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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * cec - HDMI Consumer Electronics Control support header
4 *
5 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 */
7
8#ifndef _MEDIA_CEC_H
9#define _MEDIA_CEC_H
10
11#include <linux/poll.h>
12#include <linux/fs.h>
13#include <linux/debugfs.h>
14#include <linux/device.h>
15#include <linux/cdev.h>
16#include <linux/kthread.h>
17#include <linux/timer.h>
18#include <linux/cec-funcs.h>
19#include <media/rc-core.h>
20
21#define CEC_CAP_DEFAULTS (CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT | \
22 CEC_CAP_PASSTHROUGH | CEC_CAP_RC)
23
24/**
25 * struct cec_devnode - cec device node
26 * @dev: cec device
27 * @cdev: cec character device
28 * @minor: device node minor number
29 * @lock: lock to serialize open/release and registration
30 * @registered: the device was correctly registered
31 * @unregistered: the device was unregistered
32 * @lock_fhs: lock to control access to @fhs
33 * @fhs: the list of open filehandles (cec_fh)
34 *
35 * This structure represents a cec-related device node.
36 *
37 * To add or remove filehandles from @fhs the @lock must be taken first,
38 * followed by @lock_fhs. It is safe to access @fhs if either lock is held.
39 *
40 * The @parent is a physical device. It must be set by core or device drivers
41 * before registering the node.
42 */
43struct cec_devnode {
44 /* sysfs */
45 struct device dev;
46 struct cdev cdev;
47
48 /* device info */
49 int minor;
50 /* serialize open/release and registration */
51 struct mutex lock;
52 bool registered;
53 bool unregistered;
54 /* protect access to fhs */
55 struct mutex lock_fhs;
56 struct list_head fhs;
57};
58
59struct cec_adapter;
60struct cec_data;
61struct cec_pin;
62struct cec_notifier;
63
64struct cec_data {
65 struct list_head list;
66 struct list_head xfer_list;
67 struct cec_adapter *adap;
68 struct cec_msg msg;
69 u8 match_len;
70 u8 match_reply[5];
71 struct cec_fh *fh;
72 struct delayed_work work;
73 struct completion c;
74 u8 attempts;
75 bool blocking;
76 bool completed;
77};
78
79struct cec_msg_entry {
80 struct list_head list;
81 struct cec_msg msg;
82};
83
84struct cec_event_entry {
85 struct list_head list;
86 struct cec_event ev;
87};
88
89#define CEC_NUM_CORE_EVENTS 2
90#define CEC_NUM_EVENTS CEC_EVENT_PIN_5V_HIGH
91
92struct cec_fh {
93 struct list_head list;
94 struct list_head xfer_list;
95 struct cec_adapter *adap;
96 u8 mode_initiator;
97 u8 mode_follower;
98
99 /* Events */
100 wait_queue_head_t wait;
101 struct mutex lock;
102 struct list_head events[CEC_NUM_EVENTS]; /* queued events */
103 u16 queued_events[CEC_NUM_EVENTS];
104 unsigned int total_queued_events;
105 struct cec_event_entry core_events[CEC_NUM_CORE_EVENTS];
106 struct list_head msgs; /* queued messages */
107 unsigned int queued_msgs;
108};
109
110#define CEC_SIGNAL_FREE_TIME_RETRY 3
111#define CEC_SIGNAL_FREE_TIME_NEW_INITIATOR 5
112#define CEC_SIGNAL_FREE_TIME_NEXT_XFER 7
113
114/* The nominal data bit period is 2.4 ms */
115#define CEC_FREE_TIME_TO_USEC(ft) ((ft) * 2400)
116
117struct cec_adap_ops {
118 /* Low-level callbacks, called with adap->lock held */
119 int (*adap_enable)(struct cec_adapter *adap, bool enable);
120 int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
121 int (*adap_monitor_pin_enable)(struct cec_adapter *adap, bool enable);
122 int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
123 void (*adap_unconfigured)(struct cec_adapter *adap);
124 int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
125 u32 signal_free_time, struct cec_msg *msg);
126 void (*adap_nb_transmit_canceled)(struct cec_adapter *adap,
127 const struct cec_msg *msg);
128 void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
129 void (*adap_free)(struct cec_adapter *adap);
130
131 /* Error injection callbacks, called without adap->lock held */
132 int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
133 bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);
134
135 /* High-level CEC message callback, called without adap->lock held */
136 void (*configured)(struct cec_adapter *adap);
137 int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
138};
139
140/*
141 * The minimum message length you can receive (excepting poll messages) is 2.
142 * With a transfer rate of at most 36 bytes per second this makes 18 messages
143 * per second worst case.
144 *
145 * We queue at most 3 seconds worth of received messages. The CEC specification
146 * requires that messages are replied to within a second, so 3 seconds should
147 * give more than enough margin. Since most messages are actually more than 2
148 * bytes, this is in practice a lot more than 3 seconds.
149 */
150#define CEC_MAX_MSG_RX_QUEUE_SZ (18 * 3)
151
152/*
153 * The transmit queue is limited to 1 second worth of messages (worst case).
154 * Messages can be transmitted by userspace and kernel space. But for both it
155 * makes no sense to have a lot of messages queued up. One second seems
156 * reasonable.
157 */
158#define CEC_MAX_MSG_TX_QUEUE_SZ (18 * 1)
159
160/**
161 * struct cec_adapter - cec adapter structure
162 * @owner: module owner
163 * @name: name of the CEC adapter
164 * @devnode: device node for the /dev/cecX device
165 * @lock: mutex controlling access to this structure
166 * @rc: remote control device
167 * @transmit_queue: queue of pending transmits
168 * @transmit_queue_sz: number of pending transmits
169 * @wait_queue: queue of transmits waiting for a reply
170 * @transmitting: CEC messages currently being transmitted
171 * @transmit_in_progress: true if a transmit is in progress
172 * @transmit_in_progress_aborted: true if a transmit is in progress is to be
173 * aborted. This happens if the logical address is
174 * invalidated while the transmit is ongoing. In that
175 * case the transmit will finish, but will not retransmit
176 * and be marked as ABORTED.
177 * @xfer_timeout_ms: the transfer timeout in ms.
178 * If 0, then timeout after 2100 ms.
179 * @kthread_config: kthread used to configure a CEC adapter
180 * @config_completion: used to signal completion of the config kthread
181 * @kthread: main CEC processing thread
182 * @kthread_waitq: main CEC processing wait_queue
183 * @ops: cec adapter ops
184 * @priv: cec driver's private data
185 * @capabilities: cec adapter capabilities
186 * @available_log_addrs: maximum number of available logical addresses
187 * @phys_addr: the current physical address
188 * @needs_hpd: if true, then the HDMI HotPlug Detect pin must be high
189 * in order to transmit or receive CEC messages. This is usually a HW
190 * limitation.
191 * @is_enabled: the CEC adapter is enabled
192 * @is_claiming_log_addrs: true if cec_claim_log_addrs() is running
193 * @is_configuring: the CEC adapter is configuring (i.e. claiming LAs)
194 * @must_reconfigure: while configuring, the PA changed, so reclaim LAs
195 * @is_configured: the CEC adapter is configured (i.e. has claimed LAs)
196 * @cec_pin_is_high: if true then the CEC pin is high. Only used with the
197 * CEC pin framework.
198 * @adap_controls_phys_addr: if true, then the CEC adapter controls the
199 * physical address, i.e. the CEC hardware can detect HPD changes and
200 * read the EDID and is not dependent on an external HDMI driver.
201 * Drivers that need this can set this field to true after the
202 * cec_allocate_adapter() call.
203 * @last_initiator: the initiator of the last transmitted message.
204 * @monitor_all_cnt: number of filehandles monitoring all msgs
205 * @monitor_pin_cnt: number of filehandles monitoring pin changes
206 * @follower_cnt: number of filehandles in follower mode
207 * @cec_follower: filehandle of the exclusive follower
208 * @cec_initiator: filehandle of the exclusive initiator
209 * @passthrough: if true, then the exclusive follower is in
210 * passthrough mode.
211 * @log_addrs: current logical addresses
212 * @conn_info: current connector info
213 * @tx_timeout_cnt: count the number of Timed Out transmits.
214 * Reset to 0 when this is reported in cec_adap_status().
215 * @tx_low_drive_cnt: count the number of Low Drive transmits.
216 * Reset to 0 when this is reported in cec_adap_status().
217 * @tx_error_cnt: count the number of Error transmits.
218 * Reset to 0 when this is reported in cec_adap_status().
219 * @tx_arb_lost_cnt: count the number of Arb Lost transmits.
220 * Reset to 0 when this is reported in cec_adap_status().
221 * @tx_low_drive_log_cnt: number of logged Low Drive transmits since the
222 * adapter was enabled. Used to avoid flooding the kernel
223 * log if this happens a lot.
224 * @tx_error_log_cnt: number of logged Error transmits since the adapter was
225 * enabled. Used to avoid flooding the kernel log if this
226 * happens a lot.
227 * @notifier: CEC notifier
228 * @pin: CEC pin status struct
229 * @cec_dir: debugfs cec directory
230 * @sequence: transmit sequence counter
231 * @input_phys: remote control input_phys name
232 *
233 * This structure represents a cec adapter.
234 */
235struct cec_adapter {
236 struct module *owner;
237 char name[32];
238 struct cec_devnode devnode;
239 struct mutex lock;
240 struct rc_dev *rc;
241
242 struct list_head transmit_queue;
243 unsigned int transmit_queue_sz;
244 struct list_head wait_queue;
245 struct cec_data *transmitting;
246 bool transmit_in_progress;
247 bool transmit_in_progress_aborted;
248 unsigned int xfer_timeout_ms;
249
250 struct task_struct *kthread_config;
251 struct completion config_completion;
252
253 struct task_struct *kthread;
254 wait_queue_head_t kthread_waitq;
255
256 const struct cec_adap_ops *ops;
257 void *priv;
258 u32 capabilities;
259 u8 available_log_addrs;
260
261 u16 phys_addr;
262 bool needs_hpd;
263 bool is_enabled;
264 bool is_claiming_log_addrs;
265 bool is_configuring;
266 bool must_reconfigure;
267 bool is_configured;
268 bool cec_pin_is_high;
269 bool adap_controls_phys_addr;
270 u8 last_initiator;
271 u32 monitor_all_cnt;
272 u32 monitor_pin_cnt;
273 u32 follower_cnt;
274 struct cec_fh *cec_follower;
275 struct cec_fh *cec_initiator;
276 bool passthrough;
277 struct cec_log_addrs log_addrs;
278 struct cec_connector_info conn_info;
279
280 u32 tx_timeout_cnt;
281 u32 tx_low_drive_cnt;
282 u32 tx_error_cnt;
283 u32 tx_arb_lost_cnt;
284 u32 tx_low_drive_log_cnt;
285 u32 tx_error_log_cnt;
286
287#ifdef CONFIG_CEC_NOTIFIER
288 struct cec_notifier *notifier;
289#endif
290#ifdef CONFIG_CEC_PIN
291 struct cec_pin *pin;
292#endif
293
294 struct dentry *cec_dir;
295
296 u32 sequence;
297
298 char input_phys[40];
299};
300
301static inline int cec_get_device(struct cec_adapter *adap)
302{
303 struct cec_devnode *devnode = &adap->devnode;
304
305 /*
306 * Check if the cec device is available. This needs to be done with
307 * the devnode->lock held to prevent an open/unregister race:
308 * without the lock, the device could be unregistered and freed between
309 * the devnode->registered check and get_device() calls, leading to
310 * a crash.
311 */
312 mutex_lock(&devnode->lock);
313 /*
314 * return ENODEV if the cec device has been removed
315 * already or if it is not registered anymore.
316 */
317 if (!devnode->registered) {
318 mutex_unlock(&devnode->lock);
319 return -ENODEV;
320 }
321 /* and increase the device refcount */
322 get_device(&devnode->dev);
323 mutex_unlock(&devnode->lock);
324 return 0;
325}
326
327static inline void cec_put_device(struct cec_adapter *adap)
328{
329 put_device(&adap->devnode.dev);
330}
331
332static inline void *cec_get_drvdata(const struct cec_adapter *adap)
333{
334 return adap->priv;
335}
336
337static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
338{
339 return adap->log_addrs.log_addr_mask & (1 << log_addr);
340}
341
342static inline bool cec_is_sink(const struct cec_adapter *adap)
343{
344 return adap->phys_addr == 0;
345}
346
347/**
348 * cec_is_registered() - is the CEC adapter registered?
349 *
350 * @adap: the CEC adapter, may be NULL.
351 *
352 * Return: true if the adapter is registered, false otherwise.
353 */
354static inline bool cec_is_registered(const struct cec_adapter *adap)
355{
356 return adap && adap->devnode.registered;
357}
358
359#define cec_phys_addr_exp(pa) \
360 ((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf
361
362struct edid;
363struct drm_connector;
364
365#if IS_REACHABLE(CONFIG_CEC_CORE)
366struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
367 void *priv, const char *name, u32 caps, u8 available_las);
368int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
369void cec_unregister_adapter(struct cec_adapter *adap);
370void cec_delete_adapter(struct cec_adapter *adap);
371
372int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
373 bool block);
374void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
375 bool block);
376void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
377 const struct edid *edid);
378void cec_s_conn_info(struct cec_adapter *adap,
379 const struct cec_connector_info *conn_info);
380int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
381 bool block);
382
383/* Called by the adapter */
384void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
385 u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
386 u8 error_cnt, ktime_t ts);
387
388static inline void cec_transmit_done(struct cec_adapter *adap, u8 status,
389 u8 arb_lost_cnt, u8 nack_cnt,
390 u8 low_drive_cnt, u8 error_cnt)
391{
392 cec_transmit_done_ts(adap, status, arb_lost_cnt, nack_cnt,
393 low_drive_cnt, error_cnt, ktime_get());
394}
395/*
396 * Simplified version of cec_transmit_done for hardware that doesn't retry
397 * failed transmits. So this is always just one attempt in which case
398 * the status is sufficient.
399 */
400void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
401 u8 status, ktime_t ts);
402
403static inline void cec_transmit_attempt_done(struct cec_adapter *adap,
404 u8 status)
405{
406 cec_transmit_attempt_done_ts(adap, status, ktime_get());
407}
408
409void cec_received_msg_ts(struct cec_adapter *adap,
410 struct cec_msg *msg, ktime_t ts);
411
412static inline void cec_received_msg(struct cec_adapter *adap,
413 struct cec_msg *msg)
414{
415 cec_received_msg_ts(adap, msg, ktime_get());
416}
417
418/**
419 * cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp.
420 *
421 * @adap: pointer to the cec adapter
422 * @is_high: when true the CEC pin is high, otherwise it is low
423 * @dropped_events: when true some events were dropped
424 * @ts: the timestamp for this event
425 *
426 */
427void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high,
428 bool dropped_events, ktime_t ts);
429
430/**
431 * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
432 *
433 * @adap: pointer to the cec adapter
434 * @is_high: when true the HPD pin is high, otherwise it is low
435 * @ts: the timestamp for this event
436 *
437 */
438void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
439
440/**
441 * cec_queue_pin_5v_event() - queue a pin event with a given timestamp.
442 *
443 * @adap: pointer to the cec adapter
444 * @is_high: when true the 5V pin is high, otherwise it is low
445 * @ts: the timestamp for this event
446 *
447 */
448void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
449
450/**
451 * cec_get_edid_phys_addr() - find and return the physical address
452 *
453 * @edid: pointer to the EDID data
454 * @size: size in bytes of the EDID data
455 * @offset: If not %NULL then the location of the physical address
456 * bytes in the EDID will be returned here. This is set to 0
457 * if there is no physical address found.
458 *
459 * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
460 */
461u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
462 unsigned int *offset);
463
464void cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
465 const struct drm_connector *connector);
466
467#else
468
469static inline int cec_register_adapter(struct cec_adapter *adap,
470 struct device *parent)
471{
472 return 0;
473}
474
475static inline void cec_unregister_adapter(struct cec_adapter *adap)
476{
477}
478
479static inline void cec_delete_adapter(struct cec_adapter *adap)
480{
481}
482
483static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
484 bool block)
485{
486}
487
488static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
489 const struct edid *edid)
490{
491}
492
493static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
494 unsigned int *offset)
495{
496 if (offset)
497 *offset = 0;
498 return CEC_PHYS_ADDR_INVALID;
499}
500
501static inline void cec_s_conn_info(struct cec_adapter *adap,
502 const struct cec_connector_info *conn_info)
503{
504}
505
506static inline void
507cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
508 const struct drm_connector *connector)
509{
510 memset(conn_info, 0, sizeof(*conn_info));
511}
512
513#endif
514
515/**
516 * cec_phys_addr_invalidate() - set the physical address to INVALID
517 *
518 * @adap: the CEC adapter
519 *
520 * This is a simple helper function to invalidate the physical
521 * address.
522 */
523static inline void cec_phys_addr_invalidate(struct cec_adapter *adap)
524{
525 cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
526}
527
528/**
529 * cec_get_edid_spa_location() - find location of the Source Physical Address
530 *
531 * @edid: the EDID
532 * @size: the size of the EDID
533 *
534 * This EDID is expected to be a CEA-861 compliant, which means that there are
535 * at least two blocks and one or more of the extensions blocks are CEA-861
536 * blocks.
537 *
538 * The returned location is guaranteed to be <= size-2.
539 *
540 * This is an inline function since it is used by both CEC and V4L2.
541 * Ideally this would go in a module shared by both, but it is overkill to do
542 * that for just a single function.
543 */
544static inline unsigned int cec_get_edid_spa_location(const u8 *edid,
545 unsigned int size)
546{
547 unsigned int blocks = size / 128;
548 unsigned int block;
549 u8 d;
550
551 /* Sanity check: at least 2 blocks and a multiple of the block size */
552 if (blocks < 2 || size % 128)
553 return 0;
554
555 /*
556 * If there are fewer extension blocks than the size, then update
557 * 'blocks'. It is allowed to have more extension blocks than the size,
558 * since some hardware can only read e.g. 256 bytes of the EDID, even
559 * though more blocks are present. The first CEA-861 extension block
560 * should normally be in block 1 anyway.
561 */
562 if (edid[0x7e] + 1 < blocks)
563 blocks = edid[0x7e] + 1;
564
565 for (block = 1; block < blocks; block++) {
566 unsigned int offset = block * 128;
567
568 /* Skip any non-CEA-861 extension blocks */
569 if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
570 continue;
571
572 /* search Vendor Specific Data Block (tag 3) */
573 d = edid[offset + 2] & 0x7f;
574 /* Check if there are Data Blocks */
575 if (d <= 4)
576 continue;
577 if (d > 4) {
578 unsigned int i = offset + 4;
579 unsigned int end = offset + d;
580
581 /* Note: 'end' is always < 'size' */
582 do {
583 u8 tag = edid[i] >> 5;
584 u8 len = edid[i] & 0x1f;
585
586 if (tag == 3 && len >= 5 && i + len <= end &&
587 edid[i + 1] == 0x03 &&
588 edid[i + 2] == 0x0c &&
589 edid[i + 3] == 0x00)
590 return i + 4;
591 i += len + 1;
592 } while (i < end);
593 }
594 }
595 return 0;
596}
597
598#endif /* _MEDIA_CEC_H */