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