2 * cec-core.c - HDMI Consumer Electronics Control framework - Core
4 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 * This program is free software; you may redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
10 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
11 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
12 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
13 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
14 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
15 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
16 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 #include <linux/errno.h>
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/kmod.h>
25 #include <linux/slab.h>
27 #include <linux/string.h>
28 #include <linux/types.h>
32 #define CEC_NUM_DEVICES 256
33 #define CEC_NAME "cec"
36 module_param_named(debug, cec_debug, int, 0644);
37 MODULE_PARM_DESC(debug, "debug level (0-2)");
39 static dev_t cec_dev_t;
42 static DEFINE_MUTEX(cec_devnode_lock);
43 static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);
45 static struct dentry *top_cec_dir;
47 /* dev to cec_devnode */
48 #define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)
50 int cec_get_device(struct cec_devnode *devnode)
53 * Check if the cec device is available. This needs to be done with
54 * the cec_devnode_lock held to prevent an open/unregister race:
55 * without the lock, the device could be unregistered and freed between
56 * the devnode->registered check and get_device() calls, leading to
59 mutex_lock(&cec_devnode_lock);
61 * return ENXIO if the cec device has been removed
62 * already or if it is not registered anymore.
64 if (!devnode->registered) {
65 mutex_unlock(&cec_devnode_lock);
68 /* and increase the device refcount */
69 get_device(&devnode->dev);
70 mutex_unlock(&cec_devnode_lock);
74 void cec_put_device(struct cec_devnode *devnode)
76 mutex_lock(&cec_devnode_lock);
77 put_device(&devnode->dev);
78 mutex_unlock(&cec_devnode_lock);
81 /* Called when the last user of the cec device exits. */
82 static void cec_devnode_release(struct device *cd)
84 struct cec_devnode *devnode = to_cec_devnode(cd);
86 mutex_lock(&cec_devnode_lock);
88 /* Mark device node number as free */
89 clear_bit(devnode->minor, cec_devnode_nums);
91 mutex_unlock(&cec_devnode_lock);
92 cec_delete_adapter(to_cec_adapter(devnode));
95 static struct bus_type cec_bus_type = {
100 * Register a cec device node
102 * The registration code assigns minor numbers and registers the new device node
103 * with the kernel. An error is returned if no free minor number can be found,
104 * or if the registration of the device node fails.
106 * Zero is returned on success.
108 * Note that if the cec_devnode_register call fails, the release() callback of
109 * the cec_devnode structure is *not* called, so the caller is responsible for
112 static int __must_check cec_devnode_register(struct cec_devnode *devnode,
113 struct module *owner)
119 INIT_LIST_HEAD(&devnode->fhs);
120 mutex_init(&devnode->fhs_lock);
122 /* Part 1: Find a free minor number */
123 mutex_lock(&cec_devnode_lock);
124 minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
125 if (minor == CEC_NUM_DEVICES) {
126 mutex_unlock(&cec_devnode_lock);
127 pr_err("could not get a free minor\n");
131 set_bit(minor, cec_devnode_nums);
132 mutex_unlock(&cec_devnode_lock);
134 devnode->minor = minor;
135 devnode->dev.bus = &cec_bus_type;
136 devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
137 devnode->dev.release = cec_devnode_release;
138 devnode->dev.parent = devnode->parent;
139 dev_set_name(&devnode->dev, "cec%d", devnode->minor);
140 device_initialize(&devnode->dev);
142 /* Part 2: Initialize and register the character device */
143 cdev_init(&devnode->cdev, &cec_devnode_fops);
144 devnode->cdev.kobj.parent = &devnode->dev.kobj;
145 devnode->cdev.owner = owner;
147 ret = cdev_add(&devnode->cdev, devnode->dev.devt, 1);
149 pr_err("%s: cdev_add failed\n", __func__);
153 ret = device_add(&devnode->dev);
157 devnode->registered = true;
161 cdev_del(&devnode->cdev);
163 clear_bit(devnode->minor, cec_devnode_nums);
168 * Unregister a cec device node
170 * This unregisters the passed device. Future open calls will be met with
173 * This function can safely be called if the device node has never been
174 * registered or has already been unregistered.
176 static void cec_devnode_unregister(struct cec_devnode *devnode)
180 /* Check if devnode was never registered or already unregistered */
181 if (!devnode->registered || devnode->unregistered)
184 mutex_lock(&devnode->fhs_lock);
185 list_for_each_entry(fh, &devnode->fhs, list)
186 wake_up_interruptible(&fh->wait);
187 mutex_unlock(&devnode->fhs_lock);
189 devnode->registered = false;
190 devnode->unregistered = true;
191 device_del(&devnode->dev);
192 cdev_del(&devnode->cdev);
193 put_device(&devnode->dev);
196 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
197 void *priv, const char *name, u32 caps,
198 u8 available_las, struct device *parent)
200 struct cec_adapter *adap;
203 if (WARN_ON(!parent))
204 return ERR_PTR(-EINVAL);
206 return ERR_PTR(-EINVAL);
208 return ERR_PTR(-EINVAL);
209 if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS))
210 return ERR_PTR(-EINVAL);
211 adap = kzalloc(sizeof(*adap), GFP_KERNEL);
213 return ERR_PTR(-ENOMEM);
214 adap->owner = parent->driver->owner;
215 adap->devnode.parent = parent;
216 strlcpy(adap->name, name, sizeof(adap->name));
217 adap->phys_addr = CEC_PHYS_ADDR_INVALID;
218 adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
219 adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
220 adap->capabilities = caps;
221 adap->available_log_addrs = available_las;
225 memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
226 mutex_init(&adap->lock);
227 INIT_LIST_HEAD(&adap->transmit_queue);
228 INIT_LIST_HEAD(&adap->wait_queue);
229 init_waitqueue_head(&adap->kthread_waitq);
231 adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
232 if (IS_ERR(adap->kthread)) {
233 pr_err("cec-%s: kernel_thread() failed\n", name);
234 res = PTR_ERR(adap->kthread);
239 if (!(caps & CEC_CAP_RC))
242 #if IS_REACHABLE(CONFIG_RC_CORE)
243 /* Prepare the RC input device */
244 adap->rc = rc_allocate_device();
246 pr_err("cec-%s: failed to allocate memory for rc_dev\n",
248 kthread_stop(adap->kthread);
250 return ERR_PTR(-ENOMEM);
253 snprintf(adap->input_name, sizeof(adap->input_name),
255 snprintf(adap->input_phys, sizeof(adap->input_phys),
258 adap->rc->input_name = adap->input_name;
259 adap->rc->input_phys = adap->input_phys;
260 adap->rc->input_id.bustype = BUS_CEC;
261 adap->rc->input_id.vendor = 0;
262 adap->rc->input_id.product = 0;
263 adap->rc->input_id.version = 1;
264 adap->rc->dev.parent = parent;
265 adap->rc->driver_type = RC_DRIVER_SCANCODE;
266 adap->rc->driver_name = CEC_NAME;
267 adap->rc->allowed_protocols = RC_BIT_CEC;
268 adap->rc->priv = adap;
269 adap->rc->map_name = RC_MAP_CEC;
270 adap->rc->timeout = MS_TO_NS(100);
272 adap->capabilities &= ~CEC_CAP_RC;
276 EXPORT_SYMBOL_GPL(cec_allocate_adapter);
278 int cec_register_adapter(struct cec_adapter *adap)
282 if (IS_ERR_OR_NULL(adap))
285 #if IS_REACHABLE(CONFIG_RC_CORE)
286 if (adap->capabilities & CEC_CAP_RC) {
287 res = rc_register_device(adap->rc);
290 pr_err("cec-%s: failed to prepare input device\n",
292 rc_free_device(adap->rc);
299 res = cec_devnode_register(&adap->devnode, adap->owner);
301 #if IS_REACHABLE(CONFIG_RC_CORE)
302 /* Note: rc_unregister also calls rc_free */
303 rc_unregister_device(adap->rc);
309 dev_set_drvdata(&adap->devnode.dev, adap);
310 #ifdef CONFIG_MEDIA_CEC_DEBUG
314 adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), top_cec_dir);
315 if (IS_ERR_OR_NULL(adap->cec_dir)) {
316 pr_warn("cec-%s: Failed to create debugfs dir\n", adap->name);
319 adap->status_file = debugfs_create_devm_seqfile(&adap->devnode.dev,
320 "status", adap->cec_dir, cec_adap_status);
321 if (IS_ERR_OR_NULL(adap->status_file)) {
322 pr_warn("cec-%s: Failed to create status file\n", adap->name);
323 debugfs_remove_recursive(adap->cec_dir);
324 adap->cec_dir = NULL;
329 EXPORT_SYMBOL_GPL(cec_register_adapter);
331 void cec_unregister_adapter(struct cec_adapter *adap)
333 if (IS_ERR_OR_NULL(adap))
336 #if IS_REACHABLE(CONFIG_RC_CORE)
337 /* Note: rc_unregister also calls rc_free */
338 rc_unregister_device(adap->rc);
341 debugfs_remove_recursive(adap->cec_dir);
342 cec_devnode_unregister(&adap->devnode);
344 EXPORT_SYMBOL_GPL(cec_unregister_adapter);
346 void cec_delete_adapter(struct cec_adapter *adap)
348 if (IS_ERR_OR_NULL(adap))
350 mutex_lock(&adap->lock);
351 __cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
352 mutex_unlock(&adap->lock);
353 kthread_stop(adap->kthread);
354 if (adap->kthread_config)
355 kthread_stop(adap->kthread_config);
356 #if IS_REACHABLE(CONFIG_RC_CORE)
358 rc_free_device(adap->rc);
362 EXPORT_SYMBOL_GPL(cec_delete_adapter);
365 * Initialise cec for linux
367 static int __init cec_devnode_init(void)
371 pr_info("Linux cec interface: v0.10\n");
372 ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES,
375 pr_warn("cec: unable to allocate major\n");
379 #ifdef CONFIG_MEDIA_CEC_DEBUG
380 top_cec_dir = debugfs_create_dir("cec", NULL);
381 if (IS_ERR_OR_NULL(top_cec_dir)) {
382 pr_warn("cec: Failed to create debugfs cec dir\n");
387 ret = bus_register(&cec_bus_type);
389 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
390 pr_warn("cec: bus_register failed\n");
397 static void __exit cec_devnode_exit(void)
399 debugfs_remove_recursive(top_cec_dir);
400 bus_unregister(&cec_bus_type);
401 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
404 subsys_initcall(cec_devnode_init);
405 module_exit(cec_devnode_exit)
407 MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
408 MODULE_DESCRIPTION("Device node registration for cec drivers");
409 MODULE_LICENSE("GPL");