drivers/iio/industrialio-buffer.c

   1 /* The industrial I/O core
   2  *
   3  * Copyright (c) 2008 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * Handling of buffer allocation / resizing.
  10  *
  11  *
  12  * Things to look at here.
  13  * - Better memory allocation techniques?
  14  * - Alternative access techniques?
  15  */
  16 #include <linux/kernel.h>
  17 #include <linux/export.h>
  18 #include <linux/device.h>
  19 #include <linux/fs.h>
  20 #include <linux/cdev.h>
  21 #include <linux/slab.h>
  22 #include <linux/poll.h>
  23 #include <linux/sched.h>
  24
  25 #include <linux/iio/iio.h>
  26 #include "iio_core.h"
  27 #include <linux/iio/sysfs.h>
  28 #include <linux/iio/buffer.h>
  29
  30 static const char * const iio_endian_prefix[] = {
  31         [IIO_BE] = "be",
  32         [IIO_LE] = "le",
  33 };
  34
  35 static bool iio_buffer_is_active(struct iio_buffer *buf)
  36 {
  37         return !list_empty(&buf->buffer_list);
  38 }
  39
  40 /**
  41  * iio_buffer_read_first_n_outer() - chrdev read for buffer access
  42  *
  43  * This function relies on all buffer implementations having an
  44  * iio_buffer as their first element.
  45  **/
  46 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
  47                                       size_t n, loff_t *f_ps)
  48 {
  49         struct iio_dev *indio_dev = filp->private_data;
  50         struct iio_buffer *rb = indio_dev->buffer;
  51
  52         if (!indio_dev->info)
  53                 return -ENODEV;
  54
  55         if (!rb || !rb->access->read_first_n)
  56                 return -EINVAL;
  57         return rb->access->read_first_n(rb, n, buf);
  58 }
  59
  60 /**
  61  * iio_buffer_poll() - poll the buffer to find out if it has data
  62  */
  63 unsigned int iio_buffer_poll(struct file *filp,
  64                              struct poll_table_struct *wait)
  65 {
  66         struct iio_dev *indio_dev = filp->private_data;
  67         struct iio_buffer *rb = indio_dev->buffer;
  68
  69         if (!indio_dev->info)
  70                 return -ENODEV;
  71
  72         poll_wait(filp, &rb->pollq, wait);
  73         if (rb->stufftoread)
  74                 return POLLIN | POLLRDNORM;
  75         /* need a way of knowing if there may be enough data... */
  76         return 0;
  77 }
  78
  79 /**
  80  * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
  81  * @indio_dev: The IIO device
  82  *
  83  * Wakes up the event waitqueue used for poll(). Should usually
  84  * be called when the device is unregistered.
  85  */
  86 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
  87 {
  88         if (!indio_dev->buffer)
  89                 return;
  90
  91         wake_up(&indio_dev->buffer->pollq);
  92 }
  93
  94 void iio_buffer_init(struct iio_buffer *buffer)
  95 {
  96         INIT_LIST_HEAD(&buffer->demux_list);
  97         INIT_LIST_HEAD(&buffer->buffer_list);
  98         init_waitqueue_head(&buffer->pollq);
  99         kref_init(&buffer->ref);
 100 }
 101 EXPORT_SYMBOL(iio_buffer_init);
 102
 103 static ssize_t iio_show_scan_index(struct device *dev,
 104                                    struct device_attribute *attr,
 105                                    char *buf)
 106 {
 107         return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
 108 }
 109
 110 static ssize_t iio_show_fixed_type(struct device *dev,
 111                                    struct device_attribute *attr,
 112                                    char *buf)
 113 {
 114         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 115         u8 type = this_attr->c->scan_type.endianness;
 116
 117         if (type == IIO_CPU) {
 118 #ifdef __LITTLE_ENDIAN
 119                 type = IIO_LE;
 120 #else
 121                 type = IIO_BE;
 122 #endif
 123         }
 124         return sprintf(buf, "%s:%c%d/%d>>%u\n",
 125                        iio_endian_prefix[type],
 126                        this_attr->c->scan_type.sign,
 127                        this_attr->c->scan_type.realbits,
 128                        this_attr->c->scan_type.storagebits,
 129                        this_attr->c->scan_type.shift);
 130 }
 131
 132 static ssize_t iio_scan_el_show(struct device *dev,
 133                                 struct device_attribute *attr,
 134                                 char *buf)
 135 {
 136         int ret;
 137         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 138
 139         ret = test_bit(to_iio_dev_attr(attr)->address,
 140                        indio_dev->buffer->scan_mask);
 141
 142         return sprintf(buf, "%d\n", ret);
 143 }
 144
 145 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
 146 {
 147         clear_bit(bit, buffer->scan_mask);
 148         return 0;
 149 }
 150
 151 static ssize_t iio_scan_el_store(struct device *dev,
 152                                  struct device_attribute *attr,
 153                                  const char *buf,
 154                                  size_t len)
 155 {
 156         int ret;
 157         bool state;
 158         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 159         struct iio_buffer *buffer = indio_dev->buffer;
 160         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 161
 162         ret = strtobool(buf, &state);
 163         if (ret < 0)
 164                 return ret;
 165         mutex_lock(&indio_dev->mlock);
 166         if (iio_buffer_is_active(indio_dev->buffer)) {
 167                 ret = -EBUSY;
 168                 goto error_ret;
 169         }
 170         ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
 171         if (ret < 0)
 172                 goto error_ret;
 173         if (!state && ret) {
 174                 ret = iio_scan_mask_clear(buffer, this_attr->address);
 175                 if (ret)
 176                         goto error_ret;
 177         } else if (state && !ret) {
 178                 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
 179                 if (ret)
 180                         goto error_ret;
 181         }
 182
 183 error_ret:
 184         mutex_unlock(&indio_dev->mlock);
 185
 186         return ret < 0 ? ret : len;
 187
 188 }
 189
 190 static ssize_t iio_scan_el_ts_show(struct device *dev,
 191                                    struct device_attribute *attr,
 192                                    char *buf)
 193 {
 194         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 195         return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
 196 }
 197
 198 static ssize_t iio_scan_el_ts_store(struct device *dev,
 199                                     struct device_attribute *attr,
 200                                     const char *buf,
 201                                     size_t len)
 202 {
 203         int ret;
 204         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 205         bool state;
 206
 207         ret = strtobool(buf, &state);
 208         if (ret < 0)
 209                 return ret;
 210
 211         mutex_lock(&indio_dev->mlock);
 212         if (iio_buffer_is_active(indio_dev->buffer)) {
 213                 ret = -EBUSY;
 214                 goto error_ret;
 215         }
 216         indio_dev->buffer->scan_timestamp = state;
 217 error_ret:
 218         mutex_unlock(&indio_dev->mlock);
 219
 220         return ret ? ret : len;
 221 }
 222
 223 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
 224                                         const struct iio_chan_spec *chan)
 225 {
 226         int ret, attrcount = 0;
 227         struct iio_buffer *buffer = indio_dev->buffer;
 228
 229         ret = __iio_add_chan_devattr("index",
 230                                      chan,
 231                                      &iio_show_scan_index,
 232                                      NULL,
 233                                      0,
 234                                      IIO_SEPARATE,
 235                                      &indio_dev->dev,
 236                                      &buffer->scan_el_dev_attr_list);
 237         if (ret)
 238                 goto error_ret;
 239         attrcount++;
 240         ret = __iio_add_chan_devattr("type",
 241                                      chan,
 242                                      &iio_show_fixed_type,
 243                                      NULL,
 244                                      0,
 245                                      0,
 246                                      &indio_dev->dev,
 247                                      &buffer->scan_el_dev_attr_list);
 248         if (ret)
 249                 goto error_ret;
 250         attrcount++;
 251         if (chan->type != IIO_TIMESTAMP)
 252                 ret = __iio_add_chan_devattr("en",
 253                                              chan,
 254                                              &iio_scan_el_show,
 255                                              &iio_scan_el_store,
 256                                              chan->scan_index,
 257                                              0,
 258                                              &indio_dev->dev,
 259                                              &buffer->scan_el_dev_attr_list);
 260         else
 261                 ret = __iio_add_chan_devattr("en",
 262                                              chan,
 263                                              &iio_scan_el_ts_show,
 264                                              &iio_scan_el_ts_store,
 265                                              chan->scan_index,
 266                                              0,
 267                                              &indio_dev->dev,
 268                                              &buffer->scan_el_dev_attr_list);
 269         if (ret)
 270                 goto error_ret;
 271         attrcount++;
 272         ret = attrcount;
 273 error_ret:
 274         return ret;
 275 }
 276
 277 static const char * const iio_scan_elements_group_name = "scan_elements";
 278
 279 int iio_buffer_register(struct iio_dev *indio_dev,
 280                         const struct iio_chan_spec *channels,
 281                         int num_channels)
 282 {
 283         struct iio_dev_attr *p;
 284         struct attribute **attr;
 285         struct iio_buffer *buffer = indio_dev->buffer;
 286         int ret, i, attrn, attrcount, attrcount_orig = 0;
 287
 288         if (buffer->attrs)
 289                 indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
 290
 291         if (buffer->scan_el_attrs != NULL) {
 292                 attr = buffer->scan_el_attrs->attrs;
 293                 while (*attr++ != NULL)
 294                         attrcount_orig++;
 295         }
 296         attrcount = attrcount_orig;
 297         INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
 298         if (channels) {
 299                 /* new magic */
 300                 for (i = 0; i < num_channels; i++) {
 301                         if (channels[i].scan_index < 0)
 302                                 continue;
 303
 304                         /* Establish necessary mask length */
 305                         if (channels[i].scan_index >
 306                             (int)indio_dev->masklength - 1)
 307                                 indio_dev->masklength
 308                                         = channels[i].scan_index + 1;
 309
 310                         ret = iio_buffer_add_channel_sysfs(indio_dev,
 311                                                          &channels[i]);
 312                         if (ret < 0)
 313                                 goto error_cleanup_dynamic;
 314                         attrcount += ret;
 315                         if (channels[i].type == IIO_TIMESTAMP)
 316                                 indio_dev->scan_index_timestamp =
 317                                         channels[i].scan_index;
 318                 }
 319                 if (indio_dev->masklength && buffer->scan_mask == NULL) {
 320                         buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
 321                                                     sizeof(*buffer->scan_mask),
 322                                                     GFP_KERNEL);
 323                         if (buffer->scan_mask == NULL) {
 324                                 ret = -ENOMEM;
 325                                 goto error_cleanup_dynamic;
 326                         }
 327                 }
 328         }
 329
 330         buffer->scan_el_group.name = iio_scan_elements_group_name;
 331
 332         buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
 333                                               sizeof(buffer->scan_el_group.attrs[0]),
 334                                               GFP_KERNEL);
 335         if (buffer->scan_el_group.attrs == NULL) {
 336                 ret = -ENOMEM;
 337                 goto error_free_scan_mask;
 338         }
 339         if (buffer->scan_el_attrs)
 340                 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
 341                        sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
 342         attrn = attrcount_orig;
 343
 344         list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
 345                 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
 346         indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
 347
 348         return 0;
 349
 350 error_free_scan_mask:
 351         kfree(buffer->scan_mask);
 352 error_cleanup_dynamic:
 353         iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
 354
 355         return ret;
 356 }
 357 EXPORT_SYMBOL(iio_buffer_register);
 358
 359 void iio_buffer_unregister(struct iio_dev *indio_dev)
 360 {
 361         kfree(indio_dev->buffer->scan_mask);
 362         kfree(indio_dev->buffer->scan_el_group.attrs);
 363         iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
 364 }
 365 EXPORT_SYMBOL(iio_buffer_unregister);
 366
 367 ssize_t iio_buffer_read_length(struct device *dev,
 368                                struct device_attribute *attr,
 369                                char *buf)
 370 {
 371         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 372         struct iio_buffer *buffer = indio_dev->buffer;
 373
 374         if (buffer->access->get_length)
 375                 return sprintf(buf, "%d\n",
 376                                buffer->access->get_length(buffer));
 377
 378         return 0;
 379 }
 380 EXPORT_SYMBOL(iio_buffer_read_length);
 381
 382 ssize_t iio_buffer_write_length(struct device *dev,
 383                                 struct device_attribute *attr,
 384                                 const char *buf,
 385                                 size_t len)
 386 {
 387         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 388         struct iio_buffer *buffer = indio_dev->buffer;
 389         unsigned int val;
 390         int ret;
 391
 392         ret = kstrtouint(buf, 10, &val);
 393         if (ret)
 394                 return ret;
 395
 396         if (buffer->access->get_length)
 397                 if (val == buffer->access->get_length(buffer))
 398                         return len;
 399
 400         mutex_lock(&indio_dev->mlock);
 401         if (iio_buffer_is_active(indio_dev->buffer)) {
 402                 ret = -EBUSY;
 403         } else {
 404                 if (buffer->access->set_length)
 405                         buffer->access->set_length(buffer, val);
 406                 ret = 0;
 407         }
 408         mutex_unlock(&indio_dev->mlock);
 409
 410         return ret ? ret : len;
 411 }
 412 EXPORT_SYMBOL(iio_buffer_write_length);
 413
 414 ssize_t iio_buffer_show_enable(struct device *dev,
 415                                struct device_attribute *attr,
 416                                char *buf)
 417 {
 418         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 419         return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
 420 }
 421 EXPORT_SYMBOL(iio_buffer_show_enable);
 422
 423 /* Note NULL used as error indicator as it doesn't make sense. */
 424 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
 425                                           unsigned int masklength,
 426                                           const unsigned long *mask)
 427 {
 428         if (bitmap_empty(mask, masklength))
 429                 return NULL;
 430         while (*av_masks) {
 431                 if (bitmap_subset(mask, av_masks, masklength))
 432                         return av_masks;
 433                 av_masks += BITS_TO_LONGS(masklength);
 434         }
 435         return NULL;
 436 }
 437
 438 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
 439                                 const unsigned long *mask, bool timestamp)
 440 {
 441         const struct iio_chan_spec *ch;
 442         unsigned bytes = 0;
 443         int length, i;
 444
 445         /* How much space will the demuxed element take? */
 446         for_each_set_bit(i, mask,
 447                          indio_dev->masklength) {
 448                 ch = iio_find_channel_from_si(indio_dev, i);
 449                 length = ch->scan_type.storagebits / 8;
 450                 bytes = ALIGN(bytes, length);
 451                 bytes += length;
 452         }
 453         if (timestamp) {
 454                 ch = iio_find_channel_from_si(indio_dev,
 455                                               indio_dev->scan_index_timestamp);
 456                 length = ch->scan_type.storagebits / 8;
 457                 bytes = ALIGN(bytes, length);
 458                 bytes += length;
 459         }
 460         return bytes;
 461 }
 462
 463 static void iio_buffer_activate(struct iio_dev *indio_dev,
 464         struct iio_buffer *buffer)
 465 {
 466         iio_buffer_get(buffer);
 467         list_add(&buffer->buffer_list, &indio_dev->buffer_list);
 468 }
 469
 470 static void iio_buffer_deactivate(struct iio_buffer *buffer)
 471 {
 472         list_del_init(&buffer->buffer_list);
 473         iio_buffer_put(buffer);
 474 }
 475
 476 void iio_disable_all_buffers(struct iio_dev *indio_dev)
 477 {
 478         struct iio_buffer *buffer, *_buffer;
 479
 480         if (list_empty(&indio_dev->buffer_list))
 481                 return;
 482
 483         if (indio_dev->setup_ops->predisable)
 484                 indio_dev->setup_ops->predisable(indio_dev);
 485
 486         list_for_each_entry_safe(buffer, _buffer,
 487                         &indio_dev->buffer_list, buffer_list)
 488                 iio_buffer_deactivate(buffer);
 489
 490         indio_dev->currentmode = INDIO_DIRECT_MODE;
 491         if (indio_dev->setup_ops->postdisable)
 492                 indio_dev->setup_ops->postdisable(indio_dev);
 493
 494         if (indio_dev->available_scan_masks == NULL)
 495                 kfree(indio_dev->active_scan_mask);
 496 }
 497
 498 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
 499         struct iio_buffer *buffer)
 500 {
 501         unsigned int bytes;
 502
 503         if (!buffer->access->set_bytes_per_datum)
 504                 return;
 505
 506         bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
 507                 buffer->scan_timestamp);
 508
 509         buffer->access->set_bytes_per_datum(buffer, bytes);
 510 }
 511
 512 static int __iio_update_buffers(struct iio_dev *indio_dev,
 513                        struct iio_buffer *insert_buffer,
 514                        struct iio_buffer *remove_buffer)
 515 {
 516         int ret;
 517         int success = 0;
 518         struct iio_buffer *buffer;
 519         unsigned long *compound_mask;
 520         const unsigned long *old_mask;
 521
 522         /* Wind down existing buffers - iff there are any */
 523         if (!list_empty(&indio_dev->buffer_list)) {
 524                 if (indio_dev->setup_ops->predisable) {
 525                         ret = indio_dev->setup_ops->predisable(indio_dev);
 526                         if (ret)
 527                                 goto error_ret;
 528                 }
 529                 indio_dev->currentmode = INDIO_DIRECT_MODE;
 530                 if (indio_dev->setup_ops->postdisable) {
 531                         ret = indio_dev->setup_ops->postdisable(indio_dev);
 532                         if (ret)
 533                                 goto error_ret;
 534                 }
 535         }
 536         /* Keep a copy of current setup to allow roll back */
 537         old_mask = indio_dev->active_scan_mask;
 538         if (!indio_dev->available_scan_masks)
 539                 indio_dev->active_scan_mask = NULL;
 540
 541         if (remove_buffer)
 542                 iio_buffer_deactivate(remove_buffer);
 543         if (insert_buffer)
 544                 iio_buffer_activate(indio_dev, insert_buffer);
 545
 546         /* If no buffers in list, we are done */
 547         if (list_empty(&indio_dev->buffer_list)) {
 548                 indio_dev->currentmode = INDIO_DIRECT_MODE;
 549                 if (indio_dev->available_scan_masks == NULL)
 550                         kfree(old_mask);
 551                 return 0;
 552         }
 553
 554         /* What scan mask do we actually have? */
 555         compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
 556                                 sizeof(long), GFP_KERNEL);
 557         if (compound_mask == NULL) {
 558                 if (indio_dev->available_scan_masks == NULL)
 559                         kfree(old_mask);
 560                 return -ENOMEM;
 561         }
 562         indio_dev->scan_timestamp = 0;
 563
 564         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
 565                 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
 566                           indio_dev->masklength);
 567                 indio_dev->scan_timestamp |= buffer->scan_timestamp;
 568         }
 569         if (indio_dev->available_scan_masks) {
 570                 indio_dev->active_scan_mask =
 571                         iio_scan_mask_match(indio_dev->available_scan_masks,
 572                                             indio_dev->masklength,
 573                                             compound_mask);
 574                 if (indio_dev->active_scan_mask == NULL) {
 575                         /*
 576                          * Roll back.
 577                          * Note can only occur when adding a buffer.
 578                          */
 579                         iio_buffer_deactivate(insert_buffer);
 580                         if (old_mask) {
 581                                 indio_dev->active_scan_mask = old_mask;
 582                                 success = -EINVAL;
 583                         }
 584                         else {
 585                                 kfree(compound_mask);
 586                                 ret = -EINVAL;
 587                                 goto error_ret;
 588                         }
 589                 }
 590         } else {
 591                 indio_dev->active_scan_mask = compound_mask;
 592         }
 593
 594         iio_update_demux(indio_dev);
 595
 596         /* Wind up again */
 597         if (indio_dev->setup_ops->preenable) {
 598                 ret = indio_dev->setup_ops->preenable(indio_dev);
 599                 if (ret) {
 600                         printk(KERN_ERR
 601                                "Buffer not started: buffer preenable failed (%d)\n", ret);
 602                         goto error_remove_inserted;
 603                 }
 604         }
 605         indio_dev->scan_bytes =
 606                 iio_compute_scan_bytes(indio_dev,
 607                                        indio_dev->active_scan_mask,
 608                                        indio_dev->scan_timestamp);
 609         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
 610                 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
 611                 if (buffer->access->request_update) {
 612                         ret = buffer->access->request_update(buffer);
 613                         if (ret) {
 614                                 printk(KERN_INFO
 615                                        "Buffer not started: buffer parameter update failed (%d)\n", ret);
 616                                 goto error_run_postdisable;
 617                         }
 618                 }
 619         }
 620         if (indio_dev->info->update_scan_mode) {
 621                 ret = indio_dev->info
 622                         ->update_scan_mode(indio_dev,
 623                                            indio_dev->active_scan_mask);
 624                 if (ret < 0) {
 625                         printk(KERN_INFO "Buffer not started: update scan mode failed (%d)\n", ret);
 626                         goto error_run_postdisable;
 627                 }
 628         }
 629         /* Definitely possible for devices to support both of these. */
 630         if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
 631                 if (!indio_dev->trig) {
 632                         printk(KERN_INFO "Buffer not started: no trigger\n");
 633                         ret = -EINVAL;
 634                         /* Can only occur on first buffer */
 635                         goto error_run_postdisable;
 636                 }
 637                 indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
 638         } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
 639                 indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
 640         } else { /* Should never be reached */
 641                 ret = -EINVAL;
 642                 goto error_run_postdisable;
 643         }
 644
 645         if (indio_dev->setup_ops->postenable) {
 646                 ret = indio_dev->setup_ops->postenable(indio_dev);
 647                 if (ret) {
 648                         printk(KERN_INFO
 649                                "Buffer not started: postenable failed (%d)\n", ret);
 650                         indio_dev->currentmode = INDIO_DIRECT_MODE;
 651                         if (indio_dev->setup_ops->postdisable)
 652                                 indio_dev->setup_ops->postdisable(indio_dev);
 653                         goto error_disable_all_buffers;
 654                 }
 655         }
 656
 657         if (indio_dev->available_scan_masks)
 658                 kfree(compound_mask);
 659         else
 660                 kfree(old_mask);
 661
 662         return success;
 663
 664 error_disable_all_buffers:
 665         indio_dev->currentmode = INDIO_DIRECT_MODE;
 666 error_run_postdisable:
 667         if (indio_dev->setup_ops->postdisable)
 668                 indio_dev->setup_ops->postdisable(indio_dev);
 669 error_remove_inserted:
 670
 671         if (insert_buffer)
 672                 iio_buffer_deactivate(insert_buffer);
 673         indio_dev->active_scan_mask = old_mask;
 674         kfree(compound_mask);
 675 error_ret:
 676
 677         return ret;
 678 }
 679
 680 int iio_update_buffers(struct iio_dev *indio_dev,
 681                        struct iio_buffer *insert_buffer,
 682                        struct iio_buffer *remove_buffer)
 683 {
 684         int ret;
 685
 686         if (insert_buffer == remove_buffer)
 687                 return 0;
 688
 689         mutex_lock(&indio_dev->info_exist_lock);
 690         mutex_lock(&indio_dev->mlock);
 691
 692         if (insert_buffer && iio_buffer_is_active(insert_buffer))
 693                 insert_buffer = NULL;
 694
 695         if (remove_buffer && !iio_buffer_is_active(remove_buffer))
 696                 remove_buffer = NULL;
 697
 698         if (!insert_buffer && !remove_buffer) {
 699                 ret = 0;
 700                 goto out_unlock;
 701         }
 702
 703         if (indio_dev->info == NULL) {
 704                 ret = -ENODEV;
 705                 goto out_unlock;
 706         }
 707
 708         ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
 709
 710 out_unlock:
 711         mutex_unlock(&indio_dev->mlock);
 712         mutex_unlock(&indio_dev->info_exist_lock);
 713
 714         return ret;
 715 }
 716 EXPORT_SYMBOL_GPL(iio_update_buffers);
 717
 718 ssize_t iio_buffer_store_enable(struct device *dev,
 719                                 struct device_attribute *attr,
 720                                 const char *buf,
 721                                 size_t len)
 722 {
 723         int ret;
 724         bool requested_state;
 725         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 726         bool inlist;
 727
 728         ret = strtobool(buf, &requested_state);
 729         if (ret < 0)
 730                 return ret;
 731
 732         mutex_lock(&indio_dev->mlock);
 733
 734         /* Find out if it is in the list */
 735         inlist = iio_buffer_is_active(indio_dev->buffer);
 736         /* Already in desired state */
 737         if (inlist == requested_state)
 738                 goto done;
 739
 740         if (requested_state)
 741                 ret = __iio_update_buffers(indio_dev,
 742                                          indio_dev->buffer, NULL);
 743         else
 744                 ret = __iio_update_buffers(indio_dev,
 745                                          NULL, indio_dev->buffer);
 746
 747         if (ret < 0)
 748                 goto done;
 749 done:
 750         mutex_unlock(&indio_dev->mlock);
 751         return (ret < 0) ? ret : len;
 752 }
 753 EXPORT_SYMBOL(iio_buffer_store_enable);
 754
 755 /**
 756  * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
 757  * @indio_dev: the iio device
 758  * @mask: scan mask to be checked
 759  *
 760  * Return true if exactly one bit is set in the scan mask, false otherwise. It
 761  * can be used for devices where only one channel can be active for sampling at
 762  * a time.
 763  */
 764 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
 765         const unsigned long *mask)
 766 {
 767         return bitmap_weight(mask, indio_dev->masklength) == 1;
 768 }
 769 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
 770
 771 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
 772         const unsigned long *mask)
 773 {
 774         if (!indio_dev->setup_ops->validate_scan_mask)
 775                 return true;
 776
 777         return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
 778 }
 779
 780 /**
 781  * iio_scan_mask_set() - set particular bit in the scan mask
 782  * @indio_dev: the iio device
 783  * @buffer: the buffer whose scan mask we are interested in
 784  * @bit: the bit to be set.
 785  *
 786  * Note that at this point we have no way of knowing what other
 787  * buffers might request, hence this code only verifies that the
 788  * individual buffers request is plausible.
 789  */
 790 int iio_scan_mask_set(struct iio_dev *indio_dev,
 791                       struct iio_buffer *buffer, int bit)
 792 {
 793         const unsigned long *mask;
 794         unsigned long *trialmask;
 795
 796         trialmask = kmalloc(sizeof(*trialmask)*
 797                             BITS_TO_LONGS(indio_dev->masklength),
 798                             GFP_KERNEL);
 799
 800         if (trialmask == NULL)
 801                 return -ENOMEM;
 802         if (!indio_dev->masklength) {
 803                 WARN_ON("Trying to set scanmask prior to registering buffer\n");
 804                 goto err_invalid_mask;
 805         }
 806         bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
 807         set_bit(bit, trialmask);
 808
 809         if (!iio_validate_scan_mask(indio_dev, trialmask))
 810                 goto err_invalid_mask;
 811
 812         if (indio_dev->available_scan_masks) {
 813                 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 814                                            indio_dev->masklength,
 815                                            trialmask);
 816                 if (!mask)
 817                         goto err_invalid_mask;
 818         }
 819         bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
 820
 821         kfree(trialmask);
 822
 823         return 0;
 824
 825 err_invalid_mask:
 826         kfree(trialmask);
 827         return -EINVAL;
 828 }
 829 EXPORT_SYMBOL_GPL(iio_scan_mask_set);
 830
 831 int iio_scan_mask_query(struct iio_dev *indio_dev,
 832                         struct iio_buffer *buffer, int bit)
 833 {
 834         if (bit > indio_dev->masklength)
 835                 return -EINVAL;
 836
 837         if (!buffer->scan_mask)
 838                 return 0;
 839
 840         return test_bit(bit, buffer->scan_mask);
 841 };
 842 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
 843
 844 /**
 845  * struct iio_demux_table() - table describing demux memcpy ops
 846  * @from:       index to copy from
 847  * @to:         index to copy to
 848  * @length:     how many bytes to copy
 849  * @l:          list head used for management
 850  */
 851 struct iio_demux_table {
 852         unsigned from;
 853         unsigned to;
 854         unsigned length;
 855         struct list_head l;
 856 };
 857
 858 static const void *iio_demux(struct iio_buffer *buffer,
 859                                  const void *datain)
 860 {
 861         struct iio_demux_table *t;
 862
 863         if (list_empty(&buffer->demux_list))
 864                 return datain;
 865         list_for_each_entry(t, &buffer->demux_list, l)
 866                 memcpy(buffer->demux_bounce + t->to,
 867                        datain + t->from, t->length);
 868
 869         return buffer->demux_bounce;
 870 }
 871
 872 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
 873 {
 874         const void *dataout = iio_demux(buffer, data);
 875
 876         return buffer->access->store_to(buffer, dataout);
 877 }
 878
 879 static void iio_buffer_demux_free(struct iio_buffer *buffer)
 880 {
 881         struct iio_demux_table *p, *q;
 882         list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
 883                 list_del(&p->l);
 884                 kfree(p);
 885         }
 886 }
 887
 888
 889 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
 890 {
 891         int ret;
 892         struct iio_buffer *buf;
 893
 894         list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
 895                 ret = iio_push_to_buffer(buf, data);
 896                 if (ret < 0)
 897                         return ret;
 898         }
 899
 900         return 0;
 901 }
 902 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
 903
 904 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
 905                                    struct iio_buffer *buffer)
 906 {
 907         const struct iio_chan_spec *ch;
 908         int ret, in_ind = -1, out_ind, length;
 909         unsigned in_loc = 0, out_loc = 0;
 910         struct iio_demux_table *p;
 911
 912         /* Clear out any old demux */
 913         iio_buffer_demux_free(buffer);
 914         kfree(buffer->demux_bounce);
 915         buffer->demux_bounce = NULL;
 916
 917         /* First work out which scan mode we will actually have */
 918         if (bitmap_equal(indio_dev->active_scan_mask,
 919                          buffer->scan_mask,
 920                          indio_dev->masklength))
 921                 return 0;
 922
 923         /* Now we have the two masks, work from least sig and build up sizes */
 924         for_each_set_bit(out_ind,
 925                          indio_dev->active_scan_mask,
 926                          indio_dev->masklength) {
 927                 in_ind = find_next_bit(indio_dev->active_scan_mask,
 928                                        indio_dev->masklength,
 929                                        in_ind + 1);
 930                 while (in_ind != out_ind) {
 931                         in_ind = find_next_bit(indio_dev->active_scan_mask,
 932                                                indio_dev->masklength,
 933                                                in_ind + 1);
 934                         ch = iio_find_channel_from_si(indio_dev, in_ind);
 935                         length = ch->scan_type.storagebits/8;
 936                         /* Make sure we are aligned */
 937                         in_loc += length;
 938                         if (in_loc % length)
 939                                 in_loc += length - in_loc % length;
 940                 }
 941                 p = kmalloc(sizeof(*p), GFP_KERNEL);
 942                 if (p == NULL) {
 943                         ret = -ENOMEM;
 944                         goto error_clear_mux_table;
 945                 }
 946                 ch = iio_find_channel_from_si(indio_dev, in_ind);
 947                 length = ch->scan_type.storagebits/8;
 948                 if (out_loc % length)
 949                         out_loc += length - out_loc % length;
 950                 if (in_loc % length)
 951                         in_loc += length - in_loc % length;
 952                 p->from = in_loc;
 953                 p->to = out_loc;
 954                 p->length = length;
 955                 list_add_tail(&p->l, &buffer->demux_list);
 956                 out_loc += length;
 957                 in_loc += length;
 958         }
 959         /* Relies on scan_timestamp being last */
 960         if (buffer->scan_timestamp) {
 961                 p = kmalloc(sizeof(*p), GFP_KERNEL);
 962                 if (p == NULL) {
 963                         ret = -ENOMEM;
 964                         goto error_clear_mux_table;
 965                 }
 966                 ch = iio_find_channel_from_si(indio_dev,
 967                         indio_dev->scan_index_timestamp);
 968                 length = ch->scan_type.storagebits/8;
 969                 if (out_loc % length)
 970                         out_loc += length - out_loc % length;
 971                 if (in_loc % length)
 972                         in_loc += length - in_loc % length;
 973                 p->from = in_loc;
 974                 p->to = out_loc;
 975                 p->length = length;
 976                 list_add_tail(&p->l, &buffer->demux_list);
 977                 out_loc += length;
 978                 in_loc += length;
 979         }
 980         buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
 981         if (buffer->demux_bounce == NULL) {
 982                 ret = -ENOMEM;
 983                 goto error_clear_mux_table;
 984         }
 985         return 0;
 986
 987 error_clear_mux_table:
 988         iio_buffer_demux_free(buffer);
 989
 990         return ret;
 991 }
 992
 993 int iio_update_demux(struct iio_dev *indio_dev)
 994 {
 995         struct iio_buffer *buffer;
 996         int ret;
 997
 998         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
 999                 ret = iio_buffer_update_demux(indio_dev, buffer);
1000                 if (ret < 0)
1001                         goto error_clear_mux_table;
1002         }
1003         return 0;
1004
1005 error_clear_mux_table:
1006         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1007                 iio_buffer_demux_free(buffer);
1008
1009         return ret;
1010 }
1011 EXPORT_SYMBOL_GPL(iio_update_demux);
1012
1013 /**
1014  * iio_buffer_release() - Free a buffer's resources
1015  * @ref: Pointer to the kref embedded in the iio_buffer struct
1016  *
1017  * This function is called when the last reference to the buffer has been
1018  * dropped. It will typically free all resources allocated by the buffer. Do not
1019  * call this function manually, always use iio_buffer_put() when done using a
1020  * buffer.
1021  */
1022 static void iio_buffer_release(struct kref *ref)
1023 {
1024         struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1025
1026         buffer->access->release(buffer);
1027 }
1028
1029 /**
1030  * iio_buffer_get() - Grab a reference to the buffer
1031  * @buffer: The buffer to grab a reference for, may be NULL
1032  *
1033  * Returns the pointer to the buffer that was passed into the function.
1034  */
1035 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1036 {
1037         if (buffer)
1038                 kref_get(&buffer->ref);
1039
1040         return buffer;
1041 }
1042 EXPORT_SYMBOL_GPL(iio_buffer_get);
1043
1044 /**
1045  * iio_buffer_put() - Release the reference to the buffer
1046  * @buffer: The buffer to release the reference for, may be NULL
1047  */
1048 void iio_buffer_put(struct iio_buffer *buffer)
1049 {
1050         if (buffer)
1051                 kref_put(&buffer->ref, iio_buffer_release);
1052 }
1053 EXPORT_SYMBOL_GPL(iio_buffer_put);