1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * cec-core.c - HDMI Consumer Electronics Control framework - Core
4 *
5 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 */
7
8 #include <linux/errno.h>
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/kmod.h>
13 #include <linux/slab.h>
14 #include <linux/mm.h>
15 #include <linux/string.h>
16 #include <linux/types.h>
17
18 #include "cec-priv.h"
19
20 #define CEC_NUM_DEVICES 256
21 #define CEC_NAME "cec"
22
23 int cec_debug;
24 module_param_named(debug, cec_debug, int, 0644);
25 MODULE_PARM_DESC(debug, "debug level (0-2)");
26
27 static bool debug_phys_addr;
28 module_param(debug_phys_addr, bool, 0644);
29 MODULE_PARM_DESC(debug_phys_addr, "add CEC_CAP_PHYS_ADDR if set");
30
31 static dev_t cec_dev_t;
32
33 /* Active devices */
34 static DEFINE_MUTEX(cec_devnode_lock);
35 static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);
36
37 static struct dentry *top_cec_dir;
38
39 /* dev to cec_devnode */
40 #define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)
41
cec_get_device(struct cec_devnode * devnode)42 int cec_get_device(struct cec_devnode *devnode)
43 {
44 /*
45 * Check if the cec device is available. This needs to be done with
46 * the devnode->lock held to prevent an open/unregister race:
47 * without the lock, the device could be unregistered and freed between
48 * the devnode->registered check and get_device() calls, leading to
49 * a crash.
50 */
51 mutex_lock(&devnode->lock);
52 /*
53 * return ENXIO if the cec device has been removed
54 * already or if it is not registered anymore.
55 */
56 if (!devnode->registered) {
57 mutex_unlock(&devnode->lock);
58 return -ENXIO;
59 }
60 /* and increase the device refcount */
61 get_device(&devnode->dev);
62 mutex_unlock(&devnode->lock);
63 return 0;
64 }
65
cec_put_device(struct cec_devnode * devnode)66 void cec_put_device(struct cec_devnode *devnode)
67 {
68 put_device(&devnode->dev);
69 }
70
71 /* Called when the last user of the cec device exits. */
cec_devnode_release(struct device * cd)72 static void cec_devnode_release(struct device *cd)
73 {
74 struct cec_devnode *devnode = to_cec_devnode(cd);
75
76 mutex_lock(&cec_devnode_lock);
77 /* Mark device node number as free */
78 clear_bit(devnode->minor, cec_devnode_nums);
79 mutex_unlock(&cec_devnode_lock);
80
81 cec_delete_adapter(to_cec_adapter(devnode));
82 }
83
84 static struct bus_type cec_bus_type = {
85 .name = CEC_NAME,
86 };
87
88 /*
89 * Register a cec device node
90 *
91 * The registration code assigns minor numbers and registers the new device node
92 * with the kernel. An error is returned if no free minor number can be found,
93 * or if the registration of the device node fails.
94 *
95 * Zero is returned on success.
96 *
97 * Note that if the cec_devnode_register call fails, the release() callback of
98 * the cec_devnode structure is *not* called, so the caller is responsible for
99 * freeing any data.
100 */
cec_devnode_register(struct cec_devnode * devnode,struct module * owner)101 static int __must_check cec_devnode_register(struct cec_devnode *devnode,
102 struct module *owner)
103 {
104 int minor;
105 int ret;
106
107 /* Part 1: Find a free minor number */
108 mutex_lock(&cec_devnode_lock);
109 minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
110 if (minor == CEC_NUM_DEVICES) {
111 mutex_unlock(&cec_devnode_lock);
112 pr_err("could not get a free minor\n");
113 return -ENFILE;
114 }
115
116 set_bit(minor, cec_devnode_nums);
117 mutex_unlock(&cec_devnode_lock);
118
119 devnode->minor = minor;
120 devnode->dev.bus = &cec_bus_type;
121 devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
122 devnode->dev.release = cec_devnode_release;
123 dev_set_name(&devnode->dev, "cec%d", devnode->minor);
124 device_initialize(&devnode->dev);
125
126 /* Part 2: Initialize and register the character device */
127 cdev_init(&devnode->cdev, &cec_devnode_fops);
128 devnode->cdev.owner = owner;
129 kobject_set_name(&devnode->cdev.kobj, "cec%d", devnode->minor);
130
131 devnode->registered = true;
132 ret = cdev_device_add(&devnode->cdev, &devnode->dev);
133 if (ret) {
134 devnode->registered = false;
135 pr_err("%s: cdev_device_add failed\n", __func__);
136 goto clr_bit;
137 }
138
139 return 0;
140
141 clr_bit:
142 mutex_lock(&cec_devnode_lock);
143 clear_bit(devnode->minor, cec_devnode_nums);
144 mutex_unlock(&cec_devnode_lock);
145 return ret;
146 }
147
148 /*
149 * Unregister a cec device node
150 *
151 * This unregisters the passed device. Future open calls will be met with
152 * errors.
153 *
154 * This function can safely be called if the device node has never been
155 * registered or has already been unregistered.
156 */
cec_devnode_unregister(struct cec_adapter * adap)157 static void cec_devnode_unregister(struct cec_adapter *adap)
158 {
159 struct cec_devnode *devnode = &adap->devnode;
160 struct cec_fh *fh;
161
162 mutex_lock(&devnode->lock);
163
164 /* Check if devnode was never registered or already unregistered */
165 if (!devnode->registered || devnode->unregistered) {
166 mutex_unlock(&devnode->lock);
167 return;
168 }
169
170 list_for_each_entry(fh, &devnode->fhs, list)
171 wake_up_interruptible(&fh->wait);
172
173 devnode->registered = false;
174 devnode->unregistered = true;
175 mutex_unlock(&devnode->lock);
176
177 mutex_lock(&adap->lock);
178 __cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
179 __cec_s_log_addrs(adap, NULL, false);
180 mutex_unlock(&adap->lock);
181
182 cdev_device_del(&devnode->cdev, &devnode->dev);
183 put_device(&devnode->dev);
184 }
185
186 #ifdef CONFIG_CEC_NOTIFIER
cec_cec_notify(struct cec_adapter * adap,u16 pa)187 static void cec_cec_notify(struct cec_adapter *adap, u16 pa)
188 {
189 cec_s_phys_addr(adap, pa, false);
190 }
191
cec_register_cec_notifier(struct cec_adapter * adap,struct cec_notifier * notifier)192 void cec_register_cec_notifier(struct cec_adapter *adap,
193 struct cec_notifier *notifier)
194 {
195 if (WARN_ON(!cec_is_registered(adap)))
196 return;
197
198 adap->notifier = notifier;
199 cec_notifier_register(adap->notifier, adap, cec_cec_notify);
200 }
201 EXPORT_SYMBOL_GPL(cec_register_cec_notifier);
202 #endif
203
204 #ifdef CONFIG_DEBUG_FS
cec_error_inj_write(struct file * file,const char __user * ubuf,size_t count,loff_t * ppos)205 static ssize_t cec_error_inj_write(struct file *file,
206 const char __user *ubuf, size_t count, loff_t *ppos)
207 {
208 struct seq_file *sf = file->private_data;
209 struct cec_adapter *adap = sf->private;
210 char *buf;
211 char *line;
212 char *p;
213
214 buf = memdup_user_nul(ubuf, min_t(size_t, PAGE_SIZE, count));
215 if (IS_ERR(buf))
216 return PTR_ERR(buf);
217 p = buf;
218 while (p && *p) {
219 p = skip_spaces(p);
220 line = strsep(&p, "\n");
221 if (!*line || *line == '#')
222 continue;
223 if (!adap->ops->error_inj_parse_line(adap, line)) {
224 kfree(buf);
225 return -EINVAL;
226 }
227 }
228 kfree(buf);
229 return count;
230 }
231
cec_error_inj_show(struct seq_file * sf,void * unused)232 static int cec_error_inj_show(struct seq_file *sf, void *unused)
233 {
234 struct cec_adapter *adap = sf->private;
235
236 return adap->ops->error_inj_show(adap, sf);
237 }
238
cec_error_inj_open(struct inode * inode,struct file * file)239 static int cec_error_inj_open(struct inode *inode, struct file *file)
240 {
241 return single_open(file, cec_error_inj_show, inode->i_private);
242 }
243
244 static const struct file_operations cec_error_inj_fops = {
245 .open = cec_error_inj_open,
246 .write = cec_error_inj_write,
247 .read = seq_read,
248 .llseek = seq_lseek,
249 .release = single_release,
250 };
251 #endif
252
cec_allocate_adapter(const struct cec_adap_ops * ops,void * priv,const char * name,u32 caps,u8 available_las)253 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
254 void *priv, const char *name, u32 caps,
255 u8 available_las)
256 {
257 struct cec_adapter *adap;
258 int res;
259
260 /*
261 * Disable this capability until the connector info public API
262 * is ready.
263 */
264 caps &= ~CEC_CAP_CONNECTOR_INFO;
265 #ifndef CONFIG_MEDIA_CEC_RC
266 caps &= ~CEC_CAP_RC;
267 #endif
268
269 if (WARN_ON(!caps))
270 return ERR_PTR(-EINVAL);
271 if (WARN_ON(!ops))
272 return ERR_PTR(-EINVAL);
273 if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS))
274 return ERR_PTR(-EINVAL);
275 adap = kzalloc(sizeof(*adap), GFP_KERNEL);
276 if (!adap)
277 return ERR_PTR(-ENOMEM);
278 strscpy(adap->name, name, sizeof(adap->name));
279 adap->phys_addr = CEC_PHYS_ADDR_INVALID;
280 adap->cec_pin_is_high = true;
281 adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
282 adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
283 adap->capabilities = caps;
284 if (debug_phys_addr)
285 adap->capabilities |= CEC_CAP_PHYS_ADDR;
286 adap->needs_hpd = caps & CEC_CAP_NEEDS_HPD;
287 adap->available_log_addrs = available_las;
288 adap->sequence = 0;
289 adap->ops = ops;
290 adap->priv = priv;
291 memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
292 mutex_init(&adap->lock);
293 INIT_LIST_HEAD(&adap->transmit_queue);
294 INIT_LIST_HEAD(&adap->wait_queue);
295 init_waitqueue_head(&adap->kthread_waitq);
296
297 /* adap->devnode initialization */
298 INIT_LIST_HEAD(&adap->devnode.fhs);
299 mutex_init(&adap->devnode.lock);
300
301 adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
302 if (IS_ERR(adap->kthread)) {
303 pr_err("cec-%s: kernel_thread() failed\n", name);
304 res = PTR_ERR(adap->kthread);
305 kfree(adap);
306 return ERR_PTR(res);
307 }
308
309 #ifdef CONFIG_MEDIA_CEC_RC
310 if (!(caps & CEC_CAP_RC))
311 return adap;
312
313 /* Prepare the RC input device */
314 adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE);
315 if (!adap->rc) {
316 pr_err("cec-%s: failed to allocate memory for rc_dev\n",
317 name);
318 kthread_stop(adap->kthread);
319 kfree(adap);
320 return ERR_PTR(-ENOMEM);
321 }
322
323 snprintf(adap->input_phys, sizeof(adap->input_phys),
324 "%s/input0", adap->name);
325
326 adap->rc->device_name = adap->name;
327 adap->rc->input_phys = adap->input_phys;
328 adap->rc->input_id.bustype = BUS_CEC;
329 adap->rc->input_id.vendor = 0;
330 adap->rc->input_id.product = 0;
331 adap->rc->input_id.version = 1;
332 adap->rc->driver_name = CEC_NAME;
333 adap->rc->allowed_protocols = RC_PROTO_BIT_CEC;
334 adap->rc->priv = adap;
335 adap->rc->map_name = RC_MAP_CEC;
336 adap->rc->timeout = MS_TO_NS(550);
337 #endif
338 return adap;
339 }
340 EXPORT_SYMBOL_GPL(cec_allocate_adapter);
341
cec_register_adapter(struct cec_adapter * adap,struct device * parent)342 int cec_register_adapter(struct cec_adapter *adap,
343 struct device *parent)
344 {
345 int res;
346
347 if (IS_ERR_OR_NULL(adap))
348 return 0;
349
350 if (WARN_ON(!parent))
351 return -EINVAL;
352
353 adap->owner = parent->driver->owner;
354 adap->devnode.dev.parent = parent;
355
356 #ifdef CONFIG_MEDIA_CEC_RC
357 if (adap->capabilities & CEC_CAP_RC) {
358 adap->rc->dev.parent = parent;
359 res = rc_register_device(adap->rc);
360
361 if (res) {
362 pr_err("cec-%s: failed to prepare input device\n",
363 adap->name);
364 rc_free_device(adap->rc);
365 adap->rc = NULL;
366 return res;
367 }
368 }
369 #endif
370
371 res = cec_devnode_register(&adap->devnode, adap->owner);
372 if (res) {
373 #ifdef CONFIG_MEDIA_CEC_RC
374 /* Note: rc_unregister also calls rc_free */
375 rc_unregister_device(adap->rc);
376 adap->rc = NULL;
377 #endif
378 return res;
379 }
380
381 dev_set_drvdata(&adap->devnode.dev, adap);
382 #ifdef CONFIG_DEBUG_FS
383 if (!top_cec_dir)
384 return 0;
385
386 adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), top_cec_dir);
387 if (IS_ERR_OR_NULL(adap->cec_dir)) {
388 pr_warn("cec-%s: Failed to create debugfs dir\n", adap->name);
389 return 0;
390 }
391 adap->status_file = debugfs_create_devm_seqfile(&adap->devnode.dev,
392 "status", adap->cec_dir, cec_adap_status);
393 if (IS_ERR_OR_NULL(adap->status_file)) {
394 pr_warn("cec-%s: Failed to create status file\n", adap->name);
395 debugfs_remove_recursive(adap->cec_dir);
396 adap->cec_dir = NULL;
397 return 0;
398 }
399 if (!adap->ops->error_inj_show || !adap->ops->error_inj_parse_line)
400 return 0;
401 adap->error_inj_file = debugfs_create_file("error-inj", 0644,
402 adap->cec_dir, adap,
403 &cec_error_inj_fops);
404 if (IS_ERR_OR_NULL(adap->error_inj_file))
405 pr_warn("cec-%s: Failed to create error-inj file\n",
406 adap->name);
407 #endif
408 return 0;
409 }
410 EXPORT_SYMBOL_GPL(cec_register_adapter);
411
cec_unregister_adapter(struct cec_adapter * adap)412 void cec_unregister_adapter(struct cec_adapter *adap)
413 {
414 if (IS_ERR_OR_NULL(adap))
415 return;
416
417 #ifdef CONFIG_MEDIA_CEC_RC
418 /* Note: rc_unregister also calls rc_free */
419 rc_unregister_device(adap->rc);
420 adap->rc = NULL;
421 #endif
422 debugfs_remove_recursive(adap->cec_dir);
423 #ifdef CONFIG_CEC_NOTIFIER
424 if (adap->notifier)
425 cec_notifier_unregister(adap->notifier);
426 #endif
427 cec_devnode_unregister(adap);
428 }
429 EXPORT_SYMBOL_GPL(cec_unregister_adapter);
430
cec_delete_adapter(struct cec_adapter * adap)431 void cec_delete_adapter(struct cec_adapter *adap)
432 {
433 if (IS_ERR_OR_NULL(adap))
434 return;
435 kthread_stop(adap->kthread);
436 if (adap->kthread_config)
437 kthread_stop(adap->kthread_config);
438 if (adap->ops->adap_free)
439 adap->ops->adap_free(adap);
440 #ifdef CONFIG_MEDIA_CEC_RC
441 rc_free_device(adap->rc);
442 #endif
443 kfree(adap);
444 }
445 EXPORT_SYMBOL_GPL(cec_delete_adapter);
446
447 /*
448 * Initialise cec for linux
449 */
cec_devnode_init(void)450 static int __init cec_devnode_init(void)
451 {
452 int ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES, CEC_NAME);
453
454 if (ret < 0) {
455 pr_warn("cec: unable to allocate major\n");
456 return ret;
457 }
458
459 #ifdef CONFIG_DEBUG_FS
460 top_cec_dir = debugfs_create_dir("cec", NULL);
461 if (IS_ERR_OR_NULL(top_cec_dir)) {
462 pr_warn("cec: Failed to create debugfs cec dir\n");
463 top_cec_dir = NULL;
464 }
465 #endif
466
467 ret = bus_register(&cec_bus_type);
468 if (ret < 0) {
469 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
470 pr_warn("cec: bus_register failed\n");
471 return -EIO;
472 }
473
474 return 0;
475 }
476
cec_devnode_exit(void)477 static void __exit cec_devnode_exit(void)
478 {
479 debugfs_remove_recursive(top_cec_dir);
480 bus_unregister(&cec_bus_type);
481 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
482 }
483
484 subsys_initcall(cec_devnode_init);
485 module_exit(cec_devnode_exit)
486
487 MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
488 MODULE_DESCRIPTION("Device node registration for cec drivers");
489 MODULE_LICENSE("GPL");
490
