diff options
| -rw-r--r-- | drivers/media/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/media/cec/Makefile | 4 | ||||
| -rw-r--r-- | drivers/media/cec/cec-api.c | 10 | ||||
| -rw-r--r-- | drivers/media/cec/cec-pin.c | 794 | ||||
| -rw-r--r-- | include/media/cec-pin.h | 183 | ||||
| -rw-r--r-- | include/media/cec.h | 4 |
6 files changed, 998 insertions, 0 deletions
diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig index 55d9c2b82b7e..94d4e7759127 100644 --- a/drivers/media/Kconfig +++ b/drivers/media/Kconfig @@ -8,6 +8,9 @@ config CEC_CORE config CEC_NOTIFIER bool +config CEC_PIN + bool + menuconfig MEDIA_SUPPORT tristate "Multimedia support" depends on HAS_IOMEM diff --git a/drivers/media/cec/Makefile b/drivers/media/cec/Makefile index eaf408e64669..3353c1741961 100644 --- a/drivers/media/cec/Makefile +++ b/drivers/media/cec/Makefile @@ -4,4 +4,8 @@ ifeq ($(CONFIG_CEC_NOTIFIER),y) cec-objs += cec-notifier.o endif +ifeq ($(CONFIG_CEC_PIN),y) + cec-objs += cec-pin.o +endif + obj-$(CONFIG_CEC_CORE) += cec.o diff --git a/drivers/media/cec/cec-api.c b/drivers/media/cec/cec-api.c index 14279958dca1..8dd16e263452 100644 --- a/drivers/media/cec/cec-api.c +++ b/drivers/media/cec/cec-api.c @@ -30,6 +30,7 @@ #include <linux/uaccess.h> #include <linux/version.h> +#include <media/cec-pin.h> #include "cec-priv.h" static inline struct cec_devnode *cec_devnode_data(struct file *filp) @@ -430,6 +431,15 @@ static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh, if (mode_follower == CEC_MODE_FOLLOWER) adap->follower_cnt++; if (mode_follower == CEC_MODE_MONITOR_PIN) { +#ifdef CONFIG_CEC_PIN + struct cec_event ev = { + .flags = CEC_EVENT_FL_INITIAL_STATE, + }; + + ev.event = adap->pin->cur_value ? CEC_EVENT_PIN_HIGH : + CEC_EVENT_PIN_LOW; + cec_queue_event_fh(fh, &ev, 0); +#endif adap->monitor_pin_cnt++; } if (mode_follower == CEC_MODE_EXCL_FOLLOWER || diff --git a/drivers/media/cec/cec-pin.c b/drivers/media/cec/cec-pin.c new file mode 100644 index 000000000000..03f800e5ec1f --- /dev/null +++ b/drivers/media/cec/cec-pin.c @@ -0,0 +1,794 @@ +/* + * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved. + * + * This program is free software; you may redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/sched/types.h> + +#include <media/cec-pin.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 micoseconds */ +#define CEC_TIM_SAMPLE 50 + +#define CEC_TIM_LOW_DRIVE_ERROR (1.5 * CEC_TIM_DATA_BIT_TOTAL) + +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 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 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 Pre Sample", CEC_TIM_DATA_BIT_SAMPLE - CEC_TIM_DATA_BIT_1_LOW }, + { "Tx Data 1 Post Sample", CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_SAMPLE }, + { "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 High", 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->cur_value) + return; + + pin->cur_value = v; + if (atomic_read(&pin->work_pin_events) < CEC_NUM_PIN_EVENTS) { + pin->work_pin_is_high[pin->work_pin_events_wr] = v; + 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_events); + } + 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 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->state = CEC_ST_IDLE; + pin->ts = 0; +} + +/* + * 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: + pin->state = CEC_ST_TX_START_BIT_HIGH; + /* Generate start bit */ + cec_pin_high(pin); + break; + + case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE: + /* If the read value is 1, then all is OK */ + if (!cec_pin_read(pin)) { + /* + * 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->work_tx_ts = ts; + pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE; + pin->state = CEC_ST_TX_WAIT_FOR_HIGH; + wake_up_interruptible(&pin->kthread_waitq); + break; + } + if (pin->tx_nacked) { + cec_pin_to_idle(pin); + pin->tx_msg.len = 0; + 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_1_HIGH: + pin->tx_bit++; + /* fall through */ + case CEC_ST_TX_START_BIT_HIGH: + if (pin->tx_bit / 10 >= pin->tx_msg.len) { + cec_pin_to_idle(pin); + pin->tx_msg.len = 0; + 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: + v = pin->tx_msg.msg[pin->tx_bit / 10] & + (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 8: + v = pin->tx_bit / 10 == pin->tx_msg.len - 1; + pin->state = v ? CEC_ST_TX_DATA_BIT_1_LOW : + CEC_ST_TX_DATA_BIT_0_LOW; + break; + case 9: + pin->state = CEC_ST_TX_DATA_BIT_1_LOW; + break; + } + 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; + pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH : + CEC_ST_TX_DATA_BIT_0_HIGH; + is_ack_bit = pin->tx_bit % 10 == 9; + if (v && (pin->tx_bit < 4 || is_ack_bit)) + pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE; + 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 == 9; + /* + * 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_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] &= ~(1 << (7 - pin->rx_bit)); + pin->rx_msg.len = 0; + 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) + break; + /* Was the message ACKed? */ + ack = cec_msg_is_broadcast(&pin->tx_msg) ? v : !v; + if (!ack) { + /* + * 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; + + 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; + + 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); + pin->ts = ts; + /* Start bit low is too short, go back to idle */ + if (delta < CEC_TIM_START_BIT_LOW_MIN - + CEC_TIM_IDLE_SAMPLE) { + cec_pin_to_idle(pin); + } + break; + + case CEC_ST_RX_START_BIT_HIGH: + v = cec_pin_read(pin); + delta = ktime_us_delta(ts, pin->ts); + if (v && delta > CEC_TIM_START_BIT_TOTAL_MAX - + CEC_TIM_START_BIT_LOW_MIN) { + cec_pin_to_idle(pin); + break; + } + if (v) + 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 8: + pin->rx_eom = v; + pin->rx_msg.len = pin->rx_bit / 10 + 1; + break; + case 9: + break; + } + pin->rx_bit++; + break; + + case CEC_ST_RX_DATA_POST_SAMPLE: + pin->state = CEC_ST_RX_DATA_HIGH; + break; + + case CEC_ST_RX_DATA_HIGH: + v = cec_pin_read(pin); + delta = ktime_us_delta(ts, pin->ts); + if (v && delta > CEC_TIM_DATA_BIT_TOTAL_MAX) { + cec_pin_to_idle(pin); + break; + } + if (v) + break; + /* + * Go to low drive state when the total bit time is + * too short. + */ + if (delta < CEC_TIM_DATA_BIT_TOTAL_MIN) { + cec_pin_low(pin); + pin->state = CEC_ST_LOW_DRIVE; + 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 (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 = 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_HIGH; + 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; + + ts = ktime_get(); + if (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, 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, pin->wait_usecs * 1000); + return HRTIMER_RESTART; + } + pin->timer_ts = ktime_add_us(ts, pin->wait_usecs); + hrtimer_forward_now(timer, 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_DATA_BIT_1_HIGH_POST_SAMPLE: + case CEC_ST_TX_DATA_BIT_0_HIGH: + case CEC_ST_TX_DATA_BIT_1_HIGH: + case CEC_ST_TX_START_BIT_HIGH: + case CEC_ST_TX_DATA_BIT_0_LOW: + case CEC_ST_TX_DATA_BIT_1_LOW: + case CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE: + 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_HIGH: + 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; + break; + } + if (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; + 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->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 */ + pin->work_enable_irq = true; + pin->state = CEC_ST_RX_IRQ; + wake_up_interruptible(&pin->kthread_waitq); + return HRTIMER_NORESTART; + + case CEC_ST_LOW_DRIVE: + cec_pin_to_idle(pin); + break; + + default: + break; + } + if (!adap->monitor_pin_cnt || states[pin->state].usecs <= 150) { + pin->wait_usecs = 0; + pin->timer_ts = ktime_add_us(ts, states[pin->state].usecs); + hrtimer_forward_now(timer, states[pin->state].usecs * 1000); + return HRTIMER_RESTART; + } + pin->wait_usecs = states[pin->state].usecs - 100; + pin->timer_ts = ktime_add_us(ts, 100); + hrtimer_forward_now(timer, 100000); + return HRTIMER_RESTART; +} + +static int cec_pin_thread_func(void *_adap) +{ + struct cec_adapter *adap = _adap; + struct cec_pin *pin = adap->pin; + + for (;;) { + wait_event_interruptible(pin->kthread_waitq, + kthread_should_stop() || + pin->work_rx_msg.len || + pin->work_tx_status || + pin->work_enable_irq || + atomic_read(&pin->work_pin_events)); + + if (pin->work_rx_msg.len) { + cec_received_msg_ts(adap, &pin->work_rx_msg, + pin->work_rx_msg.rx_ts); + pin->work_rx_msg.len = 0; + } + if (pin->work_tx_status) { + unsigned int tx_status = pin->work_tx_status; + + pin->work_tx_status = 0; + cec_transmit_attempt_done_ts(adap, tx_status, + pin->work_tx_ts); + } + while (atomic_read(&pin->work_pin_events)) { + unsigned int idx = pin->work_pin_events_rd; + + cec_queue_pin_event(adap, pin->work_pin_is_high[idx], + pin->work_pin_ts[idx]); + pin->work_pin_events_rd = (idx + 1) % CEC_NUM_PIN_EVENTS; + atomic_dec(&pin->work_pin_events); + } + if (pin->work_enable_irq) { + pin->work_enable_irq = false; + pin->enable_irq_failed = !pin->ops->enable_irq(adap); + if (pin->enable_irq_failed) { + cec_pin_to_idle(pin); + hrtimer_start(&pin->timer, 0, HRTIMER_MODE_REL); + } + } + if (kthread_should_stop()) + break; + } + return 0; +} + +static int cec_pin_adap_enable(struct cec_adapter *adap, bool enable) +{ + struct cec_pin *pin = adap->pin; + + pin->enabled = enable; + if (enable) { + atomic_set(&pin->work_pin_events, 0); + pin->work_pin_events_rd = pin->work_pin_events_wr = 0; + cec_pin_read(pin); + cec_pin_to_idle(pin); + pin->tx_msg.len = 0; + pin->timer_ts = 0; + pin->work_enable_irq = false; + pin->kthread = kthread_run(cec_pin_thread_func, adap, + "cec-pin"); + if (IS_ERR(pin->kthread)) { + pr_err("cec-pin: kernel_thread() failed\n"); + return PTR_ERR(pin->kthread); + } + hrtimer_start(&pin->timer, 0, HRTIMER_MODE_REL); + } else { + if (pin->ops->disable_irq) + pin->ops->disable_irq(adap); + hrtimer_cancel(&pin->timer); + kthread_stop(pin->kthread); + cec_pin_read(pin); + cec_pin_to_idle(pin); + pin->state = CEC_ST_OFF; + } + return 0; +} + +static int cec_pin_adap_log_addr(struct cec_adapter *adap, u8 log_addr) +{ + struct cec_pin *pin = adap->pin; + + if (log_addr == CEC_LOG_ADDR_INVALID) + pin->la_mask = 0; + else + pin->la_mask |= (1 << log_addr); + return 0; +} + +static int cec_pin_adap_transmit(struct cec_adapter *adap, u8 attempts, + u32 signal_free_time, struct cec_msg *msg) +{ + struct cec_pin *pin = adap->pin; + + pin->tx_signal_free_time = signal_free_time; + pin->tx_msg = *msg; + pin->work_tx_status = 0; + pin->tx_bit = 0; + if (pin->state == CEC_ST_RX_IRQ) { + pin->work_enable_irq = false; + pin->ops->disable_irq(adap); + cec_pin_high(pin); + cec_pin_to_idle(pin); + hrtimer_start(&pin->timer, 0, HRTIMER_MODE_REL); + } + return 0; +} + +static void cec_pin_adap_status(struct cec_adapter *adap, + struct seq_file *file) +{ + struct cec_pin *pin = adap->pin; + + seq_printf(file, "state: %s\n", states[pin->state].name); + seq_printf(file, "tx_bit: %d\n", pin->tx_bit); + seq_printf(file, "rx_bit: %d\n", pin->rx_bit); + seq_printf(file, "cec pin: %d\n", pin->ops->read(adap)); + seq_printf(file, "irq failed: %d\n", pin->enable_irq_failed); + if (pin->timer_100ms_overruns) { + seq_printf(file, "timer overruns > 100ms: %u of %u\n", + pin->timer_100ms_overruns, pin->timer_cnt); + seq_printf(file, "timer overruns > 300ms: %u of %u\n", + pin->timer_300ms_overruns, pin->timer_cnt); + seq_printf(file, "max timer overrun: %u usecs\n", + pin->timer_max_overrun); + seq_printf(file, "avg timer overrun: %u usecs\n", + pin->timer_sum_overrun / pin->timer_100ms_overruns); + } + pin->timer_cnt = 0; + pin->timer_100ms_overruns = 0; + pin->timer_300ms_overruns = 0; + pin->timer_max_overrun = 0; + pin->timer_sum_overrun = 0; + if (pin->ops->status) + pin->ops->status(adap, file); +} + +static int cec_pin_adap_monitor_all_enable(struct cec_adapter *adap, + bool enable) +{ + struct cec_pin *pin = adap->pin; + + pin->monitor_all = enable; + return 0; +} + +static void cec_pin_adap_free(struct cec_adapter *adap) +{ + struct cec_pin *pin = adap->pin; + + if (pin->ops->free) + pin->ops->free(adap); + adap->pin = NULL; + kfree(pin); +} + +void cec_pin_changed(struct cec_adapter *adap, bool value) +{ + struct cec_pin *pin = adap->pin; + + cec_pin_update(pin, value, false); + if (!value && (adap->is_configuring || adap->is_configured || + adap->monitor_all_cnt)) { + pin->work_enable_irq = false; + pin->ops->disable_irq(adap); + cec_pin_high(pin); + cec_pin_to_idle(pin); + hrtimer_start(&pin->timer, 0, HRTIMER_MODE_REL); + } +} +EXPORT_SYMBOL_GPL(cec_pin_changed); + +static const struct cec_adap_ops cec_pin_adap_ops = { + .adap_enable = cec_pin_adap_enable, + .adap_monitor_all_enable = cec_pin_adap_monitor_all_enable, + .adap_log_addr = cec_pin_adap_log_addr, + .adap_transmit = cec_pin_adap_transmit, + .adap_status = cec_pin_adap_status, + .adap_free = cec_pin_adap_free, +}; + +struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops, + void *priv, const char *name, u32 caps) +{ + struct cec_adapter *adap; + struct cec_pin *pin = kzalloc(sizeof(*pin), GFP_KERNEL); + + if (pin == NULL) + return ERR_PTR(-ENOMEM); + pin->ops = pin_ops; + pin->cur_value = true; + hrtimer_init(&pin->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + pin->timer.function = cec_pin_timer; + init_waitqueue_head(&pin->kthread_waitq); + + adap = cec_allocate_adapter(&cec_pin_adap_ops, priv, name, + caps | CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN, + CEC_MAX_LOG_ADDRS); + + if (PTR_ERR_OR_ZERO(adap)) { + kfree(pin); + return adap; + } + + adap->pin = pin; + pin->adap = adap; + cec_pin_update(pin, cec_pin_high(pin), true); + return adap; +} +EXPORT_SYMBOL_GPL(cec_pin_allocate_adapter); diff --git a/include/media/cec-pin.h b/include/media/cec-pin.h new file mode 100644 index 000000000000..44b82d29d480 --- /dev/null +++ b/include/media/cec-pin.h @@ -0,0 +1,183 @@ +/* + * cec-pin.h - low-level CEC pin control + * + * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved. + * + * This program is free software; you may redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#ifndef LINUX_CEC_PIN_H +#define LINUX_CEC_PIN_H + +#include <linux/types.h> +#include <linux/atomic.h> +#include <media/cec.h> + +enum cec_pin_state { + /* CEC is off */ + CEC_ST_OFF, + /* CEC is idle, waiting for Rx or Tx */ + CEC_ST_IDLE, + + /* Tx states */ + + /* Pending Tx, waiting for Signal Free Time to expire */ + CEC_ST_TX_WAIT, + /* Low-drive was detected, wait for bus to go high */ + CEC_ST_TX_WAIT_FOR_HIGH, + /* Drive CEC low for the start bit */ + CEC_ST_TX_START_BIT_LOW, + /* Drive CEC high for the start bit */ + CEC_ST_TX_START_BIT_HIGH, + /* Drive CEC low for the 0 bit */ + CEC_ST_TX_DATA_BIT_0_LOW, + /* Drive CEC high for the 0 bit */ + CEC_ST_TX_DATA_BIT_0_HIGH, + /* Drive CEC low for the 1 bit */ + CEC_ST_TX_DATA_BIT_1_LOW, + /* Drive CEC high for the 1 bit */ + CEC_ST_TX_DATA_BIT_1_HIGH, + /* + * Wait for start of sample time to check for Ack bit or first + * four initiator bits to check for Arbitration Lost. + */ + CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE, + /* Wait for end of bit period after sampling */ + CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE, + + /* Rx states */ + + /* Start bit low detected */ + CEC_ST_RX_START_BIT_LOW, + /* Start bit high detected */ + CEC_ST_RX_START_BIT_HIGH, + /* Wait for bit sample time */ + CEC_ST_RX_DATA_SAMPLE, + /* Wait for earliest end of bit period after sampling */ + CEC_ST_RX_DATA_POST_SAMPLE, + /* Wait for CEC to go high (i.e. end of bit period */ + CEC_ST_RX_DATA_HIGH, + /* Drive CEC low to send 0 Ack bit */ + CEC_ST_RX_ACK_LOW, + /* End of 0 Ack time, wait for earliest end of bit period */ + CEC_ST_RX_ACK_LOW_POST, + /* Wait for CEC to go high (i.e. end of bit period */ + CEC_ST_RX_ACK_HIGH_POST, + /* Wait for earliest end of bit period and end of message */ + CEC_ST_RX_ACK_FINISH, + + /* Start low drive */ + CEC_ST_LOW_DRIVE, + /* Monitor pin using interrupts */ + CEC_ST_RX_IRQ, + + /* Total number of pin states */ + CEC_PIN_STATES +}; + +/** + * struct cec_pin_ops - low-level CEC pin operations + * @read: read the CEC pin. Return true if high, false if low. + * @low: drive the CEC pin low. + * @high: stop driving the CEC pin. The pull-up will drive the pin + * high, unless someone else is driving the pin low. + * @enable_irq: optional, enable the interrupt to detect pin voltage changes. + * @disable_irq: optional, disable the interrupt. + * @free: optional. Free any allocated resources. Called when the + * adapter is deleted. + * @status: optional, log status information. + * + * These operations are used by the cec pin framework to manipulate + * the CEC pin. + */ +struct cec_pin_ops { + bool (*read)(struct cec_adapter *adap); + void (*low)(struct cec_adapter *adap); + void (*high)(struct cec_adapter *adap); + bool (*enable_irq)(struct cec_adapter *adap); + void (*disable_irq)(struct cec_adapter *adap); + void (*free)(struct cec_adapter *adap); + void (*status)(struct cec_adapter *adap, struct seq_file *file); +}; + +#define CEC_NUM_PIN_EVENTS 128 + +struct cec_pin { + struct cec_adapter *adap; + const struct cec_pin_ops *ops; + struct task_struct *kthread; + wait_queue_head_t kthread_waitq; + struct hrtimer timer; + ktime_t ts; + unsigned int wait_usecs; + u16 la_mask; + bool enabled; + bool monitor_all; + bool cur_value; + bool rx_eom; + bool enable_irq_failed; + enum cec_pin_state state; + struct cec_msg tx_msg; + u32 tx_bit; + bool tx_nacked; + u32 tx_signal_free_time; + struct cec_msg rx_msg; + u32 rx_bit; + + struct cec_msg work_rx_msg; + u8 work_tx_status; + bool work_enable_irq; + ktime_t work_tx_ts; + atomic_t work_pin_events; + unsigned int work_pin_events_wr; + unsigned int work_pin_events_rd; + ktime_t work_pin_ts[CEC_NUM_PIN_EVENTS]; + bool work_pin_is_high[CEC_NUM_PIN_EVENTS]; + ktime_t timer_ts; + u32 timer_cnt; + u32 timer_100ms_overruns; + u32 timer_300ms_overruns; + u32 timer_max_overrun; + u32 timer_sum_overrun; +}; + +/** + * cec_pin_changed() - update pin state from interrupt + * + * @adap: pointer to the cec adapter + * @value: when true the pin is high, otherwise it is low + * + * If changes of the CEC voltage are detected via an interrupt, then + * cec_pin_changed is called from the interrupt with the new value. + */ +void cec_pin_changed(struct cec_adapter *adap, bool value); + +/** + * cec_pin_allocate_adapter() - allocate a pin-based cec adapter + * + * @pin_ops: low-level pin operations + * @priv: will be stored in adap->priv and can be used by the adapter ops. + * Use cec_get_drvdata(adap) to get the priv pointer. + * @name: the name of the CEC adapter. Note: this name will be copied. + * @caps: capabilities of the CEC adapter. This will be ORed with + * CEC_CAP_MONITOR_ALL and CEC_CAP_MONITOR_PIN. + * + * Allocate a cec adapter using the cec pin framework. + * + * Return: a pointer to the cec adapter or an error pointer + */ +struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops, + void *priv, const char *name, u32 caps); + +#endif diff --git a/include/media/cec.h b/include/media/cec.h index d983960b37ad..f9cab1a9f912 100644 --- a/include/media/cec.h +++ b/include/media/cec.h @@ -61,6 +61,7 @@ struct cec_devnode { struct cec_adapter; struct cec_data; +struct cec_pin; struct cec_data { struct list_head list; @@ -189,6 +190,9 @@ struct cec_adapter { #ifdef CONFIG_CEC_NOTIFIER struct cec_notifier *notifier; #endif +#ifdef CONFIG_CEC_PIN + struct cec_pin *pin; +#endif struct dentry *cec_dir; struct dentry *status_file; |