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 #include <linux/slab.h>
  25
  26 #include "iio.h"
  27 #include "ring_generic.h"
  28
  29 /* IDR for ring buffer identifier */
  30 static DEFINE_IDR(iio_ring_idr);
  31 /* IDR for ring event identifier */
  32 static DEFINE_IDR(iio_ring_event_idr);
  33 /* IDR for ring access identifier */
  34 static DEFINE_IDR(iio_ring_access_idr);
  35
  36 int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
  37                        int event_code,
  38                        s64 timestamp)
  39 {
  40         return __iio_push_event(&ring_buf->ev_int,
  41                                event_code,
  42                                timestamp,
  43                                &ring_buf->shared_ev_pointer);
  44 }
  45 EXPORT_SYMBOL(iio_push_ring_event);
  46
  47 int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
  48                                     int event_code,
  49                                     s64 timestamp)
  50 {
  51         if (ring_buf->shared_ev_pointer.ev_p)
  52                 __iio_change_event(ring_buf->shared_ev_pointer.ev_p,
  53                                    event_code,
  54                                    timestamp);
  55         else
  56                 return iio_push_ring_event(ring_buf,
  57                                           event_code,
  58                                           timestamp);
  59         return 0;
  60 }
  61 EXPORT_SYMBOL(iio_push_or_escallate_ring_event);
  62
  63 /**
  64  * iio_ring_open() chrdev file open for ring buffer access
  65  *
  66  * This function relies on all ring buffer implementations having an
  67  * iio_ring_buffer as their first element.
  68  **/
  69 int iio_ring_open(struct inode *inode, struct file *filp)
  70 {
  71         struct iio_handler *hand
  72                 = container_of(inode->i_cdev, struct iio_handler, chrdev);
  73         struct iio_ring_buffer *rb = hand->private;
  74
  75         filp->private_data = hand->private;
  76         if (rb->access.mark_in_use)
  77                 rb->access.mark_in_use(rb);
  78
  79         return 0;
  80 }
  81
  82 /**
  83  * iio_ring_release() -chrdev file close ring buffer access
  84  *
  85  * This function relies on all ring buffer implementations having an
  86  * iio_ring_buffer as their first element.
  87  **/
  88 int iio_ring_release(struct inode *inode, struct file *filp)
  89 {
  90         struct cdev *cd = inode->i_cdev;
  91         struct iio_handler *hand = iio_cdev_to_handler(cd);
  92         struct iio_ring_buffer *rb = hand->private;
  93
  94         clear_bit(IIO_BUSY_BIT_POS, &rb->access_handler.flags);
  95         if (rb->access.unmark_in_use)
  96                 rb->access.unmark_in_use(rb);
  97
  98         return 0;
  99 }
 100
 101 /**
 102  * iio_ring_rip_outer() chrdev read for ring buffer access
 103  *
 104  * This function relies on all ring buffer implementations having an
 105  * iio_ring _bufer as their first element.
 106  **/
 107 ssize_t iio_ring_rip_outer(struct file *filp,
 108                            char *buf,
 109                            size_t count,
 110                            loff_t *f_ps)
 111 {
 112         struct iio_ring_buffer *rb = filp->private_data;
 113         int ret, dead_offset, copied;
 114         u8 *data;
 115         /* rip lots must exist. */
 116         if (!rb->access.rip_lots)
 117                 return -EINVAL;
 118         copied = rb->access.rip_lots(rb, count, &data, &dead_offset);
 119
 120         if (copied < 0) {
 121                 ret = copied;
 122                 goto error_ret;
 123         }
 124         if (copy_to_user(buf, data + dead_offset, copied))  {
 125                 ret =  -EFAULT;
 126                 goto error_free_data_cpy;
 127         }
 128         /* In clever ring buffer designs this may not need to be freed.
 129          * When such a design exists I'll add this to ring access funcs.
 130          */
 131         kfree(data);
 132
 133         return copied;
 134
 135 error_free_data_cpy:
 136         kfree(data);
 137 error_ret:
 138         return ret;
 139 }
 140
 141 static const struct file_operations iio_ring_fileops = {
 142         .read = iio_ring_rip_outer,
 143         .release = iio_ring_release,
 144         .open = iio_ring_open,
 145         .owner = THIS_MODULE,
 146 };
 147
 148 /**
 149  * __iio_request_ring_buffer_event_chrdev() allocate ring event chrdev
 150  * @buf:        ring buffer whose event chrdev we are allocating
 151  * @owner:      the module who owns the ring buffer (for ref counting)
 152  * @dev:        device with which the chrdev is associated
 153  **/
 154 static inline int
 155 __iio_request_ring_buffer_event_chrdev(struct iio_ring_buffer *buf,
 156                                        int id,
 157                                        struct module *owner,
 158                                        struct device *dev)
 159 {
 160         int ret;
 161         ret = iio_get_new_idr_val(&iio_ring_event_idr);
 162         if (ret < 0)
 163                 goto error_ret;
 164         else
 165                 buf->ev_int.id = ret;
 166
 167         snprintf(buf->ev_int._name, 20,
 168                  "ring_event_line%d",
 169                  buf->ev_int.id);
 170         ret = iio_setup_ev_int(&(buf->ev_int),
 171                                buf->ev_int._name,
 172                                owner,
 173                                dev);
 174         if (ret)
 175                 goto error_free_id;
 176         return 0;
 177
 178 error_free_id:
 179         iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id);
 180 error_ret:
 181         return ret;
 182 }
 183
 184 static inline void
 185 __iio_free_ring_buffer_event_chrdev(struct iio_ring_buffer *buf)
 186 {
 187         iio_free_ev_int(&(buf->ev_int));
 188         iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id);
 189 }
 190
 191 static void iio_ring_access_release(struct device *dev)
 192 {
 193         struct iio_ring_buffer *buf
 194                 = access_dev_to_iio_ring_buffer(dev);
 195         cdev_del(&buf->access_handler.chrdev);
 196         iio_device_free_chrdev_minor(MINOR(dev->devt));
 197 }
 198
 199 static struct device_type iio_ring_access_type = {
 200         .release = iio_ring_access_release,
 201 };
 202
 203 static inline int
 204 __iio_request_ring_buffer_access_chrdev(struct iio_ring_buffer *buf,
 205                                         int id,
 206                                         struct module *owner)
 207 {
 208         int ret, minor;
 209
 210         buf->access_handler.flags = 0;
 211
 212         buf->access_dev.parent = &buf->dev;
 213         buf->access_dev.class = &iio_class;
 214         buf->access_dev.type = &iio_ring_access_type;
 215         device_initialize(&buf->access_dev);
 216
 217         minor = iio_device_get_chrdev_minor();
 218         if (minor < 0) {
 219                 ret = minor;
 220                 goto error_device_put;
 221         }
 222         buf->access_dev.devt = MKDEV(MAJOR(iio_devt), minor);
 223
 224         ret = iio_get_new_idr_val(&iio_ring_access_idr);
 225         if (ret < 0)
 226                 goto error_device_put;
 227         else
 228                 buf->access_id = ret;
 229         dev_set_name(&buf->access_dev, "ring_access%d", buf->access_id);
 230         ret = device_add(&buf->access_dev);
 231         if (ret < 0) {
 232                 printk(KERN_ERR "failed to add the ring access dev\n");
 233                 goto error_free_idr;
 234         }
 235
 236         cdev_init(&buf->access_handler.chrdev, &iio_ring_fileops);
 237         buf->access_handler.chrdev.owner = owner;
 238
 239         ret = cdev_add(&buf->access_handler.chrdev, buf->access_dev.devt, 1);
 240         if (ret) {
 241                 printk(KERN_ERR "failed to allocate ring access chrdev\n");
 242                 goto error_device_unregister;
 243         }
 244         return 0;
 245 error_device_unregister:
 246         device_unregister(&buf->access_dev);
 247 error_free_idr:
 248         iio_free_idr_val(&iio_ring_access_idr, buf->access_id);
 249 error_device_put:
 250         put_device(&buf->access_dev);
 251
 252         return ret;
 253 }
 254
 255 static void __iio_free_ring_buffer_access_chrdev(struct iio_ring_buffer *buf)
 256 {
 257         iio_free_idr_val(&iio_ring_access_idr, buf->access_id);
 258         device_unregister(&buf->access_dev);
 259 }
 260
 261 void iio_ring_buffer_init(struct iio_ring_buffer *ring,
 262                           struct iio_dev *dev_info)
 263 {
 264         if (ring->access.mark_param_change)
 265                 ring->access.mark_param_change(ring);
 266         ring->indio_dev = dev_info;
 267         ring->ev_int.private = ring;
 268         ring->access_handler.private = ring;
 269 }
 270 EXPORT_SYMBOL(iio_ring_buffer_init);
 271
 272 int iio_ring_buffer_register(struct iio_ring_buffer *ring)
 273 {
 274         int ret;
 275         ret = iio_get_new_idr_val(&iio_ring_idr);
 276         if (ret < 0)
 277                 goto error_ret;
 278         else
 279                 ring->id = ret;
 280
 281         dev_set_name(&ring->dev, "ring_buffer%d", ring->id);
 282         ret = device_add(&ring->dev);
 283         if (ret)
 284                 goto error_free_id;
 285
 286         ret = __iio_request_ring_buffer_event_chrdev(ring,
 287                                                      0,
 288                                                      ring->owner,
 289                                                      &ring->dev);
 290         if (ret)
 291                 goto error_remove_device;
 292
 293         ret = __iio_request_ring_buffer_access_chrdev(ring,
 294                                                       0,
 295                                                       ring->owner);
 296
 297         if (ret)
 298                 goto error_free_ring_buffer_event_chrdev;
 299
 300         return ret;
 301 error_free_ring_buffer_event_chrdev:
 302         __iio_free_ring_buffer_event_chrdev(ring);
 303 error_remove_device:
 304         device_del(&ring->dev);
 305 error_free_id:
 306         iio_free_idr_val(&iio_ring_idr, ring->id);
 307 error_ret:
 308         return ret;
 309 }
 310 EXPORT_SYMBOL(iio_ring_buffer_register);
 311
 312 void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
 313 {
 314         __iio_free_ring_buffer_access_chrdev(ring);
 315         __iio_free_ring_buffer_event_chrdev(ring);
 316         device_del(&ring->dev);
 317         iio_free_idr_val(&iio_ring_idr, ring->id);
 318 }
 319 EXPORT_SYMBOL(iio_ring_buffer_unregister);
 320
 321 ssize_t iio_read_ring_length(struct device *dev,
 322                              struct device_attribute *attr,
 323                              char *buf)
 324 {
 325         int len = 0;
 326         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 327
 328         if (ring->access.get_length)
 329                 len = sprintf(buf, "%d\n",
 330                               ring->access.get_length(ring));
 331
 332         return len;
 333 }
 334 EXPORT_SYMBOL(iio_read_ring_length);
 335
 336  ssize_t iio_write_ring_length(struct device *dev,
 337                                struct device_attribute *attr,
 338                                const char *buf,
 339                                size_t len)
 340 {
 341         int ret;
 342         ulong val;
 343         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 344         ret = strict_strtoul(buf, 10, &val);
 345         if (ret)
 346                 return ret;
 347
 348         if (ring->access.get_length)
 349                 if (val == ring->access.get_length(ring))
 350                         return len;
 351
 352         if (ring->access.set_length) {
 353                 ring->access.set_length(ring, val);
 354                 if (ring->access.mark_param_change)
 355                         ring->access.mark_param_change(ring);
 356         }
 357
 358         return len;
 359 }
 360 EXPORT_SYMBOL(iio_write_ring_length);
 361
 362 ssize_t iio_read_ring_bps(struct device *dev,
 363                           struct device_attribute *attr,
 364                           char *buf)
 365 {
 366         int len = 0;
 367         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 368
 369         if (ring->access.get_bpd)
 370                 len = sprintf(buf, "%d\n",
 371                               ring->access.get_bpd(ring));
 372
 373         return len;
 374 }
 375 EXPORT_SYMBOL(iio_read_ring_bps);
 376
 377 ssize_t iio_store_ring_enable(struct device *dev,
 378                               struct device_attribute *attr,
 379                               const char *buf,
 380                               size_t len)
 381 {
 382         int ret;
 383         bool requested_state, current_state;
 384         int previous_mode;
 385         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 386         struct iio_dev *dev_info = ring->indio_dev;
 387
 388         mutex_lock(&dev_info->mlock);
 389         previous_mode = dev_info->currentmode;
 390         requested_state = !(buf[0] == '0');
 391         current_state = !!(previous_mode & INDIO_ALL_RING_MODES);
 392         if (current_state == requested_state) {
 393                 printk(KERN_INFO "iio-ring, current state requested again\n");
 394                 goto done;
 395         }
 396         if (requested_state) {
 397                 if (ring->preenable) {
 398                         ret = ring->preenable(dev_info);
 399                         if (ret) {
 400                                 printk(KERN_ERR
 401                                        "Buffer not started:"
 402                                        "ring preenable failed\n");
 403                                 goto error_ret;
 404                         }
 405                 }
 406                 if (ring->access.request_update) {
 407                         ret = ring->access.request_update(ring);
 408                         if (ret) {
 409                                 printk(KERN_INFO
 410                                        "Buffer not started:"
 411                                        "ring parameter update failed\n");
 412                                 goto error_ret;
 413                         }
 414                 }
 415                 if (ring->access.mark_in_use)
 416                         ring->access.mark_in_use(ring);
 417                 /* Definitely possible for devices to support both of these.*/
 418                 if (dev_info->modes & INDIO_RING_TRIGGERED) {
 419                         if (!dev_info->trig) {
 420                                 printk(KERN_INFO
 421                                        "Buffer not started: no trigger\n");
 422                                 ret = -EINVAL;
 423                                 if (ring->access.unmark_in_use)
 424                                         ring->access.unmark_in_use(ring);
 425                                 goto error_ret;
 426                         }
 427                         dev_info->currentmode = INDIO_RING_TRIGGERED;
 428                 } else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER)
 429                         dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER;
 430                 else { /* should never be reached */
 431                         ret = -EINVAL;
 432                         goto error_ret;
 433                 }
 434
 435                 if (ring->postenable) {
 436
 437                         ret = ring->postenable(dev_info);
 438                         if (ret) {
 439                                 printk(KERN_INFO
 440                                        "Buffer not started:"
 441                                        "postenable failed\n");
 442                                 if (ring->access.unmark_in_use)
 443                                         ring->access.unmark_in_use(ring);
 444                                 dev_info->currentmode = previous_mode;
 445                                 if (ring->postdisable)
 446                                         ring->postdisable(dev_info);
 447                                 goto error_ret;
 448                         }
 449                 }
 450         } else {
 451                 if (ring->predisable) {
 452                         ret = ring->predisable(dev_info);
 453                         if (ret)
 454                                 goto error_ret;
 455                 }
 456                 if (ring->access.unmark_in_use)
 457                         ring->access.unmark_in_use(ring);
 458                 dev_info->currentmode = INDIO_DIRECT_MODE;
 459                 if (ring->postdisable) {
 460                         ret = ring->postdisable(dev_info);
 461                         if (ret)
 462                                 goto error_ret;
 463                 }
 464         }
 465 done:
 466         mutex_unlock(&dev_info->mlock);
 467         return len;
 468
 469 error_ret:
 470         mutex_unlock(&dev_info->mlock);
 471         return ret;
 472 }
 473 EXPORT_SYMBOL(iio_store_ring_enable);
 474 ssize_t iio_show_ring_enable(struct device *dev,
 475                                     struct device_attribute *attr,
 476                                     char *buf)
 477 {
 478         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 479         return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode
 480                                        & INDIO_ALL_RING_MODES));
 481 }
 482 EXPORT_SYMBOL(iio_show_ring_enable);
 483
 484 ssize_t iio_scan_el_show(struct device *dev,
 485                          struct device_attribute *attr,
 486                          char *buf)
 487 {
 488         int ret;
 489         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 490         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 491
 492         ret = iio_scan_mask_query(indio_dev, this_el->number);
 493         if (ret < 0)
 494                 return ret;
 495         return sprintf(buf, "%d\n", ret);
 496 }
 497 EXPORT_SYMBOL(iio_scan_el_show);
 498
 499 ssize_t iio_scan_el_store(struct device *dev,
 500                           struct device_attribute *attr,
 501                           const char *buf,
 502                           size_t len)
 503 {
 504         int ret = 0;
 505         bool state;
 506         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 507         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 508
 509         state = !(buf[0] == '0');
 510         mutex_lock(&indio_dev->mlock);
 511         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 512                 ret = -EBUSY;
 513                 goto error_ret;
 514         }
 515         ret = iio_scan_mask_query(indio_dev, this_el->number);
 516         if (ret < 0)
 517                 goto error_ret;
 518         if (!state && ret) {
 519                 ret = iio_scan_mask_clear(indio_dev, this_el->number);
 520                 if (ret)
 521                         goto error_ret;
 522                 indio_dev->scan_count--;
 523         } else if (state && !ret) {
 524                 ret = iio_scan_mask_set(indio_dev, this_el->number);
 525                 if (ret)
 526                         goto error_ret;
 527                 indio_dev->scan_count++;
 528         }
 529         if (this_el->set_state)
 530                 ret = this_el->set_state(this_el, indio_dev, state);
 531 error_ret:
 532         mutex_unlock(&indio_dev->mlock);
 533
 534         return ret ? ret : len;
 535
 536 }
 537 EXPORT_SYMBOL(iio_scan_el_store);
 538
 539 ssize_t iio_scan_el_ts_show(struct device *dev,
 540                             struct device_attribute *attr,
 541                             char *buf)
 542 {
 543         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 544         return sprintf(buf, "%d\n", indio_dev->scan_timestamp);
 545 }
 546 EXPORT_SYMBOL(iio_scan_el_ts_show);
 547
 548 ssize_t iio_scan_el_ts_store(struct device *dev,
 549                              struct device_attribute *attr,
 550                              const char *buf,
 551                              size_t len)
 552 {
 553         int ret = 0;
 554         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 555         bool state;
 556         state = !(buf[0] == '0');
 557         mutex_lock(&indio_dev->mlock);
 558         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 559                 ret = -EBUSY;
 560                 goto error_ret;
 561         }
 562         indio_dev->scan_timestamp = state;
 563 error_ret:
 564         mutex_unlock(&indio_dev->mlock);
 565
 566         return ret ? ret : len;
 567 }
 568 EXPORT_SYMBOL(iio_scan_el_ts_store);
 569