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