drivers/staging/iio/industrialio-ring.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 ring 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/device.h>
  18 #include <linux/fs.h>
  19 #include <linux/cdev.h>
  20 #include <linux/slab.h>
  21 #include <linux/poll.h>
  22
  23 #include "iio.h"
  24 #include "iio_core.h"
  25 #include "sysfs.h"
  26 #include "buffer_generic.h"
  27
  28 static const char * const iio_endian_prefix[] = {
  29         [IIO_BE] = "be",
  30         [IIO_LE] = "le",
  31 };
  32
  33 /**
  34  * iio_ring_read_first_n_outer() - chrdev read for ring buffer access
  35  *
  36  * This function relies on all ring buffer implementations having an
  37  * iio_ring _bufer as their first element.
  38  **/
  39 ssize_t iio_ring_read_first_n_outer(struct file *filp, char __user *buf,
  40                                     size_t n, loff_t *f_ps)
  41 {
  42         struct iio_dev *indio_dev = filp->private_data;
  43         struct iio_ring_buffer *rb = indio_dev->ring;
  44
  45         if (!rb->access->read_first_n)
  46                 return -EINVAL;
  47         return rb->access->read_first_n(rb, n, buf);
  48 }
  49
  50 /**
  51  * iio_ring_poll() - poll the ring to find out if it has data
  52  */
  53 unsigned int iio_ring_poll(struct file *filp,
  54                            struct poll_table_struct *wait)
  55 {
  56         struct iio_dev *indio_dev = filp->private_data;
  57         struct iio_ring_buffer *rb = indio_dev->ring;
  58
  59         poll_wait(filp, &rb->pollq, wait);
  60         if (rb->stufftoread)
  61                 return POLLIN | POLLRDNORM;
  62         /* need a way of knowing if there may be enough data... */
  63         return 0;
  64 }
  65
  66 void iio_chrdev_ring_open(struct iio_dev *indio_dev)
  67 {
  68         struct iio_ring_buffer *rb = indio_dev->ring;
  69         if (rb && rb->access->mark_in_use)
  70                 rb->access->mark_in_use(rb);
  71 }
  72
  73 void iio_chrdev_ring_release(struct iio_dev *indio_dev)
  74 {
  75         struct iio_ring_buffer *rb = indio_dev->ring;
  76
  77         clear_bit(IIO_BUSY_BIT_POS, &rb->flags);
  78         if (rb->access->unmark_in_use)
  79                 rb->access->unmark_in_use(rb);
  80
  81 }
  82
  83 void iio_ring_buffer_init(struct iio_ring_buffer *ring,
  84                           struct iio_dev *dev_info)
  85 {
  86         ring->indio_dev = dev_info;
  87         init_waitqueue_head(&ring->pollq);
  88 }
  89 EXPORT_SYMBOL(iio_ring_buffer_init);
  90
  91 static ssize_t iio_show_scan_index(struct device *dev,
  92                                    struct device_attribute *attr,
  93                                    char *buf)
  94 {
  95         return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
  96 }
  97
  98 static ssize_t iio_show_fixed_type(struct device *dev,
  99                                    struct device_attribute *attr,
 100                                    char *buf)
 101 {
 102         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 103         u8 type = this_attr->c->scan_type.endianness;
 104
 105         if (type == IIO_CPU) {
 106                 if (__LITTLE_ENDIAN)
 107                         type = IIO_LE;
 108                 else
 109                         type = IIO_BE;
 110         }
 111         return sprintf(buf, "%s:%c%d/%d>>%u\n",
 112                        iio_endian_prefix[type],
 113                        this_attr->c->scan_type.sign,
 114                        this_attr->c->scan_type.realbits,
 115                        this_attr->c->scan_type.storagebits,
 116                        this_attr->c->scan_type.shift);
 117 }
 118
 119 static ssize_t iio_scan_el_show(struct device *dev,
 120                                 struct device_attribute *attr,
 121                                 char *buf)
 122 {
 123         int ret;
 124         struct iio_dev *dev_info = dev_get_drvdata(dev);
 125
 126         ret = iio_scan_mask_query(dev_info->ring,
 127                                   to_iio_dev_attr(attr)->address);
 128         if (ret < 0)
 129                 return ret;
 130         return sprintf(buf, "%d\n", ret);
 131 }
 132
 133 static int iio_scan_mask_clear(struct iio_ring_buffer *ring, int bit)
 134 {
 135         clear_bit(bit, ring->scan_mask);
 136         ring->scan_count--;
 137         return 0;
 138 }
 139
 140 static ssize_t iio_scan_el_store(struct device *dev,
 141                                  struct device_attribute *attr,
 142                                  const char *buf,
 143                                  size_t len)
 144 {
 145         int ret = 0;
 146         bool state;
 147         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 148         struct iio_ring_buffer *ring = indio_dev->ring;
 149         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 150
 151         state = !(buf[0] == '0');
 152         mutex_lock(&indio_dev->mlock);
 153         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 154                 ret = -EBUSY;
 155                 goto error_ret;
 156         }
 157         ret = iio_scan_mask_query(ring, this_attr->address);
 158         if (ret < 0)
 159                 goto error_ret;
 160         if (!state && ret) {
 161                 ret = iio_scan_mask_clear(ring, this_attr->address);
 162                 if (ret)
 163                         goto error_ret;
 164         } else if (state && !ret) {
 165                 ret = iio_scan_mask_set(ring, this_attr->address);
 166                 if (ret)
 167                         goto error_ret;
 168         }
 169
 170 error_ret:
 171         mutex_unlock(&indio_dev->mlock);
 172
 173         return ret ? ret : len;
 174
 175 }
 176
 177 static ssize_t iio_scan_el_ts_show(struct device *dev,
 178                                    struct device_attribute *attr,
 179                                    char *buf)
 180 {
 181         struct iio_dev *dev_info = dev_get_drvdata(dev);
 182         return sprintf(buf, "%d\n", dev_info->ring->scan_timestamp);
 183 }
 184
 185 static ssize_t iio_scan_el_ts_store(struct device *dev,
 186                                     struct device_attribute *attr,
 187                                     const char *buf,
 188                                     size_t len)
 189 {
 190         int ret = 0;
 191         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 192         bool state;
 193
 194         state = !(buf[0] == '0');
 195         mutex_lock(&indio_dev->mlock);
 196         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 197                 ret = -EBUSY;
 198                 goto error_ret;
 199         }
 200         indio_dev->ring->scan_timestamp = state;
 201 error_ret:
 202         mutex_unlock(&indio_dev->mlock);
 203
 204         return ret ? ret : len;
 205 }
 206
 207 static int iio_ring_add_channel_sysfs(struct iio_dev *indio_dev,
 208                                       const struct iio_chan_spec *chan)
 209 {
 210         int ret, attrcount = 0;
 211         struct iio_ring_buffer *ring = indio_dev->ring;
 212
 213         ret = __iio_add_chan_devattr("index",
 214                                      chan,
 215                                      &iio_show_scan_index,
 216                                      NULL,
 217                                      0,
 218                                      0,
 219                                      &indio_dev->dev,
 220                                      &ring->scan_el_dev_attr_list);
 221         if (ret)
 222                 goto error_ret;
 223         attrcount++;
 224         ret = __iio_add_chan_devattr("type",
 225                                      chan,
 226                                      &iio_show_fixed_type,
 227                                      NULL,
 228                                      0,
 229                                      0,
 230                                      &indio_dev->dev,
 231                                      &ring->scan_el_dev_attr_list);
 232         if (ret)
 233                 goto error_ret;
 234         attrcount++;
 235         if (chan->type != IIO_TIMESTAMP)
 236                 ret = __iio_add_chan_devattr("en",
 237                                              chan,
 238                                              &iio_scan_el_show,
 239                                              &iio_scan_el_store,
 240                                              chan->scan_index,
 241                                              0,
 242                                              &indio_dev->dev,
 243                                              &ring->scan_el_dev_attr_list);
 244         else
 245                 ret = __iio_add_chan_devattr("en",
 246                                              chan,
 247                                              &iio_scan_el_ts_show,
 248                                              &iio_scan_el_ts_store,
 249                                              chan->scan_index,
 250                                              0,
 251                                              &indio_dev->dev,
 252                                              &ring->scan_el_dev_attr_list);
 253         attrcount++;
 254         ret = attrcount;
 255 error_ret:
 256         return ret;
 257 }
 258
 259 static void iio_ring_remove_and_free_scan_dev_attr(struct iio_dev *indio_dev,
 260                                                    struct iio_dev_attr *p)
 261 {
 262         kfree(p->dev_attr.attr.name);
 263         kfree(p);
 264 }
 265
 266 static void __iio_ring_attr_cleanup(struct iio_dev *indio_dev)
 267 {
 268         struct iio_dev_attr *p, *n;
 269         struct iio_ring_buffer *ring = indio_dev->ring;
 270
 271         list_for_each_entry_safe(p, n,
 272                                  &ring->scan_el_dev_attr_list, l)
 273                 iio_ring_remove_and_free_scan_dev_attr(indio_dev, p);
 274 }
 275
 276 static const char * const iio_scan_elements_group_name = "scan_elements";
 277
 278 int iio_ring_buffer_register(struct iio_dev *indio_dev,
 279                              const struct iio_chan_spec *channels,
 280                              int num_channels)
 281 {
 282         struct iio_dev_attr *p;
 283         struct attribute **attr;
 284         struct iio_ring_buffer *ring = indio_dev->ring;
 285         int ret, i, attrn, attrcount, attrcount_orig = 0;
 286
 287         if (ring->attrs)
 288                 indio_dev->groups[indio_dev->groupcounter++] = ring->attrs;
 289
 290         if (ring->scan_el_attrs != NULL) {
 291                 attr = ring->scan_el_attrs->attrs;
 292                 while (*attr++ != NULL)
 293                         attrcount_orig++;
 294         }
 295         attrcount = attrcount_orig;
 296         INIT_LIST_HEAD(&ring->scan_el_dev_attr_list);
 297         if (channels) {
 298                 /* new magic */
 299                 for (i = 0; i < num_channels; i++) {
 300                         /* Establish necessary mask length */
 301                         if (channels[i].scan_index >
 302                             (int)indio_dev->masklength - 1)
 303                                 indio_dev->masklength
 304                                         = indio_dev->channels[i].scan_index + 1;
 305
 306                         ret = iio_ring_add_channel_sysfs(indio_dev,
 307                                                          &channels[i]);
 308                         if (ret < 0)
 309                                 goto error_cleanup_dynamic;
 310                         attrcount += ret;
 311                 }
 312                 if (indio_dev->masklength && ring->scan_mask == NULL) {
 313                         ring->scan_mask
 314                                 = kzalloc(sizeof(*ring->scan_mask)*
 315                                           BITS_TO_LONGS(indio_dev->masklength),
 316                                           GFP_KERNEL);
 317                         if (ring->scan_mask == NULL) {
 318                                 ret = -ENOMEM;
 319                                 goto error_cleanup_dynamic;
 320                         }
 321                 }
 322         }
 323
 324         ring->scan_el_group.name = iio_scan_elements_group_name;
 325
 326         ring->scan_el_group.attrs
 327                 = kzalloc(sizeof(ring->scan_el_group.attrs[0])*(attrcount + 1),
 328                           GFP_KERNEL);
 329         if (ring->scan_el_group.attrs == NULL) {
 330                 ret = -ENOMEM;
 331                 goto error_free_scan_mask;
 332         }
 333         if (ring->scan_el_attrs)
 334                 memcpy(ring->scan_el_group.attrs, ring->scan_el_attrs,
 335                        sizeof(ring->scan_el_group.attrs[0])*attrcount_orig);
 336         attrn = attrcount_orig;
 337
 338         list_for_each_entry(p, &ring->scan_el_dev_attr_list, l)
 339                 ring->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
 340         indio_dev->groups[indio_dev->groupcounter++] = &ring->scan_el_group;
 341
 342         return 0;
 343
 344 error_free_scan_mask:
 345         kfree(ring->scan_mask);
 346 error_cleanup_dynamic:
 347         __iio_ring_attr_cleanup(indio_dev);
 348
 349         return ret;
 350 }
 351 EXPORT_SYMBOL(iio_ring_buffer_register);
 352
 353 void iio_ring_buffer_unregister(struct iio_dev *indio_dev)
 354 {
 355         kfree(indio_dev->ring->scan_mask);
 356         kfree(indio_dev->ring->scan_el_group.attrs);
 357         __iio_ring_attr_cleanup(indio_dev);
 358 }
 359 EXPORT_SYMBOL(iio_ring_buffer_unregister);
 360
 361 ssize_t iio_read_ring_length(struct device *dev,
 362                              struct device_attribute *attr,
 363                              char *buf)
 364 {
 365         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 366         struct iio_ring_buffer *ring = indio_dev->ring;
 367
 368         if (ring->access->get_length)
 369                 return sprintf(buf, "%d\n",
 370                                ring->access->get_length(ring));
 371
 372         return 0;
 373 }
 374 EXPORT_SYMBOL(iio_read_ring_length);
 375
 376 ssize_t iio_write_ring_length(struct device *dev,
 377                                struct device_attribute *attr,
 378                                const char *buf,
 379                                size_t len)
 380 {
 381         int ret;
 382         ulong val;
 383         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 384         struct iio_ring_buffer *ring = indio_dev->ring;
 385
 386         ret = strict_strtoul(buf, 10, &val);
 387         if (ret)
 388                 return ret;
 389
 390         if (ring->access->get_length)
 391                 if (val == ring->access->get_length(ring))
 392                         return len;
 393
 394         if (ring->access->set_length) {
 395                 ring->access->set_length(ring, val);
 396                 if (ring->access->mark_param_change)
 397                         ring->access->mark_param_change(ring);
 398         }
 399
 400         return len;
 401 }
 402 EXPORT_SYMBOL(iio_write_ring_length);
 403
 404 ssize_t iio_read_ring_bytes_per_datum(struct device *dev,
 405                           struct device_attribute *attr,
 406                           char *buf)
 407 {
 408         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 409         struct iio_ring_buffer *ring = indio_dev->ring;
 410
 411         if (ring->access->get_bytes_per_datum)
 412                 return sprintf(buf, "%d\n",
 413                                ring->access->get_bytes_per_datum(ring));
 414
 415         return 0;
 416 }
 417 EXPORT_SYMBOL(iio_read_ring_bytes_per_datum);
 418
 419 ssize_t iio_store_ring_enable(struct device *dev,
 420                               struct device_attribute *attr,
 421                               const char *buf,
 422                               size_t len)
 423 {
 424         int ret;
 425         bool requested_state, current_state;
 426         int previous_mode;
 427         struct iio_dev *dev_info = dev_get_drvdata(dev);
 428         struct iio_ring_buffer *ring = dev_info->ring;
 429
 430         mutex_lock(&dev_info->mlock);
 431         previous_mode = dev_info->currentmode;
 432         requested_state = !(buf[0] == '0');
 433         current_state = !!(previous_mode & INDIO_ALL_BUFFER_MODES);
 434         if (current_state == requested_state) {
 435                 printk(KERN_INFO "iio-ring, current state requested again\n");
 436                 goto done;
 437         }
 438         if (requested_state) {
 439                 if (ring->setup_ops->preenable) {
 440                         ret = ring->setup_ops->preenable(dev_info);
 441                         if (ret) {
 442                                 printk(KERN_ERR
 443                                        "Buffer not started:"
 444                                        "ring preenable failed\n");
 445                                 goto error_ret;
 446                         }
 447                 }
 448                 if (ring->access->request_update) {
 449                         ret = ring->access->request_update(ring);
 450                         if (ret) {
 451                                 printk(KERN_INFO
 452                                        "Buffer not started:"
 453                                        "ring parameter update failed\n");
 454                                 goto error_ret;
 455                         }
 456                 }
 457                 if (ring->access->mark_in_use)
 458                         ring->access->mark_in_use(ring);
 459                 /* Definitely possible for devices to support both of these.*/
 460                 if (dev_info->modes & INDIO_BUFFER_TRIGGERED) {
 461                         if (!dev_info->trig) {
 462                                 printk(KERN_INFO
 463                                        "Buffer not started: no trigger\n");
 464                                 ret = -EINVAL;
 465                                 if (ring->access->unmark_in_use)
 466                                         ring->access->unmark_in_use(ring);
 467                                 goto error_ret;
 468                         }
 469                         dev_info->currentmode = INDIO_BUFFER_TRIGGERED;
 470                 } else if (dev_info->modes & INDIO_BUFFER_HARDWARE)
 471                         dev_info->currentmode = INDIO_BUFFER_HARDWARE;
 472                 else { /* should never be reached */
 473                         ret = -EINVAL;
 474                         goto error_ret;
 475                 }
 476
 477                 if (ring->setup_ops->postenable) {
 478                         ret = ring->setup_ops->postenable(dev_info);
 479                         if (ret) {
 480                                 printk(KERN_INFO
 481                                        "Buffer not started:"
 482                                        "postenable failed\n");
 483                                 if (ring->access->unmark_in_use)
 484                                         ring->access->unmark_in_use(ring);
 485                                 dev_info->currentmode = previous_mode;
 486                                 if (ring->setup_ops->postdisable)
 487                                         ring->setup_ops->postdisable(dev_info);
 488                                 goto error_ret;
 489                         }
 490                 }
 491         } else {
 492                 if (ring->setup_ops->predisable) {
 493                         ret = ring->setup_ops->predisable(dev_info);
 494                         if (ret)
 495                                 goto error_ret;
 496                 }
 497                 if (ring->access->unmark_in_use)
 498                         ring->access->unmark_in_use(ring);
 499                 dev_info->currentmode = INDIO_DIRECT_MODE;
 500                 if (ring->setup_ops->postdisable) {
 501                         ret = ring->setup_ops->postdisable(dev_info);
 502                         if (ret)
 503                                 goto error_ret;
 504                 }
 505         }
 506 done:
 507         mutex_unlock(&dev_info->mlock);
 508         return len;
 509
 510 error_ret:
 511         mutex_unlock(&dev_info->mlock);
 512         return ret;
 513 }
 514 EXPORT_SYMBOL(iio_store_ring_enable);
 515
 516 ssize_t iio_show_ring_enable(struct device *dev,
 517                                     struct device_attribute *attr,
 518                                     char *buf)
 519 {
 520         struct iio_dev *dev_info = dev_get_drvdata(dev);
 521         return sprintf(buf, "%d\n", !!(dev_info->currentmode
 522                                        & INDIO_ALL_BUFFER_MODES));
 523 }
 524 EXPORT_SYMBOL(iio_show_ring_enable);
 525
 526 int iio_sw_ring_preenable(struct iio_dev *indio_dev)
 527 {
 528         struct iio_ring_buffer *ring = indio_dev->ring;
 529         size_t size;
 530         dev_dbg(&indio_dev->dev, "%s\n", __func__);
 531         /* Check if there are any scan elements enabled, if not fail*/
 532         if (!(ring->scan_count || ring->scan_timestamp))
 533                 return -EINVAL;
 534         if (ring->scan_timestamp)
 535                 if (ring->scan_count)
 536                         /* Timestamp (aligned to s64) and data */
 537                         size = (((ring->scan_count * ring->bpe)
 538                                         + sizeof(s64) - 1)
 539                                 & ~(sizeof(s64) - 1))
 540                                 + sizeof(s64);
 541                 else /* Timestamp only  */
 542                         size = sizeof(s64);
 543         else /* Data only */
 544                 size = ring->scan_count * ring->bpe;
 545         ring->access->set_bytes_per_datum(ring, size);
 546
 547         return 0;
 548 }
 549 EXPORT_SYMBOL(iio_sw_ring_preenable);
 550
 551
 552 /* note NULL used as error indicator as it doesn't make sense. */
 553 static unsigned long *iio_scan_mask_match(unsigned long *av_masks,
 554                                           unsigned int masklength,
 555                                           unsigned long *mask)
 556 {
 557         if (bitmap_empty(mask, masklength))
 558                 return NULL;
 559         while (*av_masks) {
 560                 if (bitmap_subset(mask, av_masks, masklength))
 561                         return av_masks;
 562                 av_masks += BITS_TO_LONGS(masklength);
 563         }
 564         return NULL;
 565 }
 566
 567 /**
 568  * iio_scan_mask_set() - set particular bit in the scan mask
 569  * @ring: the ring buffer whose scan mask we are interested in
 570  * @bit: the bit to be set.
 571  **/
 572 int iio_scan_mask_set(struct iio_ring_buffer *ring, int bit)
 573 {
 574         struct iio_dev *dev_info = ring->indio_dev;
 575         unsigned long *mask;
 576         unsigned long *trialmask;
 577
 578         trialmask = kmalloc(sizeof(*trialmask)*
 579                             BITS_TO_LONGS(dev_info->masklength),
 580                             GFP_KERNEL);
 581
 582         if (trialmask == NULL)
 583                 return -ENOMEM;
 584         if (!dev_info->masklength) {
 585                 WARN_ON("trying to set scan mask prior to registering ring\n");
 586                 kfree(trialmask);
 587                 return -EINVAL;
 588         }
 589         bitmap_copy(trialmask, ring->scan_mask, dev_info->masklength);
 590         set_bit(bit, trialmask);
 591
 592         if (dev_info->available_scan_masks) {
 593                 mask = iio_scan_mask_match(dev_info->available_scan_masks,
 594                                            dev_info->masklength,
 595                                            trialmask);
 596                 if (!mask) {
 597                         kfree(trialmask);
 598                         return -EINVAL;
 599                 }
 600         }
 601         bitmap_copy(ring->scan_mask, trialmask, dev_info->masklength);
 602         ring->scan_count++;
 603
 604         kfree(trialmask);
 605
 606         return 0;
 607 };
 608 EXPORT_SYMBOL_GPL(iio_scan_mask_set);
 609
 610 int iio_scan_mask_query(struct iio_ring_buffer *ring, int bit)
 611 {
 612         struct iio_dev *dev_info = ring->indio_dev;
 613         long *mask;
 614
 615         if (bit > dev_info->masklength)
 616                 return -EINVAL;
 617
 618         if (!ring->scan_mask)
 619                 return 0;
 620         if (dev_info->available_scan_masks)
 621                 mask = iio_scan_mask_match(dev_info->available_scan_masks,
 622                                            dev_info->masklength,
 623                                            ring->scan_mask);
 624         else
 625                 mask = ring->scan_mask;
 626         if (!mask)
 627                 return 0;
 628
 629         return test_bit(bit, mask);
 630 };
 631 EXPORT_SYMBOL_GPL(iio_scan_mask_query);