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/interrupt.h>
  19 #include <linux/fs.h>
  20 #include <linux/poll.h>
  21 #include <linux/module.h>
  22 #include <linux/cdev.h>
  23 #include <linux/idr.h>
  24
  25 #include "iio.h"
  26 #include "ring_generic.h"
  27
  28 /* IDR for ring buffer identifier */
  29 static DEFINE_IDR(iio_ring_idr);
  30 /* IDR for ring event identifier */
  31 static DEFINE_IDR(iio_ring_event_idr);
  32 /* IDR for ring access identifier */
  33 static DEFINE_IDR(iio_ring_access_idr);
  34
  35 int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
  36                        int event_code,
  37                        s64 timestamp)
  38 {
  39         return __iio_push_event(&ring_buf->ev_int,
  40                                event_code,
  41                                timestamp,
  42                                &ring_buf->shared_ev_pointer);
  43 }
  44 EXPORT_SYMBOL(iio_push_ring_event);
  45
  46 int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
  47                                     int event_code,
  48                                     s64 timestamp)
  49 {
  50         if (ring_buf->shared_ev_pointer.ev_p)
  51                 __iio_change_event(ring_buf->shared_ev_pointer.ev_p,
  52                                    event_code,
  53                                    timestamp);
  54         else
  55                 return iio_push_ring_event(ring_buf,
  56                                           event_code,
  57                                           timestamp);
  58         return 0;
  59 }
  60 EXPORT_SYMBOL(iio_push_or_escallate_ring_event);
  61
  62 /**
  63  * iio_ring_open() chrdev file open for ring buffer access
  64  *
  65  * This function relies on all ring buffer implementations having an
  66  * iio_ring_buffer as their first element.
  67  **/
  68 int iio_ring_open(struct inode *inode, struct file *filp)
  69 {
  70         struct iio_handler *hand
  71                 = container_of(inode->i_cdev, struct iio_handler, chrdev);
  72         struct iio_ring_buffer *rb = hand->private;
  73
  74         filp->private_data = hand->private;
  75         if (rb->access.mark_in_use)
  76                 rb->access.mark_in_use(rb);
  77
  78         return 0;
  79 }
  80
  81 /**
  82  * iio_ring_release() -chrdev file close ring buffer access
  83  *
  84  * This function relies on all ring buffer implementations having an
  85  * iio_ring_buffer as their first element.
  86  **/
  87 int iio_ring_release(struct inode *inode, struct file *filp)
  88 {
  89         struct cdev *cd = inode->i_cdev;
  90         struct iio_handler *hand = iio_cdev_to_handler(cd);
  91         struct iio_ring_buffer *rb = hand->private;
  92
  93         clear_bit(IIO_BUSY_BIT_POS, &rb->access_handler.flags);
  94         if (rb->access.unmark_in_use)
  95                 rb->access.unmark_in_use(rb);
  96
  97         return 0;
  98 }
  99
 100 /**
 101  * iio_ring_rip_outer() chrdev read for ring buffer access
 102  *
 103  * This function relies on all ring buffer implementations having an
 104  * iio_ring _bufer as their first element.
 105  **/
 106 ssize_t iio_ring_rip_outer(struct file *filp,
 107                            char *buf,
 108                            size_t count,
 109                            loff_t *f_ps)
 110 {
 111         struct iio_ring_buffer *rb = filp->private_data;
 112         int ret, dead_offset, copied;
 113         u8 *data;
 114         /* rip lots must exist. */
 115         if (!rb->access.rip_lots)
 116                 return -EINVAL;
 117         copied = rb->access.rip_lots(rb, count, &data, &dead_offset);
 118
 119         if (copied < 0) {
 120                 ret = copied;
 121                 goto error_ret;
 122         }
 123         if (copy_to_user(buf, data + dead_offset, copied))  {
 124                 ret =  -EFAULT;
 125                 goto error_free_data_cpy;
 126         }
 127         /* In clever ring buffer designs this may not need to be freed.
 128          * When such a design exists I'll add this to ring access funcs.
 129          */
 130         kfree(data);
 131
 132         return copied;
 133
 134 error_free_data_cpy:
 135         kfree(data);
 136 error_ret:
 137         return ret;
 138 }
 139
 140 static const struct file_operations iio_ring_fileops = {
 141         .read = iio_ring_rip_outer,
 142         .release = iio_ring_release,
 143         .open = iio_ring_open,
 144         .owner = THIS_MODULE,
 145 };
 146
 147 /**
 148  * __iio_request_ring_buffer_event_chrdev() allocate ring event chrdev
 149  * @buf:        ring buffer whose event chrdev we are allocating
 150  * @owner:      the module who owns the ring buffer (for ref counting)
 151  * @dev:        device with which the chrdev is associated
 152  **/
 153 static inline int
 154 __iio_request_ring_buffer_event_chrdev(struct iio_ring_buffer *buf,
 155                                        int id,
 156                                        struct module *owner,
 157                                        struct device *dev)
 158 {
 159         int ret;
 160         ret = iio_get_new_idr_val(&iio_ring_event_idr);
 161         if (ret < 0)
 162                 goto error_ret;
 163         else
 164                 buf->ev_int.id = ret;
 165
 166         snprintf(buf->ev_int._name, 20,
 167                  "ring_event_line%d",
 168                  buf->ev_int.id);
 169         ret = iio_setup_ev_int(&(buf->ev_int),
 170                                buf->ev_int._name,
 171                                owner,
 172                                dev);
 173         if (ret)
 174                 goto error_free_id;
 175         return 0;
 176
 177 error_free_id:
 178         iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id);
 179 error_ret:
 180         return ret;
 181 }
 182
 183 static inline void
 184 __iio_free_ring_buffer_event_chrdev(struct iio_ring_buffer *buf)
 185 {
 186         iio_free_ev_int(&(buf->ev_int));
 187         iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id);
 188 }
 189
 190 static void iio_ring_access_release(struct device *dev)
 191 {
 192         struct iio_ring_buffer *buf
 193                 = access_dev_to_iio_ring_buffer(dev);
 194         cdev_del(&buf->access_handler.chrdev);
 195         iio_device_free_chrdev_minor(MINOR(dev->devt));
 196 }
 197
 198 static struct device_type iio_ring_access_type = {
 199         .release = iio_ring_access_release,
 200 };
 201
 202 static inline int
 203 __iio_request_ring_buffer_access_chrdev(struct iio_ring_buffer *buf,
 204                                         int id,
 205                                         struct module *owner)
 206 {
 207         int ret, minor;
 208
 209         buf->access_handler.flags = 0;
 210
 211         buf->access_dev.parent = &buf->dev;
 212         buf->access_dev.class = &iio_class;
 213         buf->access_dev.type = &iio_ring_access_type;
 214         device_initialize(&buf->access_dev);
 215
 216         minor = iio_device_get_chrdev_minor();
 217         if (minor < 0) {
 218                 ret = minor;
 219                 goto error_device_put;
 220         }
 221         buf->access_dev.devt = MKDEV(MAJOR(iio_devt), minor);
 222
 223         ret = iio_get_new_idr_val(&iio_ring_access_idr);
 224         if (ret < 0)
 225                 goto error_device_put;
 226         else
 227                 buf->access_id = ret;
 228         dev_set_name(&buf->access_dev, "ring_access%d", buf->access_id);
 229         ret = device_add(&buf->access_dev);
 230         if (ret < 0) {
 231                 printk(KERN_ERR "failed to add the ring access dev\n");
 232                 goto error_free_idr;
 233         }
 234
 235         cdev_init(&buf->access_handler.chrdev, &iio_ring_fileops);
 236         buf->access_handler.chrdev.owner = owner;
 237
 238         ret = cdev_add(&buf->access_handler.chrdev, buf->access_dev.devt, 1);
 239         if (ret) {
 240                 printk(KERN_ERR "failed to allocate ring access chrdev\n");
 241                 goto error_device_unregister;
 242         }
 243         return 0;
 244 error_device_unregister:
 245         device_unregister(&buf->access_dev);
 246 error_free_idr:
 247         iio_free_idr_val(&iio_ring_access_idr, buf->access_id);
 248 error_device_put:
 249         put_device(&buf->access_dev);
 250
 251         return ret;
 252 }
 253
 254 static void __iio_free_ring_buffer_access_chrdev(struct iio_ring_buffer *buf)
 255 {
 256         iio_free_idr_val(&iio_ring_access_idr, buf->access_id);
 257         device_unregister(&buf->access_dev);
 258 }
 259
 260 void iio_ring_buffer_init(struct iio_ring_buffer *ring,
 261                           struct iio_dev *dev_info)
 262 {
 263         if (ring->access.mark_param_change)
 264                 ring->access.mark_param_change(ring);
 265         ring->indio_dev = dev_info;
 266         ring->ev_int.private = ring;
 267         ring->access_handler.private = ring;
 268 }
 269 EXPORT_SYMBOL(iio_ring_buffer_init);
 270
 271 int iio_ring_buffer_register(struct iio_ring_buffer *ring)
 272 {
 273         int ret;
 274         ret = iio_get_new_idr_val(&iio_ring_idr);
 275         if (ret < 0)
 276                 goto error_ret;
 277         else
 278                 ring->id = ret;
 279
 280         dev_set_name(&ring->dev, "ring_buffer%d", ring->id);
 281         ret = device_add(&ring->dev);
 282         if (ret)
 283                 goto error_free_id;
 284
 285         ret = __iio_request_ring_buffer_event_chrdev(ring,
 286                                                      0,
 287                                                      ring->owner,
 288                                                      &ring->dev);
 289         if (ret)
 290                 goto error_remove_device;
 291
 292         ret = __iio_request_ring_buffer_access_chrdev(ring,
 293                                                       0,
 294                                                       ring->owner);
 295
 296         if (ret)
 297                 goto error_free_ring_buffer_event_chrdev;
 298
 299         return ret;
 300 error_free_ring_buffer_event_chrdev:
 301         __iio_free_ring_buffer_event_chrdev(ring);
 302 error_remove_device:
 303         device_del(&ring->dev);
 304 error_free_id:
 305         iio_free_idr_val(&iio_ring_idr, ring->id);
 306 error_ret:
 307         return ret;
 308 }
 309 EXPORT_SYMBOL(iio_ring_buffer_register);
 310
 311 void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
 312 {
 313         __iio_free_ring_buffer_access_chrdev(ring);
 314         __iio_free_ring_buffer_event_chrdev(ring);
 315         device_del(&ring->dev);
 316         iio_free_idr_val(&iio_ring_idr, ring->id);
 317 }
 318 EXPORT_SYMBOL(iio_ring_buffer_unregister);
 319
 320 ssize_t iio_read_ring_length(struct device *dev,
 321                              struct device_attribute *attr,
 322                              char *buf)
 323 {
 324         int len = 0;
 325         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 326
 327         if (ring->access.get_length)
 328                 len = sprintf(buf, "%d\n",
 329                               ring->access.get_length(ring));
 330
 331         return len;
 332 }
 333 EXPORT_SYMBOL(iio_read_ring_length);
 334
 335  ssize_t iio_write_ring_length(struct device *dev,
 336                                struct device_attribute *attr,
 337                                const char *buf,
 338                                size_t len)
 339 {
 340         int ret;
 341         ulong val;
 342         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 343         ret = strict_strtoul(buf, 10, &val);
 344         if (ret)
 345                 return ret;
 346
 347         if (ring->access.get_length)
 348                 if (val == ring->access.get_length(ring))
 349                         return len;
 350
 351         if (ring->access.set_length) {
 352                 ring->access.set_length(ring, val);
 353                 if (ring->access.mark_param_change)
 354                         ring->access.mark_param_change(ring);
 355         }
 356
 357         return len;
 358 }
 359 EXPORT_SYMBOL(iio_write_ring_length);
 360
 361 ssize_t iio_read_ring_bps(struct device *dev,
 362                           struct device_attribute *attr,
 363                           char *buf)
 364 {
 365         int len = 0;
 366         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 367
 368         if (ring->access.get_bpd)
 369                 len = sprintf(buf, "%d\n",
 370                               ring->access.get_bpd(ring));
 371
 372         return len;
 373 }
 374 EXPORT_SYMBOL(iio_read_ring_bps);
 375
 376 ssize_t iio_store_ring_enable(struct device *dev,
 377                               struct device_attribute *attr,
 378                               const char *buf,
 379                               size_t len)
 380 {
 381         int ret;
 382         bool requested_state, current_state;
 383         int previous_mode;
 384         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 385         struct iio_dev *dev_info = ring->indio_dev;
 386
 387         mutex_lock(&dev_info->mlock);
 388         previous_mode = dev_info->currentmode;
 389         requested_state = !(buf[0] == '0');
 390         current_state = !!(previous_mode & INDIO_ALL_RING_MODES);
 391         if (current_state == requested_state) {
 392                 printk(KERN_INFO "iio-ring, current state requested again\n");
 393                 goto done;
 394         }
 395         if (requested_state) {
 396                 if (ring->preenable) {
 397                         ret = ring->preenable(dev_info);
 398                         if (ret) {
 399                                 printk(KERN_ERR
 400                                        "Buffer not started:"
 401                                        "ring preenable failed\n");
 402                                 goto error_ret;
 403                         }
 404                 }
 405                 if (ring->access.request_update) {
 406                         ret = ring->access.request_update(ring);
 407                         if (ret) {
 408                                 printk(KERN_INFO
 409                                        "Buffer not started:"
 410                                        "ring parameter update failed\n");
 411                                 goto error_ret;
 412                         }
 413                 }
 414                 if (ring->access.mark_in_use)
 415                         ring->access.mark_in_use(ring);
 416                 /* Definitely possible for devices to support both of these.*/
 417                 if (dev_info->modes & INDIO_RING_TRIGGERED) {
 418                         if (!dev_info->trig) {
 419                                 printk(KERN_INFO
 420                                        "Buffer not started: no trigger\n");
 421                                 ret = -EINVAL;
 422                                 if (ring->access.unmark_in_use)
 423                                         ring->access.unmark_in_use(ring);
 424                                 goto error_ret;
 425                         }
 426                         dev_info->currentmode = INDIO_RING_TRIGGERED;
 427                 } else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER)
 428                         dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER;
 429                 else { /* should never be reached */
 430                         ret = -EINVAL;
 431                         goto error_ret;
 432                 }
 433
 434                 if (ring->postenable) {
 435
 436                         ret = ring->postenable(dev_info);
 437                         if (ret) {
 438                                 printk(KERN_INFO
 439                                        "Buffer not started:"
 440                                        "postenable failed\n");
 441                                 if (ring->access.unmark_in_use)
 442                                         ring->access.unmark_in_use(ring);
 443                                 dev_info->currentmode = previous_mode;
 444                                 if (ring->postdisable)
 445                                         ring->postdisable(dev_info);
 446                                 goto error_ret;
 447                         }
 448                 }
 449         } else {
 450                 if (ring->predisable) {
 451                         ret = ring->predisable(dev_info);
 452                         if (ret)
 453                                 goto error_ret;
 454                 }
 455                 if (ring->access.unmark_in_use)
 456                         ring->access.unmark_in_use(ring);
 457                 dev_info->currentmode = INDIO_DIRECT_MODE;
 458                 if (ring->postdisable) {
 459                         ret = ring->postdisable(dev_info);
 460                         if (ret)
 461                                 goto error_ret;
 462                 }
 463         }
 464 done:
 465         mutex_unlock(&dev_info->mlock);
 466         return len;
 467
 468 error_ret:
 469         mutex_unlock(&dev_info->mlock);
 470         return ret;
 471 }
 472 EXPORT_SYMBOL(iio_store_ring_enable);
 473 ssize_t iio_show_ring_enable(struct device *dev,
 474                                     struct device_attribute *attr,
 475                                     char *buf)
 476 {
 477         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 478         return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode
 479                                        & INDIO_ALL_RING_MODES));
 480 }
 481 EXPORT_SYMBOL(iio_show_ring_enable);
 482
 483 ssize_t iio_scan_el_show(struct device *dev,
 484                          struct device_attribute *attr,
 485                          char *buf)
 486 {
 487         int ret;
 488         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 489         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 490
 491         ret = iio_scan_mask_query(indio_dev, this_el->number);
 492         if (ret < 0)
 493                 return ret;
 494         return sprintf(buf, "%d\n", ret);
 495 }
 496 EXPORT_SYMBOL(iio_scan_el_show);
 497
 498 ssize_t iio_scan_el_store(struct device *dev,
 499                           struct device_attribute *attr,
 500                           const char *buf,
 501                           size_t len)
 502 {
 503         int ret = 0;
 504         bool state;
 505         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 506         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 507
 508         state = !(buf[0] == '0');
 509         mutex_lock(&indio_dev->mlock);
 510         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 511                 ret = -EBUSY;
 512                 goto error_ret;
 513         }
 514         ret = iio_scan_mask_query(indio_dev, this_el->number);
 515         if (ret < 0)
 516                 goto error_ret;
 517         if (!state && ret) {
 518                 ret = iio_scan_mask_clear(indio_dev, this_el->number);
 519                 if (ret)
 520                         goto error_ret;
 521                 indio_dev->scan_count--;
 522         } else if (state && !ret) {
 523                 ret = iio_scan_mask_set(indio_dev, this_el->number);
 524                 if (ret)
 525                         goto error_ret;
 526                 indio_dev->scan_count++;
 527         }
 528         if (this_el->set_state)
 529                 ret = this_el->set_state(this_el, indio_dev, state);
 530 error_ret:
 531         mutex_unlock(&indio_dev->mlock);
 532
 533         return ret ? ret : len;
 534
 535 }
 536 EXPORT_SYMBOL(iio_scan_el_store);
 537
 538 ssize_t iio_scan_el_ts_show(struct device *dev,
 539                             struct device_attribute *attr,
 540                             char *buf)
 541 {
 542         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 543         return sprintf(buf, "%d\n", indio_dev->scan_timestamp);
 544 }
 545 EXPORT_SYMBOL(iio_scan_el_ts_show);
 546
 547 ssize_t iio_scan_el_ts_store(struct device *dev,
 548                              struct device_attribute *attr,
 549                              const char *buf,
 550                              size_t len)
 551 {
 552         int ret = 0;
 553         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 554         bool state;
 555         state = !(buf[0] == '0');
 556         mutex_lock(&indio_dev->mlock);
 557         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 558                 ret = -EBUSY;
 559                 goto error_ret;
 560         }
 561         indio_dev->scan_timestamp = state;
 562 error_ret:
 563         mutex_unlock(&indio_dev->mlock);
 564
 565         return ret ? ret : len;
 566 }
 567 EXPORT_SYMBOL(iio_scan_el_ts_store);
 568