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 static bool iio_buffer_data_available(struct iio_buffer *buf)
  41 {
  42         if (buf->access->data_available)
  43                 return buf->access->data_available(buf);
  44
  45         return buf->stufftoread;
  46 }
  47
  48 /**
  49  * iio_buffer_read_first_n_outer() - chrdev read for buffer access
  50  *
  51  * This function relies on all buffer implementations having an
  52  * iio_buffer as their first element.
  53  **/
  54 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
  55                                       size_t n, loff_t *f_ps)
  56 {
  57         struct iio_dev *indio_dev = filp->private_data;
  58         struct iio_buffer *rb = indio_dev->buffer;
  59         int ret;
  60
  61         if (!indio_dev->info)
  62                 return -ENODEV;
  63
  64         if (!rb || !rb->access->read_first_n)
  65                 return -EINVAL;
  66
  67         do {
  68                 if (!iio_buffer_data_available(rb)) {
  69                         if (filp->f_flags & O_NONBLOCK)
  70                                 return -EAGAIN;
  71
  72                         ret = wait_event_interruptible(rb->pollq,
  73                                         iio_buffer_data_available(rb) ||
  74                                         indio_dev->info == NULL);
  75                         if (ret)
  76                                 return ret;
  77                         if (indio_dev->info == NULL)
  78                                 return -ENODEV;
  79                 }
  80
  81                 ret = rb->access->read_first_n(rb, n, buf);
  82                 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
  83                         ret = -EAGAIN;
  84          } while (ret == 0);
  85
  86         return ret;
  87 }
  88
  89 /**
  90  * iio_buffer_poll() - poll the buffer to find out if it has data
  91  */
  92 unsigned int iio_buffer_poll(struct file *filp,
  93                              struct poll_table_struct *wait)
  94 {
  95         struct iio_dev *indio_dev = filp->private_data;
  96         struct iio_buffer *rb = indio_dev->buffer;
  97
  98         if (!indio_dev->info)
  99                 return -ENODEV;
 100
 101         poll_wait(filp, &rb->pollq, wait);
 102         if (iio_buffer_data_available(rb))
 103                 return POLLIN | POLLRDNORM;
 104         /* need a way of knowing if there may be enough data... */
 105         return 0;
 106 }
 107
 108 /**
 109  * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
 110  * @indio_dev: The IIO device
 111  *
 112  * Wakes up the event waitqueue used for poll(). Should usually
 113  * be called when the device is unregistered.
 114  */
 115 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
 116 {
 117         if (!indio_dev->buffer)
 118                 return;
 119
 120         wake_up(&indio_dev->buffer->pollq);
 121 }
 122
 123 void iio_buffer_init(struct iio_buffer *buffer)
 124 {
 125         INIT_LIST_HEAD(&buffer->demux_list);
 126         INIT_LIST_HEAD(&buffer->buffer_list);
 127         init_waitqueue_head(&buffer->pollq);
 128         kref_init(&buffer->ref);
 129 }
 130 EXPORT_SYMBOL(iio_buffer_init);
 131
 132 static ssize_t iio_show_scan_index(struct device *dev,
 133                                    struct device_attribute *attr,
 134                                    char *buf)
 135 {
 136         return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
 137 }
 138
 139 static ssize_t iio_show_fixed_type(struct device *dev,
 140                                    struct device_attribute *attr,
 141                                    char *buf)
 142 {
 143         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 144         u8 type = this_attr->c->scan_type.endianness;
 145
 146         if (type == IIO_CPU) {
 147 #ifdef __LITTLE_ENDIAN
 148                 type = IIO_LE;
 149 #else
 150                 type = IIO_BE;
 151 #endif
 152         }
 153         return sprintf(buf, "%s:%c%d/%d>>%u\n",
 154                        iio_endian_prefix[type],
 155                        this_attr->c->scan_type.sign,
 156                        this_attr->c->scan_type.realbits,
 157                        this_attr->c->scan_type.storagebits,
 158                        this_attr->c->scan_type.shift);
 159 }
 160
 161 static ssize_t iio_scan_el_show(struct device *dev,
 162                                 struct device_attribute *attr,
 163                                 char *buf)
 164 {
 165         int ret;
 166         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 167
 168         /* Ensure ret is 0 or 1. */
 169         ret = !!test_bit(to_iio_dev_attr(attr)->address,
 170                        indio_dev->buffer->scan_mask);
 171
 172         return sprintf(buf, "%d\n", ret);
 173 }
 174
 175 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
 176 {
 177         clear_bit(bit, buffer->scan_mask);
 178         return 0;
 179 }
 180
 181 static ssize_t iio_scan_el_store(struct device *dev,
 182                                  struct device_attribute *attr,
 183                                  const char *buf,
 184                                  size_t len)
 185 {
 186         int ret;
 187         bool state;
 188         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 189         struct iio_buffer *buffer = indio_dev->buffer;
 190         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 191
 192         ret = strtobool(buf, &state);
 193         if (ret < 0)
 194                 return ret;
 195         mutex_lock(&indio_dev->mlock);
 196         if (iio_buffer_is_active(indio_dev->buffer)) {
 197                 ret = -EBUSY;
 198                 goto error_ret;
 199         }
 200         ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
 201         if (ret < 0)
 202                 goto error_ret;
 203         if (!state && ret) {
 204                 ret = iio_scan_mask_clear(buffer, this_attr->address);
 205                 if (ret)
 206                         goto error_ret;
 207         } else if (state && !ret) {
 208                 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
 209                 if (ret)
 210                         goto error_ret;
 211         }
 212
 213 error_ret:
 214         mutex_unlock(&indio_dev->mlock);
 215
 216         return ret < 0 ? ret : len;
 217
 218 }
 219
 220 static ssize_t iio_scan_el_ts_show(struct device *dev,
 221                                    struct device_attribute *attr,
 222                                    char *buf)
 223 {
 224         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 225         return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
 226 }
 227
 228 static ssize_t iio_scan_el_ts_store(struct device *dev,
 229                                     struct device_attribute *attr,
 230                                     const char *buf,
 231                                     size_t len)
 232 {
 233         int ret;
 234         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 235         bool state;
 236
 237         ret = strtobool(buf, &state);
 238         if (ret < 0)
 239                 return ret;
 240
 241         mutex_lock(&indio_dev->mlock);
 242         if (iio_buffer_is_active(indio_dev->buffer)) {
 243                 ret = -EBUSY;
 244                 goto error_ret;
 245         }
 246         indio_dev->buffer->scan_timestamp = state;
 247 error_ret:
 248         mutex_unlock(&indio_dev->mlock);
 249
 250         return ret ? ret : len;
 251 }
 252
 253 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
 254                                         const struct iio_chan_spec *chan)
 255 {
 256         int ret, attrcount = 0;
 257         struct iio_buffer *buffer = indio_dev->buffer;
 258
 259         ret = __iio_add_chan_devattr("index",
 260                                      chan,
 261                                      &iio_show_scan_index,
 262                                      NULL,
 263                                      0,
 264                                      IIO_SEPARATE,
 265                                      &indio_dev->dev,
 266                                      &buffer->scan_el_dev_attr_list);
 267         if (ret)
 268                 goto error_ret;
 269         attrcount++;
 270         ret = __iio_add_chan_devattr("type",
 271                                      chan,
 272                                      &iio_show_fixed_type,
 273                                      NULL,
 274                                      0,
 275                                      0,
 276                                      &indio_dev->dev,
 277                                      &buffer->scan_el_dev_attr_list);
 278         if (ret)
 279                 goto error_ret;
 280         attrcount++;
 281         if (chan->type != IIO_TIMESTAMP)
 282                 ret = __iio_add_chan_devattr("en",
 283                                              chan,
 284                                              &iio_scan_el_show,
 285                                              &iio_scan_el_store,
 286                                              chan->scan_index,
 287                                              0,
 288                                              &indio_dev->dev,
 289                                              &buffer->scan_el_dev_attr_list);
 290         else
 291                 ret = __iio_add_chan_devattr("en",
 292                                              chan,
 293                                              &iio_scan_el_ts_show,
 294                                              &iio_scan_el_ts_store,
 295                                              chan->scan_index,
 296                                              0,
 297                                              &indio_dev->dev,
 298                                              &buffer->scan_el_dev_attr_list);
 299         if (ret)
 300                 goto error_ret;
 301         attrcount++;
 302         ret = attrcount;
 303 error_ret:
 304         return ret;
 305 }
 306
 307 static const char * const iio_scan_elements_group_name = "scan_elements";
 308
 309 int iio_buffer_register(struct iio_dev *indio_dev,
 310                         const struct iio_chan_spec *channels,
 311                         int num_channels)
 312 {
 313         struct iio_dev_attr *p;
 314         struct attribute **attr;
 315         struct iio_buffer *buffer = indio_dev->buffer;
 316         int ret, i, attrn, attrcount, attrcount_orig = 0;
 317
 318         if (buffer->attrs)
 319                 indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
 320
 321         if (buffer->scan_el_attrs != NULL) {
 322                 attr = buffer->scan_el_attrs->attrs;
 323                 while (*attr++ != NULL)
 324                         attrcount_orig++;
 325         }
 326         attrcount = attrcount_orig;
 327         INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
 328         if (channels) {
 329                 /* new magic */
 330                 for (i = 0; i < num_channels; i++) {
 331                         if (channels[i].scan_index < 0)
 332                                 continue;
 333
 334                         /* Establish necessary mask length */
 335                         if (channels[i].scan_index >
 336                             (int)indio_dev->masklength - 1)
 337                                 indio_dev->masklength
 338                                         = channels[i].scan_index + 1;
 339
 340                         ret = iio_buffer_add_channel_sysfs(indio_dev,
 341                                                          &channels[i]);
 342                         if (ret < 0)
 343                                 goto error_cleanup_dynamic;
 344                         attrcount += ret;
 345                         if (channels[i].type == IIO_TIMESTAMP)
 346                                 indio_dev->scan_index_timestamp =
 347                                         channels[i].scan_index;
 348                 }
 349                 if (indio_dev->masklength && buffer->scan_mask == NULL) {
 350                         buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
 351                                                     sizeof(*buffer->scan_mask),
 352                                                     GFP_KERNEL);
 353                         if (buffer->scan_mask == NULL) {
 354                                 ret = -ENOMEM;
 355                                 goto error_cleanup_dynamic;
 356                         }
 357                 }
 358         }
 359
 360         buffer->scan_el_group.name = iio_scan_elements_group_name;
 361
 362         buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
 363                                               sizeof(buffer->scan_el_group.attrs[0]),
 364                                               GFP_KERNEL);
 365         if (buffer->scan_el_group.attrs == NULL) {
 366                 ret = -ENOMEM;
 367                 goto error_free_scan_mask;
 368         }
 369         if (buffer->scan_el_attrs)
 370                 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
 371                        sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
 372         attrn = attrcount_orig;
 373
 374         list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
 375                 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
 376         indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
 377
 378         return 0;
 379
 380 error_free_scan_mask:
 381         kfree(buffer->scan_mask);
 382 error_cleanup_dynamic:
 383         iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
 384
 385         return ret;
 386 }
 387 EXPORT_SYMBOL(iio_buffer_register);
 388
 389 void iio_buffer_unregister(struct iio_dev *indio_dev)
 390 {
 391         kfree(indio_dev->buffer->scan_mask);
 392         kfree(indio_dev->buffer->scan_el_group.attrs);
 393         iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
 394 }
 395 EXPORT_SYMBOL(iio_buffer_unregister);
 396
 397 ssize_t iio_buffer_read_length(struct device *dev,
 398                                struct device_attribute *attr,
 399                                char *buf)
 400 {
 401         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 402         struct iio_buffer *buffer = indio_dev->buffer;
 403
 404         if (buffer->access->get_length)
 405                 return sprintf(buf, "%d\n",
 406                                buffer->access->get_length(buffer));
 407
 408         return 0;
 409 }
 410 EXPORT_SYMBOL(iio_buffer_read_length);
 411
 412 ssize_t iio_buffer_write_length(struct device *dev,
 413                                 struct device_attribute *attr,
 414                                 const char *buf,
 415                                 size_t len)
 416 {
 417         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 418         struct iio_buffer *buffer = indio_dev->buffer;
 419         unsigned int val;
 420         int ret;
 421
 422         ret = kstrtouint(buf, 10, &val);
 423         if (ret)
 424                 return ret;
 425
 426         if (buffer->access->get_length)
 427                 if (val == buffer->access->get_length(buffer))
 428                         return len;
 429
 430         mutex_lock(&indio_dev->mlock);
 431         if (iio_buffer_is_active(indio_dev->buffer)) {
 432                 ret = -EBUSY;
 433         } else {
 434                 if (buffer->access->set_length)
 435                         buffer->access->set_length(buffer, val);
 436                 ret = 0;
 437         }
 438         mutex_unlock(&indio_dev->mlock);
 439
 440         return ret ? ret : len;
 441 }
 442 EXPORT_SYMBOL(iio_buffer_write_length);
 443
 444 ssize_t iio_buffer_show_enable(struct device *dev,
 445                                struct device_attribute *attr,
 446                                char *buf)
 447 {
 448         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 449         return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
 450 }
 451 EXPORT_SYMBOL(iio_buffer_show_enable);
 452
 453 /* Note NULL used as error indicator as it doesn't make sense. */
 454 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
 455                                           unsigned int masklength,
 456                                           const unsigned long *mask)
 457 {
 458         if (bitmap_empty(mask, masklength))
 459                 return NULL;
 460         while (*av_masks) {
 461                 if (bitmap_subset(mask, av_masks, masklength))
 462                         return av_masks;
 463                 av_masks += BITS_TO_LONGS(masklength);
 464         }
 465         return NULL;
 466 }
 467
 468 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
 469                                 const unsigned long *mask, bool timestamp)
 470 {
 471         const struct iio_chan_spec *ch;
 472         unsigned bytes = 0;
 473         int length, i;
 474
 475         /* How much space will the demuxed element take? */
 476         for_each_set_bit(i, mask,
 477                          indio_dev->masklength) {
 478                 ch = iio_find_channel_from_si(indio_dev, i);
 479                 length = ch->scan_type.storagebits / 8;
 480                 bytes = ALIGN(bytes, length);
 481                 bytes += length;
 482         }
 483         if (timestamp) {
 484                 ch = iio_find_channel_from_si(indio_dev,
 485                                               indio_dev->scan_index_timestamp);
 486                 length = ch->scan_type.storagebits / 8;
 487                 bytes = ALIGN(bytes, length);
 488                 bytes += length;
 489         }
 490         return bytes;
 491 }
 492
 493 static void iio_buffer_activate(struct iio_dev *indio_dev,
 494         struct iio_buffer *buffer)
 495 {
 496         iio_buffer_get(buffer);
 497         list_add(&buffer->buffer_list, &indio_dev->buffer_list);
 498 }
 499
 500 static void iio_buffer_deactivate(struct iio_buffer *buffer)
 501 {
 502         list_del_init(&buffer->buffer_list);
 503         iio_buffer_put(buffer);
 504 }
 505
 506 void iio_disable_all_buffers(struct iio_dev *indio_dev)
 507 {
 508         struct iio_buffer *buffer, *_buffer;
 509
 510         if (list_empty(&indio_dev->buffer_list))
 511                 return;
 512
 513         if (indio_dev->setup_ops->predisable)
 514                 indio_dev->setup_ops->predisable(indio_dev);
 515
 516         list_for_each_entry_safe(buffer, _buffer,
 517                         &indio_dev->buffer_list, buffer_list)
 518                 iio_buffer_deactivate(buffer);
 519
 520         indio_dev->currentmode = INDIO_DIRECT_MODE;
 521         if (indio_dev->setup_ops->postdisable)
 522                 indio_dev->setup_ops->postdisable(indio_dev);
 523
 524         if (indio_dev->available_scan_masks == NULL)
 525                 kfree(indio_dev->active_scan_mask);
 526 }
 527
 528 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
 529         struct iio_buffer *buffer)
 530 {
 531         unsigned int bytes;
 532
 533         if (!buffer->access->set_bytes_per_datum)
 534                 return;
 535
 536         bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
 537                 buffer->scan_timestamp);
 538
 539         buffer->access->set_bytes_per_datum(buffer, bytes);
 540 }
 541
 542 static int __iio_update_buffers(struct iio_dev *indio_dev,
 543                        struct iio_buffer *insert_buffer,
 544                        struct iio_buffer *remove_buffer)
 545 {
 546         int ret;
 547         int success = 0;
 548         struct iio_buffer *buffer;
 549         unsigned long *compound_mask;
 550         const unsigned long *old_mask;
 551
 552         /* Wind down existing buffers - iff there are any */
 553         if (!list_empty(&indio_dev->buffer_list)) {
 554                 if (indio_dev->setup_ops->predisable) {
 555                         ret = indio_dev->setup_ops->predisable(indio_dev);
 556                         if (ret)
 557                                 goto error_ret;
 558                 }
 559                 indio_dev->currentmode = INDIO_DIRECT_MODE;
 560                 if (indio_dev->setup_ops->postdisable) {
 561                         ret = indio_dev->setup_ops->postdisable(indio_dev);
 562                         if (ret)
 563                                 goto error_ret;
 564                 }
 565         }
 566         /* Keep a copy of current setup to allow roll back */
 567         old_mask = indio_dev->active_scan_mask;
 568         if (!indio_dev->available_scan_masks)
 569                 indio_dev->active_scan_mask = NULL;
 570
 571         if (remove_buffer)
 572                 iio_buffer_deactivate(remove_buffer);
 573         if (insert_buffer)
 574                 iio_buffer_activate(indio_dev, insert_buffer);
 575
 576         /* If no buffers in list, we are done */
 577         if (list_empty(&indio_dev->buffer_list)) {
 578                 indio_dev->currentmode = INDIO_DIRECT_MODE;
 579                 if (indio_dev->available_scan_masks == NULL)
 580                         kfree(old_mask);
 581                 return 0;
 582         }
 583
 584         /* What scan mask do we actually have? */
 585         compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
 586                                 sizeof(long), GFP_KERNEL);
 587         if (compound_mask == NULL) {
 588                 if (indio_dev->available_scan_masks == NULL)
 589                         kfree(old_mask);
 590                 return -ENOMEM;
 591         }
 592         indio_dev->scan_timestamp = 0;
 593
 594         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
 595                 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
 596                           indio_dev->masklength);
 597                 indio_dev->scan_timestamp |= buffer->scan_timestamp;
 598         }
 599         if (indio_dev->available_scan_masks) {
 600                 indio_dev->active_scan_mask =
 601                         iio_scan_mask_match(indio_dev->available_scan_masks,
 602                                             indio_dev->masklength,
 603                                             compound_mask);
 604                 if (indio_dev->active_scan_mask == NULL) {
 605                         /*
 606                          * Roll back.
 607                          * Note can only occur when adding a buffer.
 608                          */
 609                         iio_buffer_deactivate(insert_buffer);
 610                         if (old_mask) {
 611                                 indio_dev->active_scan_mask = old_mask;
 612                                 success = -EINVAL;
 613                         }
 614                         else {
 615                                 kfree(compound_mask);
 616                                 ret = -EINVAL;
 617                                 goto error_ret;
 618                         }
 619                 }
 620         } else {
 621                 indio_dev->active_scan_mask = compound_mask;
 622         }
 623
 624         iio_update_demux(indio_dev);
 625
 626         /* Wind up again */
 627         if (indio_dev->setup_ops->preenable) {
 628                 ret = indio_dev->setup_ops->preenable(indio_dev);
 629                 if (ret) {
 630                         printk(KERN_ERR
 631                                "Buffer not started: buffer preenable failed (%d)\n", ret);
 632                         goto error_remove_inserted;
 633                 }
 634         }
 635         indio_dev->scan_bytes =
 636                 iio_compute_scan_bytes(indio_dev,
 637                                        indio_dev->active_scan_mask,
 638                                        indio_dev->scan_timestamp);
 639         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
 640                 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
 641                 if (buffer->access->request_update) {
 642                         ret = buffer->access->request_update(buffer);
 643                         if (ret) {
 644                                 printk(KERN_INFO
 645                                        "Buffer not started: buffer parameter update failed (%d)\n", ret);
 646                                 goto error_run_postdisable;
 647                         }
 648                 }
 649         }
 650         if (indio_dev->info->update_scan_mode) {
 651                 ret = indio_dev->info
 652                         ->update_scan_mode(indio_dev,
 653                                            indio_dev->active_scan_mask);
 654                 if (ret < 0) {
 655                         printk(KERN_INFO "Buffer not started: update scan mode failed (%d)\n", ret);
 656                         goto error_run_postdisable;
 657                 }
 658         }
 659         /* Definitely possible for devices to support both of these. */
 660         if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
 661                 if (!indio_dev->trig) {
 662                         printk(KERN_INFO "Buffer not started: no trigger\n");
 663                         ret = -EINVAL;
 664                         /* Can only occur on first buffer */
 665                         goto error_run_postdisable;
 666                 }
 667                 indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
 668         } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
 669                 indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
 670         } else { /* Should never be reached */
 671                 ret = -EINVAL;
 672                 goto error_run_postdisable;
 673         }
 674
 675         if (indio_dev->setup_ops->postenable) {
 676                 ret = indio_dev->setup_ops->postenable(indio_dev);
 677                 if (ret) {
 678                         printk(KERN_INFO
 679                                "Buffer not started: postenable failed (%d)\n", ret);
 680                         indio_dev->currentmode = INDIO_DIRECT_MODE;
 681                         if (indio_dev->setup_ops->postdisable)
 682                                 indio_dev->setup_ops->postdisable(indio_dev);
 683                         goto error_disable_all_buffers;
 684                 }
 685         }
 686
 687         if (indio_dev->available_scan_masks)
 688                 kfree(compound_mask);
 689         else
 690                 kfree(old_mask);
 691
 692         return success;
 693
 694 error_disable_all_buffers:
 695         indio_dev->currentmode = INDIO_DIRECT_MODE;
 696 error_run_postdisable:
 697         if (indio_dev->setup_ops->postdisable)
 698                 indio_dev->setup_ops->postdisable(indio_dev);
 699 error_remove_inserted:
 700
 701         if (insert_buffer)
 702                 iio_buffer_deactivate(insert_buffer);
 703         indio_dev->active_scan_mask = old_mask;
 704         kfree(compound_mask);
 705 error_ret:
 706
 707         return ret;
 708 }
 709
 710 int iio_update_buffers(struct iio_dev *indio_dev,
 711                        struct iio_buffer *insert_buffer,
 712                        struct iio_buffer *remove_buffer)
 713 {
 714         int ret;
 715
 716         if (insert_buffer == remove_buffer)
 717                 return 0;
 718
 719         mutex_lock(&indio_dev->info_exist_lock);
 720         mutex_lock(&indio_dev->mlock);
 721
 722         if (insert_buffer && iio_buffer_is_active(insert_buffer))
 723                 insert_buffer = NULL;
 724
 725         if (remove_buffer && !iio_buffer_is_active(remove_buffer))
 726                 remove_buffer = NULL;
 727
 728         if (!insert_buffer && !remove_buffer) {
 729                 ret = 0;
 730                 goto out_unlock;
 731         }
 732
 733         if (indio_dev->info == NULL) {
 734                 ret = -ENODEV;
 735                 goto out_unlock;
 736         }
 737
 738         ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
 739
 740 out_unlock:
 741         mutex_unlock(&indio_dev->mlock);
 742         mutex_unlock(&indio_dev->info_exist_lock);
 743
 744         return ret;
 745 }
 746 EXPORT_SYMBOL_GPL(iio_update_buffers);
 747
 748 ssize_t iio_buffer_store_enable(struct device *dev,
 749                                 struct device_attribute *attr,
 750                                 const char *buf,
 751                                 size_t len)
 752 {
 753         int ret;
 754         bool requested_state;
 755         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 756         bool inlist;
 757
 758         ret = strtobool(buf, &requested_state);
 759         if (ret < 0)
 760                 return ret;
 761
 762         mutex_lock(&indio_dev->mlock);
 763
 764         /* Find out if it is in the list */
 765         inlist = iio_buffer_is_active(indio_dev->buffer);
 766         /* Already in desired state */
 767         if (inlist == requested_state)
 768                 goto done;
 769
 770         if (requested_state)
 771                 ret = __iio_update_buffers(indio_dev,
 772                                          indio_dev->buffer, NULL);
 773         else
 774                 ret = __iio_update_buffers(indio_dev,
 775                                          NULL, indio_dev->buffer);
 776
 777         if (ret < 0)
 778                 goto done;
 779 done:
 780         mutex_unlock(&indio_dev->mlock);
 781         return (ret < 0) ? ret : len;
 782 }
 783 EXPORT_SYMBOL(iio_buffer_store_enable);
 784
 785 /**
 786  * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
 787  * @indio_dev: the iio device
 788  * @mask: scan mask to be checked
 789  *
 790  * Return true if exactly one bit is set in the scan mask, false otherwise. It
 791  * can be used for devices where only one channel can be active for sampling at
 792  * a time.
 793  */
 794 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
 795         const unsigned long *mask)
 796 {
 797         return bitmap_weight(mask, indio_dev->masklength) == 1;
 798 }
 799 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
 800
 801 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
 802         const unsigned long *mask)
 803 {
 804         if (!indio_dev->setup_ops->validate_scan_mask)
 805                 return true;
 806
 807         return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
 808 }
 809
 810 /**
 811  * iio_scan_mask_set() - set particular bit in the scan mask
 812  * @indio_dev: the iio device
 813  * @buffer: the buffer whose scan mask we are interested in
 814  * @bit: the bit to be set.
 815  *
 816  * Note that at this point we have no way of knowing what other
 817  * buffers might request, hence this code only verifies that the
 818  * individual buffers request is plausible.
 819  */
 820 int iio_scan_mask_set(struct iio_dev *indio_dev,
 821                       struct iio_buffer *buffer, int bit)
 822 {
 823         const unsigned long *mask;
 824         unsigned long *trialmask;
 825
 826         trialmask = kmalloc(sizeof(*trialmask)*
 827                             BITS_TO_LONGS(indio_dev->masklength),
 828                             GFP_KERNEL);
 829
 830         if (trialmask == NULL)
 831                 return -ENOMEM;
 832         if (!indio_dev->masklength) {
 833                 WARN_ON("Trying to set scanmask prior to registering buffer\n");
 834                 goto err_invalid_mask;
 835         }
 836         bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
 837         set_bit(bit, trialmask);
 838
 839         if (!iio_validate_scan_mask(indio_dev, trialmask))
 840                 goto err_invalid_mask;
 841
 842         if (indio_dev->available_scan_masks) {
 843                 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 844                                            indio_dev->masklength,
 845                                            trialmask);
 846                 if (!mask)
 847                         goto err_invalid_mask;
 848         }
 849         bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
 850
 851         kfree(trialmask);
 852
 853         return 0;
 854
 855 err_invalid_mask:
 856         kfree(trialmask);
 857         return -EINVAL;
 858 }
 859 EXPORT_SYMBOL_GPL(iio_scan_mask_set);
 860
 861 int iio_scan_mask_query(struct iio_dev *indio_dev,
 862                         struct iio_buffer *buffer, int bit)
 863 {
 864         if (bit > indio_dev->masklength)
 865                 return -EINVAL;
 866
 867         if (!buffer->scan_mask)
 868                 return 0;
 869
 870         /* Ensure return value is 0 or 1. */
 871         return !!test_bit(bit, buffer->scan_mask);
 872 };
 873 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
 874
 875 /**
 876  * struct iio_demux_table() - table describing demux memcpy ops
 877  * @from:       index to copy from
 878  * @to:         index to copy to
 879  * @length:     how many bytes to copy
 880  * @l:          list head used for management
 881  */
 882 struct iio_demux_table {
 883         unsigned from;
 884         unsigned to;
 885         unsigned length;
 886         struct list_head l;
 887 };
 888
 889 static const void *iio_demux(struct iio_buffer *buffer,
 890                                  const void *datain)
 891 {
 892         struct iio_demux_table *t;
 893
 894         if (list_empty(&buffer->demux_list))
 895                 return datain;
 896         list_for_each_entry(t, &buffer->demux_list, l)
 897                 memcpy(buffer->demux_bounce + t->to,
 898                        datain + t->from, t->length);
 899
 900         return buffer->demux_bounce;
 901 }
 902
 903 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
 904 {
 905         const void *dataout = iio_demux(buffer, data);
 906
 907         return buffer->access->store_to(buffer, dataout);
 908 }
 909
 910 static void iio_buffer_demux_free(struct iio_buffer *buffer)
 911 {
 912         struct iio_demux_table *p, *q;
 913         list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
 914                 list_del(&p->l);
 915                 kfree(p);
 916         }
 917 }
 918
 919
 920 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
 921 {
 922         int ret;
 923         struct iio_buffer *buf;
 924
 925         list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
 926                 ret = iio_push_to_buffer(buf, data);
 927                 if (ret < 0)
 928                         return ret;
 929         }
 930
 931         return 0;
 932 }
 933 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
 934
 935 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
 936                                    struct iio_buffer *buffer)
 937 {
 938         const struct iio_chan_spec *ch;
 939         int ret, in_ind = -1, out_ind, length;
 940         unsigned in_loc = 0, out_loc = 0;
 941         struct iio_demux_table *p;
 942
 943         /* Clear out any old demux */
 944         iio_buffer_demux_free(buffer);
 945         kfree(buffer->demux_bounce);
 946         buffer->demux_bounce = NULL;
 947
 948         /* First work out which scan mode we will actually have */
 949         if (bitmap_equal(indio_dev->active_scan_mask,
 950                          buffer->scan_mask,
 951                          indio_dev->masklength))
 952                 return 0;
 953
 954         /* Now we have the two masks, work from least sig and build up sizes */
 955         for_each_set_bit(out_ind,
 956                          buffer->scan_mask,
 957                          indio_dev->masklength) {
 958                 in_ind = find_next_bit(indio_dev->active_scan_mask,
 959                                        indio_dev->masklength,
 960                                        in_ind + 1);
 961                 while (in_ind != out_ind) {
 962                         in_ind = find_next_bit(indio_dev->active_scan_mask,
 963                                                indio_dev->masklength,
 964                                                in_ind + 1);
 965                         ch = iio_find_channel_from_si(indio_dev, in_ind);
 966                         length = ch->scan_type.storagebits/8;
 967                         /* Make sure we are aligned */
 968                         in_loc += length;
 969                         if (in_loc % length)
 970                                 in_loc += length - in_loc % length;
 971                 }
 972                 p = kmalloc(sizeof(*p), GFP_KERNEL);
 973                 if (p == NULL) {
 974                         ret = -ENOMEM;
 975                         goto error_clear_mux_table;
 976                 }
 977                 ch = iio_find_channel_from_si(indio_dev, in_ind);
 978                 length = ch->scan_type.storagebits/8;
 979                 if (out_loc % length)
 980                         out_loc += length - out_loc % length;
 981                 if (in_loc % length)
 982                         in_loc += length - in_loc % length;
 983                 p->from = in_loc;
 984                 p->to = out_loc;
 985                 p->length = length;
 986                 list_add_tail(&p->l, &buffer->demux_list);
 987                 out_loc += length;
 988                 in_loc += length;
 989         }
 990         /* Relies on scan_timestamp being last */
 991         if (buffer->scan_timestamp) {
 992                 p = kmalloc(sizeof(*p), GFP_KERNEL);
 993                 if (p == NULL) {
 994                         ret = -ENOMEM;
 995                         goto error_clear_mux_table;
 996                 }
 997                 ch = iio_find_channel_from_si(indio_dev,
 998                         indio_dev->scan_index_timestamp);
 999                 length = ch->scan_type.storagebits/8;
1000                 if (out_loc % length)
1001                         out_loc += length - out_loc % length;
1002                 if (in_loc % length)
1003                         in_loc += length - in_loc % length;
1004                 p->from = in_loc;
1005                 p->to = out_loc;
1006                 p->length = length;
1007                 list_add_tail(&p->l, &buffer->demux_list);
1008                 out_loc += length;
1009                 in_loc += length;
1010         }
1011         buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1012         if (buffer->demux_bounce == NULL) {
1013                 ret = -ENOMEM;
1014                 goto error_clear_mux_table;
1015         }
1016         return 0;
1017
1018 error_clear_mux_table:
1019         iio_buffer_demux_free(buffer);
1020
1021         return ret;
1022 }
1023
1024 int iio_update_demux(struct iio_dev *indio_dev)
1025 {
1026         struct iio_buffer *buffer;
1027         int ret;
1028
1029         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1030                 ret = iio_buffer_update_demux(indio_dev, buffer);
1031                 if (ret < 0)
1032                         goto error_clear_mux_table;
1033         }
1034         return 0;
1035
1036 error_clear_mux_table:
1037         list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1038                 iio_buffer_demux_free(buffer);
1039
1040         return ret;
1041 }
1042 EXPORT_SYMBOL_GPL(iio_update_demux);
1043
1044 /**
1045  * iio_buffer_release() - Free a buffer's resources
1046  * @ref: Pointer to the kref embedded in the iio_buffer struct
1047  *
1048  * This function is called when the last reference to the buffer has been
1049  * dropped. It will typically free all resources allocated by the buffer. Do not
1050  * call this function manually, always use iio_buffer_put() when done using a
1051  * buffer.
1052  */
1053 static void iio_buffer_release(struct kref *ref)
1054 {
1055         struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1056
1057         buffer->access->release(buffer);
1058 }
1059
1060 /**
1061  * iio_buffer_get() - Grab a reference to the buffer
1062  * @buffer: The buffer to grab a reference for, may be NULL
1063  *
1064  * Returns the pointer to the buffer that was passed into the function.
1065  */
1066 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1067 {
1068         if (buffer)
1069                 kref_get(&buffer->ref);
1070
1071         return buffer;
1072 }
1073 EXPORT_SYMBOL_GPL(iio_buffer_get);
1074
1075 /**
1076  * iio_buffer_put() - Release the reference to the buffer
1077  * @buffer: The buffer to release the reference for, may be NULL
1078  */
1079 void iio_buffer_put(struct iio_buffer *buffer)
1080 {
1081         if (buffer)
1082                 kref_put(&buffer->ref, iio_buffer_release);
1083 }
1084 EXPORT_SYMBOL_GPL(iio_buffer_put);