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 };
 137
 138 /**
 139  * __iio_request_ring_buffer_event_chrdev() allocate ring event chrdev
 140  * @buf:        ring buffer whose event chrdev we are allocating
 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         buf->ev_int.id = id;
 153
 154         snprintf(buf->ev_int._name, sizeof(buf->ev_int._name),
 155                  "%s:event%d",
 156                  dev_name(&buf->dev),
 157                  buf->ev_int.id);
 158         ret = iio_setup_ev_int(&(buf->ev_int),
 159                                buf->ev_int._name,
 160                                owner,
 161                                dev);
 162         if (ret)
 163                 goto error_ret;
 164         return 0;
 165
 166 error_ret:
 167         return ret;
 168 }
 169
 170 static inline void
 171 __iio_free_ring_buffer_event_chrdev(struct iio_ring_buffer *buf)
 172 {
 173         iio_free_ev_int(&(buf->ev_int));
 174 }
 175
 176 static void iio_ring_access_release(struct device *dev)
 177 {
 178         struct iio_ring_buffer *buf
 179                 = access_dev_to_iio_ring_buffer(dev);
 180         cdev_del(&buf->access_handler.chrdev);
 181         iio_device_free_chrdev_minor(MINOR(dev->devt));
 182 }
 183
 184 static struct device_type iio_ring_access_type = {
 185         .release = iio_ring_access_release,
 186 };
 187
 188 static inline int
 189 __iio_request_ring_buffer_access_chrdev(struct iio_ring_buffer *buf,
 190                                         int id,
 191                                         struct module *owner)
 192 {
 193         int ret, minor;
 194
 195         buf->access_handler.flags = 0;
 196
 197         buf->access_dev.parent = &buf->dev;
 198         buf->access_dev.bus = &iio_bus_type;
 199         buf->access_dev.type = &iio_ring_access_type;
 200         device_initialize(&buf->access_dev);
 201
 202         minor = iio_device_get_chrdev_minor();
 203         if (minor < 0) {
 204                 ret = minor;
 205                 goto error_device_put;
 206         }
 207         buf->access_dev.devt = MKDEV(MAJOR(iio_devt), minor);
 208
 209
 210         buf->access_id = id;
 211
 212         dev_set_name(&buf->access_dev, "%s:access%d",
 213                      dev_name(&buf->dev),
 214                      buf->access_id);
 215         ret = device_add(&buf->access_dev);
 216         if (ret < 0) {
 217                 printk(KERN_ERR "failed to add the ring access dev\n");
 218                 goto error_device_put;
 219         }
 220
 221         cdev_init(&buf->access_handler.chrdev, &iio_ring_fileops);
 222         buf->access_handler.chrdev.owner = owner;
 223
 224         ret = cdev_add(&buf->access_handler.chrdev, buf->access_dev.devt, 1);
 225         if (ret) {
 226                 printk(KERN_ERR "failed to allocate ring access chrdev\n");
 227                 goto error_device_unregister;
 228         }
 229         return 0;
 230
 231 error_device_unregister:
 232         device_unregister(&buf->access_dev);
 233 error_device_put:
 234         put_device(&buf->access_dev);
 235
 236         return ret;
 237 }
 238
 239 static void __iio_free_ring_buffer_access_chrdev(struct iio_ring_buffer *buf)
 240 {
 241         device_unregister(&buf->access_dev);
 242 }
 243
 244 void iio_ring_buffer_init(struct iio_ring_buffer *ring,
 245                           struct iio_dev *dev_info)
 246 {
 247         if (ring->access.mark_param_change)
 248                 ring->access.mark_param_change(ring);
 249         ring->indio_dev = dev_info;
 250         ring->ev_int.private = ring;
 251         ring->access_handler.private = ring;
 252         ring->shared_ev_pointer.ev_p = NULL;
 253         spin_lock_init(&ring->shared_ev_pointer.lock);
 254 }
 255 EXPORT_SYMBOL(iio_ring_buffer_init);
 256
 257 int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id)
 258 {
 259         int ret;
 260
 261         ring->id = id;
 262
 263         dev_set_name(&ring->dev, "%s:buffer%d",
 264                      dev_name(ring->dev.parent),
 265                      ring->id);
 266         ret = device_add(&ring->dev);
 267         if (ret)
 268                 goto error_ret;
 269
 270         ret = __iio_request_ring_buffer_event_chrdev(ring,
 271                                                      0,
 272                                                      ring->owner,
 273                                                      &ring->dev);
 274         if (ret)
 275                 goto error_remove_device;
 276
 277         ret = __iio_request_ring_buffer_access_chrdev(ring,
 278                                                       0,
 279                                                       ring->owner);
 280
 281         if (ret)
 282                 goto error_free_ring_buffer_event_chrdev;
 283
 284         return ret;
 285 error_free_ring_buffer_event_chrdev:
 286         __iio_free_ring_buffer_event_chrdev(ring);
 287 error_remove_device:
 288         device_del(&ring->dev);
 289 error_ret:
 290         return ret;
 291 }
 292 EXPORT_SYMBOL(iio_ring_buffer_register);
 293
 294 void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
 295 {
 296         __iio_free_ring_buffer_access_chrdev(ring);
 297         __iio_free_ring_buffer_event_chrdev(ring);
 298         device_del(&ring->dev);
 299 }
 300 EXPORT_SYMBOL(iio_ring_buffer_unregister);
 301
 302 ssize_t iio_read_ring_length(struct device *dev,
 303                              struct device_attribute *attr,
 304                              char *buf)
 305 {
 306         int len = 0;
 307         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 308
 309         if (ring->access.get_length)
 310                 len = sprintf(buf, "%d\n",
 311                               ring->access.get_length(ring));
 312
 313         return len;
 314 }
 315 EXPORT_SYMBOL(iio_read_ring_length);
 316
 317  ssize_t iio_write_ring_length(struct device *dev,
 318                                struct device_attribute *attr,
 319                                const char *buf,
 320                                size_t len)
 321 {
 322         int ret;
 323         ulong val;
 324         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 325         ret = strict_strtoul(buf, 10, &val);
 326         if (ret)
 327                 return ret;
 328
 329         if (ring->access.get_length)
 330                 if (val == ring->access.get_length(ring))
 331                         return len;
 332
 333         if (ring->access.set_length) {
 334                 ring->access.set_length(ring, val);
 335                 if (ring->access.mark_param_change)
 336                         ring->access.mark_param_change(ring);
 337         }
 338
 339         return len;
 340 }
 341 EXPORT_SYMBOL(iio_write_ring_length);
 342
 343 ssize_t iio_read_ring_bps(struct device *dev,
 344                           struct device_attribute *attr,
 345                           char *buf)
 346 {
 347         int len = 0;
 348         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 349
 350         if (ring->access.get_bpd)
 351                 len = sprintf(buf, "%d\n",
 352                               ring->access.get_bpd(ring));
 353
 354         return len;
 355 }
 356 EXPORT_SYMBOL(iio_read_ring_bps);
 357
 358 ssize_t iio_store_ring_enable(struct device *dev,
 359                               struct device_attribute *attr,
 360                               const char *buf,
 361                               size_t len)
 362 {
 363         int ret;
 364         bool requested_state, current_state;
 365         int previous_mode;
 366         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 367         struct iio_dev *dev_info = ring->indio_dev;
 368
 369         mutex_lock(&dev_info->mlock);
 370         previous_mode = dev_info->currentmode;
 371         requested_state = !(buf[0] == '0');
 372         current_state = !!(previous_mode & INDIO_ALL_RING_MODES);
 373         if (current_state == requested_state) {
 374                 printk(KERN_INFO "iio-ring, current state requested again\n");
 375                 goto done;
 376         }
 377         if (requested_state) {
 378                 if (ring->preenable) {
 379                         ret = ring->preenable(dev_info);
 380                         if (ret) {
 381                                 printk(KERN_ERR
 382                                        "Buffer not started:"
 383                                        "ring preenable failed\n");
 384                                 goto error_ret;
 385                         }
 386                 }
 387                 if (ring->access.request_update) {
 388                         ret = ring->access.request_update(ring);
 389                         if (ret) {
 390                                 printk(KERN_INFO
 391                                        "Buffer not started:"
 392                                        "ring parameter update failed\n");
 393                                 goto error_ret;
 394                         }
 395                 }
 396                 if (ring->access.mark_in_use)
 397                         ring->access.mark_in_use(ring);
 398                 /* Definitely possible for devices to support both of these.*/
 399                 if (dev_info->modes & INDIO_RING_TRIGGERED) {
 400                         if (!dev_info->trig) {
 401                                 printk(KERN_INFO
 402                                        "Buffer not started: no trigger\n");
 403                                 ret = -EINVAL;
 404                                 if (ring->access.unmark_in_use)
 405                                         ring->access.unmark_in_use(ring);
 406                                 goto error_ret;
 407                         }
 408                         dev_info->currentmode = INDIO_RING_TRIGGERED;
 409                 } else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER)
 410                         dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER;
 411                 else { /* should never be reached */
 412                         ret = -EINVAL;
 413                         goto error_ret;
 414                 }
 415
 416                 if (ring->postenable) {
 417
 418                         ret = ring->postenable(dev_info);
 419                         if (ret) {
 420                                 printk(KERN_INFO
 421                                        "Buffer not started:"
 422                                        "postenable failed\n");
 423                                 if (ring->access.unmark_in_use)
 424                                         ring->access.unmark_in_use(ring);
 425                                 dev_info->currentmode = previous_mode;
 426                                 if (ring->postdisable)
 427                                         ring->postdisable(dev_info);
 428                                 goto error_ret;
 429                         }
 430                 }
 431         } else {
 432                 if (ring->predisable) {
 433                         ret = ring->predisable(dev_info);
 434                         if (ret)
 435                                 goto error_ret;
 436                 }
 437                 if (ring->access.unmark_in_use)
 438                         ring->access.unmark_in_use(ring);
 439                 dev_info->currentmode = INDIO_DIRECT_MODE;
 440                 if (ring->postdisable) {
 441                         ret = ring->postdisable(dev_info);
 442                         if (ret)
 443                                 goto error_ret;
 444                 }
 445         }
 446 done:
 447         mutex_unlock(&dev_info->mlock);
 448         return len;
 449
 450 error_ret:
 451         mutex_unlock(&dev_info->mlock);
 452         return ret;
 453 }
 454 EXPORT_SYMBOL(iio_store_ring_enable);
 455 ssize_t iio_show_ring_enable(struct device *dev,
 456                                     struct device_attribute *attr,
 457                                     char *buf)
 458 {
 459         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 460         return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode
 461                                        & INDIO_ALL_RING_MODES));
 462 }
 463 EXPORT_SYMBOL(iio_show_ring_enable);
 464
 465 ssize_t iio_scan_el_show(struct device *dev,
 466                          struct device_attribute *attr,
 467                          char *buf)
 468 {
 469         int ret;
 470         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 471         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 472
 473         ret = iio_scan_mask_query(indio_dev, this_el->number);
 474         if (ret < 0)
 475                 return ret;
 476         return sprintf(buf, "%d\n", ret);
 477 }
 478 EXPORT_SYMBOL(iio_scan_el_show);
 479
 480 ssize_t iio_scan_el_store(struct device *dev,
 481                           struct device_attribute *attr,
 482                           const char *buf,
 483                           size_t len)
 484 {
 485         int ret = 0;
 486         bool state;
 487         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 488         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 489
 490         state = !(buf[0] == '0');
 491         mutex_lock(&indio_dev->mlock);
 492         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 493                 ret = -EBUSY;
 494                 goto error_ret;
 495         }
 496         ret = iio_scan_mask_query(indio_dev, this_el->number);
 497         if (ret < 0)
 498                 goto error_ret;
 499         if (!state && ret) {
 500                 ret = iio_scan_mask_clear(indio_dev, this_el->number);
 501                 if (ret)
 502                         goto error_ret;
 503                 indio_dev->scan_count--;
 504         } else if (state && !ret) {
 505                 ret = iio_scan_mask_set(indio_dev, this_el->number);
 506                 if (ret)
 507                         goto error_ret;
 508                 indio_dev->scan_count++;
 509         }
 510         if (this_el->set_state)
 511                 ret = this_el->set_state(this_el, indio_dev, state);
 512 error_ret:
 513         mutex_unlock(&indio_dev->mlock);
 514
 515         return ret ? ret : len;
 516
 517 }
 518 EXPORT_SYMBOL(iio_scan_el_store);
 519
 520 ssize_t iio_scan_el_ts_show(struct device *dev,
 521                             struct device_attribute *attr,
 522                             char *buf)
 523 {
 524         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 525         return sprintf(buf, "%d\n", indio_dev->scan_timestamp);
 526 }
 527 EXPORT_SYMBOL(iio_scan_el_ts_show);
 528
 529 ssize_t iio_scan_el_ts_store(struct device *dev,
 530                              struct device_attribute *attr,
 531                              const char *buf,
 532                              size_t len)
 533 {
 534         int ret = 0;
 535         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 536         bool state;
 537         state = !(buf[0] == '0');
 538         mutex_lock(&indio_dev->mlock);
 539         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 540                 ret = -EBUSY;
 541                 goto error_ret;
 542         }
 543         indio_dev->scan_timestamp = state;
 544 error_ret:
 545         mutex_unlock(&indio_dev->mlock);
 546
 547         return ret ? ret : len;
 548 }
 549 EXPORT_SYMBOL(iio_scan_el_ts_store);
 550