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