 * short or unsigned int values according to the subdevice's %SDF_LSAMPL
 411 * flag.  For other types of subdevice, samples are assumed to occupy a
 412 * whole unsigned short or unsigned int according to the %SDF_LSAMPL flag.
 413 *
 414 * Returns the overall scan length in bytes.
 415 */
 416unsigned int comedi_bytes_per_scan_cmd(struct comedi_subdevice *s,
 417                                       struct comedi_cmd *cmd)
 418{
 419        unsigned int num_samples;
 420        unsigned int bits_per_sample;
 421
 422        switch (s->type) {
 423        case COMEDI_SUBD_DI:
 424        case COMEDI_SUBD_DO:
 425        case COMEDI_SUBD_DIO:
 426                bits_per_sample = 8 * comedi_bytes_per_sample(s);
 427                num_samples = DIV_ROUND_UP(cmd->scan_end_arg, bits_per_sample);
 428                break;
 429        default:
 430                num_samples = cmd->scan_end_arg;
 431                break;
 432        }
 433        return comedi_samples_to_bytes(s, num_samples);
 434}
 435EXPORT_SYMBOL_GPL(comedi_bytes_per_scan_cmd);
 436
 437/**
 438 * comedi_bytes_per_scan() - Get length of asynchronous command "scan" in bytes
 439 * @s: COMEDI subdevice.
 440 *
 441 * Determines the overall scan length according to the subdevice type and the
 442 * number of channels in the scan for the current command.
 443 *
 444 * For digital input, output or input/output subdevices, samples for
 445 * multiple channels are assumed to be packed into one or more unsigned
 446 * short or unsigned int values according to the subdevice's %SDF_LSAMPL
 447 * flag.  For other types of subdevice, samples are assumed to occupy a
 448 * whole unsigned short or unsigned int according to the %SDF_LSAMPL flag.
 449 *
 450 * Returns the overall scan length in bytes.
 451 */
 452unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s)
 453{
 454        struct comedi_cmd *cmd = &s->async->cmd;
 455
 456        return comedi_bytes_per_scan_cmd(s, cmd);
 457}
 458EXPORT_SYMBOL_GPL(comedi_bytes_per_scan);
 459
 460static unsigned int __comedi_nscans_left(struct comedi_subdevice *s,
 461                                         unsigned int nscans)
 462{
 463        struct comedi_async *async = s->async;
 464        struct comedi_cmd *cmd = &async->cmd;
 465
 466        if (cmd->stop_src == TRIG_COUNT) {
 467                unsigned int scans_left = 0;
 468
 469                if (async->scans_done < cmd->stop_arg)
 470                        scans_left = cmd->stop_arg - async->scans_done;
 471
 472                if (nscans > scans_left)
 473                        nscans = scans_left;
 474        }
 475        return nscans;
 476}
 477
 478/**
 479 * comedi_nscans_left() - Return the number of scans left in the command
 480 * @s: COMEDI subdevice.
 481 * @nscans: The expected number of scans or 0 for all available scans.
 482 *
 483 * If @nscans is 0, it is set to the number of scans available in the
 484 * async buffer.
 485 *
 486 * If the async command has a stop_src of %TRIG_COUNT, the @nscans will be
 487 * checked against the number of scans remaining to complete the command.
 488 *
 489 * The return value will then be either the expected number of scans or the
 490 * number of scans remaining to complete the command, whichever is fewer.
 491 */
 492unsigned int comedi_nscans_left(struct comedi_subdevice *s,
 493                                unsigned int nscans)
 494{
 495        if (nscans == 0) {
 496                unsigned int nbytes = comedi_buf_read_n_available(s);
 497
 498                nscans = nbytes / comedi_bytes_per_scan(s);
 499        }
 500        return __comedi_nscans_left(s, nscans);
 501}
 502EXPORT_SYMBOL_GPL(comedi_nscans_left);
 503
 504/**
 505 * comedi_nsamples_left() - Return the number of samples left in the command
 506 * @s: COMEDI subdevice.
 507 * @nsamples: The expected number of samples.
 508 *
 509 * Returns the number of samples remaining to complete the command, or the
 510 * specified expected number of samples (@nsamples), whichever is fewer.
 511 */
 512unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
 513                                  unsigned int nsamples)
 514{
 515        struct comedi_async *async = s->async;
 516        struct comedi_cmd *cmd = &async->cmd;
 517        unsigned long long scans_left;
 518        unsigned long long samples_left;
 519
 520        if (cmd->stop_src != TRIG_COUNT)
 521                return nsamples;
 522
 523        scans_left = __comedi_nscans_left(s, cmd->stop_arg);
 524        if (!scans_left)
 525                return 0;
 526
 527        samples_left = scans_left * cmd->scan_end_arg -
 528                comedi_bytes_to_samples(s, async->scan_progress);
 529
 530        if (samples_left < nsamples)
 531                return samples_left;
 532        return nsamples;
 533}
 534EXPORT_SYMBOL_GPL(comedi_nsamples_left);
 535
 536/**
 537 * comedi_inc_scan_progress() - Update scan progress in asynchronous command
 538 * @s: COMEDI subdevice.
 539 * @num_bytes: Amount of data in bytes to increment scan progress.
 540 *
 541 * Increments the scan progress by the number of bytes specified by @num_bytes.
 542 * If the scan progress reaches or exceeds the scan length in bytes, reduce
 543 * it modulo the scan length in bytes and set the "end of scan" asynchronous
 544 * event flag (%COMEDI_CB_EOS) to be processed later.
 545 */
 546void comedi_inc_scan_progress(struct comedi_subdevice *s,
 547                              unsigned int num_bytes)
 548{
 549        struct comedi_async *async = s->async;
 550        struct comedi_cmd *cmd = &async->cmd;
 551        unsigned int scan_length = comedi_bytes_per_scan(s);
 552
 553        /* track the 'cur_chan' for non-SDF_PACKED subdevices */
 554        if (!(s->subdev_flags & SDF_PACKED)) {
 555                async->cur_chan += comedi_bytes_to_samples(s, num_bytes);
 556                async->cur_chan %= cmd->chanlist_len;
 557        }
 558
 559        async->scan_progress += num_bytes;
 560        if (async->scan_progress >= scan_length) {
 561                unsigned int nscans = async->scan_progress / scan_length;
 562
 563                if (async->scans_done < (UINT_MAX - nscans))
 564                        async->scans_done += nscans;
 565                else
 566                        async->scans_done = UINT_MAX;
 567
 568                async->scan_progress %= scan_length;
 569                async->events |= COMEDI_CB_EOS;
 570        }
 571}
 572EXPORT_SYMBOL_GPL(comedi_inc_scan_progress);
 573
 574/**
 575 * comedi_handle_events() - Handle events and possibly stop acquisition
 576 * @dev: COMEDI device.
 577 * @s: COMEDI subdevice.
 578 *
 579 * Handles outstanding asynchronous acquisition event flags associated
 580 * with the subdevice.  Call the subdevice's @s->cancel() handler if the
 581 * "end of acquisition", "error" or "overflow" event flags are set in order
 582 * to stop the acquisition at the driver level.
 583 *
 584 * Calls comedi_event() to further process the event flags, which may mark
 585 * the asynchronous command as no longer running, possibly terminated with
 586 * an error, and may wake up tasks.
 587 *
 588 * Return a bit-mask of the handled events.
 589 */
 590unsigned int comedi_handle_events(struct comedi_device *dev,
 591                                  struct comedi_subdevice *s)
 592{
 593        unsigned int events = s->async->events;
 594
 595        if (events == 0)
 596                return events;
 597
 598        if ((events & COMEDI_CB_CANCEL_MASK) && s->cancel)
 599                s->cancel(dev, s);
 600
 601        comedi_event(dev, s);
 602
 603        return events;
 604}
 605EXPORT_SYMBOL_GPL(comedi_handle_events);
 606
 607static int insn_rw_emulate_bits(struct comedi_device *dev,
 608                                struct comedi_subdevice *s,
 609                                struct comedi_insn *insn,
 610                                unsigned int *data)
 611{
 612        struct comedi_insn _insn;
 613        unsigned int chan = CR_CHAN(insn->chanspec);
 614        unsigned int base_chan = (chan < 32) ? 0 : chan;
 615        unsigned int _data[2];
 616        int ret;
 617
 618        memset(_data, 0, sizeof(_data));
 619        memset(&_insn, 0, sizeof(_insn));
 620        _insn.insn = INSN_BITS;
 621        _insn.chanspec = base_chan;
 622        _insn.n = 2;
 623        _insn.subdev = insn->subdev;
 624
 625        if (insn->insn == INSN_WRITE) {
 626                if (!(s->subdev_flags & SDF_WRITABLE))
 627                        return -EINVAL;
 628                _data[0] = 1 << (chan - base_chan);                 /* mask */
 629                _data[1] = data[0] ? (1 << (chan - base_chan)) : 0; /* bits */
 630        }
 631
 632        ret = s->insn_bits(dev, s, &_insn, _data);
 633        if (ret < 0)
 634                return ret;
 635
 636        if (insn->insn == INSN_READ)
 637                data[0] = (_data[1] >> (chan - base_chan)) & 1;
 638
 639        return 1;
 640}
 641
 642static int __comedi_device_postconfig_async(struct comedi_device *dev,
 643                                            struct comedi_subdevice *s)
 644{
 645        struct comedi_async *async;
 646        unsigned int buf_size;
 647        int ret;
 648
 649        lockdep_assert_held(&dev->mutex);
 650        if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) {
 651                dev_warn(dev->class_dev,
 652                         "async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n");
 653                return -EINVAL;
 654        }
 655        if (!s->do_cmdtest) {
 656                dev_warn(dev->class_dev,
 657                         "async subdevices must have a do_cmdtest() function\n");
 658                return -EINVAL;
 659        }
 660        if (!s->cancel)
 661                dev_warn(dev->class_dev,
 662                         "async subdevices should have a cancel() function\n");
 663
 664        async = kzalloc(sizeof(*async), GFP_KERNEL);
 665        if (!async)
 666                return -ENOMEM;
 667
 668        init_waitqueue_head(&async->wait_head);
 669        s->async = async;
 670
 671        async->max_bufsize = comedi_default_buf_maxsize_kb * 1024;
 672        buf_size = comedi_default_buf_size_kb * 1024;
 673        if (buf_size > async->max_bufsize)
 674                buf_size = async->max_bufsize;
 675
 676        if (comedi_buf_alloc(dev, s, buf_size) < 0) {
 677                dev_warn(dev->class_dev, "Buffer allocation failed\n");
 678                return -ENOMEM;
 679        }
 680        if (s->buf_change) {
 681                ret = s->buf_change(dev, s);
 682                if (ret < 0)
 683                        return ret;
 684        }
 685
 686        comedi_alloc_subdevice_minor(s);
 687
 688        return 0;
 689}
 690
 691static int __comedi_device_postconfig(struct comedi_device *dev)
 692{
 693        struct comedi_subdevice *s;
 694        int ret;
 695        int i;
 696
 697        lockdep_assert_held(&dev->mutex);
 698        if (!dev->insn_device_config)
 699                dev->insn_device_config = insn_device_inval;
 700
 701        if (!dev->get_valid_routes)
 702                dev->get_valid_routes = get_zero_valid_routes;
 703
 704        for (i = 0; i < dev->n_subdevices; i++) {
 705                s = &dev->subdevices[i];
 706
 707                if (s->type == COMEDI_SUBD_UNUSED)
 708                        continue;
 709
 710                if (s->type == COMEDI_SUBD_DO) {
 711                        if (s->n_chan < 32)
 712                                s->io_bits = (1 << s->n_chan) - 1;
 713                        else
 714                                s->io_bits = 0xffffffff;
 715                }
 716
 717                if (s->len_chanlist == 0)
 718                        s->len_chanlist = 1;
 719
 720                if (s->do_cmd) {
 721                        ret = __comedi_device_postconfig_async(dev, s);
 722                        if (ret)
 723                                return ret;
 724                }
 725
 726                if (!s->range_table && !s->range_table_list)
 727                        s->range_table = &range_unknown;
 728
 729                if (!s->insn_read && s->insn_bits)
 730                        s->insn_read = insn_rw_emulate_bits;
 731                if (!s->insn_write && s->insn_bits)
 732                        s->insn_write = insn_rw_emulate_bits;
 733
 734                if (!s->insn_read)
 735                        s->insn_read = insn_inval;
 736                if (!s->insn_write)
 737                        s->insn_write = insn_inval;
 738                if (!s->insn_bits)
 739                        s->insn_bits = insn_inval;
 740                if (!s->insn_config)
 741                        s->insn_config = insn_inval;
 742
 743                if (!s->poll)
 744                        s->poll = poll_invalid;
 745        }
 746
 747        return 0;
 748}
 749
 750/* do a little post-config cleanup */
 751static int comedi_device_postconfig(struct comedi_device *dev)
 752{
 753        int ret;
 754
 755        lockdep_assert_held(&dev->mutex);
 756        ret = __comedi_device_postconfig(dev);
 757        if (ret < 0)
 758                return ret;
 759        down_write(&dev->attach_lock);
 760        dev->attached = true;
 761        up_write(&dev->attach_lock);
 762        return 0;
 763}
 764
 765/*
 766 * Generic recognize function for drivers that register their supported
 767 * board names.
 768 *
 769 * 'driv->board_name' points to a 'const char *' member within the
 770 * zeroth element of an array of some private board information
 771 * structure, say 'struct foo_board' containing a member 'const char
 772 * *board_name' that is initialized to point to a board name string that
 773 * is one of the candidates matched against this function's 'name'
 774 * parameter.
 775 *
 776 * 'driv->offset' is the size of the private board information
 777 * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
 778 * the length of the array of private board information structures.
 779 *
 780 * If one of the board names in the array of private board information
 781 * structures matches the name supplied to this function, the function
 782 * returns a pointer to the pointer to the board name, otherwise it
 783 * returns NULL.  The return value ends up in the 'board_ptr' member of
 784 * a 'struct comedi_device' that the low-level comedi driver's
 785 * 'attach()' hook can convert to a point to a particular element of its
 786 * array of private board information structures by subtracting the
 787 * offset of the member that points to the board name.  (No subtraction
 788 * is required if the board name pointer is the first member of the
 789 * private board information structure, which is generally the case.)
 790 */
 791static void *comedi_recognize(struct comedi_driver *driv, const char *name)
 792{
 793        char **name_ptr = (char **)driv->board_name;
 794        int i;
 795
 796        for (i = 0; i < driv->num_names; i++) {
 797                if (strcmp(*name_ptr, name) == 0)
 798                        return name_ptr;
 799                name_ptr = (void *)name_ptr + driv->offset;
 800        }
 801
 802        return NULL;
 803}
 804
 805static void comedi_report_boards(struct comedi_driver *driv)
 806{
 807        unsigned int i;
 808        const char *const *name_ptr;
 809
 810        pr_info("comedi: valid board names for %s driver are:\n",
 811                driv->driver_name);
 812
 813        name_ptr = driv->board_name;
 814        for (i = 0; i < driv->num_names; i++) {
 815                pr_info(" %s\n", *name_ptr);
 816                name_ptr = (const char **)((char *)name_ptr + driv->offset);
 817        }
 818
 819        if (driv->num_names == 0)
 820                pr_info(" %s\n", driv->driver_name);
 821}
 822
 823/**
 824 * comedi_load_firmware() - Request and load firmware for a device
 825 * @dev: COMEDI device.
 826 * @device: Hardware device.
 827 * @name: The name of the firmware image.
 828 * @cb: Callback to the upload the firmware image.
 829 * @context: Private context from the driver.
 830 *
 831 * Sends a firmware request for the hardware device and waits for it.  Calls
 832 * the callback function to upload the firmware to the device, them releases
 833 * the firmware.
 834 *
 835 * Returns 0 on success, -EINVAL if @cb is NULL, or a negative error number
 836 * from the firmware request or the callback function.
 837 */
 838int comedi_load_firmware(struct comedi_device *dev,
 839                         struct device *device,
 840                         const char *name,
 841                         int (*cb)(struct comedi_device *dev,
 842                                   const u8 *data, size_t size,
 843                                   unsigned long context),
 844                         unsigned long context)
 845{
 846        const struct firmware *fw;
 847        int ret;
 848
 849        if (!cb)
 850                return -EINVAL;
 851
 852        ret = request_firmware(&fw, name, device);
 853        if (ret == 0) {
 854                ret = cb(dev, fw->data, fw->size, context);
 855                release_firmware(fw);
 856        }
 857
 858        return ret < 0 ? ret : 0;
 859}
 860EXPORT_SYMBOL_GPL(comedi_load_firmware);
 861
 862/**
 863 * __comedi_request_region() - Request an I/O region for a legacy driver
 864 * @dev: COMEDI device.
 865 * @start: Base address of the I/O region.
 866 * @len: Length of the I/O region.
 867 *
 868 * Requests the specified I/O port region which must start at a non-zero
 869 * address.
 870 *
 871 * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request
 872 * fails.
 873 */
 874int __comedi_request_region(struct comedi_device *dev,
 875                            unsigned long start, unsigned long len)
 876{
 877        if (!start) {
 878                dev_warn(dev->class_dev,
 879                         "%s: a I/O base address must be specified\n",
 880                         dev->board_name);
 881                return -EINVAL;
 882        }
 883
 884        if (!request_region(start, len, dev->board_name)) {
 885                dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n",
 886                         dev->board_name, start, len);
 887                return -EIO;
 888        }
 889
 890        return 0;
 891}
 892EXPORT_SYMBOL_GPL(__comedi_request_region);
 893
 894/**
 895 * comedi_request_region() - Request an I/O region for a legacy driver
 896 * @dev: COMEDI device.
 897 * @start: Base address of the I/O region.
 898 * @len: Length of the I/O region.
 899 *
 900 * Requests the specified I/O port region which must start at a non-zero
 901 * address.
 902 *
 903 * On success, @dev->iobase is set to the base address of the region and
 904 * @dev->iolen is set to its length.
 905 *
 906 * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request
 907 * fails.
 908 */
 909int comedi_request_region(struct comedi_device *dev,
 910                          unsigned long start, unsigned long len)
 911{
 912        int ret;
 913
 914        ret = __comedi_request_region(dev, start, len);
 915        if (ret == 0) {
 916                dev->iobase = start;
 917                dev->iolen = len;
 918        }
 919
 920        return ret;
 921}
 922EXPORT_SYMBOL_GPL(comedi_request_region);
 923
 924/**
 925 * comedi_legacy_detach() - A generic (*detach) function for legacy drivers
 926 * @dev: COMEDI device.
 927 *
 928 * This is a simple, generic 'detach' handler for legacy COMEDI devices that
 929 * just use a single I/O port region and possibly an IRQ and that don't need
 930 * any special clean-up for their private device or subdevice storage.  It
 931 * can also be called by a driver-specific 'detach' handler.
 932 *
 933 * If @dev->irq is non-zero, the IRQ will be freed.  If @dev->iobase and
 934 * @dev->iolen are both non-zero, the I/O port region will be released.
 935 */
 936void comedi_legacy_detach(struct comedi_device *dev)
 937{
 938        if (dev->irq) {
 939                free_irq(dev->irq, dev);
 940                dev->irq = 0;
 941        }
 942        if (dev->iobase && dev->iolen) {
 943                release_region(dev->iobase, dev->iolen);
 944                dev->iobase = 0;
 945                dev->iolen = 0;
 946        }
 947}
 948EXPORT_SYMBOL_GPL(comedi_legacy_detach);
 949
 950int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 951{
 952        struct comedi_driver *driv;
 953        int ret;
 954
 955        lockdep_assert_held(&dev->mutex);
 956        if (dev->attached)
 957                return -EBUSY;
 958
 959        mutex_lock(&comedi_drivers_list_lock);
 960        for (driv = comedi_drivers; driv; driv = driv->next) {
 961                if (!try_module_get(driv->module))
 962                        continue;
 963                if (driv->num_names) {
 964                        dev->board_ptr = comedi_recognize(driv, it->board_name);
 965                        if (dev->board_ptr)
 966                                break;
 967                } else if (strcmp(driv->driver_name, it->board_name) == 0) {
 968                        break;
 969                }
 970                module_put(driv->module);
 971        }
 972        if (!driv) {
 973                /*  recognize has failed if we get here */
 974                /*  report valid board names before returning error */
 975                for (driv = comedi_drivers; driv; driv = driv->next) {
 976                        if (!try_module_get(driv->module))
 977                                continue;
 978                        comedi_report_boards(driv);
 979                        module_put(driv->module);
 980                }
 981                ret = -EIO;
 982                goto out;
 983        }
 984        if (!driv->attach) {
 985                /* driver does not support manual configuration */
 986                dev_warn(dev->class_dev,
 987                         "driver '%s' does not support attach using comedi_config\n",
 988                         driv->driver_name);
 989                module_put(driv->module);
 990                ret = -EIO;
 991                goto out;
 992        }
 993        dev->driver = driv;
 994        dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr
 995                                         : dev->driver->driver_name;
 996        ret = driv->attach(dev, it);
 997        if (ret >= 0)
 998                ret = comedi_device_postconfig(dev);
 999        if (ret < 0) {
1000                comedi_device_detach(dev);
1001                module_put(driv->module);
1002        }
1003        /* On success, the driver module count has been incremented. */
1004out:
1005        mutex_unlock(&comedi_drivers_list_lock);
1006        return ret;
1007}
1008
1009/**
1010 * comedi_auto_config() - Create a COMEDI device for a hardware device
1011 * @hardware_device: Hardware device.
1012 * @driver: COMEDI low-level driver for the hardware device.
1013 * @context: Driver context for the auto_attach handler.
1014 *
1015 * Allocates a new COMEDI device for the hardware device and calls the
1016 * low-level driver's 'auto_attach' handler to set-up the hardware and
1017 * allocate the COMEDI subdevices.  Additional "post-configuration" setting
1018 * up is performed on successful return from the 'auto_attach' handler.
1019 * If the 'auto_attach' handler fails, the low-level driver's 'detach'
1020 * handler will be called as part of the clean-up.
1021 *
1022 * This is usually called from a wrapper function in a bus-specific COMEDI
1023 * module, which in turn is usually called from a bus device 'probe'
1024 * function in the low-level driver.
1025 *
1026 * Returns 0 on success, -EINVAL if the parameters are invalid or the
1027 * post-configuration determines the driver has set the COMEDI device up
1028 * incorrectly, -ENOMEM if failed to allocate memory, -EBUSY if run out of
1029 * COMEDI minor device numbers, or some negative error number returned by
1030 * the driver's 'auto_attach' handler.
1031 */
1032int comedi_auto_config(struct device *hardware_device,
1033                       struct comedi_driver *driver, unsigned long context)
1034{
1035        struct comedi_device *dev;
1036        int ret;
1037
1038        if (!hardware_device) {
1039                pr_warn("BUG! %s called with NULL hardware_device\n", __func__);
1040                return -EINVAL;
1041        }
1042        if (!driver) {
1043                dev_warn(hardware_device,
1044                         "BUG! %s called with NULL comedi driver\n", __func__);
1045                return -EINVAL;
1046        }
1047
1048        if (!driver->auto_attach) {
1049                dev_warn(hardware_device,
1050                         "BUG! comedi driver '%s' has no auto_attach handler\n",
1051                         driver->driver_name);
1052                return -EINVAL;
1053        }
1054
1055        dev = comedi_alloc_board_minor(hardware_device);
1056        if (IS_ERR(dev)) {
1057                dev_warn(hardware_device,
1058                         "driver '%s' could not create device.\n",
1059                         driver->driver_name);
1060                return PTR_ERR(dev);
1061        }
1062        /* Note: comedi_alloc_board_minor() locked dev->mutex. */
1063        lockdep_assert_held(&dev->mutex);
1064
1065        dev->driver = driver;
1066        dev->board_name = dev->driver->driver_name;
1067        ret = driver->auto_attach(dev, context);
1068        if (ret >= 0)
1069                ret = comedi_device_postconfig(dev);
1070
1071        if (ret < 0) {
1072                dev_warn(hardware_device,
1073                         "driver '%s' failed to auto-configure device.\n",
1074                         driver->driver_name);
1075                mutex_unlock(&dev->mutex);
1076                comedi_release_hardware_device(hardware_device);
1077        } else {
1078                /*
1079                 * class_dev should be set properly here
1080                 *  after a successful auto config
1081                 */
1082                dev_info(dev->class_dev,
1083                         "driver '%s' has successfully auto-configured '%s'.\n",
1084                         driver->driver_name, dev->board_name);
1085                mutex_unlock(&dev->mutex);
1086        }
1087        return ret;
1088}
1089EXPORT_SYMBOL_GPL(comedi_auto_config);
1090
1091/**
1092 * comedi_auto_unconfig() - Unconfigure auto-allocated COMEDI device
1093 * @hardware_device: Hardware device previously passed to
1094 *                   comedi_auto_config().
1095 *
1096 * Cleans up and eventually destroys the COMEDI device allocated by
1097 * comedi_auto_config() for the same hardware device.  As part of this
1098 * clean-up, the low-level COMEDI driver's 'detach' handler will be called.
1099 * (The COMEDI device itself will persist in an unattached state if it is
1100 * still open, until it is released, and any mmapped buffers will persist
1101 * until they are munmapped.)
1102 *
1103 * This is usually called from a wrapper module in a bus-specific COMEDI
1104 * module, which in turn is usually set as the bus device 'remove' function
1105 * in the low-level COMEDI driver.
1106 */
1107void comedi_auto_unconfig(struct device *hardware_device)
1108{
1109        if (!hardware_device)
1110                return;
1111        comedi_release_hardware_device(hardware_device);
1112}
1113EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
1114
1115/**
1116 * comedi_driver_register() - Register a low-level COMEDI driver
1117 * @driver: Low-level COMEDI driver.
1118 *
1119 * The low-level COMEDI driver is added to the list of registered COMEDI
1120 * drivers.  This is used by the handler for the "/proc/comedi" file and is
1121 * also used by the handler for the %COMEDI_DEVCONFIG ioctl to configure
1122 * "legacy" COMEDI devices (for those low-level drivers that support it).
1123 *
1124 * Returns 0.
1125 */
1126int comedi_driver_register(struct comedi_driver *driver)
1127{
1128        mutex_lock(&comedi_drivers_list_lock);
1129        driver->next = comedi_drivers;
1130        comedi_drivers = driver;
1131        mutex_unlock(&comedi_drivers_list_lock);
1132
1133        return 0;
1134}
1135EXPORT_SYMBOL_GPL(comedi_driver_register);
1136
1137/**
1138 * comedi_driver_unregister() - Unregister a low-level COMEDI driver
1139 * @driver: Low-level COMEDI driver.
1140 *
1141 * The low-level COMEDI driver is removed from the list of registered COMEDI
1142 * drivers.  Detaches any COMEDI devices attached to the driver, which will
1143 * result in the low-level driver's 'detach' handler being called for those
1144 * devices before this function returns.
1145 */
1146void comedi_driver_unregister(struct comedi_driver *driver)
1147{
1148        struct comedi_driver *prev;
1149        int i;
1150
1151        /* unlink the driver */
1152        mutex_lock(&comedi_drivers_list_lock);
1153        if (comedi_drivers == driver) {
1154                comedi_drivers = driver->next;
1155        } else {
1156                for (prev = comedi_drivers; prev->next; prev = prev->next) {
1157                        if (prev->next == driver) {
1158                                prev->next = driver->next;
1159                                break;
1160                        }
1161                }
1162        }
1163        mutex_unlock(&comedi_drivers_list_lock);
1164
1165        /* check for devices using this driver */
1166        for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
1167                struct comedi_device *dev = comedi_dev_get_from_minor(i);
1168
1169                if (!dev)
1170                        continue;
1171
1172                mutex_lock(&dev->mutex);
1173                if (dev->attached && dev->driver == driver) {
1174                        if (dev->use_count)
1175                                dev_warn(dev->class_dev,
1176                                         "BUG! detaching device with use_count=%d\n",
1177                                         dev->use_count);
1178                        comedi_device_detach(dev);
1179                }
1180                mutex_unlock(&dev->mutex);
1181                comedi_dev_put(dev);
1182        }
1183}
1184EXPORT_SYMBOL_GPL(comedi_driver_unregister);
1185