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