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 #include <media/cec-notifier.h>
  21
  22 #define CEC_CAP_DEFAULTS (CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT | \
  23                           CEC_CAP_PASSTHROUGH | CEC_CAP_RC)
  24
  25 /**
  26  * struct cec_devnode - cec device node
  27  * @dev:        cec device
  28  * @cdev:       cec character device
  29  * @minor:      device node minor number
  30  * @registered: the device was correctly registered
  31  * @unregistered: the device was unregistered
  32  * @fhs_lock:   lock to control access to the filehandle list
  33  * @fhs:        the list of open filehandles (cec_fh)
  34  *
  35  * This structure represents a cec-related device node.
  36  *
  37  * The @parent is a physical device. It must be set by core or device drivers
  38  * before registering the node.
  39  */
  40 struct cec_devnode {
  41         /* sysfs */
  42         struct device dev;
  43         struct cdev cdev;
  44
  45         /* device info */
  46         int minor;
  47         bool registered;
  48         bool unregistered;
  49         struct list_head fhs;
  50         struct mutex lock;
  51 };
  52
  53 struct cec_adapter;
  54 struct cec_data;
  55 struct cec_pin;
  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 struct cec_adapter {
 148         struct module *owner;
 149         char name[32];
 150         struct cec_devnode devnode;
 151         struct mutex lock;
 152         struct rc_dev *rc;
 153
 154         struct list_head transmit_queue;
 155         unsigned int transmit_queue_sz;
 156         struct list_head wait_queue;
 157         struct cec_data *transmitting;
 158         bool transmit_in_progress;
 159
 160         struct task_struct *kthread_config;
 161         struct completion config_completion;
 162
 163         struct task_struct *kthread;
 164         wait_queue_head_t kthread_waitq;
 165         wait_queue_head_t waitq;
 166
 167         const struct cec_adap_ops *ops;
 168         void *priv;
 169         u32 capabilities;
 170         u8 available_log_addrs;
 171
 172         u16 phys_addr;
 173         bool needs_hpd;
 174         bool is_configuring;
 175         bool is_configured;
 176         bool cec_pin_is_high;
 177         u8 last_initiator;
 178         u32 monitor_all_cnt;
 179         u32 monitor_pin_cnt;
 180         u32 follower_cnt;
 181         struct cec_fh *cec_follower;
 182         struct cec_fh *cec_initiator;
 183         bool passthrough;
 184         struct cec_log_addrs log_addrs;
 185
 186         u32 tx_timeouts;
 187
 188 #ifdef CONFIG_CEC_NOTIFIER
 189         struct cec_notifier *notifier;
 190 #endif
 191 #ifdef CONFIG_CEC_PIN
 192         struct cec_pin *pin;
 193 #endif
 194
 195         struct dentry *cec_dir;
 196         struct dentry *status_file;
 197         struct dentry *error_inj_file;
 198
 199         u16 phys_addrs[15];
 200         u32 sequence;
 201
 202         char input_phys[32];
 203 };
 204
 205 static inline void *cec_get_drvdata(const struct cec_adapter *adap)
 206 {
 207         return adap->priv;
 208 }
 209
 210 static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
 211 {
 212         return adap->log_addrs.log_addr_mask & (1 << log_addr);
 213 }
 214
 215 static inline bool cec_is_sink(const struct cec_adapter *adap)
 216 {
 217         return adap->phys_addr == 0;
 218 }
 219
 220 /**
 221  * cec_is_registered() - is the CEC adapter registered?
 222  *
 223  * @adap:       the CEC adapter, may be NULL.
 224  *
 225  * Return: true if the adapter is registered, false otherwise.
 226  */
 227 static inline bool cec_is_registered(const struct cec_adapter *adap)
 228 {
 229         return adap && adap->devnode.registered;
 230 }
 231
 232 #define cec_phys_addr_exp(pa) \
 233         ((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf
 234
 235 struct edid;
 236
 237 #if IS_REACHABLE(CONFIG_CEC_CORE)
 238 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
 239                 void *priv, const char *name, u32 caps, u8 available_las);
 240 int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
 241 void cec_unregister_adapter(struct cec_adapter *adap);
 242 void cec_delete_adapter(struct cec_adapter *adap);
 243
 244 int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
 245                     bool block);
 246 void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 247                      bool block);
 248 void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
 249                                const struct edid *edid);
 250 int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
 251                      bool block);
 252
 253 /* Called by the adapter */
 254 void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
 255                           u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
 256                           u8 error_cnt, ktime_t ts);
 257
 258 static inline void cec_transmit_done(struct cec_adapter *adap, u8 status,
 259                                      u8 arb_lost_cnt, u8 nack_cnt,
 260                                      u8 low_drive_cnt, u8 error_cnt)
 261 {
 262         cec_transmit_done_ts(adap, status, arb_lost_cnt, nack_cnt,
 263                              low_drive_cnt, error_cnt, ktime_get());
 264 }
 265 /*
 266  * Simplified version of cec_transmit_done for hardware that doesn't retry
 267  * failed transmits. So this is always just one attempt in which case
 268  * the status is sufficient.
 269  */
 270 void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
 271                                   u8 status, ktime_t ts);
 272
 273 static inline void cec_transmit_attempt_done(struct cec_adapter *adap,
 274                                              u8 status)
 275 {
 276         cec_transmit_attempt_done_ts(adap, status, ktime_get());
 277 }
 278
 279 void cec_received_msg_ts(struct cec_adapter *adap,
 280                          struct cec_msg *msg, ktime_t ts);
 281
 282 static inline void cec_received_msg(struct cec_adapter *adap,
 283                                     struct cec_msg *msg)
 284 {
 285         cec_received_msg_ts(adap, msg, ktime_get());
 286 }
 287
 288 /**
 289  * cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp.
 290  *
 291  * @adap:       pointer to the cec adapter
 292  * @is_high:    when true the CEC pin is high, otherwise it is low
 293  * @dropped_events: when true some events were dropped
 294  * @ts:         the timestamp for this event
 295  *
 296  */
 297 void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high,
 298                              bool dropped_events, ktime_t ts);
 299
 300 /**
 301  * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
 302  *
 303  * @adap:       pointer to the cec adapter
 304  * @is_high:    when true the HPD pin is high, otherwise it is low
 305  * @ts:         the timestamp for this event
 306  *
 307  */
 308 void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
 309
 310 /**
 311  * cec_queue_pin_5v_event() - queue a pin event with a given timestamp.
 312  *
 313  * @adap:       pointer to the cec adapter
 314  * @is_high:    when true the 5V pin is high, otherwise it is low
 315  * @ts:         the timestamp for this event
 316  *
 317  */
 318 void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
 319
 320 /**
 321  * cec_get_edid_phys_addr() - find and return the physical address
 322  *
 323  * @edid:       pointer to the EDID data
 324  * @size:       size in bytes of the EDID data
 325  * @offset:     If not %NULL then the location of the physical address
 326  *              bytes in the EDID will be returned here. This is set to 0
 327  *              if there is no physical address found.
 328  *
 329  * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
 330  */
 331 u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
 332                            unsigned int *offset);
 333
 334 #else
 335
 336 static inline int cec_register_adapter(struct cec_adapter *adap,
 337                                        struct device *parent)
 338 {
 339         return 0;
 340 }
 341
 342 static inline void cec_unregister_adapter(struct cec_adapter *adap)
 343 {
 344 }
 345
 346 static inline void cec_delete_adapter(struct cec_adapter *adap)
 347 {
 348 }
 349
 350 static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 351                                    bool block)
 352 {
 353 }
 354
 355 static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
 356                                              const struct edid *edid)
 357 {
 358 }
 359
 360 static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
 361                                          unsigned int *offset)
 362 {
 363         if (offset)
 364                 *offset = 0;
 365         return CEC_PHYS_ADDR_INVALID;
 366 }
 367
 368 #endif
 369
 370 /**
 371  * cec_phys_addr_invalidate() - set the physical address to INVALID
 372  *
 373  * @adap:       the CEC adapter
 374  *
 375  * This is a simple helper function to invalidate the physical
 376  * address.
 377  */
 378 static inline void cec_phys_addr_invalidate(struct cec_adapter *adap)
 379 {
 380         cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
 381 }
 382
 383 /**
 384  * cec_get_edid_spa_location() - find location of the Source Physical Address
 385  *
 386  * @edid: the EDID
 387  * @size: the size of the EDID
 388  *
 389  * This EDID is expected to be a CEA-861 compliant, which means that there are
 390  * at least two blocks and one or more of the extensions blocks are CEA-861
 391  * blocks.
 392  *
 393  * The returned location is guaranteed to be <= size-2.
 394  *
 395  * This is an inline function since it is used by both CEC and V4L2.
 396  * Ideally this would go in a module shared by both, but it is overkill to do
 397  * that for just a single function.
 398  */
 399 static inline unsigned int cec_get_edid_spa_location(const u8 *edid,
 400                                                      unsigned int size)
 401 {
 402         unsigned int blocks = size / 128;
 403         unsigned int block;
 404         u8 d;
 405
 406         /* Sanity check: at least 2 blocks and a multiple of the block size */
 407         if (blocks < 2 || size % 128)
 408                 return 0;
 409
 410         /*
 411          * If there are fewer extension blocks than the size, then update
 412          * 'blocks'. It is allowed to have more extension blocks than the size,
 413          * since some hardware can only read e.g. 256 bytes of the EDID, even
 414          * though more blocks are present. The first CEA-861 extension block
 415          * should normally be in block 1 anyway.
 416          */
 417         if (edid[0x7e] + 1 < blocks)
 418                 blocks = edid[0x7e] + 1;
 419
 420         for (block = 1; block < blocks; block++) {
 421                 unsigned int offset = block * 128;
 422
 423                 /* Skip any non-CEA-861 extension blocks */
 424                 if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
 425                         continue;
 426
 427                 /* search Vendor Specific Data Block (tag 3) */
 428                 d = edid[offset + 2] & 0x7f;
 429                 /* Check if there are Data Blocks */
 430                 if (d <= 4)
 431                         continue;
 432                 if (d > 4) {
 433                         unsigned int i = offset + 4;
 434                         unsigned int end = offset + d;
 435
 436                         /* Note: 'end' is always < 'size' */
 437                         do {
 438                                 u8 tag = edid[i] >> 5;
 439                                 u8 len = edid[i] & 0x1f;
 440
 441                                 if (tag == 3 && len >= 5 && i + len <= end &&
 442                                     edid[i + 1] == 0x03 &&
 443                                     edid[i + 2] == 0x0c &&
 444                                     edid[i + 3] == 0x00)
 445                                         return i + 4;
 446                                 i += len + 1;
 447                         } while (i < end);
 448                 }
 449         }
 450         return 0;
 451 }
 452
 453 #endif /* _MEDIA_CEC_H */