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         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         return ret;
 283 error_free_ring_buffer_event_chrdev:
 284         __iio_free_ring_buffer_event_chrdev(ring);
 285 error_remove_device:
 286         device_del(&ring->dev);
 287 error_ret:
 288         return ret;
 289 }
 290 EXPORT_SYMBOL(iio_ring_buffer_register);
 291
 292 void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
 293 {
 294         __iio_free_ring_buffer_access_chrdev(ring);
 295         __iio_free_ring_buffer_event_chrdev(ring);
 296         device_del(&ring->dev);
 297 }
 298 EXPORT_SYMBOL(iio_ring_buffer_unregister);
 299
 300 ssize_t iio_read_ring_length(struct device *dev,
 301                              struct device_attribute *attr,
 302                              char *buf)
 303 {
 304         int len = 0;
 305         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 306
 307         if (ring->access.get_length)
 308                 len = sprintf(buf, "%d\n",
 309                               ring->access.get_length(ring));
 310
 311         return len;
 312 }
 313 EXPORT_SYMBOL(iio_read_ring_length);
 314
 315  ssize_t iio_write_ring_length(struct device *dev,
 316                                struct device_attribute *attr,
 317                                const char *buf,
 318                                size_t len)
 319 {
 320         int ret;
 321         ulong val;
 322         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 323         ret = strict_strtoul(buf, 10, &val);
 324         if (ret)
 325                 return ret;
 326
 327         if (ring->access.get_length)
 328                 if (val == ring->access.get_length(ring))
 329                         return len;
 330
 331         if (ring->access.set_length) {
 332                 ring->access.set_length(ring, val);
 333                 if (ring->access.mark_param_change)
 334                         ring->access.mark_param_change(ring);
 335         }
 336
 337         return len;
 338 }
 339 EXPORT_SYMBOL(iio_write_ring_length);
 340
 341 ssize_t iio_read_ring_bps(struct device *dev,
 342                           struct device_attribute *attr,
 343                           char *buf)
 344 {
 345         int len = 0;
 346         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 347
 348         if (ring->access.get_bpd)
 349                 len = sprintf(buf, "%d\n",
 350                               ring->access.get_bpd(ring));
 351
 352         return len;
 353 }
 354 EXPORT_SYMBOL(iio_read_ring_bps);
 355
 356 ssize_t iio_store_ring_enable(struct device *dev,
 357                               struct device_attribute *attr,
 358                               const char *buf,
 359                               size_t len)
 360 {
 361         int ret;
 362         bool requested_state, current_state;
 363         int previous_mode;
 364         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 365         struct iio_dev *dev_info = ring->indio_dev;
 366
 367         mutex_lock(&dev_info->mlock);
 368         previous_mode = dev_info->currentmode;
 369         requested_state = !(buf[0] == '0');
 370         current_state = !!(previous_mode & INDIO_ALL_RING_MODES);
 371         if (current_state == requested_state) {
 372                 printk(KERN_INFO "iio-ring, current state requested again\n");
 373                 goto done;
 374         }
 375         if (requested_state) {
 376                 if (ring->preenable) {
 377                         ret = ring->preenable(dev_info);
 378                         if (ret) {
 379                                 printk(KERN_ERR
 380                                        "Buffer not started:"
 381                                        "ring preenable failed\n");
 382                                 goto error_ret;
 383                         }
 384                 }
 385                 if (ring->access.request_update) {
 386                         ret = ring->access.request_update(ring);
 387                         if (ret) {
 388                                 printk(KERN_INFO
 389                                        "Buffer not started:"
 390                                        "ring parameter update failed\n");
 391                                 goto error_ret;
 392                         }
 393                 }
 394                 if (ring->access.mark_in_use)
 395                         ring->access.mark_in_use(ring);
 396                 /* Definitely possible for devices to support both of these.*/
 397                 if (dev_info->modes & INDIO_RING_TRIGGERED) {
 398                         if (!dev_info->trig) {
 399                                 printk(KERN_INFO
 400                                        "Buffer not started: no trigger\n");
 401                                 ret = -EINVAL;
 402                                 if (ring->access.unmark_in_use)
 403                                         ring->access.unmark_in_use(ring);
 404                                 goto error_ret;
 405                         }
 406                         dev_info->currentmode = INDIO_RING_TRIGGERED;
 407                 } else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER)
 408                         dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER;
 409                 else { /* should never be reached */
 410                         ret = -EINVAL;
 411                         goto error_ret;
 412                 }
 413
 414                 if (ring->postenable) {
 415
 416                         ret = ring->postenable(dev_info);
 417                         if (ret) {
 418                                 printk(KERN_INFO
 419                                        "Buffer not started:"
 420                                        "postenable failed\n");
 421                                 if (ring->access.unmark_in_use)
 422                                         ring->access.unmark_in_use(ring);
 423                                 dev_info->currentmode = previous_mode;
 424                                 if (ring->postdisable)
 425                                         ring->postdisable(dev_info);
 426                                 goto error_ret;
 427                         }
 428                 }
 429         } else {
 430                 if (ring->predisable) {
 431                         ret = ring->predisable(dev_info);
 432                         if (ret)
 433                                 goto error_ret;
 434                 }
 435                 if (ring->access.unmark_in_use)
 436                         ring->access.unmark_in_use(ring);
 437                 dev_info->currentmode = INDIO_DIRECT_MODE;
 438                 if (ring->postdisable) {
 439                         ret = ring->postdisable(dev_info);
 440                         if (ret)
 441                                 goto error_ret;
 442                 }
 443         }
 444 done:
 445         mutex_unlock(&dev_info->mlock);
 446         return len;
 447
 448 error_ret:
 449         mutex_unlock(&dev_info->mlock);
 450         return ret;
 451 }
 452 EXPORT_SYMBOL(iio_store_ring_enable);
 453 ssize_t iio_show_ring_enable(struct device *dev,
 454                                     struct device_attribute *attr,
 455                                     char *buf)
 456 {
 457         struct iio_ring_buffer *ring = dev_get_drvdata(dev);
 458         return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode
 459                                        & INDIO_ALL_RING_MODES));
 460 }
 461 EXPORT_SYMBOL(iio_show_ring_enable);
 462
 463 ssize_t iio_scan_el_show(struct device *dev,
 464                          struct device_attribute *attr,
 465                          char *buf)
 466 {
 467         int ret;
 468         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 469         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 470
 471         ret = iio_scan_mask_query(indio_dev, this_el->number);
 472         if (ret < 0)
 473                 return ret;
 474         return sprintf(buf, "%d\n", ret);
 475 }
 476 EXPORT_SYMBOL(iio_scan_el_show);
 477
 478 ssize_t iio_scan_el_store(struct device *dev,
 479                           struct device_attribute *attr,
 480                           const char *buf,
 481                           size_t len)
 482 {
 483         int ret = 0;
 484         bool state;
 485         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 486         struct iio_scan_el *this_el = to_iio_scan_el(attr);
 487
 488         state = !(buf[0] == '0');
 489         mutex_lock(&indio_dev->mlock);
 490         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 491                 ret = -EBUSY;
 492                 goto error_ret;
 493         }
 494         ret = iio_scan_mask_query(indio_dev, this_el->number);
 495         if (ret < 0)
 496                 goto error_ret;
 497         if (!state && ret) {
 498                 ret = iio_scan_mask_clear(indio_dev, this_el->number);
 499                 if (ret)
 500                         goto error_ret;
 501                 indio_dev->scan_count--;
 502         } else if (state && !ret) {
 503                 ret = iio_scan_mask_set(indio_dev, this_el->number);
 504                 if (ret)
 505                         goto error_ret;
 506                 indio_dev->scan_count++;
 507         }
 508         if (this_el->set_state)
 509                 ret = this_el->set_state(this_el, indio_dev, state);
 510 error_ret:
 511         mutex_unlock(&indio_dev->mlock);
 512
 513         return ret ? ret : len;
 514
 515 }
 516 EXPORT_SYMBOL(iio_scan_el_store);
 517
 518 ssize_t iio_scan_el_ts_show(struct device *dev,
 519                             struct device_attribute *attr,
 520                             char *buf)
 521 {
 522         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 523         return sprintf(buf, "%d\n", indio_dev->scan_timestamp);
 524 }
 525 EXPORT_SYMBOL(iio_scan_el_ts_show);
 526
 527 ssize_t iio_scan_el_ts_store(struct device *dev,
 528                              struct device_attribute *attr,
 529                              const char *buf,
 530                              size_t len)
 531 {
 532         int ret = 0;
 533         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 534         bool state;
 535         state = !(buf[0] == '0');
 536         mutex_lock(&indio_dev->mlock);
 537         if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
 538                 ret = -EBUSY;
 539                 goto error_ret;
 540         }
 541         indio_dev->scan_timestamp = state;
 542 error_ret:
 543         mutex_unlock(&indio_dev->mlock);
 544
 545         return ret ? ret : len;
 546 }
 547 EXPORT_SYMBOL(iio_scan_el_ts_store);
 548