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