linux/drivers/media/cec/core/cec-pin.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
   4 */
   5
   6#include <linux/delay.h>
   7#include <linux/slab.h>
   8#include <linux/sched/types.h>
   9
  10#include <media/cec-pin.h>
  11#include "cec-pin-priv.h"
  12
  13/* All timings are in microseconds */
  14
  15/* start bit timings */
  16#define CEC_TIM_START_BIT_LOW           3700
  17#define CEC_TIM_START_BIT_LOW_MIN       3500
  18#define CEC_TIM_START_BIT_LOW_MAX       3900
  19#define CEC_TIM_START_BIT_TOTAL         4500
  20#define CEC_TIM_START_BIT_TOTAL_MIN     4300
  21#define CEC_TIM_START_BIT_TOTAL_MAX     4700
  22
  23/* data bit timings */
  24#define CEC_TIM_DATA_BIT_0_LOW          1500
  25#define CEC_TIM_DATA_BIT_0_LOW_MIN      1300
  26#define CEC_TIM_DATA_BIT_0_LOW_MAX      1700
  27#define CEC_TIM_DATA_BIT_1_LOW          600
  28#define CEC_TIM_DATA_BIT_1_LOW_MIN      400
  29#define CEC_TIM_DATA_BIT_1_LOW_MAX      800
  30#define CEC_TIM_DATA_BIT_TOTAL          2400
  31#define CEC_TIM_DATA_BIT_TOTAL_MIN      2050
  32#define CEC_TIM_DATA_BIT_TOTAL_MAX      2750
  33/* earliest safe time to sample the bit state */
  34#define CEC_TIM_DATA_BIT_SAMPLE         850
  35/* earliest time the bit is back to 1 (T7 + 50) */
  36#define CEC_TIM_DATA_BIT_HIGH           1750
  37
  38/* when idle, sample once per millisecond */
  39#define CEC_TIM_IDLE_SAMPLE             1000
  40/* when processing the start bit, sample twice per millisecond */
  41#define CEC_TIM_START_BIT_SAMPLE        500
  42/* when polling for a state change, sample once every 50 microseconds */
  43#define CEC_TIM_SAMPLE                  50
  44
  45#define CEC_TIM_LOW_DRIVE_ERROR         (1.5 * CEC_TIM_DATA_BIT_TOTAL)
  46
  47/*
  48 * Total data bit time that is too short/long for a valid bit,
  49 * used for error injection.
  50 */
  51#define CEC_TIM_DATA_BIT_TOTAL_SHORT    1800
  52#define CEC_TIM_DATA_BIT_TOTAL_LONG     2900
  53
  54/*
  55 * Total start bit time that is too short/long for a valid bit,
  56 * used for error injection.
  57 */
  58#define CEC_TIM_START_BIT_TOTAL_SHORT   4100
  59#define CEC_TIM_START_BIT_TOTAL_LONG    5000
  60
  61/* Data bits are 0-7, EOM is bit 8 and ACK is bit 9 */
  62#define EOM_BIT                         8
  63#define ACK_BIT                         9
  64
  65struct cec_state {
  66        const char * const name;
  67        unsigned int usecs;
  68};
  69
  70static const struct cec_state states[CEC_PIN_STATES] = {
  71        { "Off",                   0 },
  72        { "Idle",                  CEC_TIM_IDLE_SAMPLE },
  73        { "Tx Wait",               CEC_TIM_SAMPLE },
  74        { "Tx Wait for High",      CEC_TIM_IDLE_SAMPLE },
  75        { "Tx Start Bit Low",      CEC_TIM_START_BIT_LOW },
  76        { "Tx Start Bit High",     CEC_TIM_START_BIT_TOTAL - CEC_TIM_START_BIT_LOW },
  77        { "Tx Start Bit High Short", CEC_TIM_START_BIT_TOTAL_SHORT - CEC_TIM_START_BIT_LOW },
  78        { "Tx Start Bit High Long", CEC_TIM_START_BIT_TOTAL_LONG - CEC_TIM_START_BIT_LOW },
  79        { "Tx Start Bit Low Custom", 0 },
  80        { "Tx Start Bit High Custom", 0 },
  81        { "Tx Data 0 Low",         CEC_TIM_DATA_BIT_0_LOW },
  82        { "Tx Data 0 High",        CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_0_LOW },
  83        { "Tx Data 0 High Short",  CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_0_LOW },
  84        { "Tx Data 0 High Long",   CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_0_LOW },
  85        { "Tx Data 1 Low",         CEC_TIM_DATA_BIT_1_LOW },
  86        { "Tx Data 1 High",        CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_1_LOW },
  87        { "Tx Data 1 High Short",  CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_1_LOW },
  88        { "Tx Data 1 High Long",   CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_1_LOW },
  89        { "Tx Data 1 High Pre Sample", CEC_TIM_DATA_BIT_SAMPLE - CEC_TIM_DATA_BIT_1_LOW },
  90        { "Tx Data 1 High Post Sample", CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_SAMPLE },
  91        { "Tx Data 1 High Post Sample Short", CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_SAMPLE },
  92        { "Tx Data 1 High Post Sample Long", CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_SAMPLE },
  93        { "Tx Data Bit Low Custom", 0 },
  94        { "Tx Data Bit High Custom", 0 },
  95        { "Tx Pulse Low Custom",   0 },
  96        { "Tx Pulse High Custom",  0 },
  97        { "Tx Low Drive",          CEC_TIM_LOW_DRIVE_ERROR },
  98        { "Rx Start Bit Low",      CEC_TIM_SAMPLE },
  99        { "Rx Start Bit High",     CEC_TIM_SAMPLE },
 100        { "Rx Data Sample",        CEC_TIM_DATA_BIT_SAMPLE },
 101        { "Rx Data Post Sample",   CEC_TIM_DATA_BIT_HIGH - CEC_TIM_DATA_BIT_SAMPLE },
 102        { "Rx Data Wait for Low",  CEC_TIM_SAMPLE },
 103        { "Rx Ack Low",            CEC_TIM_DATA_BIT_0_LOW },
 104        { "Rx Ack Low Post",       CEC_TIM_DATA_BIT_HIGH - CEC_TIM_DATA_BIT_0_LOW },
 105        { "Rx Ack High Post",      CEC_TIM_DATA_BIT_HIGH },
 106        { "Rx Ack Finish",         CEC_TIM_DATA_BIT_TOTAL_MIN - CEC_TIM_DATA_BIT_HIGH },
 107        { "Rx Low Drive",          CEC_TIM_LOW_DRIVE_ERROR },
 108        { "Rx Irq",                0 },
 109};
 110
 111static void cec_pin_update(struct cec_pin *pin, bool v, bool force)
 112{
 113        if (!force && v == pin->adap->cec_pin_is_high)
 114                return;
 115
 116        pin->adap->cec_pin_is_high = v;
 117        if (atomic_read(&pin->work_pin_num_events) < CEC_NUM_PIN_EVENTS) {
 118                u8 ev = v;
 119
 120                if (pin->work_pin_events_dropped) {
 121                        pin->work_pin_events_dropped = false;
 122                        ev |= CEC_PIN_EVENT_FL_DROPPED;
 123                }
 124                pin->work_pin_events[pin->work_pin_events_wr] = ev;
 125                pin->work_pin_ts[pin->work_pin_events_wr] = ktime_get();
 126                pin->work_pin_events_wr =
 127                        (pin->work_pin_events_wr + 1) % CEC_NUM_PIN_EVENTS;
 128                atomic_inc(&pin->work_pin_num_events);
 129        } else {
 130                pin->work_pin_events_dropped = true;
 131                pin->work_pin_events_dropped_cnt++;
 132        }
 133        wake_up_interruptible(&pin->kthread_waitq);
 134}
 135
 136static bool cec_pin_read(struct cec_pin *pin)
 137{
 138        bool v = pin->ops->read(pin->adap);
 139
 140        cec_pin_update(pin, v, false);
 141        return v;
 142}
 143
 144static void cec_pin_low(struct cec_pin *pin)
 145{
 146        pin->ops->low(pin->adap);
 147        cec_pin_update(pin, false, false);
 148}
 149
 150static bool cec_pin_high(struct cec_pin *pin)
 151{
 152        pin->ops->high(pin->adap);
 153        return cec_pin_read(pin);
 154}
 155
 156static bool rx_error_inj(struct cec_pin *pin, unsigned int mode_offset,
 157                         int arg_idx, u8 *arg)
 158{
 159#ifdef CONFIG_CEC_PIN_ERROR_INJ
 160        u16 cmd = cec_pin_rx_error_inj(pin);
 161        u64 e = pin->error_inj[cmd];
 162        unsigned int mode = (e >> mode_offset) & CEC_ERROR_INJ_MODE_MASK;
 163
 164        if (arg_idx >= 0) {
 165                u8 pos = pin->error_inj_args[cmd][arg_idx];
 166
 167                if (arg)
 168                        *arg = pos;
 169                else if (pos != pin->rx_bit)
 170                        return false;
 171        }
 172
 173        switch (mode) {
 174        case CEC_ERROR_INJ_MODE_ONCE:
 175                pin->error_inj[cmd] &=
 176                        ~(CEC_ERROR_INJ_MODE_MASK << mode_offset);
 177                return true;
 178        case CEC_ERROR_INJ_MODE_ALWAYS:
 179                return true;
 180        case CEC_ERROR_INJ_MODE_TOGGLE:
 181                return pin->rx_toggle;
 182        default:
 183                return false;
 184        }
 185#else
 186        return false;
 187#endif
 188}
 189
 190static bool rx_nack(struct cec_pin *pin)
 191{
 192        return rx_error_inj(pin, CEC_ERROR_INJ_RX_NACK_OFFSET, -1, NULL);
 193}
 194
 195static bool rx_low_drive(struct cec_pin *pin)
 196{
 197        return rx_error_inj(pin, CEC_ERROR_INJ_RX_LOW_DRIVE_OFFSET,
 198                            CEC_ERROR_INJ_RX_LOW_DRIVE_ARG_IDX, NULL);
 199}
 200
 201static bool rx_add_byte(struct cec_pin *pin)
 202{
 203        return rx_error_inj(pin, CEC_ERROR_INJ_RX_ADD_BYTE_OFFSET, -1, NULL);
 204}
 205
 206static bool rx_remove_byte(struct cec_pin *pin)
 207{
 208        return rx_error_inj(pin, CEC_ERROR_INJ_RX_REMOVE_BYTE_OFFSET, -1, NULL);
 209}
 210
 211static bool rx_arb_lost(struct cec_pin *pin, u8 *poll)
 212{
 213        return pin->tx_msg.len == 0 &&
 214                rx_error_inj(pin, CEC_ERROR_INJ_RX_ARB_LOST_OFFSET,
 215                             CEC_ERROR_INJ_RX_ARB_LOST_ARG_IDX, poll);
 216}
 217
 218static bool tx_error_inj(struct cec_pin *pin, unsigned int mode_offset,
 219                         int arg_idx, u8 *arg)
 220{
 221#ifdef CONFIG_CEC_PIN_ERROR_INJ
 222        u16 cmd = cec_pin_tx_error_inj(pin);
 223        u64 e = pin->error_inj[cmd];
 224        unsigned int mode = (e >> mode_offset) & CEC_ERROR_INJ_MODE_MASK;
 225
 226        if (arg_idx >= 0) {
 227                u8 pos = pin->error_inj_args[cmd][arg_idx];
 228
 229                if (arg)
 230                        *arg = pos;
 231                else if (pos != pin->tx_bit)
 232                        return false;
 233        }
 234
 235        switch (mode) {
 236        case CEC_ERROR_INJ_MODE_ONCE:
 237                pin->error_inj[cmd] &=
 238                        ~(CEC_ERROR_INJ_MODE_MASK << mode_offset);
 239                return true;
 240        case CEC_ERROR_INJ_MODE_ALWAYS:
 241                return true;
 242        case CEC_ERROR_INJ_MODE_TOGGLE:
 243                return pin->tx_toggle;
 244        default:
 245                return false;
 246        }
 247#else
 248        return false;
 249#endif
 250}
 251
 252static bool tx_no_eom(struct cec_pin *pin)
 253{
 254        return tx_error_inj(pin, CEC_ERROR_INJ_TX_NO_EOM_OFFSET, -1, NULL);
 255}
 256
 257static bool tx_early_eom(struct cec_pin *pin)
 258{
 259        return tx_error_inj(pin, CEC_ERROR_INJ_TX_EARLY_EOM_OFFSET, -1, NULL);
 260}
 261
 262static bool tx_short_bit(struct cec_pin *pin)
 263{
 264        return tx_error_inj(pin, CEC_ERROR_INJ_TX_SHORT_BIT_OFFSET,
 265                            CEC_ERROR_INJ_TX_SHORT_BIT_ARG_IDX, NULL);
 266}
 267
 268static bool tx_long_bit(struct cec_pin *pin)
 269{
 270        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LONG_BIT_OFFSET,
 271                            CEC_ERROR_INJ_TX_LONG_BIT_ARG_IDX, NULL);
 272}
 273
 274static bool tx_custom_bit(struct cec_pin *pin)
 275{
 276        return tx_error_inj(pin, CEC_ERROR_INJ_TX_CUSTOM_BIT_OFFSET,
 277                            CEC_ERROR_INJ_TX_CUSTOM_BIT_ARG_IDX, NULL);
 278}
 279
 280static bool tx_short_start(struct cec_pin *pin)
 281{
 282        return tx_error_inj(pin, CEC_ERROR_INJ_TX_SHORT_START_OFFSET, -1, NULL);
 283}
 284
 285static bool tx_long_start(struct cec_pin *pin)
 286{
 287        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LONG_START_OFFSET, -1, NULL);
 288}
 289
 290static bool tx_custom_start(struct cec_pin *pin)
 291{
 292        return tx_error_inj(pin, CEC_ERROR_INJ_TX_CUSTOM_START_OFFSET,
 293                            -1, NULL);
 294}
 295
 296static bool tx_last_bit(struct cec_pin *pin)
 297{
 298        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LAST_BIT_OFFSET,
 299                            CEC_ERROR_INJ_TX_LAST_BIT_ARG_IDX, NULL);
 300}
 301
 302static u8 tx_add_bytes(struct cec_pin *pin)
 303{
 304        u8 bytes;
 305
 306        if (tx_error_inj(pin, CEC_ERROR_INJ_TX_ADD_BYTES_OFFSET,
 307                         CEC_ERROR_INJ_TX_ADD_BYTES_ARG_IDX, &bytes))
 308                return bytes;
 309        return 0;
 310}
 311
 312static bool tx_remove_byte(struct cec_pin *pin)
 313{
 314        return tx_error_inj(pin, CEC_ERROR_INJ_TX_REMOVE_BYTE_OFFSET, -1, NULL);
 315}
 316
 317static bool tx_low_drive(struct cec_pin *pin)
 318{
 319        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LOW_DRIVE_OFFSET,
 320                            CEC_ERROR_INJ_TX_LOW_DRIVE_ARG_IDX, NULL);
 321}
 322
 323static void cec_pin_to_idle(struct cec_pin *pin)
 324{
 325        /*
 326         * Reset all status fields, release the bus and
 327         * go to idle state.
 328         */
 329        pin->rx_bit = pin->tx_bit = 0;
 330        pin->rx_msg.len = 0;
 331        memset(pin->rx_msg.msg, 0, sizeof(pin->rx_msg.msg));
 332        pin->ts = ns_to_ktime(0);
 333        pin->tx_generated_poll = false;
 334        pin->tx_post_eom = false;
 335        if (pin->state >= CEC_ST_TX_WAIT &&
 336            pin->state <= CEC_ST_TX_LOW_DRIVE)
 337                pin->tx_toggle ^= 1;
 338        if (pin->state >= CEC_ST_RX_START_BIT_LOW &&
 339            pin->state <= CEC_ST_RX_LOW_DRIVE)
 340                pin->rx_toggle ^= 1;
 341        pin->state = CEC_ST_IDLE;
 342}
 343
 344/*
 345 * Handle Transmit-related states
 346 *
 347 * Basic state changes when transmitting:
 348 *
 349 * Idle -> Tx Wait (waiting for the end of signal free time) ->
 350 *      Tx Start Bit Low -> Tx Start Bit High ->
 351 *
 352 *   Regular data bits + EOM:
 353 *      Tx Data 0 Low -> Tx Data 0 High ->
 354 *   or:
 355 *      Tx Data 1 Low -> Tx Data 1 High ->
 356 *
 357 *   First 4 data bits or Ack bit:
 358 *      Tx Data 0 Low -> Tx Data 0 High ->
 359 *   or:
 360 *      Tx Data 1 Low -> Tx Data 1 High -> Tx Data 1 Pre Sample ->
 361 *              Tx Data 1 Post Sample ->
 362 *
 363 *   After the last Ack go to Idle.
 364 *
 365 * If it detects a Low Drive condition then:
 366 *      Tx Wait For High -> Idle
 367 *
 368 * If it loses arbitration, then it switches to state Rx Data Post Sample.
 369 */
 370static void cec_pin_tx_states(struct cec_pin *pin, ktime_t ts)
 371{
 372        bool v;
 373        bool is_ack_bit, ack;
 374
 375        switch (pin->state) {
 376        case CEC_ST_TX_WAIT_FOR_HIGH:
 377                if (cec_pin_read(pin))
 378                        cec_pin_to_idle(pin);
 379                break;
 380
 381        case CEC_ST_TX_START_BIT_LOW:
 382                if (tx_short_start(pin)) {
 383                        /*
 384                         * Error Injection: send an invalid (too short)
 385                         * start pulse.
 386                         */
 387                        pin->state = CEC_ST_TX_START_BIT_HIGH_SHORT;
 388                } else if (tx_long_start(pin)) {
 389                        /*
 390                         * Error Injection: send an invalid (too long)
 391                         * start pulse.
 392                         */
 393                        pin->state = CEC_ST_TX_START_BIT_HIGH_LONG;
 394                } else {
 395                        pin->state = CEC_ST_TX_START_BIT_HIGH;
 396                }
 397                /* Generate start bit */
 398                cec_pin_high(pin);
 399                break;
 400
 401        case CEC_ST_TX_START_BIT_LOW_CUSTOM:
 402                pin->state = CEC_ST_TX_START_BIT_HIGH_CUSTOM;
 403                /* Generate start bit */
 404                cec_pin_high(pin);
 405                break;
 406
 407        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE:
 408        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT:
 409        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG:
 410                if (pin->tx_nacked) {
 411                        cec_pin_to_idle(pin);
 412                        pin->tx_msg.len = 0;
 413                        if (pin->tx_generated_poll)
 414                                break;
 415                        pin->work_tx_ts = ts;
 416                        pin->work_tx_status = CEC_TX_STATUS_NACK;
 417                        wake_up_interruptible(&pin->kthread_waitq);
 418                        break;
 419                }
 420                /* fall through */
 421        case CEC_ST_TX_DATA_BIT_0_HIGH:
 422        case CEC_ST_TX_DATA_BIT_0_HIGH_SHORT:
 423        case CEC_ST_TX_DATA_BIT_0_HIGH_LONG:
 424        case CEC_ST_TX_DATA_BIT_1_HIGH:
 425        case CEC_ST_TX_DATA_BIT_1_HIGH_SHORT:
 426        case CEC_ST_TX_DATA_BIT_1_HIGH_LONG:
 427                /*
 428                 * If the read value is 1, then all is OK, otherwise we have a
 429                 * low drive condition.
 430                 *
 431                 * Special case: when we generate a poll message due to an
 432                 * Arbitration Lost error injection, then ignore this since
 433                 * the pin can actually be low in that case.
 434                 */
 435                if (!cec_pin_read(pin) && !pin->tx_generated_poll) {
 436                        /*
 437                         * It's 0, so someone detected an error and pulled the
 438                         * line low for 1.5 times the nominal bit period.
 439                         */
 440                        pin->tx_msg.len = 0;
 441                        pin->state = CEC_ST_TX_WAIT_FOR_HIGH;
 442                        pin->work_tx_ts = ts;
 443                        pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
 444                        pin->tx_low_drive_cnt++;
 445                        wake_up_interruptible(&pin->kthread_waitq);
 446                        break;
 447                }
 448                /* fall through */
 449        case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
 450                if (tx_last_bit(pin)) {
 451                        /* Error Injection: just stop sending after this bit */
 452                        cec_pin_to_idle(pin);
 453                        pin->tx_msg.len = 0;
 454                        if (pin->tx_generated_poll)
 455                                break;
 456                        pin->work_tx_ts = ts;
 457                        pin->work_tx_status = CEC_TX_STATUS_OK;
 458                        wake_up_interruptible(&pin->kthread_waitq);
 459                        break;
 460                }
 461                pin->tx_bit++;
 462                /* fall through */
 463        case CEC_ST_TX_START_BIT_HIGH:
 464        case CEC_ST_TX_START_BIT_HIGH_SHORT:
 465        case CEC_ST_TX_START_BIT_HIGH_LONG:
 466        case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
 467                if (tx_low_drive(pin)) {
 468                        /* Error injection: go to low drive */
 469                        cec_pin_low(pin);
 470                        pin->state = CEC_ST_TX_LOW_DRIVE;
 471                        pin->tx_msg.len = 0;
 472                        if (pin->tx_generated_poll)
 473                                break;
 474                        pin->work_tx_ts = ts;
 475                        pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
 476                        pin->tx_low_drive_cnt++;
 477                        wake_up_interruptible(&pin->kthread_waitq);
 478                        break;
 479                }
 480                if (pin->tx_bit / 10 >= pin->tx_msg.len + pin->tx_extra_bytes) {
 481                        cec_pin_to_idle(pin);
 482                        pin->tx_msg.len = 0;
 483                        if (pin->tx_generated_poll)
 484                                break;
 485                        pin->work_tx_ts = ts;
 486                        pin->work_tx_status = CEC_TX_STATUS_OK;
 487                        wake_up_interruptible(&pin->kthread_waitq);
 488                        break;
 489                }
 490
 491                switch (pin->tx_bit % 10) {
 492                default: {
 493                        /*
 494                         * In the CEC_ERROR_INJ_TX_ADD_BYTES case we transmit
 495                         * extra bytes, so pin->tx_bit / 10 can become >= 16.
 496                         * Generate bit values for those extra bytes instead
 497                         * of reading them from the transmit buffer.
 498                         */
 499                        unsigned int idx = (pin->tx_bit / 10);
 500                        u8 val = idx;
 501
 502                        if (idx < pin->tx_msg.len)
 503                                val = pin->tx_msg.msg[idx];
 504                        v = val & (1 << (7 - (pin->tx_bit % 10)));
 505
 506                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_LOW :
 507                                         CEC_ST_TX_DATA_BIT_0_LOW;
 508                        break;
 509                }
 510                case EOM_BIT: {
 511                        unsigned int tot_len = pin->tx_msg.len +
 512                                               pin->tx_extra_bytes;
 513                        unsigned int tx_byte_idx = pin->tx_bit / 10;
 514
 515                        v = !pin->tx_post_eom && tx_byte_idx == tot_len - 1;
 516                        if (tot_len > 1 && tx_byte_idx == tot_len - 2 &&
 517                            tx_early_eom(pin)) {
 518                                /* Error injection: set EOM one byte early */
 519                                v = true;
 520                                pin->tx_post_eom = true;
 521                        } else if (v && tx_no_eom(pin)) {
 522                                /* Error injection: no EOM */
 523                                v = false;
 524                        }
 525                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_LOW :
 526                                         CEC_ST_TX_DATA_BIT_0_LOW;
 527                        break;
 528                }
 529                case ACK_BIT:
 530                        pin->state = CEC_ST_TX_DATA_BIT_1_LOW;
 531                        break;
 532                }
 533                if (tx_custom_bit(pin))
 534                        pin->state = CEC_ST_TX_DATA_BIT_LOW_CUSTOM;
 535                cec_pin_low(pin);
 536                break;
 537
 538        case CEC_ST_TX_DATA_BIT_0_LOW:
 539        case CEC_ST_TX_DATA_BIT_1_LOW:
 540                v = pin->state == CEC_ST_TX_DATA_BIT_1_LOW;
 541                is_ack_bit = pin->tx_bit % 10 == ACK_BIT;
 542                if (v && (pin->tx_bit < 4 || is_ack_bit)) {
 543                        pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE;
 544                } else if (!is_ack_bit && tx_short_bit(pin)) {
 545                        /* Error Injection: send an invalid (too short) bit */
 546                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH_SHORT :
 547                                         CEC_ST_TX_DATA_BIT_0_HIGH_SHORT;
 548                } else if (!is_ack_bit && tx_long_bit(pin)) {
 549                        /* Error Injection: send an invalid (too long) bit */
 550                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH_LONG :
 551                                         CEC_ST_TX_DATA_BIT_0_HIGH_LONG;
 552                } else {
 553                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH :
 554                                         CEC_ST_TX_DATA_BIT_0_HIGH;
 555                }
 556                cec_pin_high(pin);
 557                break;
 558
 559        case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
 560                pin->state = CEC_ST_TX_DATA_BIT_HIGH_CUSTOM;
 561                cec_pin_high(pin);
 562                break;
 563
 564        case CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE:
 565                /* Read the CEC value at the sample time */
 566                v = cec_pin_read(pin);
 567                is_ack_bit = pin->tx_bit % 10 == ACK_BIT;
 568                /*
 569                 * If v == 0 and we're within the first 4 bits
 570                 * of the initiator, then someone else started
 571                 * transmitting and we lost the arbitration
 572                 * (i.e. the logical address of the other
 573                 * transmitter has more leading 0 bits in the
 574                 * initiator).
 575                 */
 576                if (!v && !is_ack_bit && !pin->tx_generated_poll) {
 577                        pin->tx_msg.len = 0;
 578                        pin->work_tx_ts = ts;
 579                        pin->work_tx_status = CEC_TX_STATUS_ARB_LOST;
 580                        wake_up_interruptible(&pin->kthread_waitq);
 581                        pin->rx_bit = pin->tx_bit;
 582                        pin->tx_bit = 0;
 583                        memset(pin->rx_msg.msg, 0, sizeof(pin->rx_msg.msg));
 584                        pin->rx_msg.msg[0] = pin->tx_msg.msg[0];
 585                        pin->rx_msg.msg[0] &= (0xff << (8 - pin->rx_bit));
 586                        pin->rx_msg.len = 0;
 587                        pin->ts = ktime_sub_us(ts, CEC_TIM_DATA_BIT_SAMPLE);
 588                        pin->state = CEC_ST_RX_DATA_POST_SAMPLE;
 589                        pin->rx_bit++;
 590                        break;
 591                }
 592                pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE;
 593                if (!is_ack_bit && tx_short_bit(pin)) {
 594                        /* Error Injection: send an invalid (too short) bit */
 595                        pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT;
 596                } else if (!is_ack_bit && tx_long_bit(pin)) {
 597                        /* Error Injection: send an invalid (too long) bit */
 598                        pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG;
 599                }
 600                if (!is_ack_bit)
 601                        break;
 602                /* Was the message ACKed? */
 603                ack = cec_msg_is_broadcast(&pin->tx_msg) ? v : !v;
 604                if (!ack && (!pin->tx_ignore_nack_until_eom ||
 605                    pin->tx_bit / 10 == pin->tx_msg.len - 1) &&
 606                    !pin->tx_post_eom) {
 607                        /*
 608                         * Note: the CEC spec is ambiguous regarding
 609                         * what action to take when a NACK appears
 610                         * before the last byte of the payload was
 611                         * transmitted: either stop transmitting
 612                         * immediately, or wait until the last byte
 613                         * was transmitted.
 614                         *
 615                         * Most CEC implementations appear to stop
 616                         * immediately, and that's what we do here
 617                         * as well.
 618                         */
 619                        pin->tx_nacked = true;
 620                }
 621                break;
 622
 623        case CEC_ST_TX_PULSE_LOW_CUSTOM:
 624                cec_pin_high(pin);
 625                pin->state = CEC_ST_TX_PULSE_HIGH_CUSTOM;
 626                break;
 627
 628        case CEC_ST_TX_PULSE_HIGH_CUSTOM:
 629                cec_pin_to_idle(pin);
 630                break;
 631
 632        default:
 633                break;
 634        }
 635}
 636
 637/*
 638 * Handle Receive-related states
 639 *
 640 * Basic state changes when receiving:
 641 *
 642 *      Rx Start Bit Low -> Rx Start Bit High ->
 643 *   Regular data bits + EOM:
 644 *      Rx Data Sample -> Rx Data Post Sample -> Rx Data High ->
 645 *   Ack bit 0:
 646 *      Rx Ack Low -> Rx Ack Low Post -> Rx Data High ->
 647 *   Ack bit 1:
 648 *      Rx Ack High Post -> Rx Data High ->
 649 *   Ack bit 0 && EOM:
 650 *      Rx Ack Low -> Rx Ack Low Post -> Rx Ack Finish -> Idle
 651 */
 652static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 653{
 654        s32 delta;
 655        bool v;
 656        bool ack;
 657        bool bcast, for_us;
 658        u8 dest;
 659        u8 poll;
 660
 661        switch (pin->state) {
 662        /* Receive states */
 663        case CEC_ST_RX_START_BIT_LOW:
 664                v = cec_pin_read(pin);
 665                if (!v)
 666                        break;
 667                pin->state = CEC_ST_RX_START_BIT_HIGH;
 668                delta = ktime_us_delta(ts, pin->ts);
 669                /* Start bit low is too short, go back to idle */
 670                if (delta < CEC_TIM_START_BIT_LOW_MIN - CEC_TIM_IDLE_SAMPLE) {
 671                        if (!pin->rx_start_bit_low_too_short_cnt++) {
 672                                pin->rx_start_bit_low_too_short_ts = ktime_to_ns(pin->ts);
 673                                pin->rx_start_bit_low_too_short_delta = delta;
 674                        }
 675                        cec_pin_to_idle(pin);
 676                        break;
 677                }
 678                if (rx_arb_lost(pin, &poll)) {
 679                        cec_msg_init(&pin->tx_msg, poll >> 4, poll & 0xf);
 680                        pin->tx_generated_poll = true;
 681                        pin->tx_extra_bytes = 0;
 682                        pin->state = CEC_ST_TX_START_BIT_HIGH;
 683                        pin->ts = ts;
 684                }
 685                break;
 686
 687        case CEC_ST_RX_START_BIT_HIGH:
 688                v = cec_pin_read(pin);
 689                delta = ktime_us_delta(ts, pin->ts);
 690                /*
 691                 * Unfortunately the spec does not specify when to give up
 692                 * and go to idle. We just pick TOTAL_LONG.
 693                 */
 694                if (v && delta > CEC_TIM_START_BIT_TOTAL_LONG) {
 695                        pin->rx_start_bit_too_long_cnt++;
 696                        cec_pin_to_idle(pin);
 697                        break;
 698                }
 699                if (v)
 700                        break;
 701                /* Start bit is too short, go back to idle */
 702                if (delta < CEC_TIM_START_BIT_TOTAL_MIN - CEC_TIM_IDLE_SAMPLE) {
 703                        if (!pin->rx_start_bit_too_short_cnt++) {
 704                                pin->rx_start_bit_too_short_ts = ktime_to_ns(pin->ts);
 705                                pin->rx_start_bit_too_short_delta = delta;
 706                        }
 707                        cec_pin_to_idle(pin);
 708                        break;
 709                }
 710                if (rx_low_drive(pin)) {
 711                        /* Error injection: go to low drive */
 712                        cec_pin_low(pin);
 713                        pin->state = CEC_ST_RX_LOW_DRIVE;
 714                        pin->rx_low_drive_cnt++;
 715                        break;
 716                }
 717                pin->state = CEC_ST_RX_DATA_SAMPLE;
 718                pin->ts = ts;
 719                pin->rx_eom = false;
 720                break;
 721
 722        case CEC_ST_RX_DATA_SAMPLE:
 723                v = cec_pin_read(pin);
 724                pin->state = CEC_ST_RX_DATA_POST_SAMPLE;
 725                switch (pin->rx_bit % 10) {
 726                default:
 727                        if (pin->rx_bit / 10 < CEC_MAX_MSG_SIZE)
 728                                pin->rx_msg.msg[pin->rx_bit / 10] |=
 729                                        v << (7 - (pin->rx_bit % 10));
 730                        break;
 731                case EOM_BIT:
 732                        pin->rx_eom = v;
 733                        pin->rx_msg.len = pin->rx_bit / 10 + 1;
 734                        break;
 735                case ACK_BIT:
 736                        break;
 737                }
 738                pin->rx_bit++;
 739                break;
 740
 741        case CEC_ST_RX_DATA_POST_SAMPLE:
 742                pin->state = CEC_ST_RX_DATA_WAIT_FOR_LOW;
 743                break;
 744
 745        case CEC_ST_RX_DATA_WAIT_FOR_LOW:
 746                v = cec_pin_read(pin);
 747                delta = ktime_us_delta(ts, pin->ts);
 748                /*
 749                 * Unfortunately the spec does not specify when to give up
 750                 * and go to idle. We just pick TOTAL_LONG.
 751                 */
 752                if (v && delta > CEC_TIM_DATA_BIT_TOTAL_LONG) {
 753                        pin->rx_data_bit_too_long_cnt++;
 754                        cec_pin_to_idle(pin);
 755                        break;
 756                }
 757                if (v)
 758                        break;
 759
 760                if (rx_low_drive(pin)) {
 761                        /* Error injection: go to low drive */
 762                        cec_pin_low(pin);
 763                        pin->state = CEC_ST_RX_LOW_DRIVE;
 764                        pin->rx_low_drive_cnt++;
 765                        break;
 766                }
 767
 768                /*
 769                 * Go to low drive state when the total bit time is
 770                 * too short.
 771                 */
 772                if (delta < CEC_TIM_DATA_BIT_TOTAL_MIN) {
 773                        if (!pin->rx_data_bit_too_short_cnt++) {
 774                                pin->rx_data_bit_too_short_ts = ktime_to_ns(pin->ts);
 775                                pin->rx_data_bit_too_short_delta = delta;
 776                        }
 777                        cec_pin_low(pin);
 778                        pin->state = CEC_ST_RX_LOW_DRIVE;
 779                        pin->rx_low_drive_cnt++;
 780                        break;
 781                }
 782                pin->ts = ts;
 783                if (pin->rx_bit % 10 != 9) {
 784                        pin->state = CEC_ST_RX_DATA_SAMPLE;
 785                        break;
 786                }
 787
 788                dest = cec_msg_destination(&pin->rx_msg);
 789                bcast = dest == CEC_LOG_ADDR_BROADCAST;
 790                /* for_us == broadcast or directed to us */
 791                for_us = bcast || (pin->la_mask & (1 << dest));
 792                /* ACK bit value */
 793                ack = bcast ? 1 : !for_us;
 794
 795                if (for_us && rx_nack(pin)) {
 796                        /* Error injection: toggle the ACK bit */
 797                        ack = !ack;
 798                }
 799
 800                if (ack) {
 801                        /* No need to write to the bus, just wait */
 802                        pin->state = CEC_ST_RX_ACK_HIGH_POST;
 803                        break;
 804                }
 805                cec_pin_low(pin);
 806                pin->state = CEC_ST_RX_ACK_LOW;
 807                break;
 808
 809        case CEC_ST_RX_ACK_LOW:
 810                cec_pin_high(pin);
 811                pin->state = CEC_ST_RX_ACK_LOW_POST;
 812                break;
 813
 814        case CEC_ST_RX_ACK_LOW_POST:
 815        case CEC_ST_RX_ACK_HIGH_POST:
 816                v = cec_pin_read(pin);
 817                if (v && pin->rx_eom) {
 818                        pin->work_rx_msg = pin->rx_msg;
 819                        pin->work_rx_msg.rx_ts = ktime_to_ns(ts);
 820                        wake_up_interruptible(&pin->kthread_waitq);
 821                        pin->ts = ts;
 822                        pin->state = CEC_ST_RX_ACK_FINISH;
 823                        break;
 824                }
 825                pin->rx_bit++;
 826                pin->state = CEC_ST_RX_DATA_WAIT_FOR_LOW;
 827                break;
 828
 829        case CEC_ST_RX_ACK_FINISH:
 830                cec_pin_to_idle(pin);
 831                break;
 832
 833        default:
 834                break;
 835        }
 836}
 837
 838/*
 839 * Main timer function
 840 *
 841 */
 842static enum hrtimer_restart cec_pin_timer(struct hrtimer *timer)
 843{
 844        struct cec_pin *pin = container_of(timer, struct cec_pin, timer);
 845        struct cec_adapter *adap = pin->adap;
 846        ktime_t ts;
 847        s32 delta;
 848        u32 usecs;
 849
 850        ts = ktime_get();
 851        if (ktime_to_ns(pin->timer_ts)) {
 852                delta = ktime_us_delta(ts, pin->timer_ts);
 853                pin->timer_cnt++;
 854                if (delta > 100 && pin->state != CEC_ST_IDLE) {
 855                        /* Keep track of timer overruns */
 856                        pin->timer_sum_overrun += delta;
 857                        pin->timer_100ms_overruns++;
 858                        if (delta > 300)
 859                                pin->timer_300ms_overruns++;
 860                        if (delta > pin->timer_max_overrun)
 861                                pin->timer_max_overrun = delta;
 862                }
 863        }
 864        if (adap->monitor_pin_cnt)
 865                cec_pin_read(pin);
 866
 867        if (pin->wait_usecs) {
 868                /*
 869                 * If we are monitoring the pin, then we have to
 870                 * sample at regular intervals.
 871                 */
 872                if (pin->wait_usecs > 150) {
 873                        pin->wait_usecs -= 100;
 874                        pin->timer_ts = ktime_add_us(ts, 100);
 875                        hrtimer_forward_now(timer, ns_to_ktime(100000));
 876                        return HRTIMER_RESTART;
 877                }
 878                if (pin->wait_usecs > 100) {
 879                        pin->wait_usecs /= 2;
 880                        pin->timer_ts = ktime_add_us(ts, pin->wait_usecs);
 881                        hrtimer_forward_now(timer,
 882                                        ns_to_ktime(pin->wait_usecs * 1000));
 883                        return HRTIMER_RESTART;
 884                }
 885                pin->timer_ts = ktime_add_us(ts, pin->wait_usecs);
 886                hrtimer_forward_now(timer,
 887                                    ns_to_ktime(pin->wait_usecs * 1000));
 888                pin->wait_usecs = 0;
 889                return HRTIMER_RESTART;
 890        }
 891
 892        switch (pin->state) {
 893        /* Transmit states */
 894        case CEC_ST_TX_WAIT_FOR_HIGH:
 895        case CEC_ST_TX_START_BIT_LOW:
 896        case CEC_ST_TX_START_BIT_HIGH:
 897        case CEC_ST_TX_START_BIT_HIGH_SHORT:
 898        case CEC_ST_TX_START_BIT_HIGH_LONG:
 899        case CEC_ST_TX_START_BIT_LOW_CUSTOM:
 900        case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
 901        case CEC_ST_TX_DATA_BIT_0_LOW:
 902        case CEC_ST_TX_DATA_BIT_0_HIGH:
 903        case CEC_ST_TX_DATA_BIT_0_HIGH_SHORT:
 904        case CEC_ST_TX_DATA_BIT_0_HIGH_LONG:
 905        case CEC_ST_TX_DATA_BIT_1_LOW:
 906        case CEC_ST_TX_DATA_BIT_1_HIGH:
 907        case CEC_ST_TX_DATA_BIT_1_HIGH_SHORT:
 908        case CEC_ST_TX_DATA_BIT_1_HIGH_LONG:
 909        case CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE:
 910        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE:
 911        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT:
 912        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG:
 913        case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
 914        case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
 915        case CEC_ST_TX_PULSE_LOW_CUSTOM:
 916        case CEC_ST_TX_PULSE_HIGH_CUSTOM:
 917                cec_pin_tx_states(pin, ts);
 918                break;
 919
 920        /* Receive states */
 921        case CEC_ST_RX_START_BIT_LOW:
 922        case CEC_ST_RX_START_BIT_HIGH:
 923        case CEC_ST_RX_DATA_SAMPLE:
 924        case CEC_ST_RX_DATA_POST_SAMPLE:
 925        case CEC_ST_RX_DATA_WAIT_FOR_LOW:
 926        case CEC_ST_RX_ACK_LOW:
 927        case CEC_ST_RX_ACK_LOW_POST:
 928        case CEC_ST_RX_ACK_HIGH_POST:
 929        case CEC_ST_RX_ACK_FINISH:
 930                cec_pin_rx_states(pin, ts);
 931                break;
 932
 933        case CEC_ST_IDLE:
 934        case CEC_ST_TX_WAIT:
 935                if (!cec_pin_high(pin)) {
 936                        /* Start bit, switch to receive state */
 937                        pin->ts = ts;
 938                        pin->state = CEC_ST_RX_START_BIT_LOW;
 939                        /*
 940                         * If a transmit is pending, then that transmit should
 941                         * use a signal free time of no more than
 942                         * CEC_SIGNAL_FREE_TIME_NEW_INITIATOR since it will
 943                         * have a new initiator due to the receive that is now
 944                         * starting.
 945                         */
 946                        if (pin->tx_msg.len && pin->tx_signal_free_time >
 947                            CEC_SIGNAL_FREE_TIME_NEW_INITIATOR)
 948                                pin->tx_signal_free_time =
 949                                        CEC_SIGNAL_FREE_TIME_NEW_INITIATOR;
 950                        break;
 951                }
 952                if (ktime_to_ns(pin->ts) == 0)
 953                        pin->ts = ts;
 954                if (pin->tx_msg.len) {
 955                        /*
 956                         * Check if the bus has been free for long enough
 957                         * so we can kick off the pending transmit.
 958                         */
 959                        delta = ktime_us_delta(ts, pin->ts);
 960                        if (delta / CEC_TIM_DATA_BIT_TOTAL >
 961                            pin->tx_signal_free_time) {
 962                                pin->tx_nacked = false;
 963                                if (tx_custom_start(pin))
 964                                        pin->state = CEC_ST_TX_START_BIT_LOW_CUSTOM;
 965                                else
 966                                        pin->state = CEC_ST_TX_START_BIT_LOW;
 967                                /* Generate start bit */
 968                                cec_pin_low(pin);
 969                                break;
 970                        }
 971                        if (delta / CEC_TIM_DATA_BIT_TOTAL >
 972                            pin->tx_signal_free_time - 1)
 973                                pin->state = CEC_ST_TX_WAIT;
 974                        break;
 975                }
 976                if (pin->tx_custom_pulse && pin->state == CEC_ST_IDLE) {
 977                        pin->tx_custom_pulse = false;
 978                        /* Generate custom pulse */
 979                        cec_pin_low(pin);
 980                        pin->state = CEC_ST_TX_PULSE_LOW_CUSTOM;
 981                        break;
 982                }
 983                if (pin->state != CEC_ST_IDLE || pin->ops->enable_irq == NULL ||
 984                    pin->enable_irq_failed || adap->is_configuring ||
 985                    adap->is_configured || adap->monitor_all_cnt)
 986                        break;
 987                /* Switch to interrupt mode */
 988                atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_ENABLE);
 989                pin->state = CEC_ST_RX_IRQ;
 990                wake_up_interruptible(&pin->kthread_waitq);
 991                return HRTIMER_NORESTART;
 992
 993        case CEC_ST_TX_LOW_DRIVE:
 994        case CEC_ST_RX_LOW_DRIVE:
 995                cec_pin_high(pin);
 996                cec_pin_to_idle(pin);
 997                break;
 998
 999        default:
1000                break;
1001        }
1002
1003        switch (pin->state) {
1004        case CEC_ST_TX_START_BIT_LOW_CUSTOM:
1005        case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
1006        case CEC_ST_TX_PULSE_LOW_CUSTOM:
1007                usecs = pin->tx_custom_low_usecs;
1008                break;
1009        case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
1010        case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
1011        case CEC_ST_TX_PULSE_HIGH_CUSTOM:
1012                usecs = pin->tx_custom_high_usecs;
1013                break;
1014        default:
1015                usecs = states[pin->state].usecs;
1016                break;
1017        }
1018
1019        if (!adap->monitor_pin_cnt || usecs <= 150) {
1020                pin->wait_usecs = 0;
1021                pin->timer_ts = ktime_add_us(ts, usecs);
1022                hrtimer_forward_now(timer,
1023                                ns_to_ktime(usecs * 1000));
1024                return HRTIMER_RESTART;
1025        }
1026        pin->wait_usecs = usecs - 100;
1027        pin->timer_ts = ktime_add_us(ts, 100);
1028        hrtimer_forward_now(timer, ns_to_ktime(100000));
1029        return HRTIMER_RESTART;
1030}
1031
1032static int cec_pin_thread_func(void *_adap)
1033{
1034        struct cec_adapter *adap = _adap;
1035        struct cec_pin *pin = adap->pin;
1036
1037        for (;;) {
1038                wait_event_interruptible(pin->kthread_waitq,
1039                        kthread_should_stop() ||
1040                        pin->work_rx_msg.len ||
1041                        pin->work_tx_status ||
1042                        atomic_read(&pin->work_irq_change) ||
1043                        atomic_read(&pin->work_pin_num_events));
1044
1045                if (pin->work_rx_msg.len) {
1046                        struct cec_msg *msg = &pin->work_rx_msg;
1047
1048                        if (msg->len > 1 && msg->len < CEC_MAX_MSG_SIZE &&
1049                            rx_add_byte(pin)) {
1050                                /* Error injection: add byte to the message */
1051                                msg->msg[msg->len++] = 0x55;
1052                        }
1053                        if (msg->len > 2 && rx_remove_byte(pin)) {
1054                                /* Error injection: remove byte from message */
1055                                msg->len--;
1056                        }
1057                        if (msg->len > CEC_MAX_MSG_SIZE)
1058                                msg->len = CEC_MAX_MSG_SIZE;
1059                        cec_received_msg_ts(adap, msg,
1060                                ns_to_ktime(pin->work_rx_msg.rx_ts));
1061                        msg->len = 0;
1062                }
1063                if (pin->work_tx_status) {
1064                        unsigned int tx_status = pin->work_tx_status;
1065
1066                        pin->work_tx_status = 0;
1067                        cec_transmit_attempt_done_ts(adap, tx_status,
1068                                                     pin->work_tx_ts);
1069                }
1070
1071                while (atomic_read(&pin->work_pin_num_events)) {
1072                        unsigned int idx = pin->work_pin_events_rd;
1073                        u8 v = pin->work_pin_events[idx];
1074
1075                        cec_queue_pin_cec_event(adap,
1076                                                v & CEC_PIN_EVENT_FL_IS_HIGH,
1077                                                v & CEC_PIN_EVENT_FL_DROPPED,
1078                                                pin->work_pin_ts[idx]);
1079                        pin->work_pin_events_rd = (idx + 1) % CEC_NUM_PIN_EVENTS;
1080                        atomic_dec(&pin->work_pin_num_events);
1081                }
1082
1083                switch (atomic_xchg(&pin->work_irq_change,
1084                                    CEC_PIN_IRQ_UNCHANGED)) {
1085                case CEC_PIN_IRQ_DISABLE:
1086                        pin->ops->disable_irq(adap);
1087                        cec_pin_high(pin);
1088                        cec_pin_to_idle(pin);
1089                        hrtimer_start(&pin->timer, ns_to_ktime(0),
1090                                      HRTIMER_MODE_REL);
1091                        break;
1092                case CEC_PIN_IRQ_ENABLE:
1093                        pin->enable_irq_failed = !pin->ops->enable_irq(adap);
1094                        if (pin->enable_irq_failed) {
1095                                cec_pin_to_idle(pin);
1096                                hrtimer_start(&pin->timer, ns_to_ktime(0),
1097                                              HRTIMER_MODE_REL);
1098                        }
1099                        break;
1100                default:
1101                        break;
1102                }
1103
1104                if (kthread_should_stop())
1105                        break;
1106        }
1107        return 0;
1108}
1109
1110static int cec_pin_adap_enable(struct cec_adapter *adap, bool enable)
1111{
1112        struct cec_pin *pin = adap->pin;
1113
1114        pin->enabled = enable;
1115        if (enable) {
1116                atomic_set(&pin->work_pin_num_events, 0);
1117                pin->work_pin_events_rd = pin->work_pin_events_wr = 0;
1118                pin->work_pin_events_dropped = false;
1119                cec_pin_read(pin);
1120                cec_pin_to_idle(pin);
1121                pin->tx_msg.len = 0;
1122                pin->timer_ts = ns_to_ktime(0);
1123                atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_UNCHANGED);
1124                pin->kthread = kthread_run(cec_pin_thread_func, adap,
1125                                           "cec-pin");
1126                if (IS_ERR(pin->kthread)) {
1127                        pr_err("cec-pin: kernel_thread() failed\n");
1128                        return PTR_ERR(pin->kthread);
1129                }
1130                hrtimer_start(&pin->timer, ns_to_ktime(0),
1131                              HRTIMER_MODE_REL);
1132        } else {
1133                if (pin->ops->disable_irq)
1134                        pin->ops->disable_irq(adap);
1135                hrtimer_cancel(&pin->timer);
1136                kthread_stop(pin->kthread);
1137                cec_pin_read(pin);
1138                cec_pin_to_idle(pin);
1139                pin->state = CEC_ST_OFF;
1140        }
1141        return 0;
1142}
1143
1144static int cec_pin_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
1145{
1146        struct cec_pin *pin = adap->pin;
1147
1148        if (log_addr == CEC_LOG_ADDR_INVALID)
1149                pin->la_mask = 0;
1150        else
1151                pin->la_mask |= (1 << log_addr);
1152        return 0;
1153}
1154
1155void cec_pin_start_timer(struct cec_pin *pin)
1156{
1157        if (pin->state != CEC_ST_RX_IRQ)
1158                return;
1159
1160        atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_UNCHANGED);
1161        pin->ops->disable_irq(pin->adap);
1162        cec_pin_high(pin);
1163        cec_pin_to_idle(pin);
1164        hrtimer_start(&pin->timer, ns_to_ktime(0), HRTIMER_MODE_REL);
1165}
1166
1167static int cec_pin_adap_transmit(struct cec_adapter *adap, u8 attempts,
1168                                      u32 signal_free_time, struct cec_msg *msg)
1169{
1170        struct cec_pin *pin = adap->pin;
1171
1172        /*
1173         * If a receive is in progress, then this transmit should use
1174         * a signal free time of max CEC_SIGNAL_FREE_TIME_NEW_INITIATOR
1175         * since when it starts transmitting it will have a new initiator.
1176         */
1177        if (pin->state != CEC_ST_IDLE &&
1178            signal_free_time > CEC_SIGNAL_FREE_TIME_NEW_INITIATOR)
1179                signal_free_time = CEC_SIGNAL_FREE_TIME_NEW_INITIATOR;
1180
1181        pin->tx_signal_free_time = signal_free_time;
1182        pin->tx_extra_bytes = 0;
1183        pin->tx_msg = *msg;
1184        if (msg->len > 1) {
1185                /* Error injection: add byte to the message */
1186                pin->tx_extra_bytes = tx_add_bytes(pin);
1187        }
1188        if (msg->len > 2 && tx_remove_byte(pin)) {
1189                /* Error injection: remove byte from the message */
1190                pin->tx_msg.len--;
1191        }
1192        pin->work_tx_status = 0;
1193        pin->tx_bit = 0;
1194        cec_pin_start_timer(pin);
1195        return 0;
1196}
1197
1198static void cec_pin_adap_status(struct cec_adapter *adap,
1199                                       struct seq_file *file)
1200{
1201        struct cec_pin *pin = adap->pin;
1202
1203        seq_printf(file, "state: %s\n", states[pin->state].name);
1204        seq_printf(file, "tx_bit: %d\n", pin->tx_bit);
1205        seq_printf(file, "rx_bit: %d\n", pin->rx_bit);
1206        seq_printf(file, "cec pin: %d\n", pin->ops->read(adap));
1207        seq_printf(file, "cec pin events dropped: %u\n",
1208                   pin->work_pin_events_dropped_cnt);
1209        seq_printf(file, "irq failed: %d\n", pin->enable_irq_failed);
1210        if (pin->timer_100ms_overruns) {
1211                seq_printf(file, "timer overruns > 100ms: %u of %u\n",
1212                           pin->timer_100ms_overruns, pin->timer_cnt);
1213                seq_printf(file, "timer overruns > 300ms: %u of %u\n",
1214                           pin->timer_300ms_overruns, pin->timer_cnt);
1215                seq_printf(file, "max timer overrun: %u usecs\n",
1216                           pin->timer_max_overrun);
1217                seq_printf(file, "avg timer overrun: %u usecs\n",
1218                           pin->timer_sum_overrun / pin->timer_100ms_overruns);
1219        }
1220        if (pin->rx_start_bit_low_too_short_cnt)
1221                seq_printf(file,
1222                           "rx start bit low too short: %u (delta %u, ts %llu)\n",
1223                           pin->rx_start_bit_low_too_short_cnt,
1224                           pin->rx_start_bit_low_too_short_delta,
1225                           pin->rx_start_bit_low_too_short_ts);
1226        if (pin->rx_start_bit_too_short_cnt)
1227                seq_printf(file,
1228                           "rx start bit too short: %u (delta %u, ts %llu)\n",
1229                           pin->rx_start_bit_too_short_cnt,
1230                           pin->rx_start_bit_too_short_delta,
1231                           pin->rx_start_bit_too_short_ts);
1232        if (pin->rx_start_bit_too_long_cnt)
1233                seq_printf(file, "rx start bit too long: %u\n",
1234                           pin->rx_start_bit_too_long_cnt);
1235        if (pin->rx_data_bit_too_short_cnt)
1236                seq_printf(file,
1237                           "rx data bit too short: %u (delta %u, ts %llu)\n",
1238                           pin->rx_data_bit_too_short_cnt,
1239                           pin->rx_data_bit_too_short_delta,
1240                           pin->rx_data_bit_too_short_ts);
1241        if (pin->rx_data_bit_too_long_cnt)
1242                seq_printf(file, "rx data bit too long: %u\n",
1243                           pin->rx_data_bit_too_long_cnt);
1244        seq_printf(file, "rx initiated low drive: %u\n", pin->rx_low_drive_cnt);
1245        seq_printf(file, "tx detected low drive: %u\n", pin->tx_low_drive_cnt);
1246        pin->work_pin_events_dropped_cnt = 0;
1247        pin->timer_cnt = 0;
1248        pin->timer_100ms_overruns = 0;
1249        pin->timer_300ms_overruns = 0;
1250        pin->timer_max_overrun = 0;
1251        pin->timer_sum_overrun = 0;
1252        pin->rx_start_bit_low_too_short_cnt = 0;
1253        pin->rx_start_bit_too_short_cnt = 0;
1254        pin->rx_start_bit_too_long_cnt = 0;
1255        pin->rx_data_bit_too_short_cnt = 0;
1256        pin->rx_data_bit_too_long_cnt = 0;
1257        pin->rx_low_drive_cnt = 0;
1258        pin->tx_low_drive_cnt = 0;
1259        if (pin->ops->status)
1260                pin->ops->status(adap, file);
1261}
1262
1263static int cec_pin_adap_monitor_all_enable(struct cec_adapter *adap,
1264                                                  bool enable)
1265{
1266        struct cec_pin *pin = adap->pin;
1267
1268        pin->monitor_all = enable;
1269        return 0;
1270}
1271
1272static void cec_pin_adap_free(struct cec_adapter *adap)
1273{
1274        struct cec_pin *pin = adap->pin;
1275
1276        if (pin->ops->free)
1277                pin->ops->free(adap);
1278        adap->pin = NULL;
1279        kfree(pin);
1280}
1281
1282static int cec_pin_received(struct cec_adapter *adap, struct cec_msg *msg)
1283{
1284        struct cec_pin *pin = adap->pin;
1285
1286        if (pin->ops->received)
1287                return pin->ops->received(adap, msg);
1288        return -ENOMSG;
1289}
1290
1291void cec_pin_changed(struct cec_adapter *adap, bool value)
1292{
1293        struct cec_pin *pin = adap->pin;
1294
1295        cec_pin_update(pin, value, false);
1296        if (!value && (adap->is_configuring || adap->is_configured ||
1297                       adap->monitor_all_cnt))
1298                atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_DISABLE);
1299}
1300EXPORT_SYMBOL_GPL(cec_pin_changed);
1301
1302static const struct cec_adap_ops cec_pin_adap_ops = {
1303        .adap_enable = cec_pin_adap_enable,
1304        .adap_monitor_all_enable = cec_pin_adap_monitor_all_enable,
1305        .adap_log_addr = cec_pin_adap_log_addr,
1306        .adap_transmit = cec_pin_adap_transmit,
1307        .adap_status = cec_pin_adap_status,
1308        .adap_free = cec_pin_adap_free,
1309#ifdef CONFIG_CEC_PIN_ERROR_INJ
1310        .error_inj_parse_line = cec_pin_error_inj_parse_line,
1311        .error_inj_show = cec_pin_error_inj_show,
1312#endif
1313        .received = cec_pin_received,
1314};
1315
1316struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops,
1317                                        void *priv, const char *name, u32 caps)
1318{
1319        struct cec_adapter *adap;
1320        struct cec_pin *pin = kzalloc(sizeof(*pin), GFP_KERNEL);
1321
1322        if (pin == NULL)
1323                return ERR_PTR(-ENOMEM);
1324        pin->ops = pin_ops;
1325        hrtimer_init(&pin->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1326        pin->timer.function = cec_pin_timer;
1327        init_waitqueue_head(&pin->kthread_waitq);
1328        pin->tx_custom_low_usecs = CEC_TIM_CUSTOM_DEFAULT;
1329        pin->tx_custom_high_usecs = CEC_TIM_CUSTOM_DEFAULT;
1330
1331        adap = cec_allocate_adapter(&cec_pin_adap_ops, priv, name,
1332                            caps | CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN,
1333                            CEC_MAX_LOG_ADDRS);
1334
1335        if (IS_ERR(adap)) {
1336                kfree(pin);
1337                return adap;
1338        }
1339
1340        adap->pin = pin;
1341        pin->adap = adap;
1342        cec_pin_update(pin, cec_pin_high(pin), true);
1343        return adap;
1344}
1345EXPORT_SYMBOL_GPL(cec_pin_allocate_adapter);
1346