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