2 * cec-api.c - HDMI Consumer Electronics Control framework - API
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/ktime.h>
26 #include <linux/slab.h>
28 #include <linux/string.h>
29 #include <linux/types.h>
30 #include <linux/uaccess.h>
31 #include <linux/version.h>
35 static inline struct cec_devnode *cec_devnode_data(struct file *filp)
37 struct cec_fh *fh = filp->private_data;
39 return &fh->adap->devnode;
42 /* CEC file operations */
44 static unsigned int cec_poll(struct file *filp,
45 struct poll_table_struct *poll)
47 struct cec_devnode *devnode = cec_devnode_data(filp);
48 struct cec_fh *fh = filp->private_data;
49 struct cec_adapter *adap = fh->adap;
52 if (!devnode->registered)
53 return POLLERR | POLLHUP;
54 mutex_lock(&adap->lock);
55 if (adap->is_configured)
56 res |= POLLOUT | POLLWRNORM;
58 res |= POLLIN | POLLRDNORM;
59 if (fh->pending_events)
61 poll_wait(filp, &fh->wait, poll);
62 mutex_unlock(&adap->lock);
66 static bool cec_is_busy(const struct cec_adapter *adap,
67 const struct cec_fh *fh)
69 bool valid_initiator = adap->cec_initiator && adap->cec_initiator == fh;
70 bool valid_follower = adap->cec_follower && adap->cec_follower == fh;
73 * Exclusive initiators and followers can always access the CEC adapter
75 if (valid_initiator || valid_follower)
78 * All others can only access the CEC adapter if there is no
79 * exclusive initiator and they are in INITIATOR mode.
81 return adap->cec_initiator ||
82 fh->mode_initiator == CEC_MODE_NO_INITIATOR;
85 static long cec_adap_g_caps(struct cec_adapter *adap,
86 struct cec_caps __user *parg)
88 struct cec_caps caps = {};
90 strlcpy(caps.driver, adap->devnode.parent->driver->name,
92 strlcpy(caps.name, adap->name, sizeof(caps.name));
93 caps.available_log_addrs = adap->available_log_addrs;
94 caps.capabilities = adap->capabilities;
95 caps.version = LINUX_VERSION_CODE;
96 if (copy_to_user(parg, &caps, sizeof(caps)))
101 static long cec_adap_g_phys_addr(struct cec_adapter *adap,
106 mutex_lock(&adap->lock);
107 phys_addr = adap->phys_addr;
108 mutex_unlock(&adap->lock);
109 if (copy_to_user(parg, &phys_addr, sizeof(phys_addr)))
114 static long cec_adap_s_phys_addr(struct cec_adapter *adap, struct cec_fh *fh,
115 bool block, __u16 __user *parg)
120 if (!(adap->capabilities & CEC_CAP_PHYS_ADDR))
122 if (copy_from_user(&phys_addr, parg, sizeof(phys_addr)))
125 err = cec_phys_addr_validate(phys_addr, NULL, NULL);
128 mutex_lock(&adap->lock);
129 if (cec_is_busy(adap, fh))
132 __cec_s_phys_addr(adap, phys_addr, block);
133 mutex_unlock(&adap->lock);
137 static long cec_adap_g_log_addrs(struct cec_adapter *adap,
138 struct cec_log_addrs __user *parg)
140 struct cec_log_addrs log_addrs;
142 mutex_lock(&adap->lock);
143 log_addrs = adap->log_addrs;
144 if (!adap->is_configured)
145 memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
146 sizeof(log_addrs.log_addr));
147 mutex_unlock(&adap->lock);
149 if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
154 static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
155 bool block, struct cec_log_addrs __user *parg)
157 struct cec_log_addrs log_addrs;
160 if (!(adap->capabilities & CEC_CAP_LOG_ADDRS))
162 if (copy_from_user(&log_addrs, parg, sizeof(log_addrs)))
165 mutex_lock(&adap->lock);
166 if (!adap->is_configuring &&
167 (!log_addrs.num_log_addrs || !adap->is_configured) &&
168 !cec_is_busy(adap, fh)) {
169 err = __cec_s_log_addrs(adap, &log_addrs, block);
171 log_addrs = adap->log_addrs;
173 mutex_unlock(&adap->lock);
176 if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
181 static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
182 bool block, struct cec_msg __user *parg)
184 struct cec_msg msg = {};
187 if (!(adap->capabilities & CEC_CAP_TRANSMIT))
189 if (copy_from_user(&msg, parg, sizeof(msg)))
191 mutex_lock(&adap->lock);
192 if (!adap->is_configured)
194 else if (cec_is_busy(adap, fh))
197 err = cec_transmit_msg_fh(adap, &msg, fh, block);
198 mutex_unlock(&adap->lock);
201 if (copy_to_user(parg, &msg, sizeof(msg)))
206 /* Called by CEC_RECEIVE: wait for a message to arrive */
207 static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
209 u32 timeout = msg->timeout;
213 mutex_lock(&fh->lock);
214 /* Are there received messages queued up? */
215 if (fh->queued_msgs) {
216 /* Yes, return the first one */
217 struct cec_msg_entry *entry =
218 list_first_entry(&fh->msgs,
219 struct cec_msg_entry, list);
221 list_del(&entry->list);
225 mutex_unlock(&fh->lock);
226 /* restore original timeout value */
227 msg->timeout = timeout;
231 /* No, return EAGAIN in non-blocking mode or wait */
232 mutex_unlock(&fh->lock);
234 /* Return when in non-blocking mode */
239 /* The user specified a timeout */
240 res = wait_event_interruptible_timeout(fh->wait,
242 msecs_to_jiffies(msg->timeout));
248 /* Wait indefinitely */
249 res = wait_event_interruptible(fh->wait,
252 /* Exit on error, otherwise loop to get the new message */
257 static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
258 bool block, struct cec_msg __user *parg)
260 struct cec_msg msg = {};
263 if (copy_from_user(&msg, parg, sizeof(msg)))
265 mutex_lock(&adap->lock);
266 if (!adap->is_configured && fh->mode_follower < CEC_MODE_MONITOR)
268 mutex_unlock(&adap->lock);
272 err = cec_receive_msg(fh, &msg, block);
275 if (copy_to_user(parg, &msg, sizeof(msg)))
280 static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
281 bool block, struct cec_event __user *parg)
283 struct cec_event *ev = NULL;
288 mutex_lock(&fh->lock);
289 while (!fh->pending_events && block) {
290 mutex_unlock(&fh->lock);
291 err = wait_event_interruptible(fh->wait, fh->pending_events);
294 mutex_lock(&fh->lock);
297 /* Find the oldest event */
298 for (i = 0; i < CEC_NUM_EVENTS; i++) {
299 if (fh->pending_events & (1 << (i + 1)) &&
300 fh->events[i].ts <= ts) {
310 if (copy_to_user(parg, ev, sizeof(*ev))) {
315 fh->pending_events &= ~(1 << ev->event);
318 mutex_unlock(&fh->lock);
322 static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
325 u32 mode = fh->mode_initiator | fh->mode_follower;
327 if (copy_to_user(parg, &mode, sizeof(mode)))
332 static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
340 if (copy_from_user(&mode, parg, sizeof(mode)))
342 if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK))
345 mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
346 mode_follower = mode & CEC_MODE_FOLLOWER_MSK;
348 if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
349 mode_follower > CEC_MODE_MONITOR_ALL)
352 if (mode_follower == CEC_MODE_MONITOR_ALL &&
353 !(adap->capabilities & CEC_CAP_MONITOR_ALL))
356 /* Follower modes should always be able to send CEC messages */
357 if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
358 !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
359 mode_follower >= CEC_MODE_FOLLOWER &&
360 mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU)
363 /* Monitor modes require CEC_MODE_NO_INITIATOR */
364 if (mode_initiator && mode_follower >= CEC_MODE_MONITOR)
367 /* Monitor modes require CAP_NET_ADMIN */
368 if (mode_follower >= CEC_MODE_MONITOR && !capable(CAP_NET_ADMIN))
371 mutex_lock(&adap->lock);
373 * You can't become exclusive follower if someone else already
376 if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
377 mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
378 adap->cec_follower && adap->cec_follower != fh)
381 * You can't become exclusive initiator if someone else already
384 if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
385 adap->cec_initiator && adap->cec_initiator != fh)
389 bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
390 bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;
392 if (old_mon_all != new_mon_all) {
394 err = cec_monitor_all_cnt_inc(adap);
396 cec_monitor_all_cnt_dec(adap);
401 mutex_unlock(&adap->lock);
405 if (fh->mode_follower == CEC_MODE_FOLLOWER)
406 adap->follower_cnt--;
407 if (mode_follower == CEC_MODE_FOLLOWER)
408 adap->follower_cnt++;
409 if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
410 mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
412 mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
413 adap->cec_follower = fh;
414 } else if (adap->cec_follower == fh) {
415 adap->passthrough = false;
416 adap->cec_follower = NULL;
418 if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
419 adap->cec_initiator = fh;
420 else if (adap->cec_initiator == fh)
421 adap->cec_initiator = NULL;
422 fh->mode_initiator = mode_initiator;
423 fh->mode_follower = mode_follower;
424 mutex_unlock(&adap->lock);
428 static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
430 struct cec_devnode *devnode = cec_devnode_data(filp);
431 struct cec_fh *fh = filp->private_data;
432 struct cec_adapter *adap = fh->adap;
433 bool block = !(filp->f_flags & O_NONBLOCK);
434 void __user *parg = (void __user *)arg;
436 if (!devnode->registered)
440 case CEC_ADAP_G_CAPS:
441 return cec_adap_g_caps(adap, parg);
443 case CEC_ADAP_G_PHYS_ADDR:
444 return cec_adap_g_phys_addr(adap, parg);
446 case CEC_ADAP_S_PHYS_ADDR:
447 return cec_adap_s_phys_addr(adap, fh, block, parg);
449 case CEC_ADAP_G_LOG_ADDRS:
450 return cec_adap_g_log_addrs(adap, parg);
452 case CEC_ADAP_S_LOG_ADDRS:
453 return cec_adap_s_log_addrs(adap, fh, block, parg);
456 return cec_transmit(adap, fh, block, parg);
459 return cec_receive(adap, fh, block, parg);
462 return cec_dqevent(adap, fh, block, parg);
465 return cec_g_mode(adap, fh, parg);
468 return cec_s_mode(adap, fh, parg);
475 static int cec_open(struct inode *inode, struct file *filp)
477 struct cec_devnode *devnode =
478 container_of(inode->i_cdev, struct cec_devnode, cdev);
479 struct cec_adapter *adap = to_cec_adapter(devnode);
480 struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
482 * Initial events that are automatically sent when the cec device is
485 struct cec_event ev_state = {
486 .event = CEC_EVENT_STATE_CHANGE,
487 .flags = CEC_EVENT_FL_INITIAL_STATE,
494 INIT_LIST_HEAD(&fh->msgs);
495 INIT_LIST_HEAD(&fh->xfer_list);
496 mutex_init(&fh->lock);
497 init_waitqueue_head(&fh->wait);
499 fh->mode_initiator = CEC_MODE_INITIATOR;
502 err = cec_get_device(devnode);
508 filp->private_data = fh;
510 mutex_lock(&devnode->fhs_lock);
511 /* Queue up initial state events */
512 ev_state.state_change.phys_addr = adap->phys_addr;
513 ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
514 cec_queue_event_fh(fh, &ev_state, 0);
516 list_add(&fh->list, &devnode->fhs);
517 mutex_unlock(&devnode->fhs_lock);
522 /* Override for the release function */
523 static int cec_release(struct inode *inode, struct file *filp)
525 struct cec_devnode *devnode = cec_devnode_data(filp);
526 struct cec_adapter *adap = to_cec_adapter(devnode);
527 struct cec_fh *fh = filp->private_data;
529 mutex_lock(&adap->lock);
530 if (adap->cec_initiator == fh)
531 adap->cec_initiator = NULL;
532 if (adap->cec_follower == fh) {
533 adap->cec_follower = NULL;
534 adap->passthrough = false;
536 if (fh->mode_follower == CEC_MODE_FOLLOWER)
537 adap->follower_cnt--;
538 if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
539 cec_monitor_all_cnt_dec(adap);
540 mutex_unlock(&adap->lock);
542 mutex_lock(&devnode->fhs_lock);
544 mutex_unlock(&devnode->fhs_lock);
546 /* Unhook pending transmits from this filehandle. */
547 mutex_lock(&adap->lock);
548 while (!list_empty(&fh->xfer_list)) {
549 struct cec_data *data =
550 list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);
552 data->blocking = false;
554 list_del(&data->xfer_list);
556 mutex_unlock(&adap->lock);
557 while (!list_empty(&fh->msgs)) {
558 struct cec_msg_entry *entry =
559 list_first_entry(&fh->msgs, struct cec_msg_entry, list);
561 list_del(&entry->list);
566 cec_put_device(devnode);
567 filp->private_data = NULL;
571 const struct file_operations cec_devnode_fops = {
572 .owner = THIS_MODULE,
574 .unlocked_ioctl = cec_ioctl,
575 .release = cec_release,