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 = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
 319                                                     sizeof(*buffer->scan_mask),
 320                                                     GFP_KERNEL);
 321                         if (buffer->scan_mask == NULL) {
 322                                 ret = -ENOMEM;
 323                                 goto error_cleanup_dynamic;
 324                         }
 325                 }
 326         }
 327
 328         buffer->scan_el_group.name = iio_scan_elements_group_name;
 329
 330         buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
 331                                               sizeof(buffer->scan_el_group.attrs[0]),
 332                                               GFP_KERNEL);
 333         if (buffer->scan_el_group.attrs == NULL) {
 334                 ret = -ENOMEM;
 335                 goto error_free_scan_mask;
 336         }
 337         if (buffer->scan_el_attrs)
 338                 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
 339                        sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
 340         attrn = attrcount_orig;
 341
 342         list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
 343                 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
 344         indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
 345
 346         return 0;
 347
 348 error_free_scan_mask:
 349         kfree(buffer->scan_mask);
 350 error_cleanup_dynamic:
 351         __iio_buffer_attr_cleanup(indio_dev);
 352
 353         return ret;
 354 }
 355 EXPORT_SYMBOL(iio_buffer_register);
 356
 357 void iio_buffer_unregister(struct iio_dev *indio_dev)
 358 {
 359         kfree(indio_dev->buffer->scan_mask);
 360         kfree(indio_dev->buffer->scan_el_group.attrs);
 361         __iio_buffer_attr_cleanup(indio_dev);
 362 }
 363 EXPORT_SYMBOL(iio_buffer_unregister);
 364
 365 ssize_t iio_buffer_read_length(struct device *dev,
 366                                struct device_attribute *attr,
 367                                char *buf)
 368 {
 369         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 370         struct iio_buffer *buffer = indio_dev->buffer;
 371
 372         if (buffer->access->get_length)
 373                 return sprintf(buf, "%d\n",
 374                                buffer->access->get_length(buffer));
 375
 376         return 0;
 377 }
 378 EXPORT_SYMBOL(iio_buffer_read_length);
 379
 380 ssize_t iio_buffer_write_length(struct device *dev,
 381                                 struct device_attribute *attr,
 382                                 const char *buf,
 383                                 size_t len)
 384 {
 385         int ret;
 386         ulong val;
 387         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 388         struct iio_buffer *buffer = indio_dev->buffer;
 389
 390         ret = strict_strtoul(buf, 10, &val);
 391         if (ret)
 392                 return ret;
 393
 394         if (buffer->access->get_length)
 395                 if (val == buffer->access->get_length(buffer))
 396                         return len;
 397
 398         if (buffer->access->set_length) {
 399                 buffer->access->set_length(buffer, val);
 400                 if (buffer->access->mark_param_change)
 401                         buffer->access->mark_param_change(buffer);
 402         }
 403
 404         return len;
 405 }
 406 EXPORT_SYMBOL(iio_buffer_write_length);
 407
 408 ssize_t iio_buffer_read_bytes_per_datum(struct device *dev,
 409                                         struct device_attribute *attr,
 410                                         char *buf)
 411 {
 412         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 413         struct iio_buffer *buffer = indio_dev->buffer;
 414
 415         if (buffer->access->get_bytes_per_datum)
 416                 return sprintf(buf, "%d\n",
 417                                buffer->access->get_bytes_per_datum(buffer));
 418
 419         return 0;
 420 }
 421 EXPORT_SYMBOL(iio_buffer_read_bytes_per_datum);
 422
 423 ssize_t iio_buffer_store_enable(struct device *dev,
 424                                 struct device_attribute *attr,
 425                                 const char *buf,
 426                                 size_t len)
 427 {
 428         int ret;
 429         bool requested_state, current_state;
 430         int previous_mode;
 431         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 432         struct iio_buffer *buffer = indio_dev->buffer;
 433
 434         mutex_lock(&indio_dev->mlock);
 435         previous_mode = indio_dev->currentmode;
 436         requested_state = !(buf[0] == '0');
 437         current_state = !!(previous_mode & INDIO_ALL_BUFFER_MODES);
 438         if (current_state == requested_state) {
 439                 printk(KERN_INFO "iio-buffer, current state requested again\n");
 440                 goto done;
 441         }
 442         if (requested_state) {
 443                 if (buffer->setup_ops->preenable) {
 444                         ret = buffer->setup_ops->preenable(indio_dev);
 445                         if (ret) {
 446                                 printk(KERN_ERR
 447                                        "Buffer not started:"
 448                                        "buffer preenable failed\n");
 449                                 goto error_ret;
 450                         }
 451                 }
 452                 if (buffer->access->request_update) {
 453                         ret = buffer->access->request_update(buffer);
 454                         if (ret) {
 455                                 printk(KERN_INFO
 456                                        "Buffer not started:"
 457                                        "buffer parameter update failed\n");
 458                                 goto error_ret;
 459                         }
 460                 }
 461                 if (buffer->access->mark_in_use)
 462                         buffer->access->mark_in_use(buffer);
 463                 /* Definitely possible for devices to support both of these.*/
 464                 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
 465                         if (!indio_dev->trig) {
 466                                 printk(KERN_INFO
 467                                        "Buffer not started: no trigger\n");
 468                                 ret = -EINVAL;
 469                                 if (buffer->access->unmark_in_use)
 470                                         buffer->access->unmark_in_use(buffer);
 471                                 goto error_ret;
 472                         }
 473                         indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
 474                 } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE)
 475                         indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
 476                 else { /* should never be reached */
 477                         ret = -EINVAL;
 478                         goto error_ret;
 479                 }
 480
 481                 if (buffer->setup_ops->postenable) {
 482                         ret = buffer->setup_ops->postenable(indio_dev);
 483                         if (ret) {
 484                                 printk(KERN_INFO
 485                                        "Buffer not started:"
 486                                        "postenable failed\n");
 487                                 if (buffer->access->unmark_in_use)
 488                                         buffer->access->unmark_in_use(buffer);
 489                                 indio_dev->currentmode = previous_mode;
 490                                 if (buffer->setup_ops->postdisable)
 491                                         buffer->setup_ops->
 492                                                 postdisable(indio_dev);
 493                                 goto error_ret;
 494                         }
 495                 }
 496         } else {
 497                 if (buffer->setup_ops->predisable) {
 498                         ret = buffer->setup_ops->predisable(indio_dev);
 499                         if (ret)
 500                                 goto error_ret;
 501                 }
 502                 if (buffer->access->unmark_in_use)
 503                         buffer->access->unmark_in_use(buffer);
 504                 indio_dev->currentmode = INDIO_DIRECT_MODE;
 505                 if (buffer->setup_ops->postdisable) {
 506                         ret = buffer->setup_ops->postdisable(indio_dev);
 507                         if (ret)
 508                                 goto error_ret;
 509                 }
 510         }
 511 done:
 512         mutex_unlock(&indio_dev->mlock);
 513         return len;
 514
 515 error_ret:
 516         mutex_unlock(&indio_dev->mlock);
 517         return ret;
 518 }
 519 EXPORT_SYMBOL(iio_buffer_store_enable);
 520
 521 ssize_t iio_buffer_show_enable(struct device *dev,
 522                                struct device_attribute *attr,
 523                                char *buf)
 524 {
 525         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 526         return sprintf(buf, "%d\n", !!(indio_dev->currentmode
 527                                        & INDIO_ALL_BUFFER_MODES));
 528 }
 529 EXPORT_SYMBOL(iio_buffer_show_enable);
 530
 531 int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
 532 {
 533         struct iio_buffer *buffer = indio_dev->buffer;
 534         size_t size;
 535         dev_dbg(&indio_dev->dev, "%s\n", __func__);
 536         /* Check if there are any scan elements enabled, if not fail*/
 537         if (!(buffer->scan_count || buffer->scan_timestamp))
 538                 return -EINVAL;
 539         if (buffer->scan_timestamp)
 540                 if (buffer->scan_count)
 541                         /* Timestamp (aligned to s64) and data */
 542                         size = (((buffer->scan_count * buffer->bpe)
 543                                         + sizeof(s64) - 1)
 544                                 & ~(sizeof(s64) - 1))
 545                                 + sizeof(s64);
 546                 else /* Timestamp only  */
 547                         size = sizeof(s64);
 548         else /* Data only */
 549                 size = buffer->scan_count * buffer->bpe;
 550         buffer->access->set_bytes_per_datum(buffer, size);
 551
 552         return 0;
 553 }
 554 EXPORT_SYMBOL(iio_sw_buffer_preenable);
 555
 556
 557 /* note NULL used as error indicator as it doesn't make sense. */
 558 static unsigned long *iio_scan_mask_match(unsigned long *av_masks,
 559                                           unsigned int masklength,
 560                                           unsigned long *mask)
 561 {
 562         if (bitmap_empty(mask, masklength))
 563                 return NULL;
 564         while (*av_masks) {
 565                 if (bitmap_subset(mask, av_masks, masklength))
 566                         return av_masks;
 567                 av_masks += BITS_TO_LONGS(masklength);
 568         }
 569         return NULL;
 570 }
 571
 572 /**
 573  * iio_scan_mask_set() - set particular bit in the scan mask
 574  * @buffer: the buffer whose scan mask we are interested in
 575  * @bit: the bit to be set.
 576  **/
 577 int iio_scan_mask_set(struct iio_buffer *buffer, int bit)
 578 {
 579         struct iio_dev *indio_dev = buffer->indio_dev;
 580         unsigned long *mask;
 581         unsigned long *trialmask;
 582
 583         trialmask = kmalloc(sizeof(*trialmask)*
 584                             BITS_TO_LONGS(indio_dev->masklength),
 585                             GFP_KERNEL);
 586
 587         if (trialmask == NULL)
 588                 return -ENOMEM;
 589         if (!indio_dev->masklength) {
 590                 WARN_ON("trying to set scanmask prior to registering buffer\n");
 591                 kfree(trialmask);
 592                 return -EINVAL;
 593         }
 594         bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
 595         set_bit(bit, trialmask);
 596
 597         if (indio_dev->available_scan_masks) {
 598                 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 599                                            indio_dev->masklength,
 600                                            trialmask);
 601                 if (!mask) {
 602                         kfree(trialmask);
 603                         return -EINVAL;
 604                 }
 605         }
 606         bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
 607         buffer->scan_count++;
 608
 609         kfree(trialmask);
 610
 611         return 0;
 612 };
 613 EXPORT_SYMBOL_GPL(iio_scan_mask_set);
 614
 615 int iio_scan_mask_query(struct iio_buffer *buffer, int bit)
 616 {
 617         struct iio_dev *indio_dev = buffer->indio_dev;
 618         long *mask;
 619
 620         if (bit > indio_dev->masklength)
 621                 return -EINVAL;
 622
 623         if (!buffer->scan_mask)
 624                 return 0;
 625         if (indio_dev->available_scan_masks)
 626                 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 627                                            indio_dev->masklength,
 628                                            buffer->scan_mask);
 629         else
 630                 mask = buffer->scan_mask;
 631         if (!mask)
 632                 return 0;
 633
 634         return test_bit(bit, mask);
 635 };
 636 EXPORT_SYMBOL_GPL(iio_scan_mask_query);