xref: /linux/include/media/cec.h (revision 90d32e92011eaae8e70a9169b4e7acf4ca8f9d3a)
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  */
43 struct 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 
59 struct cec_adapter;
60 struct cec_data;
61 struct cec_pin;
62 struct cec_notifier;
63 
64 struct cec_data {
65 	struct list_head list;
66 	struct list_head xfer_list;
67 	struct cec_adapter *adap;
68 	struct cec_msg msg;
69 	struct cec_fh *fh;
70 	struct delayed_work work;
71 	struct completion c;
72 	u8 attempts;
73 	bool blocking;
74 	bool completed;
75 };
76 
77 struct cec_msg_entry {
78 	struct list_head	list;
79 	struct cec_msg		msg;
80 };
81 
82 struct cec_event_entry {
83 	struct list_head	list;
84 	struct cec_event	ev;
85 };
86 
87 #define CEC_NUM_CORE_EVENTS 2
88 #define CEC_NUM_EVENTS CEC_EVENT_PIN_5V_HIGH
89 
90 struct cec_fh {
91 	struct list_head	list;
92 	struct list_head	xfer_list;
93 	struct cec_adapter	*adap;
94 	u8			mode_initiator;
95 	u8			mode_follower;
96 
97 	/* Events */
98 	wait_queue_head_t	wait;
99 	struct mutex		lock;
100 	struct list_head	events[CEC_NUM_EVENTS]; /* queued events */
101 	u16			queued_events[CEC_NUM_EVENTS];
102 	unsigned int		total_queued_events;
103 	struct cec_event_entry	core_events[CEC_NUM_CORE_EVENTS];
104 	struct list_head	msgs; /* queued messages */
105 	unsigned int		queued_msgs;
106 };
107 
108 #define CEC_SIGNAL_FREE_TIME_RETRY		3
109 #define CEC_SIGNAL_FREE_TIME_NEW_INITIATOR	5
110 #define CEC_SIGNAL_FREE_TIME_NEXT_XFER		7
111 
112 /* The nominal data bit period is 2.4 ms */
113 #define CEC_FREE_TIME_TO_USEC(ft)		((ft) * 2400)
114 
115 struct cec_adap_ops {
116 	/* Low-level callbacks, called with adap->lock held */
117 	int (*adap_enable)(struct cec_adapter *adap, bool enable);
118 	int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
119 	int (*adap_monitor_pin_enable)(struct cec_adapter *adap, bool enable);
120 	int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
121 	void (*adap_unconfigured)(struct cec_adapter *adap);
122 	int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
123 			     u32 signal_free_time, struct cec_msg *msg);
124 	void (*adap_nb_transmit_canceled)(struct cec_adapter *adap,
125 					  const struct cec_msg *msg);
126 	void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
127 	void (*adap_free)(struct cec_adapter *adap);
128 
129 	/* Error injection callbacks, called without adap->lock held */
130 	int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
131 	bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);
132 
133 	/* High-level CEC message callback, called without adap->lock held */
134 	void (*configured)(struct cec_adapter *adap);
135 	int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
136 };
137 
138 /*
139  * The minimum message length you can receive (excepting poll messages) is 2.
140  * With a transfer rate of at most 36 bytes per second this makes 18 messages
141  * per second worst case.
142  *
143  * We queue at most 3 seconds worth of received messages. The CEC specification
144  * requires that messages are replied to within a second, so 3 seconds should
145  * give more than enough margin. Since most messages are actually more than 2
146  * bytes, this is in practice a lot more than 3 seconds.
147  */
148 #define CEC_MAX_MSG_RX_QUEUE_SZ		(18 * 3)
149 
150 /*
151  * The transmit queue is limited to 1 second worth of messages (worst case).
152  * Messages can be transmitted by userspace and kernel space. But for both it
153  * makes no sense to have a lot of messages queued up. One second seems
154  * reasonable.
155  */
156 #define CEC_MAX_MSG_TX_QUEUE_SZ		(18 * 1)
157 
158 /**
159  * struct cec_adapter - cec adapter structure
160  * @owner:		module owner
161  * @name:		name of the CEC adapter
162  * @devnode:		device node for the /dev/cecX device
163  * @lock:		mutex controlling access to this structure
164  * @rc:			remote control device
165  * @transmit_queue:	queue of pending transmits
166  * @transmit_queue_sz:	number of pending transmits
167  * @wait_queue:		queue of transmits waiting for a reply
168  * @transmitting:	CEC messages currently being transmitted
169  * @transmit_in_progress: true if a transmit is in progress
170  * @transmit_in_progress_aborted: true if a transmit is in progress is to be
171  *			aborted. This happens if the logical address is
172  *			invalidated while the transmit is ongoing. In that
173  *			case the transmit will finish, but will not retransmit
174  *			and be marked as ABORTED.
175  * @xfer_timeout_ms:	the transfer timeout in ms.
176  *			If 0, then timeout after 2100 ms.
177  * @kthread_config:	kthread used to configure a CEC adapter
178  * @config_completion:	used to signal completion of the config kthread
179  * @kthread:		main CEC processing thread
180  * @kthread_waitq:	main CEC processing wait_queue
181  * @ops:		cec adapter ops
182  * @priv:		cec driver's private data
183  * @capabilities:	cec adapter capabilities
184  * @available_log_addrs: maximum number of available logical addresses
185  * @phys_addr:		the current physical address
186  * @needs_hpd:		if true, then the HDMI HotPlug Detect pin must be high
187  *	in order to transmit or receive CEC messages. This is usually a HW
188  *	limitation.
189  * @is_enabled:		the CEC adapter is enabled
190  * @is_claiming_log_addrs:  true if cec_claim_log_addrs() is running
191  * @is_configuring:	the CEC adapter is configuring (i.e. claiming LAs)
192  * @must_reconfigure:	while configuring, the PA changed, so reclaim LAs
193  * @is_configured:	the CEC adapter is configured (i.e. has claimed LAs)
194  * @cec_pin_is_high:	if true then the CEC pin is high. Only used with the
195  *	CEC pin framework.
196  * @adap_controls_phys_addr: if true, then the CEC adapter controls the
197  *	physical address, i.e. the CEC hardware can detect HPD changes and
198  *	read the EDID and is not dependent on an external HDMI driver.
199  *	Drivers that need this can set this field to true after the
200  *	cec_allocate_adapter() call.
201  * @last_initiator:	the initiator of the last transmitted message.
202  * @monitor_all_cnt:	number of filehandles monitoring all msgs
203  * @monitor_pin_cnt:	number of filehandles monitoring pin changes
204  * @follower_cnt:	number of filehandles in follower mode
205  * @cec_follower:	filehandle of the exclusive follower
206  * @cec_initiator:	filehandle of the exclusive initiator
207  * @passthrough:	if true, then the exclusive follower is in
208  *	passthrough mode.
209  * @log_addrs:		current logical addresses
210  * @conn_info:		current connector info
211  * @tx_timeout_cnt:	count the number of Timed Out transmits.
212  *			Reset to 0 when this is reported in cec_adap_status().
213  * @tx_low_drive_cnt:	count the number of Low Drive transmits.
214  *			Reset to 0 when this is reported in cec_adap_status().
215  * @tx_error_cnt:	count the number of Error transmits.
216  *			Reset to 0 when this is reported in cec_adap_status().
217  * @tx_arb_lost_cnt:	count the number of Arb Lost transmits.
218  *			Reset to 0 when this is reported in cec_adap_status().
219  * @tx_low_drive_log_cnt: number of logged Low Drive transmits since the
220  *			adapter was enabled. Used to avoid flooding the kernel
221  *			log if this happens a lot.
222  * @tx_error_log_cnt:	number of logged Error transmits since the adapter was
223  *                      enabled. Used to avoid flooding the kernel log if this
224  *                      happens a lot.
225  * @notifier:		CEC notifier
226  * @pin:		CEC pin status struct
227  * @cec_dir:		debugfs cec directory
228  * @sequence:		transmit sequence counter
229  * @input_phys:		remote control input_phys name
230  *
231  * This structure represents a cec adapter.
232  */
233 struct cec_adapter {
234 	struct module *owner;
235 	char name[32];
236 	struct cec_devnode devnode;
237 	struct mutex lock;
238 	struct rc_dev *rc;
239 
240 	struct list_head transmit_queue;
241 	unsigned int transmit_queue_sz;
242 	struct list_head wait_queue;
243 	struct cec_data *transmitting;
244 	bool transmit_in_progress;
245 	bool transmit_in_progress_aborted;
246 	unsigned int xfer_timeout_ms;
247 
248 	struct task_struct *kthread_config;
249 	struct completion config_completion;
250 
251 	struct task_struct *kthread;
252 	wait_queue_head_t kthread_waitq;
253 
254 	const struct cec_adap_ops *ops;
255 	void *priv;
256 	u32 capabilities;
257 	u8 available_log_addrs;
258 
259 	u16 phys_addr;
260 	bool needs_hpd;
261 	bool is_enabled;
262 	bool is_claiming_log_addrs;
263 	bool is_configuring;
264 	bool must_reconfigure;
265 	bool is_configured;
266 	bool cec_pin_is_high;
267 	bool adap_controls_phys_addr;
268 	u8 last_initiator;
269 	u32 monitor_all_cnt;
270 	u32 monitor_pin_cnt;
271 	u32 follower_cnt;
272 	struct cec_fh *cec_follower;
273 	struct cec_fh *cec_initiator;
274 	bool passthrough;
275 	struct cec_log_addrs log_addrs;
276 	struct cec_connector_info conn_info;
277 
278 	u32 tx_timeout_cnt;
279 	u32 tx_low_drive_cnt;
280 	u32 tx_error_cnt;
281 	u32 tx_arb_lost_cnt;
282 	u32 tx_low_drive_log_cnt;
283 	u32 tx_error_log_cnt;
284 
285 #ifdef CONFIG_CEC_NOTIFIER
286 	struct cec_notifier *notifier;
287 #endif
288 #ifdef CONFIG_CEC_PIN
289 	struct cec_pin *pin;
290 #endif
291 
292 	struct dentry *cec_dir;
293 
294 	u32 sequence;
295 
296 	char input_phys[40];
297 };
298 
299 static inline void *cec_get_drvdata(const struct cec_adapter *adap)
300 {
301 	return adap->priv;
302 }
303 
304 static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
305 {
306 	return adap->log_addrs.log_addr_mask & (1 << log_addr);
307 }
308 
309 static inline bool cec_is_sink(const struct cec_adapter *adap)
310 {
311 	return adap->phys_addr == 0;
312 }
313 
314 /**
315  * cec_is_registered() - is the CEC adapter registered?
316  *
317  * @adap:	the CEC adapter, may be NULL.
318  *
319  * Return: true if the adapter is registered, false otherwise.
320  */
321 static inline bool cec_is_registered(const struct cec_adapter *adap)
322 {
323 	return adap && adap->devnode.registered;
324 }
325 
326 #define cec_phys_addr_exp(pa) \
327 	((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf
328 
329 struct edid;
330 struct drm_connector;
331 
332 #if IS_REACHABLE(CONFIG_CEC_CORE)
333 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
334 		void *priv, const char *name, u32 caps, u8 available_las);
335 int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
336 void cec_unregister_adapter(struct cec_adapter *adap);
337 void cec_delete_adapter(struct cec_adapter *adap);
338 
339 int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
340 		    bool block);
341 void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
342 		     bool block);
343 void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
344 			       const struct edid *edid);
345 void cec_s_conn_info(struct cec_adapter *adap,
346 		     const struct cec_connector_info *conn_info);
347 int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
348 		     bool block);
349 
350 /* Called by the adapter */
351 void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
352 			  u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
353 			  u8 error_cnt, ktime_t ts);
354 
355 static inline void cec_transmit_done(struct cec_adapter *adap, u8 status,
356 				     u8 arb_lost_cnt, u8 nack_cnt,
357 				     u8 low_drive_cnt, u8 error_cnt)
358 {
359 	cec_transmit_done_ts(adap, status, arb_lost_cnt, nack_cnt,
360 			     low_drive_cnt, error_cnt, ktime_get());
361 }
362 /*
363  * Simplified version of cec_transmit_done for hardware that doesn't retry
364  * failed transmits. So this is always just one attempt in which case
365  * the status is sufficient.
366  */
367 void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
368 				  u8 status, ktime_t ts);
369 
370 static inline void cec_transmit_attempt_done(struct cec_adapter *adap,
371 					     u8 status)
372 {
373 	cec_transmit_attempt_done_ts(adap, status, ktime_get());
374 }
375 
376 void cec_received_msg_ts(struct cec_adapter *adap,
377 			 struct cec_msg *msg, ktime_t ts);
378 
379 static inline void cec_received_msg(struct cec_adapter *adap,
380 				    struct cec_msg *msg)
381 {
382 	cec_received_msg_ts(adap, msg, ktime_get());
383 }
384 
385 /**
386  * cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp.
387  *
388  * @adap:	pointer to the cec adapter
389  * @is_high:	when true the CEC pin is high, otherwise it is low
390  * @dropped_events: when true some events were dropped
391  * @ts:		the timestamp for this event
392  *
393  */
394 void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high,
395 			     bool dropped_events, ktime_t ts);
396 
397 /**
398  * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
399  *
400  * @adap:	pointer to the cec adapter
401  * @is_high:	when true the HPD pin is high, otherwise it is low
402  * @ts:		the timestamp for this event
403  *
404  */
405 void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
406 
407 /**
408  * cec_queue_pin_5v_event() - queue a pin event with a given timestamp.
409  *
410  * @adap:	pointer to the cec adapter
411  * @is_high:	when true the 5V pin is high, otherwise it is low
412  * @ts:		the timestamp for this event
413  *
414  */
415 void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
416 
417 /**
418  * cec_get_edid_phys_addr() - find and return the physical address
419  *
420  * @edid:	pointer to the EDID data
421  * @size:	size in bytes of the EDID data
422  * @offset:	If not %NULL then the location of the physical address
423  *		bytes in the EDID will be returned here. This is set to 0
424  *		if there is no physical address found.
425  *
426  * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
427  */
428 u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
429 			   unsigned int *offset);
430 
431 void cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
432 				 const struct drm_connector *connector);
433 
434 #else
435 
436 static inline int cec_register_adapter(struct cec_adapter *adap,
437 				       struct device *parent)
438 {
439 	return 0;
440 }
441 
442 static inline void cec_unregister_adapter(struct cec_adapter *adap)
443 {
444 }
445 
446 static inline void cec_delete_adapter(struct cec_adapter *adap)
447 {
448 }
449 
450 static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
451 				   bool block)
452 {
453 }
454 
455 static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
456 					     const struct edid *edid)
457 {
458 }
459 
460 static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
461 					 unsigned int *offset)
462 {
463 	if (offset)
464 		*offset = 0;
465 	return CEC_PHYS_ADDR_INVALID;
466 }
467 
468 static inline void cec_s_conn_info(struct cec_adapter *adap,
469 				   const struct cec_connector_info *conn_info)
470 {
471 }
472 
473 static inline void
474 cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
475 			    const struct drm_connector *connector)
476 {
477 	memset(conn_info, 0, sizeof(*conn_info));
478 }
479 
480 #endif
481 
482 /**
483  * cec_phys_addr_invalidate() - set the physical address to INVALID
484  *
485  * @adap:	the CEC adapter
486  *
487  * This is a simple helper function to invalidate the physical
488  * address.
489  */
490 static inline void cec_phys_addr_invalidate(struct cec_adapter *adap)
491 {
492 	cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
493 }
494 
495 /**
496  * cec_get_edid_spa_location() - find location of the Source Physical Address
497  *
498  * @edid: the EDID
499  * @size: the size of the EDID
500  *
501  * This EDID is expected to be a CEA-861 compliant, which means that there are
502  * at least two blocks and one or more of the extensions blocks are CEA-861
503  * blocks.
504  *
505  * The returned location is guaranteed to be <= size-2.
506  *
507  * This is an inline function since it is used by both CEC and V4L2.
508  * Ideally this would go in a module shared by both, but it is overkill to do
509  * that for just a single function.
510  */
511 static inline unsigned int cec_get_edid_spa_location(const u8 *edid,
512 						     unsigned int size)
513 {
514 	unsigned int blocks = size / 128;
515 	unsigned int block;
516 	u8 d;
517 
518 	/* Sanity check: at least 2 blocks and a multiple of the block size */
519 	if (blocks < 2 || size % 128)
520 		return 0;
521 
522 	/*
523 	 * If there are fewer extension blocks than the size, then update
524 	 * 'blocks'. It is allowed to have more extension blocks than the size,
525 	 * since some hardware can only read e.g. 256 bytes of the EDID, even
526 	 * though more blocks are present. The first CEA-861 extension block
527 	 * should normally be in block 1 anyway.
528 	 */
529 	if (edid[0x7e] + 1 < blocks)
530 		blocks = edid[0x7e] + 1;
531 
532 	for (block = 1; block < blocks; block++) {
533 		unsigned int offset = block * 128;
534 
535 		/* Skip any non-CEA-861 extension blocks */
536 		if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
537 			continue;
538 
539 		/* search Vendor Specific Data Block (tag 3) */
540 		d = edid[offset + 2] & 0x7f;
541 		/* Check if there are Data Blocks */
542 		if (d <= 4)
543 			continue;
544 		if (d > 4) {
545 			unsigned int i = offset + 4;
546 			unsigned int end = offset + d;
547 
548 			/* Note: 'end' is always < 'size' */
549 			do {
550 				u8 tag = edid[i] >> 5;
551 				u8 len = edid[i] & 0x1f;
552 
553 				if (tag == 3 && len >= 5 && i + len <= end &&
554 				    edid[i + 1] == 0x03 &&
555 				    edid[i + 2] == 0x0c &&
556 				    edid[i + 3] == 0x00)
557 					return i + 4;
558 				i += len + 1;
559 			} while (i < end);
560 		}
561 	}
562 	return 0;
563 }
564 
565 #endif /* _MEDIA_CEC_H */
566