drivers/staging/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
  24 #include "iio.h"
  25 #include "iio_core.h"
  26 #include "sysfs.h"
  27 #include "buffer.h"
  28
  29 static const char * const iio_endian_prefix[] = {
  30         [IIO_BE] = "be",
  31         [IIO_LE] = "le",
  32 };
  33
  34 /**
  35  * iio_buffer_read_first_n_outer() - chrdev read for buffer access
  36  *
  37  * This function relies on all buffer implementations having an
  38  * iio_buffer as their first element.
  39  **/
  40 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
  41                                       size_t n, loff_t *f_ps)
  42 {
  43         struct iio_dev *indio_dev = filp->private_data;
  44         struct iio_buffer *rb = indio_dev->buffer;
  45
  46         if (!rb || !rb->access->read_first_n)
  47                 return -EINVAL;
  48         return rb->access->read_first_n(rb, n, buf);
  49 }
  50
  51 /**
  52  * iio_buffer_poll() - poll the buffer to find out if it has data
  53  */
  54 unsigned int iio_buffer_poll(struct file *filp,
  55                              struct poll_table_struct *wait)
  56 {
  57         struct iio_dev *indio_dev = filp->private_data;
  58         struct iio_buffer *rb = indio_dev->buffer;
  59
  60         poll_wait(filp, &rb->pollq, wait);
  61         if (rb->stufftoread)
  62                 return POLLIN | POLLRDNORM;
  63         /* need a way of knowing if there may be enough data... */
  64         return 0;
  65 }
  66
  67 int iio_chrdev_buffer_open(struct iio_dev *indio_dev)
  68 {
  69         struct iio_buffer *rb = indio_dev->buffer;
  70         if (!rb)
  71                 return 0;
  72         if (rb->access->mark_in_use)
  73                 rb->access->mark_in_use(rb);
  74         return 0;
  75 }
  76
  77 void iio_chrdev_buffer_release(struct iio_dev *indio_dev)
  78 {
  79         struct iio_buffer *rb = indio_dev->buffer;
  80
  81         if (!rb)
  82                 return;
  83         clear_bit(IIO_BUSY_BIT_POS, &rb->flags);
  84         if (rb->access->unmark_in_use)
  85                 rb->access->unmark_in_use(rb);
  86 }
  87
  88 void iio_buffer_init(struct iio_buffer *buffer, struct iio_dev *indio_dev)
  89 {
  90         buffer->indio_dev = indio_dev;
  91         init_waitqueue_head(&buffer->pollq);
  92 }
  93 EXPORT_SYMBOL(iio_buffer_init);
  94
  95 static ssize_t iio_show_scan_index(struct device *dev,
  96                                    struct device_attribute *attr,
  97                                    char *buf)
  98 {
  99         return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
 100 }
 101
 102 static ssize_t iio_show_fixed_type(struct device *dev,
 103                                    struct device_attribute *attr,
 104                                    char *buf)
 105 {
 106         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 107         u8 type = this_attr->c->scan_type.endianness;
 108
 109         if (type == IIO_CPU) {
 110 #ifdef __LITTLE_ENDIAN
 111                 type = IIO_LE;
 112 #else
 113                 type = IIO_BE;
 114 #endif
 115         }
 116         return sprintf(buf, "%s:%c%d/%d>>%u\n",
 117                        iio_endian_prefix[type],
 118                        this_attr->c->scan_type.sign,
 119                        this_attr->c->scan_type.realbits,
 120                        this_attr->c->scan_type.storagebits,
 121                        this_attr->c->scan_type.shift);
 122 }
 123
 124 static ssize_t iio_scan_el_show(struct device *dev,
 125                                 struct device_attribute *attr,
 126                                 char *buf)
 127 {
 128         int ret;
 129         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 130
 131         ret = iio_scan_mask_query(indio_dev->buffer,
 132                                   to_iio_dev_attr(attr)->address);
 133         if (ret < 0)
 134                 return ret;
 135         return sprintf(buf, "%d\n", ret);
 136 }
 137
 138 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
 139 {
 140         clear_bit(bit, buffer->scan_mask);
 141         buffer->scan_count--;
 142         return 0;
 143 }
 144
 145 static ssize_t iio_scan_el_store(struct device *dev,
 146                                  struct device_attribute *attr,
 147                                  const char *buf,
 148                                  size_t len)
 149 {
 150         int ret = 0;
 151         bool state;
 152         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 153         struct iio_buffer *buffer = indio_dev->buffer;
 154         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 155
 156         state = !(buf[0] == '0');
 157         mutex_lock(&indio_dev->mlock);
 158         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 159                 ret = -EBUSY;
 160                 goto error_ret;
 161         }
 162         ret = iio_scan_mask_query(buffer, this_attr->address);
 163         if (ret < 0)
 164                 goto error_ret;
 165         if (!state && ret) {
 166                 ret = iio_scan_mask_clear(buffer, this_attr->address);
 167                 if (ret)
 168                         goto error_ret;
 169         } else if (state && !ret) {
 170                 ret = iio_scan_mask_set(buffer, this_attr->address);
 171                 if (ret)
 172                         goto error_ret;
 173         }
 174
 175 error_ret:
 176         mutex_unlock(&indio_dev->mlock);
 177
 178         return ret ? ret : len;
 179
 180 }
 181
 182 static ssize_t iio_scan_el_ts_show(struct device *dev,
 183                                    struct device_attribute *attr,
 184                                    char *buf)
 185 {
 186         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 187         return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
 188 }
 189
 190 static ssize_t iio_scan_el_ts_store(struct device *dev,
 191                                     struct device_attribute *attr,
 192                                     const char *buf,
 193                                     size_t len)
 194 {
 195         int ret = 0;
 196         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 197         bool state;
 198
 199         state = !(buf[0] == '0');
 200         mutex_lock(&indio_dev->mlock);
 201         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 202                 ret = -EBUSY;
 203                 goto error_ret;
 204         }
 205         indio_dev->buffer->scan_timestamp = state;
 206 error_ret:
 207         mutex_unlock(&indio_dev->mlock);
 208
 209         return ret ? ret : len;
 210 }
 211
 212 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
 213                                         const struct iio_chan_spec *chan)
 214 {
 215         int ret, attrcount = 0;
 216         struct iio_buffer *buffer = indio_dev->buffer;
 217
 218         ret = __iio_add_chan_devattr("index",
 219                                      chan,
 220                                      &iio_show_scan_index,
 221                                      NULL,
 222                                      0,
 223                                      0,
 224                                      &indio_dev->dev,
 225                                      &buffer->scan_el_dev_attr_list);
 226         if (ret)
 227                 goto error_ret;
 228         attrcount++;
 229         ret = __iio_add_chan_devattr("type",
 230                                      chan,
 231                                      &iio_show_fixed_type,
 232                                      NULL,
 233                                      0,
 234                                      0,
 235                                      &indio_dev->dev,
 236                                      &buffer->scan_el_dev_attr_list);
 237         if (ret)
 238                 goto error_ret;
 239         attrcount++;
 240         if (chan->type != IIO_TIMESTAMP)
 241                 ret = __iio_add_chan_devattr("en",
 242                                              chan,
 243                                              &iio_scan_el_show,
 244                                              &iio_scan_el_store,
 245                                              chan->scan_index,
 246                                              0,
 247                                              &indio_dev->dev,
 248                                              &buffer->scan_el_dev_attr_list);
 249         else
 250                 ret = __iio_add_chan_devattr("en",
 251                                              chan,
 252                                              &iio_scan_el_ts_show,
 253                                              &iio_scan_el_ts_store,
 254                                              chan->scan_index,
 255                                              0,
 256                                              &indio_dev->dev,
 257                                              &buffer->scan_el_dev_attr_list);
 258         attrcount++;
 259         ret = attrcount;
 260 error_ret:
 261         return ret;
 262 }
 263
 264 static void iio_buffer_remove_and_free_scan_dev_attr(struct iio_dev *indio_dev,
 265                                                      struct iio_dev_attr *p)
 266 {
 267         kfree(p->dev_attr.attr.name);
 268         kfree(p);
 269 }
 270
 271 static void __iio_buffer_attr_cleanup(struct iio_dev *indio_dev)
 272 {
 273         struct iio_dev_attr *p, *n;
 274         struct iio_buffer *buffer = indio_dev->buffer;
 275
 276         list_for_each_entry_safe(p, n,
 277                                  &buffer->scan_el_dev_attr_list, l)
 278                 iio_buffer_remove_and_free_scan_dev_attr(indio_dev, p);
 279 }
 280
 281 static const char * const iio_scan_elements_group_name = "scan_elements";
 282
 283 int iio_buffer_register(struct iio_dev *indio_dev,
 284                         const struct iio_chan_spec *channels,
 285                         int num_channels)
 286 {
 287         struct iio_dev_attr *p;
 288         struct attribute **attr;
 289         struct iio_buffer *buffer = indio_dev->buffer;
 290         int ret, i, attrn, attrcount, attrcount_orig = 0;
 291
 292         if (buffer->attrs)
 293                 indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
 294
 295         if (buffer->scan_el_attrs != NULL) {
 296                 attr = buffer->scan_el_attrs->attrs;
 297                 while (*attr++ != NULL)
 298                         attrcount_orig++;
 299         }
 300         attrcount = attrcount_orig;
 301         INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
 302         if (channels) {
 303                 /* new magic */
 304                 for (i = 0; i < num_channels; i++) {
 305                         /* Establish necessary mask length */
 306                         if (channels[i].scan_index >
 307                             (int)indio_dev->masklength - 1)
 308                                 indio_dev->masklength
 309                                         = indio_dev->channels[i].scan_index + 1;
 310
 311                         ret = iio_buffer_add_channel_sysfs(indio_dev,
 312                                                          &channels[i]);
 313                         if (ret < 0)
 314                                 goto error_cleanup_dynamic;
 315                         attrcount += ret;
 316                 }
 317                 if (indio_dev->masklength && buffer->scan_mask == NULL) {
 318                         buffer->scan_mask
 319                                 = kzalloc(sizeof(*buffer->scan_mask)*
 320                                           BITS_TO_LONGS(indio_dev->masklength),
 321                                           GFP_KERNEL);
 322                         if (buffer->scan_mask == NULL) {
 323                                 ret = -ENOMEM;
 324                                 goto error_cleanup_dynamic;
 325                         }
 326                 }
 327         }
 328
 329         buffer->scan_el_group.name = iio_scan_elements_group_name;
 330
 331         buffer->scan_el_group.attrs
 332                 = kzalloc(sizeof(buffer->scan_el_group.attrs[0])*
 333                           (attrcount + 1),
 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_buffer_attr_cleanup(indio_dev);
 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_buffer_attr_cleanup(indio_dev);
 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_get_drvdata(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         int ret;
 388         ulong val;
 389         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 390         struct iio_buffer *buffer = indio_dev->buffer;
 391
 392         ret = strict_strtoul(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         if (buffer->access->set_length) {
 401                 buffer->access->set_length(buffer, val);
 402                 if (buffer->access->mark_param_change)
 403                         buffer->access->mark_param_change(buffer);
 404         }
 405
 406         return len;
 407 }
 408 EXPORT_SYMBOL(iio_buffer_write_length);
 409
 410 ssize_t iio_buffer_read_bytes_per_datum(struct device *dev,
 411                                         struct device_attribute *attr,
 412                                         char *buf)
 413 {
 414         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 415         struct iio_buffer *buffer = indio_dev->buffer;
 416
 417         if (buffer->access->get_bytes_per_datum)
 418                 return sprintf(buf, "%d\n",
 419                                buffer->access->get_bytes_per_datum(buffer));
 420
 421         return 0;
 422 }
 423 EXPORT_SYMBOL(iio_buffer_read_bytes_per_datum);
 424
 425 ssize_t iio_buffer_store_enable(struct device *dev,
 426                                 struct device_attribute *attr,
 427                                 const char *buf,
 428                                 size_t len)
 429 {
 430         int ret;
 431         bool requested_state, current_state;
 432         int previous_mode;
 433         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 434         struct iio_buffer *buffer = indio_dev->buffer;
 435
 436         mutex_lock(&indio_dev->mlock);
 437         previous_mode = indio_dev->currentmode;
 438         requested_state = !(buf[0] == '0');
 439         current_state = !!(previous_mode & INDIO_ALL_BUFFER_MODES);
 440         if (current_state == requested_state) {
 441                 printk(KERN_INFO "iio-buffer, current state requested again\n");
 442                 goto done;
 443         }
 444         if (requested_state) {
 445                 if (buffer->setup_ops->preenable) {
 446                         ret = buffer->setup_ops->preenable(indio_dev);
 447                         if (ret) {
 448                                 printk(KERN_ERR
 449                                        "Buffer not started:"
 450                                        "buffer preenable failed\n");
 451                                 goto error_ret;
 452                         }
 453                 }
 454                 if (buffer->access->request_update) {
 455                         ret = buffer->access->request_update(buffer);
 456                         if (ret) {
 457                                 printk(KERN_INFO
 458                                        "Buffer not started:"
 459                                        "buffer parameter update failed\n");
 460                                 goto error_ret;
 461                         }
 462                 }
 463                 if (buffer->access->mark_in_use)
 464                         buffer->access->mark_in_use(buffer);
 465                 /* Definitely possible for devices to support both of these.*/
 466                 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
 467                         if (!indio_dev->trig) {
 468                                 printk(KERN_INFO
 469                                        "Buffer not started: no trigger\n");
 470                                 ret = -EINVAL;
 471                                 if (buffer->access->unmark_in_use)
 472                                         buffer->access->unmark_in_use(buffer);
 473                                 goto error_ret;
 474                         }
 475                         indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
 476                 } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE)
 477                         indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
 478                 else { /* should never be reached */
 479                         ret = -EINVAL;
 480                         goto error_ret;
 481                 }
 482
 483                 if (buffer->setup_ops->postenable) {
 484                         ret = buffer->setup_ops->postenable(indio_dev);
 485                         if (ret) {
 486                                 printk(KERN_INFO
 487                                        "Buffer not started:"
 488                                        "postenable failed\n");
 489                                 if (buffer->access->unmark_in_use)
 490                                         buffer->access->unmark_in_use(buffer);
 491                                 indio_dev->currentmode = previous_mode;
 492                                 if (buffer->setup_ops->postdisable)
 493                                         buffer->setup_ops->
 494                                                 postdisable(indio_dev);
 495                                 goto error_ret;
 496                         }
 497                 }
 498         } else {
 499                 if (buffer->setup_ops->predisable) {
 500                         ret = buffer->setup_ops->predisable(indio_dev);
 501                         if (ret)
 502                                 goto error_ret;
 503                 }
 504                 if (buffer->access->unmark_in_use)
 505                         buffer->access->unmark_in_use(buffer);
 506                 indio_dev->currentmode = INDIO_DIRECT_MODE;
 507                 if (buffer->setup_ops->postdisable) {
 508                         ret = buffer->setup_ops->postdisable(indio_dev);
 509                         if (ret)
 510                                 goto error_ret;
 511                 }
 512         }
 513 done:
 514         mutex_unlock(&indio_dev->mlock);
 515         return len;
 516
 517 error_ret:
 518         mutex_unlock(&indio_dev->mlock);
 519         return ret;
 520 }
 521 EXPORT_SYMBOL(iio_buffer_store_enable);
 522
 523 ssize_t iio_buffer_show_enable(struct device *dev,
 524                                struct device_attribute *attr,
 525                                char *buf)
 526 {
 527         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 528         return sprintf(buf, "%d\n", !!(indio_dev->currentmode
 529                                        & INDIO_ALL_BUFFER_MODES));
 530 }
 531 EXPORT_SYMBOL(iio_buffer_show_enable);
 532
 533 int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
 534 {
 535         struct iio_buffer *buffer = indio_dev->buffer;
 536         size_t size;
 537         dev_dbg(&indio_dev->dev, "%s\n", __func__);
 538         /* Check if there are any scan elements enabled, if not fail*/
 539         if (!(buffer->scan_count || buffer->scan_timestamp))
 540                 return -EINVAL;
 541         if (buffer->scan_timestamp)
 542                 if (buffer->scan_count)
 543                         /* Timestamp (aligned to s64) and data */
 544                         size = (((buffer->scan_count * buffer->bpe)
 545                                         + sizeof(s64) - 1)
 546                                 & ~(sizeof(s64) - 1))
 547                                 + sizeof(s64);
 548                 else /* Timestamp only  */
 549                         size = sizeof(s64);
 550         else /* Data only */
 551                 size = buffer->scan_count * buffer->bpe;
 552         buffer->access->set_bytes_per_datum(buffer, size);
 553
 554         return 0;
 555 }
 556 EXPORT_SYMBOL(iio_sw_buffer_preenable);
 557
 558
 559 /* note NULL used as error indicator as it doesn't make sense. */
 560 static unsigned long *iio_scan_mask_match(unsigned long *av_masks,
 561                                           unsigned int masklength,
 562                                           unsigned long *mask)
 563 {
 564         if (bitmap_empty(mask, masklength))
 565                 return NULL;
 566         while (*av_masks) {
 567                 if (bitmap_subset(mask, av_masks, masklength))
 568                         return av_masks;
 569                 av_masks += BITS_TO_LONGS(masklength);
 570         }
 571         return NULL;
 572 }
 573
 574 /**
 575  * iio_scan_mask_set() - set particular bit in the scan mask
 576  * @buffer: the buffer whose scan mask we are interested in
 577  * @bit: the bit to be set.
 578  **/
 579 int iio_scan_mask_set(struct iio_buffer *buffer, int bit)
 580 {
 581         struct iio_dev *indio_dev = buffer->indio_dev;
 582         unsigned long *mask;
 583         unsigned long *trialmask;
 584
 585         trialmask = kmalloc(sizeof(*trialmask)*
 586                             BITS_TO_LONGS(indio_dev->masklength),
 587                             GFP_KERNEL);
 588
 589         if (trialmask == NULL)
 590                 return -ENOMEM;
 591         if (!indio_dev->masklength) {
 592                 WARN_ON("trying to set scanmask prior to registering buffer\n");
 593                 kfree(trialmask);
 594                 return -EINVAL;
 595         }
 596         bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
 597         set_bit(bit, trialmask);
 598
 599         if (indio_dev->available_scan_masks) {
 600                 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 601                                            indio_dev->masklength,
 602                                            trialmask);
 603                 if (!mask) {
 604                         kfree(trialmask);
 605                         return -EINVAL;
 606                 }
 607         }
 608         bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
 609         buffer->scan_count++;
 610
 611         kfree(trialmask);
 612
 613         return 0;
 614 };
 615 EXPORT_SYMBOL_GPL(iio_scan_mask_set);
 616
 617 int iio_scan_mask_query(struct iio_buffer *buffer, int bit)
 618 {
 619         struct iio_dev *indio_dev = buffer->indio_dev;
 620         long *mask;
 621
 622         if (bit > indio_dev->masklength)
 623                 return -EINVAL;
 624
 625         if (!buffer->scan_mask)
 626                 return 0;
 627         if (indio_dev->available_scan_masks)
 628                 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 629                                            indio_dev->masklength,
 630                                            buffer->scan_mask);
 631         else
 632                 mask = buffer->scan_mask;
 633         if (!mask)
 634                 return 0;
 635
 636         return test_bit(bit, mask);
 637 };
 638 EXPORT_SYMBOL_GPL(iio_scan_mask_query);