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	struct cec_fh *fh;
 70	struct delayed_work work;
 71	struct completion c;
 72	u8 attempts;
 73	bool blocking;
 74	bool completed;
 75};
 76
 77struct cec_msg_entry {
 78	struct list_head	list;
 79	struct cec_msg		msg;
 80};
 81
 82struct 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
 90struct 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
115struct cec_adap_ops {
116	/* Low-level callbacks */
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_configured)(struct cec_adapter *adap, bool configured);
122	int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
123			     u32 signal_free_time, struct cec_msg *msg);
124	void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
125	void (*adap_free)(struct cec_adapter *adap);
126
127	/* Error injection callbacks */
128	int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
129	bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);
130
131	/* High-level CEC message callback */
132	int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
133};
134
135/*
136 * The minimum message length you can receive (excepting poll messages) is 2.
137 * With a transfer rate of at most 36 bytes per second this makes 18 messages
138 * per second worst case.
139 *
140 * We queue at most 3 seconds worth of received messages. The CEC specification
141 * requires that messages are replied to within a second, so 3 seconds should
142 * give more than enough margin. Since most messages are actually more than 2
143 * bytes, this is in practice a lot more than 3 seconds.
144 */
145#define CEC_MAX_MSG_RX_QUEUE_SZ		(18 * 3)
146
147/*
148 * The transmit queue is limited to 1 second worth of messages (worst case).
149 * Messages can be transmitted by userspace and kernel space. But for both it
150 * makes no sense to have a lot of messages queued up. One second seems
151 * reasonable.
152 */
153#define CEC_MAX_MSG_TX_QUEUE_SZ		(18 * 1)
154
155/**
156 * struct cec_adapter - cec adapter structure
157 * @owner:		module owner
158 * @name:		name of the CEC adapter
159 * @devnode:		device node for the /dev/cecX device
160 * @lock:		mutex controlling access to this structure
161 * @rc:			remote control device
162 * @transmit_queue:	queue of pending transmits
163 * @transmit_queue_sz:	number of pending transmits
164 * @wait_queue:		queue of transmits waiting for a reply
165 * @transmitting:	CEC messages currently being transmitted
166 * @transmit_in_progress: true if a transmit is in progress
167 * @transmit_in_progress_aborted: true if a transmit is in progress is to be
168 *			aborted. This happens if the logical address is
169 *			invalidated while the transmit is ongoing. In that
170 *			case the transmit will finish, but will not retransmit
171 *			and be marked as ABORTED.
172 * @xfer_timeout_ms:	the transfer timeout in ms.
173 *			If 0, then timeout after 2.1 ms.
174 * @kthread_config:	kthread used to configure a CEC adapter
175 * @config_completion:	used to signal completion of the config kthread
176 * @kthread:		main CEC processing thread
177 * @kthread_waitq:	main CEC processing wait_queue
178 * @ops:		cec adapter ops
179 * @priv:		cec driver's private data
180 * @capabilities:	cec adapter capabilities
181 * @available_log_addrs: maximum number of available logical addresses
182 * @phys_addr:		the current physical address
183 * @needs_hpd:		if true, then the HDMI HotPlug Detect pin must be high
184 *	in order to transmit or receive CEC messages. This is usually a HW
185 *	limitation.
186 * @is_enabled:		the CEC adapter is enabled
187 * @is_configuring:	the CEC adapter is configuring (i.e. claiming LAs)
188 * @must_reconfigure:	while configuring, the PA changed, so reclaim LAs
189 * @is_configured:	the CEC adapter is configured (i.e. has claimed LAs)
190 * @cec_pin_is_high:	if true then the CEC pin is high. Only used with the
191 *	CEC pin framework.
192 * @adap_controls_phys_addr: if true, then the CEC adapter controls the
193 *	physical address, i.e. the CEC hardware can detect HPD changes and
194 *	read the EDID and is not dependent on an external HDMI driver.
195 *	Drivers that need this can set this field to true after the
196 *	cec_allocate_adapter() call.
197 * @last_initiator:	the initiator of the last transmitted message.
198 * @monitor_all_cnt:	number of filehandles monitoring all msgs
199 * @monitor_pin_cnt:	number of filehandles monitoring pin changes
200 * @follower_cnt:	number of filehandles in follower mode
201 * @cec_follower:	filehandle of the exclusive follower
202 * @cec_initiator:	filehandle of the exclusive initiator
203 * @passthrough:	if true, then the exclusive follower is in
204 *	passthrough mode.
205 * @log_addrs:		current logical addresses
206 * @conn_info:		current connector info
207 * @tx_timeouts:	number of transmit timeouts
208 * @notifier:		CEC notifier
209 * @pin:		CEC pin status struct
210 * @cec_dir:		debugfs cec directory
211 * @status_file:	debugfs cec status file
212 * @error_inj_file:	debugfs cec error injection file
213 * @sequence:		transmit sequence counter
214 * @input_phys:		remote control input_phys name
215 *
216 * This structure represents a cec adapter.
217 */
218struct cec_adapter {
219	struct module *owner;
220	char name[32];
221	struct cec_devnode devnode;
222	struct mutex lock;
223	struct rc_dev *rc;
224
225	struct list_head transmit_queue;
226	unsigned int transmit_queue_sz;
227	struct list_head wait_queue;
228	struct cec_data *transmitting;
229	bool transmit_in_progress;
230	bool transmit_in_progress_aborted;
231	unsigned int xfer_timeout_ms;
232
233	struct task_struct *kthread_config;
234	struct completion config_completion;
235
236	struct task_struct *kthread;
237	wait_queue_head_t kthread_waitq;
238
239	const struct cec_adap_ops *ops;
240	void *priv;
241	u32 capabilities;
242	u8 available_log_addrs;
243
244	u16 phys_addr;
245	bool needs_hpd;
246	bool is_enabled;
247	bool is_configuring;
248	bool must_reconfigure;
249	bool is_configured;
250	bool cec_pin_is_high;
251	bool adap_controls_phys_addr;
252	u8 last_initiator;
253	u32 monitor_all_cnt;
254	u32 monitor_pin_cnt;
255	u32 follower_cnt;
256	struct cec_fh *cec_follower;
257	struct cec_fh *cec_initiator;
258	bool passthrough;
259	struct cec_log_addrs log_addrs;
260	struct cec_connector_info conn_info;
261
262	u32 tx_timeouts;
263
264#ifdef CONFIG_CEC_NOTIFIER
265	struct cec_notifier *notifier;
266#endif
267#ifdef CONFIG_CEC_PIN
268	struct cec_pin *pin;
269#endif
270
271	struct dentry *cec_dir;
272
273	u32 sequence;
274
275	char input_phys[32];
276};
277
278static inline void *cec_get_drvdata(const struct cec_adapter *adap)
279{
280	return adap->priv;
281}
282
283static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
284{
285	return adap->log_addrs.log_addr_mask & (1 << log_addr);
286}
287
288static inline bool cec_is_sink(const struct cec_adapter *adap)
289{
290	return adap->phys_addr == 0;
291}
292
293/**
294 * cec_is_registered() - is the CEC adapter registered?
295 *
296 * @adap:	the CEC adapter, may be NULL.
297 *
298 * Return: true if the adapter is registered, false otherwise.
299 */
300static inline bool cec_is_registered(const struct cec_adapter *adap)
301{
302	return adap && adap->devnode.registered;
303}
304
305#define cec_phys_addr_exp(pa) \
306	((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf
307
308struct edid;
309struct drm_connector;
310
311#if IS_REACHABLE(CONFIG_CEC_CORE)
312struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
313		void *priv, const char *name, u32 caps, u8 available_las);
314int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
315void cec_unregister_adapter(struct cec_adapter *adap);
316void cec_delete_adapter(struct cec_adapter *adap);
317
318int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
319		    bool block);
320void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
321		     bool block);
322void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
323			       const struct edid *edid);
324void cec_s_conn_info(struct cec_adapter *adap,
325		     const struct cec_connector_info *conn_info);
326int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
327		     bool block);
328
329/* Called by the adapter */
330void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
331			  u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
332			  u8 error_cnt, ktime_t ts);
333
334static inline void cec_transmit_done(struct cec_adapter *adap, u8 status,
335				     u8 arb_lost_cnt, u8 nack_cnt,
336				     u8 low_drive_cnt, u8 error_cnt)
337{
338	cec_transmit_done_ts(adap, status, arb_lost_cnt, nack_cnt,
339			     low_drive_cnt, error_cnt, ktime_get());
340}
341/*
342 * Simplified version of cec_transmit_done for hardware that doesn't retry
343 * failed transmits. So this is always just one attempt in which case
344 * the status is sufficient.
345 */
346void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
347				  u8 status, ktime_t ts);
348
349static inline void cec_transmit_attempt_done(struct cec_adapter *adap,
350					     u8 status)
351{
352	cec_transmit_attempt_done_ts(adap, status, ktime_get());
353}
354
355void cec_received_msg_ts(struct cec_adapter *adap,
356			 struct cec_msg *msg, ktime_t ts);
357
358static inline void cec_received_msg(struct cec_adapter *adap,
359				    struct cec_msg *msg)
360{
361	cec_received_msg_ts(adap, msg, ktime_get());
362}
363
364/**
365 * cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp.
366 *
367 * @adap:	pointer to the cec adapter
368 * @is_high:	when true the CEC pin is high, otherwise it is low
369 * @dropped_events: when true some events were dropped
370 * @ts:		the timestamp for this event
371 *
372 */
373void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high,
374			     bool dropped_events, ktime_t ts);
375
376/**
377 * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
378 *
379 * @adap:	pointer to the cec adapter
380 * @is_high:	when true the HPD pin is high, otherwise it is low
381 * @ts:		the timestamp for this event
382 *
383 */
384void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
385
386/**
387 * cec_queue_pin_5v_event() - queue a pin event with a given timestamp.
388 *
389 * @adap:	pointer to the cec adapter
390 * @is_high:	when true the 5V pin is high, otherwise it is low
391 * @ts:		the timestamp for this event
392 *
393 */
394void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
395
396/**
397 * cec_get_edid_phys_addr() - find and return the physical address
398 *
399 * @edid:	pointer to the EDID data
400 * @size:	size in bytes of the EDID data
401 * @offset:	If not %NULL then the location of the physical address
402 *		bytes in the EDID will be returned here. This is set to 0
403 *		if there is no physical address found.
404 *
405 * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
406 */
407u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
408			   unsigned int *offset);
409
410void cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
411				 const struct drm_connector *connector);
412
413#else
414
415static inline int cec_register_adapter(struct cec_adapter *adap,
416				       struct device *parent)
417{
418	return 0;
419}
420
421static inline void cec_unregister_adapter(struct cec_adapter *adap)
422{
423}
424
425static inline void cec_delete_adapter(struct cec_adapter *adap)
426{
427}
428
429static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
430				   bool block)
431{
432}
433
434static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
435					     const struct edid *edid)
436{
437}
438
439static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
440					 unsigned int *offset)
441{
442	if (offset)
443		*offset = 0;
444	return CEC_PHYS_ADDR_INVALID;
445}
446
447static inline void cec_s_conn_info(struct cec_adapter *adap,
448				   const struct cec_connector_info *conn_info)
449{
450}
451
452static inline void
453cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
454			    const struct drm_connector *connector)
455{
456	memset(conn_info, 0, sizeof(*conn_info));
457}
458
459#endif
460
461/**
462 * cec_phys_addr_invalidate() - set the physical address to INVALID
463 *
464 * @adap:	the CEC adapter
465 *
466 * This is a simple helper function to invalidate the physical
467 * address.
468 */
469static inline void cec_phys_addr_invalidate(struct cec_adapter *adap)
470{
471	cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
472}
473
474/**
475 * cec_get_edid_spa_location() - find location of the Source Physical Address
476 *
477 * @edid: the EDID
478 * @size: the size of the EDID
479 *
480 * This EDID is expected to be a CEA-861 compliant, which means that there are
481 * at least two blocks and one or more of the extensions blocks are CEA-861
482 * blocks.
483 *
484 * The returned location is guaranteed to be <= size-2.
485 *
486 * This is an inline function since it is used by both CEC and V4L2.
487 * Ideally this would go in a module shared by both, but it is overkill to do
488 * that for just a single function.
489 */
490static inline unsigned int cec_get_edid_spa_location(const u8 *edid,
491						     unsigned int size)
492{
493	unsigned int blocks = size / 128;
494	unsigned int block;
495	u8 d;
496
497	/* Sanity check: at least 2 blocks and a multiple of the block size */
498	if (blocks < 2 || size % 128)
499		return 0;
500
501	/*
502	 * If there are fewer extension blocks than the size, then update
503	 * 'blocks'. It is allowed to have more extension blocks than the size,
504	 * since some hardware can only read e.g. 256 bytes of the EDID, even
505	 * though more blocks are present. The first CEA-861 extension block
506	 * should normally be in block 1 anyway.
507	 */
508	if (edid[0x7e] + 1 < blocks)
509		blocks = edid[0x7e] + 1;
510
511	for (block = 1; block < blocks; block++) {
512		unsigned int offset = block * 128;
513
514		/* Skip any non-CEA-861 extension blocks */
515		if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
516			continue;
517
518		/* search Vendor Specific Data Block (tag 3) */
519		d = edid[offset + 2] & 0x7f;
520		/* Check if there are Data Blocks */
521		if (d <= 4)
522			continue;
523		if (d > 4) {
524			unsigned int i = offset + 4;
525			unsigned int end = offset + d;
526
527			/* Note: 'end' is always < 'size' */
528			do {
529				u8 tag = edid[i] >> 5;
530				u8 len = edid[i] & 0x1f;
531
532				if (tag == 3 && len >= 5 && i + len <= end &&
533				    edid[i + 1] == 0x03 &&
534				    edid[i + 2] == 0x0c &&
535				    edid[i + 3] == 0x00)
536					return i + 4;
537				i += len + 1;
538			} while (i < end);
539		}
540	}
541	return 0;
542}
543
544#endif /* _MEDIA_CEC_H */