include/media/cec.h

   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  * @registered: the device was correctly registered
  30  * @unregistered: the device was unregistered
  31  * @fhs_lock:   lock to control access to the filehandle list
  32  * @fhs:        the list of open filehandles (cec_fh)
  33  *
  34  * This structure represents a cec-related device node.
  35  *
  36  * The @parent is a physical device. It must be set by core or device drivers
  37  * before registering the node.
  38  */
  39 struct cec_devnode {
  40         /* sysfs */
  41         struct device dev;
  42         struct cdev cdev;
  43
  44         /* device info */
  45         int minor;
  46         bool registered;
  47         bool unregistered;
  48         struct list_head fhs;
  49         struct mutex lock;
  50 };
  51
  52 struct cec_adapter;
  53 struct cec_data;
  54 struct cec_pin;
  55 struct cec_notifier;
  56
  57 struct cec_data {
  58         struct list_head list;
  59         struct list_head xfer_list;
  60         struct cec_adapter *adap;
  61         struct cec_msg msg;
  62         struct cec_fh *fh;
  63         struct delayed_work work;
  64         struct completion c;
  65         u8 attempts;
  66         bool blocking;
  67         bool completed;
  68 };
  69
  70 struct cec_msg_entry {
  71         struct list_head        list;
  72         struct cec_msg          msg;
  73 };
  74
  75 struct cec_event_entry {
  76         struct list_head        list;
  77         struct cec_event        ev;
  78 };
  79
  80 #define CEC_NUM_CORE_EVENTS 2
  81 #define CEC_NUM_EVENTS CEC_EVENT_PIN_5V_HIGH
  82
  83 struct cec_fh {
  84         struct list_head        list;
  85         struct list_head        xfer_list;
  86         struct cec_adapter      *adap;
  87         u8                      mode_initiator;
  88         u8                      mode_follower;
  89
  90         /* Events */
  91         wait_queue_head_t       wait;
  92         struct mutex            lock;
  93         struct list_head        events[CEC_NUM_EVENTS]; /* queued events */
  94         u16                     queued_events[CEC_NUM_EVENTS];
  95         unsigned int            total_queued_events;
  96         struct cec_event_entry  core_events[CEC_NUM_CORE_EVENTS];
  97         struct list_head        msgs; /* queued messages */
  98         unsigned int            queued_msgs;
  99 };
 100
 101 #define CEC_SIGNAL_FREE_TIME_RETRY              3
 102 #define CEC_SIGNAL_FREE_TIME_NEW_INITIATOR      5
 103 #define CEC_SIGNAL_FREE_TIME_NEXT_XFER          7
 104
 105 /* The nominal data bit period is 2.4 ms */
 106 #define CEC_FREE_TIME_TO_USEC(ft)               ((ft) * 2400)
 107
 108 struct cec_adap_ops {
 109         /* Low-level callbacks */
 110         int (*adap_enable)(struct cec_adapter *adap, bool enable);
 111         int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
 112         int (*adap_monitor_pin_enable)(struct cec_adapter *adap, bool enable);
 113         int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
 114         int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
 115                              u32 signal_free_time, struct cec_msg *msg);
 116         void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
 117         void (*adap_free)(struct cec_adapter *adap);
 118
 119         /* Error injection callbacks */
 120         int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
 121         bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);
 122
 123         /* High-level CEC message callback */
 124         int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
 125 };
 126
 127 /*
 128  * The minimum message length you can receive (excepting poll messages) is 2.
 129  * With a transfer rate of at most 36 bytes per second this makes 18 messages
 130  * per second worst case.
 131  *
 132  * We queue at most 3 seconds worth of received messages. The CEC specification
 133  * requires that messages are replied to within a second, so 3 seconds should
 134  * give more than enough margin. Since most messages are actually more than 2
 135  * bytes, this is in practice a lot more than 3 seconds.
 136  */
 137 #define CEC_MAX_MSG_RX_QUEUE_SZ         (18 * 3)
 138
 139 /*
 140  * The transmit queue is limited to 1 second worth of messages (worst case).
 141  * Messages can be transmitted by userspace and kernel space. But for both it
 142  * makes no sense to have a lot of messages queued up. One second seems
 143  * reasonable.
 144  */
 145 #define CEC_MAX_MSG_TX_QUEUE_SZ         (18 * 1)
 146
 147 /**
 148  * struct cec_adapter - cec adapter structure
 149  * @owner:              module owner
 150  * @name:               name of the CEC adapter
 151  * @devnode:            device node for the /dev/cecX device
 152  * @lock:               mutex controlling access to this structure
 153  * @rc:                 remote control device
 154  * @transmit_queue:     queue of pending transmits
 155  * @transmit_queue_sz:  number of pending transmits
 156  * @wait_queue:         queue of transmits waiting for a reply
 157  * @transmitting:       CEC messages currently being transmitted
 158  * @transmit_in_progress: true if a transmit is in progress
 159  * @kthread_config:     kthread used to configure a CEC adapter
 160  * @config_completion:  used to signal completion of the config kthread
 161  * @kthread:            main CEC processing thread
 162  * @kthread_waitq:      main CEC processing wait_queue
 163  * @ops:                cec adapter ops
 164  * @priv:               cec driver's private data
 165  * @capabilities:       cec adapter capabilities
 166  * @available_log_addrs: maximum number of available logical addresses
 167  * @phys_addr:          the current physical address
 168  * @needs_hpd:          if true, then the HDMI HotPlug Detect pin must be high
 169  *      in order to transmit or receive CEC messages. This is usually a HW
 170  *      limitation.
 171  * @is_configuring:     the CEC adapter is configuring (i.e. claiming LAs)
 172  * @is_configured:      the CEC adapter is configured (i.e. has claimed LAs)
 173  * @cec_pin_is_high:    if true then the CEC pin is high. Only used with the
 174  *      CEC pin framework.
 175  * @adap_controls_phys_addr: if true, then the CEC adapter controls the
 176  *      physical address, i.e. the CEC hardware can detect HPD changes and
 177  *      read the EDID and is not dependent on an external HDMI driver.
 178  *      Drivers that need this can set this field to true after the
 179  *      cec_allocate_adapter() call.
 180  * @last_initiator:     the initiator of the last transmitted message.
 181  * @monitor_all_cnt:    number of filehandles monitoring all msgs
 182  * @monitor_pin_cnt:    number of filehandles monitoring pin changes
 183  * @follower_cnt:       number of filehandles in follower mode
 184  * @cec_follower:       filehandle of the exclusive follower
 185  * @cec_initiator:      filehandle of the exclusive initiator
 186  * @passthrough:        if true, then the exclusive follower is in
 187  *      passthrough mode.
 188  * @log_addrs:          current logical addresses
 189  * @conn_info:          current connector info
 190  * @tx_timeouts:        number of transmit timeouts
 191  * @notifier:           CEC notifier
 192  * @pin:                CEC pin status struct
 193  * @cec_dir:            debugfs cec directory
 194  * @status_file:        debugfs cec status file
 195  * @error_inj_file:     debugfs cec error injection file
 196  * @sequence:           transmit sequence counter
 197  * @input_phys:         remote control input_phys name
 198  *
 199  * This structure represents a cec adapter.
 200  */
 201 struct cec_adapter {
 202         struct module *owner;
 203         char name[32];
 204         struct cec_devnode devnode;
 205         struct mutex lock;
 206         struct rc_dev *rc;
 207
 208         struct list_head transmit_queue;
 209         unsigned int transmit_queue_sz;
 210         struct list_head wait_queue;
 211         struct cec_data *transmitting;
 212         bool transmit_in_progress;
 213
 214         struct task_struct *kthread_config;
 215         struct completion config_completion;
 216
 217         struct task_struct *kthread;
 218         wait_queue_head_t kthread_waitq;
 219
 220         const struct cec_adap_ops *ops;
 221         void *priv;
 222         u32 capabilities;
 223         u8 available_log_addrs;
 224
 225         u16 phys_addr;
 226         bool needs_hpd;
 227         bool is_configuring;
 228         bool is_configured;
 229         bool cec_pin_is_high;
 230         bool adap_controls_phys_addr;
 231         u8 last_initiator;
 232         u32 monitor_all_cnt;
 233         u32 monitor_pin_cnt;
 234         u32 follower_cnt;
 235         struct cec_fh *cec_follower;
 236         struct cec_fh *cec_initiator;
 237         bool passthrough;
 238         struct cec_log_addrs log_addrs;
 239         struct cec_connector_info conn_info;
 240
 241         u32 tx_timeouts;
 242
 243 #ifdef CONFIG_CEC_NOTIFIER
 244         struct cec_notifier *notifier;
 245 #endif
 246 #ifdef CONFIG_CEC_PIN
 247         struct cec_pin *pin;
 248 #endif
 249
 250         struct dentry *cec_dir;
 251
 252         u32 sequence;
 253
 254         char input_phys[32];
 255 };
 256
 257 static inline void *cec_get_drvdata(const struct cec_adapter *adap)
 258 {
 259         return adap->priv;
 260 }
 261
 262 static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
 263 {
 264         return adap->log_addrs.log_addr_mask & (1 << log_addr);
 265 }
 266
 267 static inline bool cec_is_sink(const struct cec_adapter *adap)
 268 {
 269         return adap->phys_addr == 0;
 270 }
 271
 272 /**
 273  * cec_is_registered() - is the CEC adapter registered?
 274  *
 275  * @adap:       the CEC adapter, may be NULL.
 276  *
 277  * Return: true if the adapter is registered, false otherwise.
 278  */
 279 static inline bool cec_is_registered(const struct cec_adapter *adap)
 280 {
 281         return adap && adap->devnode.registered;
 282 }
 283
 284 #define cec_phys_addr_exp(pa) \
 285         ((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf
 286
 287 struct edid;
 288 struct drm_connector;
 289
 290 #if IS_REACHABLE(CONFIG_CEC_CORE)
 291 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
 292                 void *priv, const char *name, u32 caps, u8 available_las);
 293 int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
 294 void cec_unregister_adapter(struct cec_adapter *adap);
 295 void cec_delete_adapter(struct cec_adapter *adap);
 296
 297 int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
 298                     bool block);
 299 void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 300                      bool block);
 301 void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
 302                                const struct edid *edid);
 303 void cec_s_conn_info(struct cec_adapter *adap,
 304                      const struct cec_connector_info *conn_info);
 305 int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
 306                      bool block);
 307
 308 /* Called by the adapter */
 309 void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
 310                           u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
 311                           u8 error_cnt, ktime_t ts);
 312
 313 static inline void cec_transmit_done(struct cec_adapter *adap, u8 status,
 314                                      u8 arb_lost_cnt, u8 nack_cnt,
 315                                      u8 low_drive_cnt, u8 error_cnt)
 316 {
 317         cec_transmit_done_ts(adap, status, arb_lost_cnt, nack_cnt,
 318                              low_drive_cnt, error_cnt, ktime_get());
 319 }
 320 /*
 321  * Simplified version of cec_transmit_done for hardware that doesn't retry
 322  * failed transmits. So this is always just one attempt in which case
 323  * the status is sufficient.
 324  */
 325 void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
 326                                   u8 status, ktime_t ts);
 327
 328 static inline void cec_transmit_attempt_done(struct cec_adapter *adap,
 329                                              u8 status)
 330 {
 331         cec_transmit_attempt_done_ts(adap, status, ktime_get());
 332 }
 333
 334 void cec_received_msg_ts(struct cec_adapter *adap,
 335                          struct cec_msg *msg, ktime_t ts);
 336
 337 static inline void cec_received_msg(struct cec_adapter *adap,
 338                                     struct cec_msg *msg)
 339 {
 340         cec_received_msg_ts(adap, msg, ktime_get());
 341 }
 342
 343 /**
 344  * cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp.
 345  *
 346  * @adap:       pointer to the cec adapter
 347  * @is_high:    when true the CEC pin is high, otherwise it is low
 348  * @dropped_events: when true some events were dropped
 349  * @ts:         the timestamp for this event
 350  *
 351  */
 352 void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high,
 353                              bool dropped_events, ktime_t ts);
 354
 355 /**
 356  * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
 357  *
 358  * @adap:       pointer to the cec adapter
 359  * @is_high:    when true the HPD pin is high, otherwise it is low
 360  * @ts:         the timestamp for this event
 361  *
 362  */
 363 void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
 364
 365 /**
 366  * cec_queue_pin_5v_event() - queue a pin event with a given timestamp.
 367  *
 368  * @adap:       pointer to the cec adapter
 369  * @is_high:    when true the 5V pin is high, otherwise it is low
 370  * @ts:         the timestamp for this event
 371  *
 372  */
 373 void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
 374
 375 /**
 376  * cec_get_edid_phys_addr() - find and return the physical address
 377  *
 378  * @edid:       pointer to the EDID data
 379  * @size:       size in bytes of the EDID data
 380  * @offset:     If not %NULL then the location of the physical address
 381  *              bytes in the EDID will be returned here. This is set to 0
 382  *              if there is no physical address found.
 383  *
 384  * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
 385  */
 386 u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
 387                            unsigned int *offset);
 388
 389 void cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
 390                                  const struct drm_connector *connector);
 391
 392 #else
 393
 394 static inline int cec_register_adapter(struct cec_adapter *adap,
 395                                        struct device *parent)
 396 {
 397         return 0;
 398 }
 399
 400 static inline void cec_unregister_adapter(struct cec_adapter *adap)
 401 {
 402 }
 403
 404 static inline void cec_delete_adapter(struct cec_adapter *adap)
 405 {
 406 }
 407
 408 static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 409                                    bool block)
 410 {
 411 }
 412
 413 static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
 414                                              const struct edid *edid)
 415 {
 416 }
 417
 418 static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
 419                                          unsigned int *offset)
 420 {
 421         if (offset)
 422                 *offset = 0;
 423         return CEC_PHYS_ADDR_INVALID;
 424 }
 425
 426 static inline void cec_s_conn_info(struct cec_adapter *adap,
 427                                    const struct cec_connector_info *conn_info)
 428 {
 429 }
 430
 431 static inline void
 432 cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
 433                             const struct drm_connector *connector)
 434 {
 435         memset(conn_info, 0, sizeof(*conn_info));
 436 }
 437
 438 #endif
 439
 440 /**
 441  * cec_phys_addr_invalidate() - set the physical address to INVALID
 442  *
 443  * @adap:       the CEC adapter
 444  *
 445  * This is a simple helper function to invalidate the physical
 446  * address.
 447  */
 448 static inline void cec_phys_addr_invalidate(struct cec_adapter *adap)
 449 {
 450         cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
 451 }
 452
 453 /**
 454  * cec_get_edid_spa_location() - find location of the Source Physical Address
 455  *
 456  * @edid: the EDID
 457  * @size: the size of the EDID
 458  *
 459  * This EDID is expected to be a CEA-861 compliant, which means that there are
 460  * at least two blocks and one or more of the extensions blocks are CEA-861
 461  * blocks.
 462  *
 463  * The returned location is guaranteed to be <= size-2.
 464  *
 465  * This is an inline function since it is used by both CEC and V4L2.
 466  * Ideally this would go in a module shared by both, but it is overkill to do
 467  * that for just a single function.
 468  */
 469 static inline unsigned int cec_get_edid_spa_location(const u8 *edid,
 470                                                      unsigned int size)
 471 {
 472         unsigned int blocks = size / 128;
 473         unsigned int block;
 474         u8 d;
 475
 476         /* Sanity check: at least 2 blocks and a multiple of the block size */
 477         if (blocks < 2 || size % 128)
 478                 return 0;
 479
 480         /*
 481          * If there are fewer extension blocks than the size, then update
 482          * 'blocks'. It is allowed to have more extension blocks than the size,
 483          * since some hardware can only read e.g. 256 bytes of the EDID, even
 484          * though more blocks are present. The first CEA-861 extension block
 485          * should normally be in block 1 anyway.
 486          */
 487         if (edid[0x7e] + 1 < blocks)
 488                 blocks = edid[0x7e] + 1;
 489
 490         for (block = 1; block < blocks; block++) {
 491                 unsigned int offset = block * 128;
 492
 493                 /* Skip any non-CEA-861 extension blocks */
 494                 if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
 495                         continue;
 496
 497                 /* search Vendor Specific Data Block (tag 3) */
 498                 d = edid[offset + 2] & 0x7f;
 499                 /* Check if there are Data Blocks */
 500                 if (d <= 4)
 501                         continue;
 502                 if (d > 4) {
 503                         unsigned int i = offset + 4;
 504                         unsigned int end = offset + d;
 505
 506                         /* Note: 'end' is always < 'size' */
 507                         do {
 508                                 u8 tag = edid[i] >> 5;
 509                                 u8 len = edid[i] & 0x1f;
 510
 511                                 if (tag == 3 && len >= 5 && i + len <= end &&
 512                                     edid[i + 1] == 0x03 &&
 513                                     edid[i + 2] == 0x0c &&
 514                                     edid[i + 3] == 0x00)
 515                                         return i + 4;
 516                                 i += len + 1;
 517                         } while (i < end);
 518                 }
 519         }
 520         return 0;
 521 }
 522
 523 #endif /* _MEDIA_CEC_H */