summaryrefslogtreecommitdiffstats
path: root/drivers/media/cec/cec-core.c
blob: 5870da6a567f3e9b4bd24c685625b0be3439b737 (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
/*
 * cec-core.c - HDMI Consumer Electronics Control framework - Core
 *
 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/types.h>

#include "cec-priv.h"

#define CEC_NUM_DEVICES	256
#define CEC_NAME	"cec"

int cec_debug;
module_param_named(debug, cec_debug, int, 0644);
MODULE_PARM_DESC(debug, "debug level (0-2)");

static dev_t cec_dev_t;

/* Active devices */
static DEFINE_MUTEX(cec_devnode_lock);
static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);

static struct dentry *top_cec_dir;

/* dev to cec_devnode */
#define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)

int cec_get_device(struct cec_devnode *devnode)
{
	/*
	 * Check if the cec device is available. This needs to be done with
	 * the devnode->lock held to prevent an open/unregister race:
	 * without the lock, the device could be unregistered and freed between
	 * the devnode->registered check and get_device() calls, leading to
	 * a crash.
	 */
	mutex_lock(&devnode->lock);
	/*
	 * return ENXIO if the cec device has been removed
	 * already or if it is not registered anymore.
	 */
	if (!devnode->registered) {
		mutex_unlock(&devnode->lock);
		return -ENXIO;
	}
	/* and increase the device refcount */
	get_device(&devnode->dev);
	mutex_unlock(&devnode->lock);
	return 0;
}

void cec_put_device(struct cec_devnode *devnode)
{
	put_device(&devnode->dev);
}

/* Called when the last user of the cec device exits. */
static void cec_devnode_release(struct device *cd)
{
	struct cec_devnode *devnode = to_cec_devnode(cd);

	mutex_lock(&cec_devnode_lock);
	/* Mark device node number as free */
	clear_bit(devnode->minor, cec_devnode_nums);
	mutex_unlock(&cec_devnode_lock);

	cec_delete_adapter(to_cec_adapter(devnode));
}

static struct bus_type cec_bus_type = {
	.name = CEC_NAME,
};

/*
 * Register a cec device node
 *
 * The registration code assigns minor numbers and registers the new device node
 * with the kernel. An error is returned if no free minor number can be found,
 * or if the registration of the device node fails.
 *
 * Zero is returned on success.
 *
 * Note that if the cec_devnode_register call fails, the release() callback of
 * the cec_devnode structure is *not* called, so the caller is responsible for
 * freeing any data.
 */
static int __must_check cec_devnode_register(struct cec_devnode *devnode,
					     struct module *owner)
{
	int minor;
	int ret;

	/* Part 1: Find a free minor number */
	mutex_lock(&cec_devnode_lock);
	minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
	if (minor == CEC_NUM_DEVICES) {
		mutex_unlock(&cec_devnode_lock);
		pr_err("could not get a free minor\n");
		return -ENFILE;
	}

	set_bit(minor, cec_devnode_nums);
	mutex_unlock(&cec_devnode_lock);

	devnode->minor = minor;
	devnode->dev.bus = &cec_bus_type;
	devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
	devnode->dev.release = cec_devnode_release;
	dev_set_name(&devnode->dev, "cec%d", devnode->minor);
	device_initialize(&devnode->dev);

	/* Part 2: Initialize and register the character device */
	cdev_init(&devnode->cdev, &cec_devnode_fops);
	devnode->cdev.owner = owner;

	ret = cdev_device_add(&devnode->cdev, &devnode->dev);
	if (ret) {
		pr_err("%s: cdev_device_add failed\n", __func__);
		goto clr_bit;
	}

	devnode->registered = true;
	return 0;

clr_bit:
	mutex_lock(&cec_devnode_lock);
	clear_bit(devnode->minor, cec_devnode_nums);
	mutex_unlock(&cec_devnode_lock);
	return ret;
}

/*
 * Unregister a cec device node
 *
 * This unregisters the passed device. Future open calls will be met with
 * errors.
 *
 * This function can safely be called if the device node has never been
 * registered or has already been unregistered.
 */
static void cec_devnode_unregister(struct cec_devnode *devnode)
{
	struct cec_fh *fh;

	mutex_lock(&devnode->lock);

	/* Check if devnode was never registered or already unregistered */
	if (!devnode->registered || devnode->unregistered) {
		mutex_unlock(&devnode->lock);
		return;
	}

	list_for_each_entry(fh, &devnode->fhs, list)
		wake_up_interruptible(&fh->wait);

	devnode->registered = false;
	devnode->unregistered = true;
	mutex_unlock(&devnode->lock);

	cdev_device_del(&devnode->cdev, &devnode->dev);
	put_device(&devnode->dev);
}

#ifdef CONFIG_CEC_NOTIFIER
static void cec_cec_notify(struct cec_adapter *adap, u16 pa)
{
	cec_s_phys_addr(adap, pa, false);
}

void cec_register_cec_notifier(struct cec_adapter *adap,
			       struct cec_notifier *notifier)
{
	if (WARN_ON(!adap->devnode.registered))
		return;

	adap->notifier = notifier;
	cec_notifier_register(adap->notifier, adap, cec_cec_notify);
}
EXPORT_SYMBOL_GPL(cec_register_cec_notifier);
#endif

struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
					 void *priv, const char *name, u32 caps,
					 u8 available_las)
{
	struct cec_adapter *adap;
	int res;

#ifndef CONFIG_MEDIA_CEC_RC
	caps &= ~CEC_CAP_RC;
#endif

	if (WARN_ON(!caps))
		return ERR_PTR(-EINVAL);
	if (WARN_ON(!ops))
		return ERR_PTR(-EINVAL);
	if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS))
		return ERR_PTR(-EINVAL);
	adap = kzalloc(sizeof(*adap), GFP_KERNEL);
	if (!adap)
		return ERR_PTR(-ENOMEM);
	strlcpy(adap->name, name, sizeof(adap->name));
	adap->phys_addr = CEC_PHYS_ADDR_INVALID;
	adap->cec_pin_is_high = true;
	adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
	adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
	adap->capabilities = caps;
	adap->needs_hpd = caps & CEC_CAP_NEEDS_HPD;
	adap->available_log_addrs = available_las;
	adap->sequence = 0;
	adap->ops = ops;
	adap->priv = priv;
	memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
	mutex_init(&adap->lock);
	INIT_LIST_HEAD(&adap->transmit_queue);
	INIT_LIST_HEAD(&adap->wait_queue);
	init_waitqueue_head(&adap->kthread_waitq);

	/* adap->devnode initialization */
	INIT_LIST_HEAD(&adap->devnode.fhs);
	mutex_init(&adap->devnode.lock);

	adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
	if (IS_ERR(adap->kthread)) {
		pr_err("cec-%s: kernel_thread() failed\n", name);
		res = PTR_ERR(adap->kthread);
		kfree(adap);
		return ERR_PTR(res);
	}

#ifdef CONFIG_MEDIA_CEC_RC
	if (!(caps & CEC_CAP_RC))
		return adap;

	/* Prepare the RC input device */
	adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE);
	if (!adap->rc) {
		pr_err("cec-%s: failed to allocate memory for rc_dev\n",
		       name);
		kthread_stop(adap->kthread);
		kfree(adap);
		return ERR_PTR(-ENOMEM);
	}

	snprintf(adap->device_name, sizeof(adap->device_name),
		 "RC for %s", name);
	snprintf(adap->input_phys, sizeof(adap->input_phys),
		 "%s/input0", name);

	adap->rc->device_name = adap->device_name;
	adap->rc->input_phys = adap->input_phys;
	adap->rc->input_id.bustype = BUS_CEC;
	adap->rc->input_id.vendor = 0;
	adap->rc->input_id.product = 0;
	adap->rc->input_id.version = 1;
	adap->rc->driver_name = CEC_NAME;
	adap->rc->allowed_protocols = RC_PROTO_BIT_CEC;
	adap->rc->priv = adap;
	adap->rc->map_name = RC_MAP_CEC;
	adap->rc->timeout = MS_TO_NS(100);
	adap->rc_last_scancode = -1;
#endif
	return adap;
}
EXPORT_SYMBOL_GPL(cec_allocate_adapter);

int cec_register_adapter(struct cec_adapter *adap,
			 struct device *parent)
{
	int res;

	if (IS_ERR_OR_NULL(adap))
		return 0;

	if (WARN_ON(!parent))
		return -EINVAL;

	adap->owner = parent->driver->owner;
	adap->devnode.dev.parent = parent;

#ifdef CONFIG_MEDIA_CEC_RC
	if (adap->capabilities & CEC_CAP_RC) {
		adap->rc->dev.parent = parent;
		res = rc_register_device(adap->rc);

		if (res) {
			pr_err("cec-%s: failed to prepare input device\n",
			       adap->name);
			rc_free_device(adap->rc);
			adap->rc = NULL;
			return res;
		}
		/*
		 * The REP_DELAY for CEC is really the time between the initial
		 * 'User Control Pressed' message and the second. The first
		 * keypress is always seen as non-repeating, the second
		 * (provided it has the same UI Command) will start the 'Press
		 * and Hold' (aka repeat) behavior. By setting REP_DELAY to the
		 * same value as REP_PERIOD the expected CEC behavior is
		 * reproduced.
		 */
		adap->rc->input_dev->rep[REP_DELAY] =
			adap->rc->input_dev->rep[REP_PERIOD];
	}
#endif

	res = cec_devnode_register(&adap->devnode, adap->owner);
	if (res) {
#ifdef CONFIG_MEDIA_CEC_RC
		/* Note: rc_unregister also calls rc_free */
		rc_unregister_device(adap->rc);
		adap->rc = NULL;
#endif
		return res;
	}

	dev_set_drvdata(&adap->devnode.dev, adap);
#ifdef CONFIG_DEBUG_FS
	if (!top_cec_dir)
		return 0;

	adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), top_cec_dir);
	if (IS_ERR_OR_NULL(adap->cec_dir)) {
		pr_warn("cec-%s: Failed to create debugfs dir\n", adap->name);
		return 0;
	}
	adap->status_file = debugfs_create_devm_seqfile(&adap->devnode.dev,
		"status", adap->cec_dir, cec_adap_status);
	if (IS_ERR_OR_NULL(adap->status_file)) {
		pr_warn("cec-%s: Failed to create status file\n", adap->name);
		debugfs_remove_recursive(adap->cec_dir);
		adap->cec_dir = NULL;
	}
#endif
	return 0;
}
EXPORT_SYMBOL_GPL(cec_register_adapter);

void cec_unregister_adapter(struct cec_adapter *adap)
{
	if (IS_ERR_OR_NULL(adap))
		return;

#ifdef CONFIG_MEDIA_CEC_RC
	/* Note: rc_unregister also calls rc_free */
	rc_unregister_device(adap->rc);
	adap->rc = NULL;
#endif
	debugfs_remove_recursive(adap->cec_dir);
#ifdef CONFIG_CEC_NOTIFIER
	if (adap->notifier)
		cec_notifier_unregister(adap->notifier);
#endif
	cec_devnode_unregister(&adap->devnode);
}
EXPORT_SYMBOL_GPL(cec_unregister_adapter);

void cec_delete_adapter(struct cec_adapter *adap)
{
	if (IS_ERR_OR_NULL(adap))
		return;
	mutex_lock(&adap->lock);
	__cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
	mutex_unlock(&adap->lock);
	kthread_stop(adap->kthread);
	if (adap->kthread_config)
		kthread_stop(adap->kthread_config);
	if (adap->ops->adap_free)
		adap->ops->adap_free(adap);
#ifdef CONFIG_MEDIA_CEC_RC
	rc_free_device(adap->rc);
#endif
	kfree(adap);
}
EXPORT_SYMBOL_GPL(cec_delete_adapter);

/*
 *	Initialise cec for linux
 */
static int __init cec_devnode_init(void)
{
	int ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES, CEC_NAME);

	if (ret < 0) {
		pr_warn("cec: unable to allocate major\n");
		return ret;
	}

#ifdef CONFIG_DEBUG_FS
	top_cec_dir = debugfs_create_dir("cec", NULL);
	if (IS_ERR_OR_NULL(top_cec_dir)) {
		pr_warn("cec: Failed to create debugfs cec dir\n");
		top_cec_dir = NULL;
	}
#endif

	ret = bus_register(&cec_bus_type);
	if (ret < 0) {
		unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
		pr_warn("cec: bus_register failed\n");
		return -EIO;
	}

	return 0;
}

static void __exit cec_devnode_exit(void)
{
	debugfs_remove_recursive(top_cec_dir);
	bus_unregister(&cec_bus_type);
	unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
}

subsys_initcall(cec_devnode_init);
module_exit(cec_devnode_exit)

MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
MODULE_DESCRIPTION("Device node registration for cec drivers");
MODULE_LICENSE("GPL");