1 // SPDX-License-Identifier: GPL-2.0-only
3 * cec-api.c - HDMI Consumer Electronics Control framework - API
5 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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/ktime.h>
14 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/types.h>
18 #include <linux/uaccess.h>
19 #include <linux/version.h>
21 #include <media/cec-pin.h>
23 #include "cec-pin-priv.h"
25 static inline struct cec_devnode *cec_devnode_data(struct file *filp)
27 struct cec_fh *fh = filp->private_data;
29 return &fh->adap->devnode;
32 /* CEC file operations */
34 static __poll_t cec_poll(struct file *filp,
35 struct poll_table_struct *poll)
37 struct cec_fh *fh = filp->private_data;
38 struct cec_adapter *adap = fh->adap;
41 poll_wait(filp, &fh->wait, poll);
42 if (!cec_is_registered(adap))
43 return EPOLLERR | EPOLLHUP;
44 mutex_lock(&adap->lock);
45 if (adap->is_configured &&
46 adap->transmit_queue_sz < CEC_MAX_MSG_TX_QUEUE_SZ)
47 res |= EPOLLOUT | EPOLLWRNORM;
49 res |= EPOLLIN | EPOLLRDNORM;
50 if (fh->total_queued_events)
52 mutex_unlock(&adap->lock);
56 static bool cec_is_busy(const struct cec_adapter *adap,
57 const struct cec_fh *fh)
59 bool valid_initiator = adap->cec_initiator && adap->cec_initiator == fh;
60 bool valid_follower = adap->cec_follower && adap->cec_follower == fh;
63 * Exclusive initiators and followers can always access the CEC adapter
65 if (valid_initiator || valid_follower)
68 * All others can only access the CEC adapter if there is no
69 * exclusive initiator and they are in INITIATOR mode.
71 return adap->cec_initiator ||
72 fh->mode_initiator == CEC_MODE_NO_INITIATOR;
75 static long cec_adap_g_caps(struct cec_adapter *adap,
76 struct cec_caps __user *parg)
78 struct cec_caps caps = {};
80 strscpy(caps.driver, adap->devnode.dev.parent->driver->name,
82 strscpy(caps.name, adap->name, sizeof(caps.name));
83 caps.available_log_addrs = adap->available_log_addrs;
84 caps.capabilities = adap->capabilities;
85 caps.version = LINUX_VERSION_CODE;
86 if (copy_to_user(parg, &caps, sizeof(caps)))
91 static long cec_adap_g_phys_addr(struct cec_adapter *adap,
96 mutex_lock(&adap->lock);
97 phys_addr = adap->phys_addr;
98 mutex_unlock(&adap->lock);
99 if (copy_to_user(parg, &phys_addr, sizeof(phys_addr)))
104 static int cec_validate_phys_addr(u16 phys_addr)
108 if (phys_addr == CEC_PHYS_ADDR_INVALID)
110 for (i = 0; i < 16; i += 4)
111 if (phys_addr & (0xf << i))
115 for (i += 4; i < 16; i += 4)
116 if ((phys_addr & (0xf << i)) == 0)
121 static long cec_adap_s_phys_addr(struct cec_adapter *adap, struct cec_fh *fh,
122 bool block, __u16 __user *parg)
127 if (!(adap->capabilities & CEC_CAP_PHYS_ADDR))
129 if (copy_from_user(&phys_addr, parg, sizeof(phys_addr)))
132 err = cec_validate_phys_addr(phys_addr);
135 mutex_lock(&adap->lock);
136 if (cec_is_busy(adap, fh))
139 __cec_s_phys_addr(adap, phys_addr, block);
140 mutex_unlock(&adap->lock);
144 static long cec_adap_g_log_addrs(struct cec_adapter *adap,
145 struct cec_log_addrs __user *parg)
147 struct cec_log_addrs log_addrs;
149 mutex_lock(&adap->lock);
150 log_addrs = adap->log_addrs;
151 if (!adap->is_configured)
152 memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
153 sizeof(log_addrs.log_addr));
154 mutex_unlock(&adap->lock);
156 if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
161 static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
162 bool block, struct cec_log_addrs __user *parg)
164 struct cec_log_addrs log_addrs;
167 if (!(adap->capabilities & CEC_CAP_LOG_ADDRS))
169 if (copy_from_user(&log_addrs, parg, sizeof(log_addrs)))
171 log_addrs.flags &= CEC_LOG_ADDRS_FL_ALLOW_UNREG_FALLBACK |
172 CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU |
173 CEC_LOG_ADDRS_FL_CDC_ONLY;
174 mutex_lock(&adap->lock);
175 if (!adap->is_configuring &&
176 (!log_addrs.num_log_addrs || !adap->is_configured) &&
177 !cec_is_busy(adap, fh)) {
178 err = __cec_s_log_addrs(adap, &log_addrs, block);
180 log_addrs = adap->log_addrs;
182 mutex_unlock(&adap->lock);
185 if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
190 static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
191 bool block, struct cec_msg __user *parg)
193 struct cec_msg msg = {};
196 if (!(adap->capabilities & CEC_CAP_TRANSMIT))
198 if (copy_from_user(&msg, parg, sizeof(msg)))
201 mutex_lock(&adap->lock);
202 if (adap->log_addrs.num_log_addrs == 0)
204 else if (adap->is_configuring)
206 else if (cec_is_busy(adap, fh))
209 err = cec_transmit_msg_fh(adap, &msg, fh, block);
210 mutex_unlock(&adap->lock);
213 if (copy_to_user(parg, &msg, sizeof(msg)))
218 /* Called by CEC_RECEIVE: wait for a message to arrive */
219 static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
221 u32 timeout = msg->timeout;
225 mutex_lock(&fh->lock);
226 /* Are there received messages queued up? */
227 if (fh->queued_msgs) {
228 /* Yes, return the first one */
229 struct cec_msg_entry *entry =
230 list_first_entry(&fh->msgs,
231 struct cec_msg_entry, list);
233 list_del(&entry->list);
237 mutex_unlock(&fh->lock);
238 /* restore original timeout value */
239 msg->timeout = timeout;
243 /* No, return EAGAIN in non-blocking mode or wait */
244 mutex_unlock(&fh->lock);
246 /* Return when in non-blocking mode */
251 /* The user specified a timeout */
252 res = wait_event_interruptible_timeout(fh->wait,
254 msecs_to_jiffies(msg->timeout));
260 /* Wait indefinitely */
261 res = wait_event_interruptible(fh->wait,
264 /* Exit on error, otherwise loop to get the new message */
269 static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
270 bool block, struct cec_msg __user *parg)
272 struct cec_msg msg = {};
275 if (copy_from_user(&msg, parg, sizeof(msg)))
278 err = cec_receive_msg(fh, &msg, block);
282 if (copy_to_user(parg, &msg, sizeof(msg)))
287 static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
288 bool block, struct cec_event __user *parg)
290 struct cec_event_entry *ev = NULL;
296 mutex_lock(&fh->lock);
297 while (!fh->total_queued_events && block) {
298 mutex_unlock(&fh->lock);
299 err = wait_event_interruptible(fh->wait,
300 fh->total_queued_events);
303 mutex_lock(&fh->lock);
306 /* Find the oldest event */
307 for (i = 0; i < CEC_NUM_EVENTS; i++) {
308 struct cec_event_entry *entry =
309 list_first_entry_or_null(&fh->events[i],
310 struct cec_event_entry, list);
312 if (entry && entry->ev.ts <= ts) {
325 if (copy_to_user(parg, &ev->ev, sizeof(ev->ev)))
327 if (ev_idx >= CEC_NUM_CORE_EVENTS)
329 fh->queued_events[ev_idx]--;
330 fh->total_queued_events--;
333 mutex_unlock(&fh->lock);
337 static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
340 u32 mode = fh->mode_initiator | fh->mode_follower;
342 if (copy_to_user(parg, &mode, sizeof(mode)))
347 static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
353 bool send_pin_event = false;
356 if (copy_from_user(&mode, parg, sizeof(mode)))
358 if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK)) {
359 dprintk(1, "%s: invalid mode bits set\n", __func__);
363 mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
364 mode_follower = mode & CEC_MODE_FOLLOWER_MSK;
366 if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
367 mode_follower > CEC_MODE_MONITOR_ALL) {
368 dprintk(1, "%s: unknown mode\n", __func__);
372 if (mode_follower == CEC_MODE_MONITOR_ALL &&
373 !(adap->capabilities & CEC_CAP_MONITOR_ALL)) {
374 dprintk(1, "%s: MONITOR_ALL not supported\n", __func__);
378 if (mode_follower == CEC_MODE_MONITOR_PIN &&
379 !(adap->capabilities & CEC_CAP_MONITOR_PIN)) {
380 dprintk(1, "%s: MONITOR_PIN not supported\n", __func__);
384 /* Follower modes should always be able to send CEC messages */
385 if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
386 !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
387 mode_follower >= CEC_MODE_FOLLOWER &&
388 mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
389 dprintk(1, "%s: cannot transmit\n", __func__);
393 /* Monitor modes require CEC_MODE_NO_INITIATOR */
394 if (mode_initiator && mode_follower >= CEC_MODE_MONITOR_PIN) {
395 dprintk(1, "%s: monitor modes require NO_INITIATOR\n",
400 /* Monitor modes require CAP_NET_ADMIN */
401 if (mode_follower >= CEC_MODE_MONITOR_PIN && !capable(CAP_NET_ADMIN))
404 mutex_lock(&adap->lock);
406 * You can't become exclusive follower if someone else already
409 if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
410 mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
411 adap->cec_follower && adap->cec_follower != fh)
414 * You can't become exclusive initiator if someone else already
417 if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
418 adap->cec_initiator && adap->cec_initiator != fh)
422 bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
423 bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;
425 if (old_mon_all != new_mon_all) {
427 err = cec_monitor_all_cnt_inc(adap);
429 cec_monitor_all_cnt_dec(adap);
434 bool old_mon_pin = fh->mode_follower == CEC_MODE_MONITOR_PIN;
435 bool new_mon_pin = mode_follower == CEC_MODE_MONITOR_PIN;
437 if (old_mon_pin != new_mon_pin) {
438 send_pin_event = new_mon_pin;
440 err = cec_monitor_pin_cnt_inc(adap);
442 cec_monitor_pin_cnt_dec(adap);
447 mutex_unlock(&adap->lock);
451 if (fh->mode_follower == CEC_MODE_FOLLOWER)
452 adap->follower_cnt--;
453 if (mode_follower == CEC_MODE_FOLLOWER)
454 adap->follower_cnt++;
455 if (send_pin_event) {
456 struct cec_event ev = {
457 .flags = CEC_EVENT_FL_INITIAL_STATE,
460 ev.event = adap->cec_pin_is_high ? CEC_EVENT_PIN_CEC_HIGH :
461 CEC_EVENT_PIN_CEC_LOW;
462 cec_queue_event_fh(fh, &ev, 0);
464 if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
465 mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
467 mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
468 adap->cec_follower = fh;
469 } else if (adap->cec_follower == fh) {
470 adap->passthrough = false;
471 adap->cec_follower = NULL;
473 if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
474 adap->cec_initiator = fh;
475 else if (adap->cec_initiator == fh)
476 adap->cec_initiator = NULL;
477 fh->mode_initiator = mode_initiator;
478 fh->mode_follower = mode_follower;
479 mutex_unlock(&adap->lock);
483 static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
485 struct cec_fh *fh = filp->private_data;
486 struct cec_adapter *adap = fh->adap;
487 bool block = !(filp->f_flags & O_NONBLOCK);
488 void __user *parg = (void __user *)arg;
490 if (!cec_is_registered(adap))
494 case CEC_ADAP_G_CAPS:
495 return cec_adap_g_caps(adap, parg);
497 case CEC_ADAP_G_PHYS_ADDR:
498 return cec_adap_g_phys_addr(adap, parg);
500 case CEC_ADAP_S_PHYS_ADDR:
501 return cec_adap_s_phys_addr(adap, fh, block, parg);
503 case CEC_ADAP_G_LOG_ADDRS:
504 return cec_adap_g_log_addrs(adap, parg);
506 case CEC_ADAP_S_LOG_ADDRS:
507 return cec_adap_s_log_addrs(adap, fh, block, parg);
510 return cec_transmit(adap, fh, block, parg);
513 return cec_receive(adap, fh, block, parg);
516 return cec_dqevent(adap, fh, block, parg);
519 return cec_g_mode(adap, fh, parg);
522 return cec_s_mode(adap, fh, parg);
529 static int cec_open(struct inode *inode, struct file *filp)
531 struct cec_devnode *devnode =
532 container_of(inode->i_cdev, struct cec_devnode, cdev);
533 struct cec_adapter *adap = to_cec_adapter(devnode);
534 struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
536 * Initial events that are automatically sent when the cec device is
539 struct cec_event ev = {
540 .event = CEC_EVENT_STATE_CHANGE,
541 .flags = CEC_EVENT_FL_INITIAL_STATE,
549 INIT_LIST_HEAD(&fh->msgs);
550 INIT_LIST_HEAD(&fh->xfer_list);
551 for (i = 0; i < CEC_NUM_EVENTS; i++)
552 INIT_LIST_HEAD(&fh->events[i]);
553 mutex_init(&fh->lock);
554 init_waitqueue_head(&fh->wait);
556 fh->mode_initiator = CEC_MODE_INITIATOR;
559 err = cec_get_device(devnode);
565 mutex_lock(&devnode->lock);
566 if (list_empty(&devnode->fhs) &&
568 adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
569 err = adap->ops->adap_enable(adap, true);
571 mutex_unlock(&devnode->lock);
576 filp->private_data = fh;
578 /* Queue up initial state events */
579 ev.state_change.phys_addr = adap->phys_addr;
580 ev.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
581 cec_queue_event_fh(fh, &ev, 0);
582 #ifdef CONFIG_CEC_PIN
583 if (adap->pin && adap->pin->ops->read_hpd) {
584 err = adap->pin->ops->read_hpd(adap);
586 ev.event = err ? CEC_EVENT_PIN_HPD_HIGH :
587 CEC_EVENT_PIN_HPD_LOW;
588 cec_queue_event_fh(fh, &ev, 0);
591 if (adap->pin && adap->pin->ops->read_5v) {
592 err = adap->pin->ops->read_5v(adap);
594 ev.event = err ? CEC_EVENT_PIN_5V_HIGH :
595 CEC_EVENT_PIN_5V_LOW;
596 cec_queue_event_fh(fh, &ev, 0);
601 list_add(&fh->list, &devnode->fhs);
602 mutex_unlock(&devnode->lock);
607 /* Override for the release function */
608 static int cec_release(struct inode *inode, struct file *filp)
610 struct cec_devnode *devnode = cec_devnode_data(filp);
611 struct cec_adapter *adap = to_cec_adapter(devnode);
612 struct cec_fh *fh = filp->private_data;
615 mutex_lock(&adap->lock);
616 if (adap->cec_initiator == fh)
617 adap->cec_initiator = NULL;
618 if (adap->cec_follower == fh) {
619 adap->cec_follower = NULL;
620 adap->passthrough = false;
622 if (fh->mode_follower == CEC_MODE_FOLLOWER)
623 adap->follower_cnt--;
624 if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
625 cec_monitor_pin_cnt_dec(adap);
626 if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
627 cec_monitor_all_cnt_dec(adap);
628 mutex_unlock(&adap->lock);
630 mutex_lock(&devnode->lock);
632 if (cec_is_registered(adap) && list_empty(&devnode->fhs) &&
633 !adap->needs_hpd && adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
634 WARN_ON(adap->ops->adap_enable(adap, false));
636 mutex_unlock(&devnode->lock);
638 /* Unhook pending transmits from this filehandle. */
639 mutex_lock(&adap->lock);
640 while (!list_empty(&fh->xfer_list)) {
641 struct cec_data *data =
642 list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);
644 data->blocking = false;
646 list_del(&data->xfer_list);
648 mutex_unlock(&adap->lock);
649 while (!list_empty(&fh->msgs)) {
650 struct cec_msg_entry *entry =
651 list_first_entry(&fh->msgs, struct cec_msg_entry, list);
653 list_del(&entry->list);
656 for (i = CEC_NUM_CORE_EVENTS; i < CEC_NUM_EVENTS; i++) {
657 while (!list_empty(&fh->events[i])) {
658 struct cec_event_entry *entry =
659 list_first_entry(&fh->events[i],
660 struct cec_event_entry, list);
662 list_del(&entry->list);
668 cec_put_device(devnode);
669 filp->private_data = NULL;
673 const struct file_operations cec_devnode_fops = {
674 .owner = THIS_MODULE,
676 .unlocked_ioctl = cec_ioctl,
677 .compat_ioctl = cec_ioctl,
678 .release = cec_release,