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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 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, 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 2.1 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_configuring: the CEC adapter is configuring (i.e. claiming LAs)
191 * @must_reconfigure: while configuring, the PA changed, so reclaim LAs
192 * @is_configured: the CEC adapter is configured (i.e. has claimed LAs)
193 * @cec_pin_is_high: if true then the CEC pin is high. Only used with the
194 * CEC pin framework.
195 * @adap_controls_phys_addr: if true, then the CEC adapter controls the
196 * physical address, i.e. the CEC hardware can detect HPD changes and
197 * read the EDID and is not dependent on an external HDMI driver.
198 * Drivers that need this can set this field to true after the
199 * cec_allocate_adapter() call.
200 * @last_initiator: the initiator of the last transmitted message.
201 * @monitor_all_cnt: number of filehandles monitoring all msgs
202 * @monitor_pin_cnt: number of filehandles monitoring pin changes
203 * @follower_cnt: number of filehandles in follower mode
204 * @cec_follower: filehandle of the exclusive follower
205 * @cec_initiator: filehandle of the exclusive initiator
206 * @passthrough: if true, then the exclusive follower is in
207 * passthrough mode.
208 * @log_addrs: current logical addresses
209 * @conn_info: current connector info
210 * @tx_timeout_cnt: count the number of Timed Out transmits.
211 * Reset to 0 when this is reported in cec_adap_status().
212 * @tx_low_drive_cnt: count the number of Low Drive transmits.
213 * Reset to 0 when this is reported in cec_adap_status().
214 * @tx_error_cnt: count the number of Error transmits.
215 * Reset to 0 when this is reported in cec_adap_status().
216 * @tx_arb_lost_cnt: count the number of Arb Lost transmits.
217 * Reset to 0 when this is reported in cec_adap_status().
218 * @tx_low_drive_log_cnt: number of logged Low Drive transmits since the
219 * adapter was enabled. Used to avoid flooding the kernel
220 * log if this happens a lot.
221 * @tx_error_log_cnt: number of logged Error transmits since the adapter was
222 * enabled. Used to avoid flooding the kernel log if this
223 * happens a lot.
224 * @notifier: CEC notifier
225 * @pin: CEC pin status struct
226 * @cec_dir: debugfs cec directory
227 * @status_file: debugfs cec status file
228 * @error_inj_file: debugfs cec error injection file
229 * @sequence: transmit sequence counter
230 * @input_phys: remote control input_phys name
231 *
232 * This structure represents a cec adapter.
233 */
234struct cec_adapter {
235 struct module *owner;
236 char name[32];
237 struct cec_devnode devnode;
238 struct mutex lock;
239 struct rc_dev *rc;
240
241 struct list_head transmit_queue;
242 unsigned int transmit_queue_sz;
243 struct list_head wait_queue;
244 struct cec_data *transmitting;
245 bool transmit_in_progress;
246 bool transmit_in_progress_aborted;
247 unsigned int xfer_timeout_ms;
248
249 struct task_struct *kthread_config;
250 struct completion config_completion;
251
252 struct task_struct *kthread;
253 wait_queue_head_t kthread_waitq;
254
255 const struct cec_adap_ops *ops;
256 void *priv;
257 u32 capabilities;
258 u8 available_log_addrs;
259
260 u16 phys_addr;
261 bool needs_hpd;
262 bool is_enabled;
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
299static inline void *cec_get_drvdata(const struct cec_adapter *adap)
300{
301 return adap->priv;
302}
303
304static 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
309static 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 */
321static 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
329struct edid;
330struct drm_connector;
331
332#if IS_REACHABLE(CONFIG_CEC_CORE)
333struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
334 void *priv, const char *name, u32 caps, u8 available_las);
335int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
336void cec_unregister_adapter(struct cec_adapter *adap);
337void cec_delete_adapter(struct cec_adapter *adap);
338
339int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
340 bool block);
341void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
342 bool block);
343void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
344 const struct edid *edid);
345void cec_s_conn_info(struct cec_adapter *adap,
346 const struct cec_connector_info *conn_info);
347int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
348 bool block);
349
350/* Called by the adapter */
351void 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
355static 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 */
367void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
368 u8 status, ktime_t ts);
369
370static 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
376void cec_received_msg_ts(struct cec_adapter *adap,
377 struct cec_msg *msg, ktime_t ts);
378
379static 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 */
394void 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 */
405void 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 */
415void 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 */
428u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
429 unsigned int *offset);
430
431void cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
432 const struct drm_connector *connector);
433
434#else
435
436static inline int cec_register_adapter(struct cec_adapter *adap,
437 struct device *parent)
438{
439 return 0;
440}
441
442static inline void cec_unregister_adapter(struct cec_adapter *adap)
443{
444}
445
446static inline void cec_delete_adapter(struct cec_adapter *adap)
447{
448}
449
450static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
451 bool block)
452{
453}
454
455static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
456 const struct edid *edid)
457{
458}
459
460static 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
468static inline void cec_s_conn_info(struct cec_adapter *adap,
469 const struct cec_connector_info *conn_info)
470{
471}
472
473static inline void
474cec_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 */
490static 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 */
511static 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 */