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_generic.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->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 -EINVAL;
  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         clear_bit(IIO_BUSY_BIT_POS, &rb->flags);
  82         if (rb->access->unmark_in_use)
  83                 rb->access->unmark_in_use(rb);
  84 }
  85
  86 void iio_buffer_init(struct iio_buffer *buffer, struct iio_dev *indio_dev)
  87 {
  88         buffer->indio_dev = indio_dev;
  89         init_waitqueue_head(&buffer->pollq);
  90 }
  91 EXPORT_SYMBOL(iio_buffer_init);
  92
  93 static ssize_t iio_show_scan_index(struct device *dev,
  94                                    struct device_attribute *attr,
  95                                    char *buf)
  96 {
  97         return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
  98 }
  99
 100 static ssize_t iio_show_fixed_type(struct device *dev,
 101                                    struct device_attribute *attr,
 102                                    char *buf)
 103 {
 104         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 105         u8 type = this_attr->c->scan_type.endianness;
 106
 107         if (type == IIO_CPU) {
 108 #ifdef __LITTLE_ENDIAN
 109                 type = IIO_LE;
 110 #else
 111                 type = IIO_BE;
 112 #endif
 113         }
 114         return sprintf(buf, "%s:%c%d/%d>>%u\n",
 115                        iio_endian_prefix[type],
 116                        this_attr->c->scan_type.sign,
 117                        this_attr->c->scan_type.realbits,
 118                        this_attr->c->scan_type.storagebits,
 119                        this_attr->c->scan_type.shift);
 120 }
 121
 122 static ssize_t iio_scan_el_show(struct device *dev,
 123                                 struct device_attribute *attr,
 124                                 char *buf)
 125 {
 126         int ret;
 127         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 128
 129         ret = iio_scan_mask_query(indio_dev->buffer,
 130                                   to_iio_dev_attr(attr)->address);
 131         if (ret < 0)
 132                 return ret;
 133         return sprintf(buf, "%d\n", ret);
 134 }
 135
 136 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
 137 {
 138         clear_bit(bit, buffer->scan_mask);
 139         buffer->scan_count--;
 140         return 0;
 141 }
 142
 143 static ssize_t iio_scan_el_store(struct device *dev,
 144                                  struct device_attribute *attr,
 145                                  const char *buf,
 146                                  size_t len)
 147 {
 148         int ret = 0;
 149         bool state;
 150         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 151         struct iio_buffer *buffer = indio_dev->buffer;
 152         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 153
 154         state = !(buf[0] == '0');
 155         mutex_lock(&indio_dev->mlock);
 156         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 157                 ret = -EBUSY;
 158                 goto error_ret;
 159         }
 160         ret = iio_scan_mask_query(buffer, this_attr->address);
 161         if (ret < 0)
 162                 goto error_ret;
 163         if (!state && ret) {
 164                 ret = iio_scan_mask_clear(buffer, this_attr->address);
 165                 if (ret)
 166                         goto error_ret;
 167         } else if (state && !ret) {
 168                 ret = iio_scan_mask_set(buffer, this_attr->address);
 169                 if (ret)
 170                         goto error_ret;
 171         }
 172
 173 error_ret:
 174         mutex_unlock(&indio_dev->mlock);
 175
 176         return ret ? ret : len;
 177
 178 }
 179
 180 static ssize_t iio_scan_el_ts_show(struct device *dev,
 181                                    struct device_attribute *attr,
 182                                    char *buf)
 183 {
 184         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 185         return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
 186 }
 187
 188 static ssize_t iio_scan_el_ts_store(struct device *dev,
 189                                     struct device_attribute *attr,
 190                                     const char *buf,
 191                                     size_t len)
 192 {
 193         int ret = 0;
 194         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 195         bool state;
 196
 197         state = !(buf[0] == '0');
 198         mutex_lock(&indio_dev->mlock);
 199         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 200                 ret = -EBUSY;
 201                 goto error_ret;
 202         }
 203         indio_dev->buffer->scan_timestamp = state;
 204 error_ret:
 205         mutex_unlock(&indio_dev->mlock);
 206
 207         return ret ? ret : len;
 208 }
 209
 210 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
 211                                         const struct iio_chan_spec *chan)
 212 {
 213         int ret, attrcount = 0;
 214         struct iio_buffer *buffer = indio_dev->buffer;
 215
 216         ret = __iio_add_chan_devattr("index",
 217                                      chan,
 218                                      &iio_show_scan_index,
 219                                      NULL,
 220                                      0,
 221                                      0,
 222                                      &indio_dev->dev,
 223                                      &buffer->scan_el_dev_attr_list);
 224         if (ret)
 225                 goto error_ret;
 226         attrcount++;
 227         ret = __iio_add_chan_devattr("type",
 228                                      chan,
 229                                      &iio_show_fixed_type,
 230                                      NULL,
 231                                      0,
 232                                      0,
 233                                      &indio_dev->dev,
 234                                      &buffer->scan_el_dev_attr_list);
 235         if (ret)
 236                 goto error_ret;
 237         attrcount++;
 238         if (chan->type != IIO_TIMESTAMP)
 239                 ret = __iio_add_chan_devattr("en",
 240                                              chan,
 241                                              &iio_scan_el_show,
 242                                              &iio_scan_el_store,
 243                                              chan->scan_index,
 244                                              0,
 245                                              &indio_dev->dev,
 246                                              &buffer->scan_el_dev_attr_list);
 247         else
 248                 ret = __iio_add_chan_devattr("en",
 249                                              chan,
 250                                              &iio_scan_el_ts_show,
 251                                              &iio_scan_el_ts_store,
 252                                              chan->scan_index,
 253                                              0,
 254                                              &indio_dev->dev,
 255                                              &buffer->scan_el_dev_attr_list);
 256         attrcount++;
 257         ret = attrcount;
 258 error_ret:
 259         return ret;
 260 }
 261
 262 static void iio_buffer_remove_and_free_scan_dev_attr(struct iio_dev *indio_dev,
 263                                                      struct iio_dev_attr *p)
 264 {
 265         kfree(p->dev_attr.attr.name);
 266         kfree(p);
 267 }
 268
 269 static void __iio_buffer_attr_cleanup(struct iio_dev *indio_dev)
 270 {
 271         struct iio_dev_attr *p, *n;
 272         struct iio_buffer *buffer = indio_dev->buffer;
 273
 274         list_for_each_entry_safe(p, n,
 275                                  &buffer->scan_el_dev_attr_list, l)
 276                 iio_buffer_remove_and_free_scan_dev_attr(indio_dev, p);
 277 }
 278
 279 static const char * const iio_scan_elements_group_name = "scan_elements";
 280
 281 int iio_buffer_register(struct iio_dev *indio_dev,
 282                         const struct iio_chan_spec *channels,
 283                         int num_channels)
 284 {
 285         struct iio_dev_attr *p;
 286         struct attribute **attr;
 287         struct iio_buffer *buffer = indio_dev->buffer;
 288         int ret, i, attrn, attrcount, attrcount_orig = 0;
 289
 290         if (buffer->attrs)
 291                 indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
 292
 293         if (buffer->scan_el_attrs != NULL) {
 294                 attr = buffer->scan_el_attrs->attrs;
 295                 while (*attr++ != NULL)
 296                         attrcount_orig++;
 297         }
 298         attrcount = attrcount_orig;
 299         INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
 300         if (channels) {
 301                 /* new magic */
 302                 for (i = 0; i < num_channels; i++) {
 303                         /* Establish necessary mask length */
 304                         if (channels[i].scan_index >
 305                             (int)indio_dev->masklength - 1)
 306                                 indio_dev->masklength
 307                                         = indio_dev->channels[i].scan_index + 1;
 308
 309                         ret = iio_buffer_add_channel_sysfs(indio_dev,
 310                                                          &channels[i]);
 311                         if (ret < 0)
 312                                 goto error_cleanup_dynamic;
 313                         attrcount += ret;
 314                 }
 315                 if (indio_dev->masklength && buffer->scan_mask == NULL) {
 316                         buffer->scan_mask
 317                                 = kzalloc(sizeof(*buffer->scan_mask)*
 318                                           BITS_TO_LONGS(indio_dev->masklength),
 319                                           GFP_KERNEL);
 320                         if (buffer->scan_mask == NULL) {
 321                                 ret = -ENOMEM;
 322                                 goto error_cleanup_dynamic;
 323                         }
 324                 }
 325         }
 326
 327         buffer->scan_el_group.name = iio_scan_elements_group_name;
 328
 329         buffer->scan_el_group.attrs
 330                 = kzalloc(sizeof(buffer->scan_el_group.attrs[0])*
 331                           (attrcount + 1),
 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);