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ab15d248 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
a56960e8 HV |
2 | /* |
3 | * cec - HDMI Consumer Electronics Control support header | |
4 | * | |
5 | * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved. | |
a56960e8 HV |
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> | |
32a847f9 | 20 | |
ee0c503e HV |
21 | #define CEC_CAP_DEFAULTS (CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT | \ |
22 | CEC_CAP_PASSTHROUGH | CEC_CAP_RC) | |
23 | ||
a56960e8 HV |
24 | /** |
25 | * struct cec_devnode - cec device node | |
26 | * @dev: cec device | |
27 | * @cdev: cec character device | |
a56960e8 | 28 | * @minor: device node minor number |
a9e61076 | 29 | * @lock: lock to serialize open/release and registration |
a56960e8 HV |
30 | * @registered: the device was correctly registered |
31 | * @unregistered: the device was unregistered | |
a9e61076 | 32 | * @lock_fhs: lock to control access to @fhs |
a56960e8 HV |
33 | * @fhs: the list of open filehandles (cec_fh) |
34 | * | |
35 | * This structure represents a cec-related device node. | |
36 | * | |
a9e61076 HV |
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 | * | |
a56960e8 HV |
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; | |
a56960e8 HV |
47 | |
48 | /* device info */ | |
49 | int minor; | |
a9e61076 HV |
50 | /* serialize open/release and registration */ |
51 | struct mutex lock; | |
a56960e8 HV |
52 | bool registered; |
53 | bool unregistered; | |
a9e61076 HV |
54 | /* protect access to fhs */ |
55 | struct mutex lock_fhs; | |
a56960e8 HV |
56 | struct list_head fhs; |
57 | }; | |
58 | ||
59 | struct cec_adapter; | |
60 | struct cec_data; | |
ea5c8ef2 | 61 | struct cec_pin; |
32a847f9 | 62 | struct cec_notifier; |
a56960e8 HV |
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; | |
a56960e8 HV |
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 | ||
6b2bbb08 HV |
82 | struct cec_event_entry { |
83 | struct list_head list; | |
84 | struct cec_event ev; | |
85 | }; | |
86 | ||
87 | #define CEC_NUM_CORE_EVENTS 2 | |
4786b0d6 | 88 | #define CEC_NUM_EVENTS CEC_EVENT_PIN_5V_HIGH |
a56960e8 HV |
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; | |
a56960e8 | 99 | struct mutex lock; |
6b2bbb08 | 100 | struct list_head events[CEC_NUM_EVENTS]; /* queued events */ |
6ec1cbf6 | 101 | u16 queued_events[CEC_NUM_EVENTS]; |
6b2bbb08 HV |
102 | unsigned int total_queued_events; |
103 | struct cec_event_entry core_events[CEC_NUM_CORE_EVENTS]; | |
a56960e8 HV |
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); | |
48ea2e92 | 119 | int (*adap_monitor_pin_enable)(struct cec_adapter *adap, bool enable); |
a56960e8 | 120 | int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr); |
f1b57164 | 121 | void (*adap_configured)(struct cec_adapter *adap, bool configured); |
a56960e8 HV |
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); | |
e6259b5f | 125 | void (*adap_free)(struct cec_adapter *adap); |
a56960e8 | 126 | |
9ca400c1 HV |
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 | ||
a56960e8 HV |
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 | * | |
11065f85 HV |
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. | |
a56960e8 | 144 | */ |
11065f85 HV |
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) | |
a56960e8 | 154 | |
e233f81c HV |
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 | |
590a8e56 HV |
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. | |
dad272bd HV |
172 | * @xfer_timeout_ms: the transfer timeout in ms. |
173 | * If 0, then timeout after 2.1 ms. | |
e233f81c HV |
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. | |
f9222f8c | 186 | * @is_enabled: the CEC adapter is enabled |
e233f81c | 187 | * @is_configuring: the CEC adapter is configuring (i.e. claiming LAs) |
e3891b36 | 188 | * @must_reconfigure: while configuring, the PA changed, so reclaim LAs |
e233f81c HV |
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. | |
98f803cf JC |
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. | |
e233f81c HV |
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 | */ | |
a56960e8 HV |
218 | struct 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; | |
11065f85 | 226 | unsigned int transmit_queue_sz; |
a56960e8 HV |
227 | struct list_head wait_queue; |
228 | struct cec_data *transmitting; | |
32804fcb | 229 | bool transmit_in_progress; |
590a8e56 | 230 | bool transmit_in_progress_aborted; |
dad272bd | 231 | unsigned int xfer_timeout_ms; |
a56960e8 HV |
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; | |
a56960e8 HV |
238 | |
239 | const struct cec_adap_ops *ops; | |
240 | void *priv; | |
241 | u32 capabilities; | |
242 | u8 available_log_addrs; | |
243 | ||
244 | u16 phys_addr; | |
f902c1e9 | 245 | bool needs_hpd; |
f9222f8c | 246 | bool is_enabled; |
a56960e8 | 247 | bool is_configuring; |
e3891b36 | 248 | bool must_reconfigure; |
a56960e8 | 249 | bool is_configured; |
28e11b15 | 250 | bool cec_pin_is_high; |
98f803cf | 251 | bool adap_controls_phys_addr; |
7d867a1b | 252 | u8 last_initiator; |
a56960e8 | 253 | u32 monitor_all_cnt; |
b8d62f50 | 254 | u32 monitor_pin_cnt; |
a56960e8 HV |
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; | |
32a847f9 | 260 | struct cec_connector_info conn_info; |
a56960e8 | 261 | |
bb789e03 HV |
262 | u32 tx_timeouts; |
263 | ||
e94c3281 | 264 | #ifdef CONFIG_CEC_NOTIFIER |
e3a93adc HV |
265 | struct cec_notifier *notifier; |
266 | #endif | |
ea5c8ef2 HV |
267 | #ifdef CONFIG_CEC_PIN |
268 | struct cec_pin *pin; | |
269 | #endif | |
e3a93adc | 270 | |
a56960e8 | 271 | struct dentry *cec_dir; |
a56960e8 | 272 | |
a56960e8 HV |
273 | u32 sequence; |
274 | ||
a56960e8 | 275 | char input_phys[32]; |
a56960e8 HV |
276 | }; |
277 | ||
0b0b97dc JA |
278 | static inline void *cec_get_drvdata(const struct cec_adapter *adap) |
279 | { | |
280 | return adap->priv; | |
281 | } | |
282 | ||
a56960e8 HV |
283 | static 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 | ||
288 | static inline bool cec_is_sink(const struct cec_adapter *adap) | |
289 | { | |
290 | return adap->phys_addr == 0; | |
291 | } | |
292 | ||
c8959a39 HV |
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 | */ | |
300 | static inline bool cec_is_registered(const struct cec_adapter *adap) | |
301 | { | |
302 | return adap && adap->devnode.registered; | |
303 | } | |
304 | ||
ee7e9871 HV |
305 | #define cec_phys_addr_exp(pa) \ |
306 | ((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf | |
307 | ||
23111ec3 | 308 | struct edid; |
32a847f9 | 309 | struct drm_connector; |
23111ec3 | 310 | |
f9f314f3 | 311 | #if IS_REACHABLE(CONFIG_CEC_CORE) |
a56960e8 | 312 | struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops, |
f51e8080 HV |
313 | void *priv, const char *name, u32 caps, u8 available_las); |
314 | int cec_register_adapter(struct cec_adapter *adap, struct device *parent); | |
a56960e8 HV |
315 | void cec_unregister_adapter(struct cec_adapter *adap); |
316 | void cec_delete_adapter(struct cec_adapter *adap); | |
317 | ||
318 | int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs, | |
319 | bool block); | |
320 | void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr, | |
321 | bool block); | |
23111ec3 HV |
322 | void cec_s_phys_addr_from_edid(struct cec_adapter *adap, |
323 | const struct edid *edid); | |
32a847f9 DM |
324 | void cec_s_conn_info(struct cec_adapter *adap, |
325 | const struct cec_connector_info *conn_info); | |
a56960e8 HV |
326 | int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg, |
327 | bool block); | |
328 | ||
329 | /* Called by the adapter */ | |
0861ad14 HV |
330 | void 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 | ||
334 | static 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 | } | |
c94cdc1e HV |
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 | */ | |
0861ad14 HV |
346 | void cec_transmit_attempt_done_ts(struct cec_adapter *adap, |
347 | u8 status, ktime_t ts); | |
348 | ||
349 | static 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 | ||
355 | void cec_received_msg_ts(struct cec_adapter *adap, | |
356 | struct cec_msg *msg, ktime_t ts); | |
357 | ||
358 | static 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 | } | |
a56960e8 | 363 | |
b8d62f50 | 364 | /** |
9a6b2a87 | 365 | * cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp. |
b8d62f50 HV |
366 | * |
367 | * @adap: pointer to the cec adapter | |
9a6b2a87 | 368 | * @is_high: when true the CEC pin is high, otherwise it is low |
6ec1cbf6 | 369 | * @dropped_events: when true some events were dropped |
b8d62f50 HV |
370 | * @ts: the timestamp for this event |
371 | * | |
372 | */ | |
6ec1cbf6 HV |
373 | void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high, |
374 | bool dropped_events, ktime_t ts); | |
b8d62f50 | 375 | |
333ef6bd HV |
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 | */ | |
384 | void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts); | |
385 | ||
4786b0d6 HV |
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 | */ | |
394 | void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts); | |
395 | ||
ee7e9871 HV |
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 | */ | |
407 | u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size, | |
408 | unsigned int *offset); | |
409 | ||
32a847f9 DM |
410 | void cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info, |
411 | const struct drm_connector *connector); | |
412 | ||
a56960e8 HV |
413 | #else |
414 | ||
f51e8080 HV |
415 | static inline int cec_register_adapter(struct cec_adapter *adap, |
416 | struct device *parent) | |
a56960e8 HV |
417 | { |
418 | return 0; | |
419 | } | |
420 | ||
421 | static inline void cec_unregister_adapter(struct cec_adapter *adap) | |
422 | { | |
423 | } | |
424 | ||
425 | static inline void cec_delete_adapter(struct cec_adapter *adap) | |
426 | { | |
427 | } | |
428 | ||
429 | static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr, | |
430 | bool block) | |
431 | { | |
432 | } | |
433 | ||
23111ec3 HV |
434 | static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap, |
435 | const struct edid *edid) | |
436 | { | |
437 | } | |
438 | ||
ee7e9871 HV |
439 | static 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 | ||
32a847f9 DM |
447 | static inline void cec_s_conn_info(struct cec_adapter *adap, |
448 | const struct cec_connector_info *conn_info) | |
449 | { | |
450 | } | |
451 | ||
452 | static inline void | |
453 | cec_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 | ||
13532789 HV |
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 | */ | |
469 | static inline void cec_phys_addr_invalidate(struct cec_adapter *adap) | |
470 | { | |
471 | cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false); | |
472 | } | |
473 | ||
b915bf57 HV |
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 | */ | |
490 | static 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 | ||
a56960e8 | 544 | #endif /* _MEDIA_CEC_H */ |