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cec-pin.c
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cec-pin.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*/
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/sched/types.h>
#include <media/cec-pin.h>
#include "cec-pin-priv.h"
/* All timings are in microseconds */
/* start bit timings */
#define CEC_TIM_START_BIT_LOW 3700
#define CEC_TIM_START_BIT_LOW_MIN 3500
#define CEC_TIM_START_BIT_LOW_MAX 3900
#define CEC_TIM_START_BIT_TOTAL 4500
#define CEC_TIM_START_BIT_TOTAL_MIN 4300
#define CEC_TIM_START_BIT_TOTAL_MAX 4700
/* data bit timings */
#define CEC_TIM_DATA_BIT_0_LOW 1500
#define CEC_TIM_DATA_BIT_0_LOW_MIN 1300
#define CEC_TIM_DATA_BIT_0_LOW_MAX 1700
#define CEC_TIM_DATA_BIT_1_LOW 600
#define CEC_TIM_DATA_BIT_1_LOW_MIN 400
#define CEC_TIM_DATA_BIT_1_LOW_MAX 800
#define CEC_TIM_DATA_BIT_TOTAL 2400
#define CEC_TIM_DATA_BIT_TOTAL_MIN 2050
#define CEC_TIM_DATA_BIT_TOTAL_MAX 2750
/* earliest safe time to sample the bit state */
#define CEC_TIM_DATA_BIT_SAMPLE 850
/* earliest time the bit is back to 1 (T7 + 50) */
#define CEC_TIM_DATA_BIT_HIGH 1750
/* when idle, sample once per millisecond */
#define CEC_TIM_IDLE_SAMPLE 1000
/* when processing the start bit, sample twice per millisecond */
#define CEC_TIM_START_BIT_SAMPLE 500
/* when polling for a state change, sample once every 50 microseconds */
#define CEC_TIM_SAMPLE 50
#define CEC_TIM_LOW_DRIVE_ERROR (1.5 * CEC_TIM_DATA_BIT_TOTAL)
/*
* Total data bit time that is too short/long for a valid bit,
* used for error injection.
*/
#define CEC_TIM_DATA_BIT_TOTAL_SHORT 1800
#define CEC_TIM_DATA_BIT_TOTAL_LONG 2900
/*
* Total start bit time that is too short/long for a valid bit,
* used for error injection.
*/
#define CEC_TIM_START_BIT_TOTAL_SHORT 4100
#define CEC_TIM_START_BIT_TOTAL_LONG 5000
/* Data bits are 0-7, EOM is bit 8 and ACK is bit 9 */
#define EOM_BIT 8
#define ACK_BIT 9
struct cec_state {
const char * const name;
unsigned int usecs;
};
static const struct cec_state states[CEC_PIN_STATES] = {
{ "Off", 0 },
{ "Idle", CEC_TIM_IDLE_SAMPLE },
{ "Tx Wait", CEC_TIM_SAMPLE },
{ "Tx Wait for High", CEC_TIM_IDLE_SAMPLE },
{ "Tx Start Bit Low", CEC_TIM_START_BIT_LOW },
{ "Tx Start Bit High", CEC_TIM_START_BIT_TOTAL - CEC_TIM_START_BIT_LOW },
{ "Tx Start Bit High Short", CEC_TIM_START_BIT_TOTAL_SHORT - CEC_TIM_START_BIT_LOW },
{ "Tx Start Bit High Long", CEC_TIM_START_BIT_TOTAL_LONG - CEC_TIM_START_BIT_LOW },
{ "Tx Start Bit Low Custom", 0 },
{ "Tx Start Bit High Custom", 0 },
{ "Tx Data 0 Low", CEC_TIM_DATA_BIT_0_LOW },
{ "Tx Data 0 High", CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_0_LOW },
{ "Tx Data 0 High Short", CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_0_LOW },
{ "Tx Data 0 High Long", CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_0_LOW },
{ "Tx Data 1 Low", CEC_TIM_DATA_BIT_1_LOW },
{ "Tx Data 1 High", CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_1_LOW },
{ "Tx Data 1 High Short", CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_1_LOW },
{ "Tx Data 1 High Long", CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_1_LOW },
{ "Tx Data 1 High Pre Sample", CEC_TIM_DATA_BIT_SAMPLE - CEC_TIM_DATA_BIT_1_LOW },
{ "Tx Data 1 High Post Sample", CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_SAMPLE },
{ "Tx Data 1 High Post Sample Short", CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_SAMPLE },
{ "Tx Data 1 High Post Sample Long", CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_SAMPLE },
{ "Tx Data Bit Low Custom", 0 },
{ "Tx Data Bit High Custom", 0 },
{ "Tx Pulse Low Custom", 0 },
{ "Tx Pulse High Custom", 0 },
{ "Tx Low Drive", CEC_TIM_LOW_DRIVE_ERROR },
{ "Rx Start Bit Low", CEC_TIM_SAMPLE },
{ "Rx Start Bit High", CEC_TIM_SAMPLE },
{ "Rx Data Sample", CEC_TIM_DATA_BIT_SAMPLE },
{ "Rx Data Post Sample", CEC_TIM_DATA_BIT_HIGH - CEC_TIM_DATA_BIT_SAMPLE },
{ "Rx Data Wait for Low", CEC_TIM_SAMPLE },
{ "Rx Ack Low", CEC_TIM_DATA_BIT_0_LOW },
{ "Rx Ack Low Post", CEC_TIM_DATA_BIT_HIGH - CEC_TIM_DATA_BIT_0_LOW },
{ "Rx Ack High Post", CEC_TIM_DATA_BIT_HIGH },
{ "Rx Ack Finish", CEC_TIM_DATA_BIT_TOTAL_MIN - CEC_TIM_DATA_BIT_HIGH },
{ "Rx Low Drive", CEC_TIM_LOW_DRIVE_ERROR },
{ "Rx Irq", 0 },
};
static void cec_pin_update(struct cec_pin *pin, bool v, bool force)
{
if (!force && v == pin->adap->cec_pin_is_high)
return;
pin->adap->cec_pin_is_high = v;
if (atomic_read(&pin->work_pin_num_events) < CEC_NUM_PIN_EVENTS) {
u8 ev = v;
if (pin->work_pin_events_dropped) {
pin->work_pin_events_dropped = false;
ev |= CEC_PIN_EVENT_FL_DROPPED;
}
pin->work_pin_events[pin->work_pin_events_wr] = ev;
pin->work_pin_ts[pin->work_pin_events_wr] = ktime_get();
pin->work_pin_events_wr =
(pin->work_pin_events_wr + 1) % CEC_NUM_PIN_EVENTS;
atomic_inc(&pin->work_pin_num_events);
} else {
pin->work_pin_events_dropped = true;
pin->work_pin_events_dropped_cnt++;
}
wake_up_interruptible(&pin->kthread_waitq);
}
static bool cec_pin_read(struct cec_pin *pin)
{
bool v = pin->ops->read(pin->adap);
cec_pin_update(pin, v, false);
return v;
}
static void cec_pin_low(struct cec_pin *pin)
{
pin->ops->low(pin->adap);
cec_pin_update(pin, false, false);
}
static bool cec_pin_high(struct cec_pin *pin)
{
pin->ops->high(pin->adap);
return cec_pin_read(pin);
}
static bool rx_error_inj(struct cec_pin *pin, unsigned int mode_offset,
int arg_idx, u8 *arg)
{
#ifdef CONFIG_CEC_PIN_ERROR_INJ
u16 cmd = cec_pin_rx_error_inj(pin);
u64 e = pin->error_inj[cmd];
unsigned int mode = (e >> mode_offset) & CEC_ERROR_INJ_MODE_MASK;
if (arg_idx >= 0) {
u8 pos = pin->error_inj_args[cmd][arg_idx];
if (arg)
*arg = pos;
else if (pos != pin->rx_bit)
return false;
}
switch (mode) {
case CEC_ERROR_INJ_MODE_ONCE:
pin->error_inj[cmd] &=
~(CEC_ERROR_INJ_MODE_MASK << mode_offset);
return true;
case CEC_ERROR_INJ_MODE_ALWAYS:
return true;
case CEC_ERROR_INJ_MODE_TOGGLE:
return pin->rx_toggle;
default:
return false;
}
#else
return false;
#endif
}
static bool rx_nack(struct cec_pin *pin)
{
return rx_error_inj(pin, CEC_ERROR_INJ_RX_NACK_OFFSET, -1, NULL);
}
static bool rx_low_drive(struct cec_pin *pin)
{
return rx_error_inj(pin, CEC_ERROR_INJ_RX_LOW_DRIVE_OFFSET,
CEC_ERROR_INJ_RX_LOW_DRIVE_ARG_IDX, NULL);
}
static bool rx_add_byte(struct cec_pin *pin)
{
return rx_error_inj(pin, CEC_ERROR_INJ_RX_ADD_BYTE_OFFSET, -1, NULL);
}
static bool rx_remove_byte(struct cec_pin *pin)
{
return rx_error_inj(pin, CEC_ERROR_INJ_RX_REMOVE_BYTE_OFFSET, -1, NULL);
}
static bool rx_arb_lost(struct cec_pin *pin, u8 *poll)
{
return pin->tx_msg.len == 0 &&
rx_error_inj(pin, CEC_ERROR_INJ_RX_ARB_LOST_OFFSET,
CEC_ERROR_INJ_RX_ARB_LOST_ARG_IDX, poll);
}
static bool tx_error_inj(struct cec_pin *pin, unsigned int mode_offset,
int arg_idx, u8 *arg)
{
#ifdef CONFIG_CEC_PIN_ERROR_INJ
u16 cmd = cec_pin_tx_error_inj(pin);
u64 e = pin->error_inj[cmd];
unsigned int mode = (e >> mode_offset) & CEC_ERROR_INJ_MODE_MASK;
if (arg_idx >= 0) {
u8 pos = pin->error_inj_args[cmd][arg_idx];
if (arg)
*arg = pos;
else if (pos != pin->tx_bit)
return false;
}
switch (mode) {
case CEC_ERROR_INJ_MODE_ONCE:
pin->error_inj[cmd] &=
~(CEC_ERROR_INJ_MODE_MASK << mode_offset);
return true;
case CEC_ERROR_INJ_MODE_ALWAYS:
return true;
case CEC_ERROR_INJ_MODE_TOGGLE:
return pin->tx_toggle;
default:
return false;
}
#else
return false;
#endif
}
static bool tx_no_eom(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_NO_EOM_OFFSET, -1, NULL);
}
static bool tx_early_eom(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_EARLY_EOM_OFFSET, -1, NULL);
}
static bool tx_short_bit(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_SHORT_BIT_OFFSET,
CEC_ERROR_INJ_TX_SHORT_BIT_ARG_IDX, NULL);
}
static bool tx_long_bit(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_LONG_BIT_OFFSET,
CEC_ERROR_INJ_TX_LONG_BIT_ARG_IDX, NULL);
}
static bool tx_custom_bit(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_CUSTOM_BIT_OFFSET,
CEC_ERROR_INJ_TX_CUSTOM_BIT_ARG_IDX, NULL);
}
static bool tx_short_start(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_SHORT_START_OFFSET, -1, NULL);
}
static bool tx_long_start(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_LONG_START_OFFSET, -1, NULL);
}
static bool tx_custom_start(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_CUSTOM_START_OFFSET,
-1, NULL);
}
static bool tx_last_bit(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_LAST_BIT_OFFSET,
CEC_ERROR_INJ_TX_LAST_BIT_ARG_IDX, NULL);
}
static u8 tx_add_bytes(struct cec_pin *pin)
{
u8 bytes;
if (tx_error_inj(pin, CEC_ERROR_INJ_TX_ADD_BYTES_OFFSET,
CEC_ERROR_INJ_TX_ADD_BYTES_ARG_IDX, &bytes))
return bytes;
return 0;
}
static bool tx_remove_byte(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_REMOVE_BYTE_OFFSET, -1, NULL);
}
static bool tx_low_drive(struct cec_pin *pin)
{
return tx_error_inj(pin, CEC_ERROR_INJ_TX_LOW_DRIVE_OFFSET,
CEC_ERROR_INJ_TX_LOW_DRIVE_ARG_IDX, NULL);
}
static void cec_pin_to_idle(struct cec_pin *pin)
{
/*
* Reset all status fields, release the bus and
* go to idle state.
*/
pin->rx_bit = pin->tx_bit = 0;
pin->rx_msg.len = 0;
memset(pin->rx_msg.msg, 0, sizeof(pin->rx_msg.msg));
pin->ts = ns_to_ktime(0);
pin->tx_generated_poll = false;
pin->tx_post_eom = false;
if (pin->state >= CEC_ST_TX_WAIT &&
pin->state <= CEC_ST_TX_LOW_DRIVE)
pin->tx_toggle ^= 1;
if (pin->state >= CEC_ST_RX_START_BIT_LOW &&
pin->state <= CEC_ST_RX_LOW_DRIVE)
pin->rx_toggle ^= 1;
pin->state = CEC_ST_IDLE;
}
/*
* Handle Transmit-related states
*
* Basic state changes when transmitting:
*
* Idle -> Tx Wait (waiting for the end of signal free time) ->
* Tx Start Bit Low -> Tx Start Bit High ->
*
* Regular data bits + EOM:
* Tx Data 0 Low -> Tx Data 0 High ->
* or:
* Tx Data 1 Low -> Tx Data 1 High ->
*
* First 4 data bits or Ack bit:
* Tx Data 0 Low -> Tx Data 0 High ->
* or:
* Tx Data 1 Low -> Tx Data 1 High -> Tx Data 1 Pre Sample ->
* Tx Data 1 Post Sample ->
*
* After the last Ack go to Idle.
*
* If it detects a Low Drive condition then:
* Tx Wait For High -> Idle
*
* If it loses arbitration, then it switches to state Rx Data Post Sample.
*/
static void cec_pin_tx_states(struct cec_pin *pin, ktime_t ts)
{
bool v;
bool is_ack_bit, ack;
switch (pin->state) {
case CEC_ST_TX_WAIT_FOR_HIGH:
if (cec_pin_read(pin))
cec_pin_to_idle(pin);
break;
case CEC_ST_TX_START_BIT_LOW:
if (tx_short_start(pin)) {
/*
* Error Injection: send an invalid (too short)
* start pulse.
*/
pin->state = CEC_ST_TX_START_BIT_HIGH_SHORT;
} else if (tx_long_start(pin)) {
/*
* Error Injection: send an invalid (too long)
* start pulse.
*/
pin->state = CEC_ST_TX_START_BIT_HIGH_LONG;
} else {
pin->state = CEC_ST_TX_START_BIT_HIGH;
}
/* Generate start bit */
cec_pin_high(pin);
break;
case CEC_ST_TX_START_BIT_LOW_CUSTOM:
pin->state = CEC_ST_TX_START_BIT_HIGH_CUSTOM;
/* Generate start bit */
cec_pin_high(pin);
break;
case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE:
case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT:
case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG:
if (pin->tx_nacked) {
cec_pin_to_idle(pin);
pin->tx_msg.len = 0;
if (pin->tx_generated_poll)
break;
pin->work_tx_ts = ts;
pin->work_tx_status = CEC_TX_STATUS_NACK;
wake_up_interruptible(&pin->kthread_waitq);
break;
}
/* fall through */
case CEC_ST_TX_DATA_BIT_0_HIGH:
case CEC_ST_TX_DATA_BIT_0_HIGH_SHORT:
case CEC_ST_TX_DATA_BIT_0_HIGH_LONG:
case CEC_ST_TX_DATA_BIT_1_HIGH:
case CEC_ST_TX_DATA_BIT_1_HIGH_SHORT:
case CEC_ST_TX_DATA_BIT_1_HIGH_LONG:
/*
* If the read value is 1, then all is OK, otherwise we have a
* low drive condition.
*
* Special case: when we generate a poll message due to an
* Arbitration Lost error injection, then ignore this since
* the pin can actually be low in that case.
*/
if (!cec_pin_read(pin) && !pin->tx_generated_poll) {
/*
* It's 0, so someone detected an error and pulled the
* line low for 1.5 times the nominal bit period.
*/
pin->tx_msg.len = 0;
pin->state = CEC_ST_TX_WAIT_FOR_HIGH;
pin->work_tx_ts = ts;
pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
pin->tx_low_drive_cnt++;
wake_up_interruptible(&pin->kthread_waitq);
break;
}
/* fall through */
case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
if (tx_last_bit(pin)) {
/* Error Injection: just stop sending after this bit */
cec_pin_to_idle(pin);
pin->tx_msg.len = 0;
if (pin->tx_generated_poll)
break;
pin->work_tx_ts = ts;
pin->work_tx_status = CEC_TX_STATUS_OK;
wake_up_interruptible(&pin->kthread_waitq);
break;
}
pin->tx_bit++;
/* fall through */
case CEC_ST_TX_START_BIT_HIGH:
case CEC_ST_TX_START_BIT_HIGH_SHORT:
case CEC_ST_TX_START_BIT_HIGH_LONG:
case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
if (tx_low_drive(pin)) {
/* Error injection: go to low drive */
cec_pin_low(pin);
pin->state = CEC_ST_TX_LOW_DRIVE;
pin->tx_msg.len = 0;
if (pin->tx_generated_poll)
break;
pin->work_tx_ts = ts;
pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
pin->tx_low_drive_cnt++;
wake_up_interruptible(&pin->kthread_waitq);
break;
}
if (pin->tx_bit / 10 >= pin->tx_msg.len + pin->tx_extra_bytes) {
cec_pin_to_idle(pin);
pin->tx_msg.len = 0;
if (pin->tx_generated_poll)
break;
pin->work_tx_ts = ts;
pin->work_tx_status = CEC_TX_STATUS_OK;
wake_up_interruptible(&pin->kthread_waitq);
break;
}
switch (pin->tx_bit % 10) {
default: {
/*
* In the CEC_ERROR_INJ_TX_ADD_BYTES case we transmit
* extra bytes, so pin->tx_bit / 10 can become >= 16.
* Generate bit values for those extra bytes instead
* of reading them from the transmit buffer.
*/
unsigned int idx = (pin->tx_bit / 10);
u8 val = idx;
if (idx < pin->tx_msg.len)
val = pin->tx_msg.msg[idx];
v = val & (1 << (7 - (pin->tx_bit % 10)));
pin->state = v ? CEC_ST_TX_DATA_BIT_1_LOW :
CEC_ST_TX_DATA_BIT_0_LOW;
break;
}
case EOM_BIT: {
unsigned int tot_len = pin->tx_msg.len +
pin->tx_extra_bytes;
unsigned int tx_byte_idx = pin->tx_bit / 10;
v = !pin->tx_post_eom && tx_byte_idx == tot_len - 1;
if (tot_len > 1 && tx_byte_idx == tot_len - 2 &&
tx_early_eom(pin)) {
/* Error injection: set EOM one byte early */
v = true;
pin->tx_post_eom = true;
} else if (v && tx_no_eom(pin)) {
/* Error injection: no EOM */
v = false;
}
pin->state = v ? CEC_ST_TX_DATA_BIT_1_LOW :
CEC_ST_TX_DATA_BIT_0_LOW;
break;
}
case ACK_BIT:
pin->state = CEC_ST_TX_DATA_BIT_1_LOW;
break;
}
if (tx_custom_bit(pin))
pin->state = CEC_ST_TX_DATA_BIT_LOW_CUSTOM;
cec_pin_low(pin);
break;
case CEC_ST_TX_DATA_BIT_0_LOW:
case CEC_ST_TX_DATA_BIT_1_LOW:
v = pin->state == CEC_ST_TX_DATA_BIT_1_LOW;
is_ack_bit = pin->tx_bit % 10 == ACK_BIT;
if (v && (pin->tx_bit < 4 || is_ack_bit)) {
pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE;
} else if (!is_ack_bit && tx_short_bit(pin)) {
/* Error Injection: send an invalid (too short) bit */
pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH_SHORT :
CEC_ST_TX_DATA_BIT_0_HIGH_SHORT;
} else if (!is_ack_bit && tx_long_bit(pin)) {
/* Error Injection: send an invalid (too long) bit */
pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH_LONG :
CEC_ST_TX_DATA_BIT_0_HIGH_LONG;
} else {
pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH :
CEC_ST_TX_DATA_BIT_0_HIGH;
}
cec_pin_high(pin);
break;
case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
pin->state = CEC_ST_TX_DATA_BIT_HIGH_CUSTOM;
cec_pin_high(pin);
break;
case CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE:
/* Read the CEC value at the sample time */
v = cec_pin_read(pin);
is_ack_bit = pin->tx_bit % 10 == ACK_BIT;
/*
* If v == 0 and we're within the first 4 bits
* of the initiator, then someone else started
* transmitting and we lost the arbitration
* (i.e. the logical address of the other
* transmitter has more leading 0 bits in the
* initiator).
*/
if (!v && !is_ack_bit && !pin->tx_generated_poll) {
pin->tx_msg.len = 0;
pin->work_tx_ts = ts;
pin->work_tx_status = CEC_TX_STATUS_ARB_LOST;
wake_up_interruptible(&pin->kthread_waitq);
pin->rx_bit = pin->tx_bit;
pin->tx_bit = 0;
memset(pin->rx_msg.msg, 0, sizeof(pin->rx_msg.msg));
pin->rx_msg.msg[0] = pin->tx_msg.msg[0];
pin->rx_msg.msg[0] &= (0xff << (8 - pin->rx_bit));
pin->rx_msg.len = 0;
pin->ts = ktime_sub_us(ts, CEC_TIM_DATA_BIT_SAMPLE);
pin->state = CEC_ST_RX_DATA_POST_SAMPLE;
pin->rx_bit++;
break;
}
pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE;
if (!is_ack_bit && tx_short_bit(pin)) {
/* Error Injection: send an invalid (too short) bit */
pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT;
} else if (!is_ack_bit && tx_long_bit(pin)) {
/* Error Injection: send an invalid (too long) bit */
pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG;
}
if (!is_ack_bit)
break;
/* Was the message ACKed? */
ack = cec_msg_is_broadcast(&pin->tx_msg) ? v : !v;
if (!ack && (!pin->tx_ignore_nack_until_eom ||
pin->tx_bit / 10 == pin->tx_msg.len - 1) &&
!pin->tx_post_eom) {
/*
* Note: the CEC spec is ambiguous regarding
* what action to take when a NACK appears
* before the last byte of the payload was
* transmitted: either stop transmitting
* immediately, or wait until the last byte
* was transmitted.
*
* Most CEC implementations appear to stop
* immediately, and that's what we do here
* as well.
*/
pin->tx_nacked = true;
}
break;
case CEC_ST_TX_PULSE_LOW_CUSTOM:
cec_pin_high(pin);
pin->state = CEC_ST_TX_PULSE_HIGH_CUSTOM;
break;
case CEC_ST_TX_PULSE_HIGH_CUSTOM:
cec_pin_to_idle(pin);
break;
default:
break;
}
}
/*
* Handle Receive-related states
*
* Basic state changes when receiving:
*
* Rx Start Bit Low -> Rx Start Bit High ->
* Regular data bits + EOM:
* Rx Data Sample -> Rx Data Post Sample -> Rx Data High ->
* Ack bit 0:
* Rx Ack Low -> Rx Ack Low Post -> Rx Data High ->
* Ack bit 1:
* Rx Ack High Post -> Rx Data High ->
* Ack bit 0 && EOM:
* Rx Ack Low -> Rx Ack Low Post -> Rx Ack Finish -> Idle
*/
static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
{
s32 delta;
bool v;
bool ack;
bool bcast, for_us;
u8 dest;
u8 poll;
switch (pin->state) {
/* Receive states */
case CEC_ST_RX_START_BIT_LOW:
v = cec_pin_read(pin);
if (!v)
break;
pin->state = CEC_ST_RX_START_BIT_HIGH;
delta = ktime_us_delta(ts, pin->ts);
/* Start bit low is too short, go back to idle */
if (delta < CEC_TIM_START_BIT_LOW_MIN - CEC_TIM_IDLE_SAMPLE) {
if (!pin->rx_start_bit_low_too_short_cnt++) {
pin->rx_start_bit_low_too_short_ts = ktime_to_ns(pin->ts);
pin->rx_start_bit_low_too_short_delta = delta;
}
cec_pin_to_idle(pin);
break;
}
if (rx_arb_lost(pin, &poll)) {
cec_msg_init(&pin->tx_msg, poll >> 4, poll & 0xf);
pin->tx_generated_poll = true;
pin->tx_extra_bytes = 0;
pin->state = CEC_ST_TX_START_BIT_HIGH;
pin->ts = ts;
}
break;
case CEC_ST_RX_START_BIT_HIGH:
v = cec_pin_read(pin);
delta = ktime_us_delta(ts, pin->ts);
/*
* Unfortunately the spec does not specify when to give up
* and go to idle. We just pick TOTAL_LONG.
*/
if (v && delta > CEC_TIM_START_BIT_TOTAL_LONG) {
pin->rx_start_bit_too_long_cnt++;
cec_pin_to_idle(pin);
break;
}
if (v)
break;
/* Start bit is too short, go back to idle */
if (delta < CEC_TIM_START_BIT_TOTAL_MIN - CEC_TIM_IDLE_SAMPLE) {
if (!pin->rx_start_bit_too_short_cnt++) {
pin->rx_start_bit_too_short_ts = ktime_to_ns(pin->ts);
pin->rx_start_bit_too_short_delta = delta;
}
cec_pin_to_idle(pin);
break;
}
if (rx_low_drive(pin)) {
/* Error injection: go to low drive */
cec_pin_low(pin);
pin->state = CEC_ST_RX_LOW_DRIVE;
pin->rx_low_drive_cnt++;
break;
}
pin->state = CEC_ST_RX_DATA_SAMPLE;
pin->ts = ts;
pin->rx_eom = false;
break;
case CEC_ST_RX_DATA_SAMPLE:
v = cec_pin_read(pin);
pin->state = CEC_ST_RX_DATA_POST_SAMPLE;
switch (pin->rx_bit % 10) {
default:
if (pin->rx_bit / 10 < CEC_MAX_MSG_SIZE)
pin->rx_msg.msg[pin->rx_bit / 10] |=
v << (7 - (pin->rx_bit % 10));
break;
case EOM_BIT:
pin->rx_eom = v;
pin->rx_msg.len = pin->rx_bit / 10 + 1;
break;
case ACK_BIT:
break;
}
pin->rx_bit++;
break;
case CEC_ST_RX_DATA_POST_SAMPLE:
pin->state = CEC_ST_RX_DATA_WAIT_FOR_LOW;
break;
case CEC_ST_RX_DATA_WAIT_FOR_LOW:
v = cec_pin_read(pin);
delta = ktime_us_delta(ts, pin->ts);
/*
* Unfortunately the spec does not specify when to give up
* and go to idle. We just pick TOTAL_LONG.
*/
if (v && delta > CEC_TIM_DATA_BIT_TOTAL_LONG) {
pin->rx_data_bit_too_long_cnt++;
cec_pin_to_idle(pin);
break;
}
if (v)
break;
if (rx_low_drive(pin)) {
/* Error injection: go to low drive */
cec_pin_low(pin);
pin->state = CEC_ST_RX_LOW_DRIVE;
pin->rx_low_drive_cnt++;
break;
}
/*
* Go to low drive state when the total bit time is
* too short.
*/
if (delta < CEC_TIM_DATA_BIT_TOTAL_MIN) {
if (!pin->rx_data_bit_too_short_cnt++) {
pin->rx_data_bit_too_short_ts = ktime_to_ns(pin->ts);
pin->rx_data_bit_too_short_delta = delta;
}
cec_pin_low(pin);
pin->state = CEC_ST_RX_LOW_DRIVE;
pin->rx_low_drive_cnt++;
break;
}
pin->ts = ts;
if (pin->rx_bit % 10 != 9) {
pin->state = CEC_ST_RX_DATA_SAMPLE;
break;
}
dest = cec_msg_destination(&pin->rx_msg);
bcast = dest == CEC_LOG_ADDR_BROADCAST;
/* for_us == broadcast or directed to us */
for_us = bcast || (pin->la_mask & (1 << dest));
/* ACK bit value */
ack = bcast ? 1 : !for_us;
if (for_us && rx_nack(pin)) {
/* Error injection: toggle the ACK bit */
ack = !ack;
}
if (ack) {
/* No need to write to the bus, just wait */
pin->state = CEC_ST_RX_ACK_HIGH_POST;
break;
}
cec_pin_low(pin);
pin->state = CEC_ST_RX_ACK_LOW;
break;
case CEC_ST_RX_ACK_LOW:
cec_pin_high(pin);
pin->state = CEC_ST_RX_ACK_LOW_POST;
break;
case CEC_ST_RX_ACK_LOW_POST:
case CEC_ST_RX_ACK_HIGH_POST:
v = cec_pin_read(pin);
if (v && pin->rx_eom) {
pin->work_rx_msg = pin->rx_msg;
pin->work_rx_msg.rx_ts = ktime_to_ns(ts);
wake_up_interruptible(&pin->kthread_waitq);
pin->ts = ts;
pin->state = CEC_ST_RX_ACK_FINISH;
break;
}
pin->rx_bit++;
pin->state = CEC_ST_RX_DATA_WAIT_FOR_LOW;
break;
case CEC_ST_RX_ACK_FINISH:
cec_pin_to_idle(pin);
break;
default:
break;
}
}
/*
* Main timer function
*
*/
static enum hrtimer_restart cec_pin_timer(struct hrtimer *timer)
{
struct cec_pin *pin = container_of(timer, struct cec_pin, timer);
struct cec_adapter *adap = pin->adap;
ktime_t ts;
s32 delta;
u32 usecs;
ts = ktime_get();
if (ktime_to_ns(pin->timer_ts)) {
delta = ktime_us_delta(ts, pin->timer_ts);
pin->timer_cnt++;
if (delta > 100 && pin->state != CEC_ST_IDLE) {
/* Keep track of timer overruns */
pin->timer_sum_overrun += delta;
pin->timer_100ms_overruns++;
if (delta > 300)
pin->timer_300ms_overruns++;
if (delta > pin->timer_max_overrun)
pin->timer_max_overrun = delta;
}
}
if (adap->monitor_pin_cnt)
cec_pin_read(pin);
if (pin->wait_usecs) {
/*
* If we are monitoring the pin, then we have to
* sample at regular intervals.
*/
if (pin->wait_usecs > 150) {
pin->wait_usecs -= 100;
pin->timer_ts = ktime_add_us(ts, 100);
hrtimer_forward_now(timer, ns_to_ktime(100000));
return HRTIMER_RESTART;
}
if (pin->wait_usecs > 100) {
pin->wait_usecs /= 2;
pin->timer_ts = ktime_add_us(ts, pin->wait_usecs);
hrtimer_forward_now(timer,
ns_to_ktime(pin->wait_usecs * 1000));
return HRTIMER_RESTART;
}
pin->timer_ts = ktime_add_us(ts, pin->wait_usecs);
hrtimer_forward_now(timer,
ns_to_ktime(pin->wait_usecs * 1000));
pin->wait_usecs = 0;
return HRTIMER_RESTART;
}
switch (pin->state) {
/* Transmit states */
case CEC_ST_TX_WAIT_FOR_HIGH:
case CEC_ST_TX_START_BIT_LOW:
case CEC_ST_TX_START_BIT_HIGH:
case CEC_ST_TX_START_BIT_HIGH_SHORT:
case CEC_ST_TX_START_BIT_HIGH_LONG:
case CEC_ST_TX_START_BIT_LOW_CUSTOM:
case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
case CEC_ST_TX_DATA_BIT_0_LOW:
case CEC_ST_TX_DATA_BIT_0_HIGH:
case CEC_ST_TX_DATA_BIT_0_HIGH_SHORT:
case CEC_ST_TX_DATA_BIT_0_HIGH_LONG:
case CEC_ST_TX_DATA_BIT_1_LOW:
case CEC_ST_TX_DATA_BIT_1_HIGH:
case CEC_ST_TX_DATA_BIT_1_HIGH_SHORT:
case CEC_ST_TX_DATA_BIT_1_HIGH_LONG:
case CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE:
case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE:
case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT:
case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG:
case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
case CEC_ST_TX_PULSE_LOW_CUSTOM:
case CEC_ST_TX_PULSE_HIGH_CUSTOM:
cec_pin_tx_states(pin, ts);
break;
/* Receive states */
case CEC_ST_RX_START_BIT_LOW:
case CEC_ST_RX_START_BIT_HIGH:
case CEC_ST_RX_DATA_SAMPLE:
case CEC_ST_RX_DATA_POST_SAMPLE:
case CEC_ST_RX_DATA_WAIT_FOR_LOW:
case CEC_ST_RX_ACK_LOW:
case CEC_ST_RX_ACK_LOW_POST:
case CEC_ST_RX_ACK_HIGH_POST:
case CEC_ST_RX_ACK_FINISH:
cec_pin_rx_states(pin, ts);
break;
case CEC_ST_IDLE:
case CEC_ST_TX_WAIT:
if (!cec_pin_high(pin)) {
/* Start bit, switch to receive state */
pin->ts = ts;
pin->state = CEC_ST_RX_START_BIT_LOW;
/*
* If a transmit is pending, then that transmit should
* use a signal free time of no more than
* CEC_SIGNAL_FREE_TIME_NEW_INITIATOR since it will
* have a new initiator due to the receive that is now
* starting.
*/
if (pin->tx_msg.len && pin->tx_signal_free_time >
CEC_SIGNAL_FREE_TIME_NEW_INITIATOR)
pin->tx_signal_free_time =
CEC_SIGNAL_FREE_TIME_NEW_INITIATOR;
break;
}
if (ktime_to_ns(pin->ts) == 0)
pin->ts = ts;
if (pin->tx_msg.len) {
/*
* Check if the bus has been free for long enough
* so we can kick off the pending transmit.
*/
delta = ktime_us_delta(ts, pin->ts);
if (delta / CEC_TIM_DATA_BIT_TOTAL >
pin->tx_signal_free_time) {
pin->tx_nacked = false;
if (tx_custom_start(pin))
pin->state = CEC_ST_TX_START_BIT_LOW_CUSTOM;
else
pin->state = CEC_ST_TX_START_BIT_LOW;
/* Generate start bit */
cec_pin_low(pin);
break;
}
if (delta / CEC_TIM_DATA_BIT_TOTAL >
pin->tx_signal_free_time - 1)
pin->state = CEC_ST_TX_WAIT;
break;
}
if (pin->tx_custom_pulse && pin->state == CEC_ST_IDLE) {
pin->tx_custom_pulse = false;
/* Generate custom pulse */
cec_pin_low(pin);
pin->state = CEC_ST_TX_PULSE_LOW_CUSTOM;
break;
}
if (pin->state != CEC_ST_IDLE || pin->ops->enable_irq == NULL ||
pin->enable_irq_failed || adap->is_configuring ||
adap->is_configured || adap->monitor_all_cnt)
break;
/* Switch to interrupt mode */
atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_ENABLE);
pin->state = CEC_ST_RX_IRQ;
wake_up_interruptible(&pin->kthread_waitq);
return HRTIMER_NORESTART;
case CEC_ST_TX_LOW_DRIVE:
case CEC_ST_RX_LOW_DRIVE:
cec_pin_high(pin);
cec_pin_to_idle(pin);
break;
default:
break;