summaryrefslogtreecommitdiffstats
path: root/drivers/staging/iio/industrialio-ring.c
blob: bd4373ae066bd5030ee21961d9b86bd3e20b86d8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
/* The industrial I/O core
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * Handling of ring allocation / resizing.
 *
 *
 * Things to look at here.
 * - Better memory allocation techniques?
 * - Alternative access techniques?
 */
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/slab.h>

#include "iio.h"
#include "ring_generic.h"

int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
		       int event_code,
		       s64 timestamp)
{
	return __iio_push_event(&ring_buf->ev_int,
			       event_code,
			       timestamp,
			       &ring_buf->shared_ev_pointer);
}
EXPORT_SYMBOL(iio_push_ring_event);

int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
				    int event_code,
				    s64 timestamp)
{
	if (ring_buf->shared_ev_pointer.ev_p)
		__iio_change_event(ring_buf->shared_ev_pointer.ev_p,
				   event_code,
				   timestamp);
	else
		return iio_push_ring_event(ring_buf,
					  event_code,
					  timestamp);
	return 0;
}
EXPORT_SYMBOL(iio_push_or_escallate_ring_event);

/**
 * iio_ring_open() - chrdev file open for ring buffer access
 *
 * This function relies on all ring buffer implementations having an
 * iio_ring_buffer as their first element.
 **/
static int iio_ring_open(struct inode *inode, struct file *filp)
{
	struct iio_handler *hand
		= container_of(inode->i_cdev, struct iio_handler, chrdev);
	struct iio_ring_buffer *rb = hand->private;

	filp->private_data = hand->private;
	if (rb->access.mark_in_use)
		rb->access.mark_in_use(rb);

	return 0;
}

/**
 * iio_ring_release() - chrdev file close ring buffer access
 *
 * This function relies on all ring buffer implementations having an
 * iio_ring_buffer as their first element.
 **/
static int iio_ring_release(struct inode *inode, struct file *filp)
{
	struct cdev *cd = inode->i_cdev;
	struct iio_handler *hand = iio_cdev_to_handler(cd);
	struct iio_ring_buffer *rb = hand->private;

	clear_bit(IIO_BUSY_BIT_POS, &rb->access_handler.flags);
	if (rb->access.unmark_in_use)
		rb->access.unmark_in_use(rb);

	return 0;
}

/**
 * iio_ring_rip_outer() - chrdev read for ring buffer access
 *
 * This function relies on all ring buffer implementations having an
 * iio_ring _bufer as their first element.
 **/
static ssize_t iio_ring_rip_outer(struct file *filp, char __user *buf,
				  size_t count, loff_t *f_ps)
{
	struct iio_ring_buffer *rb = filp->private_data;
	int ret, dead_offset;

	/* rip lots must exist. */
	if (!rb->access.rip_lots)
		return -EINVAL;
	ret = rb->access.rip_lots(rb, count, buf, &dead_offset);

	return ret;
}

static const struct file_operations iio_ring_fileops = {
	.read = iio_ring_rip_outer,
	.release = iio_ring_release,
	.open = iio_ring_open,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
};

/**
 * __iio_request_ring_buffer_event_chrdev() - allocate ring event chrdev
 * @buf:	ring buffer whose event chrdev we are allocating
 * @id:		id of this ring buffer (typically 0)
 * @owner:	the module who owns the ring buffer (for ref counting)
 * @dev:	device with which the chrdev is associated
 **/
static inline int
__iio_request_ring_buffer_event_chrdev(struct iio_ring_buffer *buf,
				       int id,
				       struct module *owner,
				       struct device *dev)
{
	int ret;

	snprintf(buf->ev_int._name, sizeof(buf->ev_int._name),
		 "%s:event%d",
		 dev_name(&buf->dev),
		 id);
	ret = iio_setup_ev_int(&(buf->ev_int),
			       buf->ev_int._name,
			       owner,
			       dev);
	if (ret)
		goto error_ret;
	return 0;

error_ret:
	return ret;
}

static inline void
__iio_free_ring_buffer_event_chrdev(struct iio_ring_buffer *buf)
{
	iio_free_ev_int(&(buf->ev_int));
}

static void iio_ring_access_release(struct device *dev)
{
	struct iio_ring_buffer *buf
		= access_dev_to_iio_ring_buffer(dev);
	cdev_del(&buf->access_handler.chrdev);
	iio_device_free_chrdev_minor(MINOR(dev->devt));
}

static struct device_type iio_ring_access_type = {
	.release = iio_ring_access_release,
};

static inline int
__iio_request_ring_buffer_access_chrdev(struct iio_ring_buffer *buf,
					int id,
					struct module *owner)
{
	int ret, minor;

	buf->access_handler.flags = 0;

	buf->access_dev.parent = &buf->dev;
	buf->access_dev.bus = &iio_bus_type;
	buf->access_dev.type = &iio_ring_access_type;
	device_initialize(&buf->access_dev);

	minor = iio_device_get_chrdev_minor();
	if (minor < 0) {
		ret = minor;
		goto error_device_put;
	}
	buf->access_dev.devt = MKDEV(MAJOR(iio_devt), minor);


	buf->access_id = id;

	dev_set_name(&buf->access_dev, "%s:access%d",
		     dev_name(&buf->dev),
		     buf->access_id);
	ret = device_add(&buf->access_dev);
	if (ret < 0) {
		printk(KERN_ERR "failed to add the ring access dev\n");
		goto error_device_put;
	}

	cdev_init(&buf->access_handler.chrdev, &iio_ring_fileops);
	buf->access_handler.chrdev.owner = owner;

	ret = cdev_add(&buf->access_handler.chrdev, buf->access_dev.devt, 1);
	if (ret) {
		printk(KERN_ERR "failed to allocate ring access chrdev\n");
		goto error_device_unregister;
	}
	return 0;

error_device_unregister:
	device_unregister(&buf->access_dev);
error_device_put:
	put_device(&buf->access_dev);

	return ret;
}

static void __iio_free_ring_buffer_access_chrdev(struct iio_ring_buffer *buf)
{
	device_unregister(&buf->access_dev);
}

void iio_ring_buffer_init(struct iio_ring_buffer *ring,
			  struct iio_dev *dev_info)
{
	if (ring->access.mark_param_change)
		ring->access.mark_param_change(ring);
	ring->indio_dev = dev_info;
	ring->ev_int.private = ring;
	ring->access_handler.private = ring;
	ring->shared_ev_pointer.ev_p = NULL;
	spin_lock_init(&ring->shared_ev_pointer.lock);
}
EXPORT_SYMBOL(iio_ring_buffer_init);

int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id)
{
	int ret;

	ring->id = id;

	dev_set_name(&ring->dev, "%s:buffer%d",
		     dev_name(ring->dev.parent),
		     ring->id);
	ret = device_add(&ring->dev);
	if (ret)
		goto error_ret;

	ret = __iio_request_ring_buffer_event_chrdev(ring,
						     0,
						     ring->owner,
						     &ring->dev);
	if (ret)
		goto error_remove_device;

	ret = __iio_request_ring_buffer_access_chrdev(ring,
						      0,
						      ring->owner);

	if (ret)
		goto error_free_ring_buffer_event_chrdev;

	if (ring->scan_el_attrs) {
		ret = sysfs_create_group(&ring->dev.kobj,
					 ring->scan_el_attrs);
		if (ret) {
			dev_err(&ring->dev,
				"Failed to add sysfs scan elements\n");
			goto error_free_ring_buffer_event_chrdev;
		}
	}

	return ret;
error_free_ring_buffer_event_chrdev:
	__iio_free_ring_buffer_event_chrdev(ring);
error_remove_device:
	device_del(&ring->dev);
error_ret:
	return ret;
}
EXPORT_SYMBOL(iio_ring_buffer_register);

void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
{
	if (ring->scan_el_attrs)
		sysfs_remove_group(&ring->dev.kobj,
				   ring->scan_el_attrs);

	__iio_free_ring_buffer_access_chrdev(ring);
	__iio_free_ring_buffer_event_chrdev(ring);
	device_del(&ring->dev);
}
EXPORT_SYMBOL(iio_ring_buffer_unregister);

ssize_t iio_read_ring_length(struct device *dev,
			     struct device_attribute *attr,
			     char *buf)
{
	int len = 0;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);

	if (ring->access.get_length)
		len = sprintf(buf, "%d\n",
			      ring->access.get_length(ring));

	return len;
}
EXPORT_SYMBOL(iio_read_ring_length);

ssize_t iio_write_ring_length(struct device *dev,
			       struct device_attribute *attr,
			       const char *buf,
			       size_t len)
{
	int ret;
	ulong val;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	ret = strict_strtoul(buf, 10, &val);
	if (ret)
		return ret;

	if (ring->access.get_length)
		if (val == ring->access.get_length(ring))
			return len;

	if (ring->access.set_length) {
		ring->access.set_length(ring, val);
		if (ring->access.mark_param_change)
			ring->access.mark_param_change(ring);
	}

	return len;
}
EXPORT_SYMBOL(iio_write_ring_length);

ssize_t iio_read_ring_bytes_per_datum(struct device *dev,
			  struct device_attribute *attr,
			  char *buf)
{
	int len = 0;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);

	if (ring->access.get_bytes_per_datum)
		len = sprintf(buf, "%d\n",
			      ring->access.get_bytes_per_datum(ring));

	return len;
}
EXPORT_SYMBOL(iio_read_ring_bytes_per_datum);

ssize_t iio_store_ring_enable(struct device *dev,
			      struct device_attribute *attr,
			      const char *buf,
			      size_t len)
{
	int ret;
	bool requested_state, current_state;
	int previous_mode;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	struct iio_dev *dev_info = ring->indio_dev;

	mutex_lock(&dev_info->mlock);
	previous_mode = dev_info->currentmode;
	requested_state = !(buf[0] == '0');
	current_state = !!(previous_mode & INDIO_ALL_RING_MODES);
	if (current_state == requested_state) {
		printk(KERN_INFO "iio-ring, current state requested again\n");
		goto done;
	}
	if (requested_state) {
		if (ring->preenable) {
			ret = ring->preenable(dev_info);
			if (ret) {
				printk(KERN_ERR
				       "Buffer not started:"
				       "ring preenable failed\n");
				goto error_ret;
			}
		}
		if (ring->access.request_update) {
			ret = ring->access.request_update(ring);
			if (ret) {
				printk(KERN_INFO
				       "Buffer not started:"
				       "ring parameter update failed\n");
				goto error_ret;
			}
		}
		if (ring->access.mark_in_use)
			ring->access.mark_in_use(ring);
		/* Definitely possible for devices to support both of these.*/
		if (dev_info->modes & INDIO_RING_TRIGGERED) {
			if (!dev_info->trig) {
				printk(KERN_INFO
				       "Buffer not started: no trigger\n");
				ret = -EINVAL;
				if (ring->access.unmark_in_use)
					ring->access.unmark_in_use(ring);
				goto error_ret;
			}
			dev_info->currentmode = INDIO_RING_TRIGGERED;
		} else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER)
			dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER;
		else { /* should never be reached */
			ret = -EINVAL;
			goto error_ret;
		}

		if (ring->postenable) {

			ret = ring->postenable(dev_info);
			if (ret) {
				printk(KERN_INFO
				       "Buffer not started:"
				       "postenable failed\n");
				if (ring->access.unmark_in_use)
					ring->access.unmark_in_use(ring);
				dev_info->currentmode = previous_mode;
				if (ring->postdisable)
					ring->postdisable(dev_info);
				goto error_ret;
			}
		}
	} else {
		if (ring->predisable) {
			ret = ring->predisable(dev_info);
			if (ret)
				goto error_ret;
		}
		if (ring->access.unmark_in_use)
			ring->access.unmark_in_use(ring);
		dev_info->currentmode = INDIO_DIRECT_MODE;
		if (ring->postdisable) {
			ret = ring->postdisable(dev_info);
			if (ret)
				goto error_ret;
		}
	}
done:
	mutex_unlock(&dev_info->mlock);
	return len;

error_ret:
	mutex_unlock(&dev_info->mlock);
	return ret;
}
EXPORT_SYMBOL(iio_store_ring_enable);
ssize_t iio_show_ring_enable(struct device *dev,
				    struct device_attribute *attr,
				    char *buf)
{
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode
				       & INDIO_ALL_RING_MODES));
}
EXPORT_SYMBOL(iio_show_ring_enable);

ssize_t iio_scan_el_show(struct device *dev,
			 struct device_attribute *attr,
			 char *buf)
{
	int ret;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	struct iio_scan_el *this_el = to_iio_scan_el(attr);

	ret = iio_scan_mask_query(ring, this_el->number);
	if (ret < 0)
		return ret;
	return sprintf(buf, "%d\n", ret);
}
EXPORT_SYMBOL(iio_scan_el_show);

ssize_t iio_scan_el_store(struct device *dev,
			  struct device_attribute *attr,
			  const char *buf,
			  size_t len)
{
	int ret = 0;
	bool state;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	struct iio_dev *indio_dev = ring->indio_dev;
	struct iio_scan_el *this_el = to_iio_scan_el(attr);

	state = !(buf[0] == '0');
	mutex_lock(&indio_dev->mlock);
	if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
		ret = -EBUSY;
		goto error_ret;
	}
	ret = iio_scan_mask_query(ring, this_el->number);
	if (ret < 0)
		goto error_ret;
	if (!state && ret) {
		ret = iio_scan_mask_clear(ring, this_el->number);
		if (ret)
			goto error_ret;
	} else if (state && !ret) {
		ret = iio_scan_mask_set(ring, this_el->number);
		if (ret)
			goto error_ret;
	}
	if (this_el->set_state)
		ret = this_el->set_state(this_el, indio_dev, state);
error_ret:
	mutex_unlock(&indio_dev->mlock);

	return ret ? ret : len;

}
EXPORT_SYMBOL(iio_scan_el_store);

ssize_t iio_scan_el_ts_show(struct device *dev,
			    struct device_attribute *attr,
			    char *buf)
{
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n", ring->scan_timestamp);
}
EXPORT_SYMBOL(iio_scan_el_ts_show);

ssize_t iio_scan_el_ts_store(struct device *dev,
			     struct device_attribute *attr,
			     const char *buf,
			     size_t len)
{
	int ret = 0;
	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
	struct iio_dev *indio_dev = ring->indio_dev;
	bool state;
	state = !(buf[0] == '0');
	mutex_lock(&indio_dev->mlock);
	if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
		ret = -EBUSY;
		goto error_ret;
	}
	ring->scan_timestamp = state;
error_ret:
	mutex_unlock(&indio_dev->mlock);

	return ret ? ret : len;
}
EXPORT_SYMBOL(iio_scan_el_ts_store);