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receive functions don't block indefinitely
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@someweisguy
someweisguy committed Sep 18, 2022
1 parent 7f24799 commit 834c131
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Showing 2 changed files with 33 additions and 24 deletions.
38 changes: 23 additions & 15 deletions src/esp_dmx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -648,15 +648,15 @@ bool dmx_sniffer_is_enabled(dmx_port_t dmx_num) {
}

bool dmx_sniffer_get_data(dmx_port_t dmx_num, dmx_sniffer_data_t *sniffer_data,
TickType_t timeout) {
TickType_t wait_ticks) {
DMX_CHECK(dmx_num < DMX_NUM_MAX, ESP_ERR_INVALID_ARG, "dmx_num error");
DMX_CHECK(sniffer_data, ESP_ERR_INVALID_ARG, "sniffer_data is null");
DMX_CHECK(dmx_sniffer_is_enabled(dmx_num), ESP_ERR_INVALID_STATE,
"sniffer is not enabled");

dmx_driver_t *const driver = dmx_driver[dmx_num];

return xQueueReceive(driver->sniffer.queue, sniffer_data, timeout);
return xQueueReceive(driver->sniffer.queue, sniffer_data, wait_ticks);
}

uint32_t dmx_set_baud_rate(dmx_port_t dmx_num, uint32_t baud_rate) {
Expand Down Expand Up @@ -913,20 +913,25 @@ int dmx_write_slot(dmx_port_t dmx_num, size_t slot_num, uint8_t value) {
return value;
}

size_t dmx_receive(dmx_port_t dmx_num, dmx_event_t *event, TickType_t timeout) {
size_t dmx_receive(dmx_port_t dmx_num, dmx_event_t *event,
TickType_t wait_ticks) {
DMX_CHECK(dmx_num < DMX_NUM_MAX, 0, "dmx_num error");
DMX_CHECK(dmx_driver_is_installed(dmx_num), 0, "driver is not installed");

dmx_driver_t *const driver = dmx_driver[dmx_num];
dmx_context_t *const context = &dmx_context[dmx_num];

// Block until the mutex can be taken
if (!xSemaphoreTakeRecursive(driver->mux, portMAX_DELAY)) {
TimeOut_t timeout;
vTaskSetTimeOutState(&timeout);
if (!xSemaphoreTakeRecursive(driver->mux, wait_ticks) ||
xTaskCheckForTimeOut(&timeout, &wait_ticks)) {
return 0;
}

// Block until the driver is done sending
if (!dmx_wait_sent(dmx_num, portMAX_DELAY)) {
if (!dmx_wait_sent(dmx_num, wait_ticks) ||
xTaskCheckForTimeOut(&timeout, &wait_ticks)) {
return 0;
}

Expand Down Expand Up @@ -960,29 +965,29 @@ size_t dmx_receive(dmx_port_t dmx_num, dmx_event_t *event, TickType_t timeout) {
// If a packet hasn't been received, the driver must wait
if (!received_packet) {
// Determine if a fail-quick timeout must be set
uint32_t timeout = 0;
uint32_t fail_quick = 0;
if (sent_previous &&
(previous_uid != RDM_BROADCAST_UID ||
previous_type == RDM_CC_DISC_COMMAND) &&
(previous_type == RDM_CC_GET_COMMAND ||
previous_type == RDM_CC_SET_COMMAND ||
previous_type == RDM_CC_DISC_COMMAND)) {
timeout = RDM_CONTROLLER_RESPONSE_LOST_TIMEOUT;
fail_quick = RDM_CONTROLLER_RESPONSE_LOST_TIMEOUT;
}

// Set the timeout alarm if the timeout hasn't elapsed yet
taskENTER_CRITICAL(&context->spinlock);
const int64_t elapsed = esp_timer_get_time() - previous_ts;
if (elapsed < timeout) {
if (elapsed < fail_quick) {
timer_set_counter_value(driver->timer_group, driver->timer_num, elapsed);
timer_set_alarm_value(driver->timer_group, driver->timer_num, timeout);
timer_set_alarm_value(driver->timer_group, driver->timer_num, fail_quick);
timer_start(driver->timer_group, driver->timer_num);
driver->timer_running = true;
}
taskEXIT_CRITICAL(&context->spinlock);

// Fail immediately if the timeout has elapsed and a response was expected
if (timeout > 0 && elapsed >= timeout) {
if (fail_quick > 0 && elapsed >= fail_quick) {
taskENTER_CRITICAL(&context->spinlock);
driver->task_waiting = NULL;
taskEXIT_CRITICAL(&context->spinlock);
Expand All @@ -998,7 +1003,7 @@ size_t dmx_receive(dmx_port_t dmx_num, dmx_event_t *event, TickType_t timeout) {
}

// Wait for a task notification
if (xTaskNotifyWait(0, ULONG_MAX, &packet_size, timeout)) {
if (xTaskNotifyWait(0, ULONG_MAX, &packet_size, fail_quick)) {
err = driver->data.err;
} else {
err = DMX_ERR_TIMEOUT;
Expand Down Expand Up @@ -1182,21 +1187,24 @@ size_t dmx_send(dmx_port_t dmx_num, size_t size) {
return size;
}

bool dmx_wait_sent(dmx_port_t dmx_num, TickType_t timeout) {
bool dmx_wait_sent(dmx_port_t dmx_num, TickType_t wait_ticks) {
DMX_CHECK(dmx_num < DMX_NUM_MAX, false, "dmx_num error");
DMX_CHECK(dmx_driver_is_installed(dmx_num), false, "driver is not installed");

dmx_driver_t *const driver = dmx_driver[dmx_num];
dmx_context_t *const context = &dmx_context[dmx_num];

// Block until the mutex can be taken
if (!xSemaphoreTakeRecursive(driver->mux, portMAX_DELAY)) {
TimeOut_t timeout;
vTaskSetTimeOutState(&timeout);
if (!xSemaphoreTakeRecursive(driver->mux, wait_ticks) ||
xTaskCheckForTimeOut(&timeout, &wait_ticks)) {
return false;
}

// Determine if the task needs to block
bool result = true;
if (timeout > 0) {
if (wait_ticks > 0) {
bool task_waiting = false;
taskENTER_CRITICAL(&context->spinlock);
if (driver->is_sending) {
Expand All @@ -1207,7 +1215,7 @@ bool dmx_wait_sent(dmx_port_t dmx_num, TickType_t timeout) {

// Wait for a notification that the driver is done sending
if (task_waiting) {
result = xTaskNotifyWait(0, ULONG_MAX, NULL, timeout);
result = xTaskNotifyWait(0, ULONG_MAX, NULL, wait_ticks);
driver->task_waiting = NULL;
}
} else {
Expand Down
19 changes: 10 additions & 9 deletions src/esp_dmx.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -127,12 +127,12 @@ bool dmx_sniffer_is_enabled(dmx_port_t dmx_num);
* @param dmx_num The DMX port number.
* @param[out] sniffer_data A pointer to a dmx_sniffer_data_t struct into which
* to copy DMX sniffer data.
* @param timeout The number of ticks to wait before this function times out.
* @param wait_ticks The number of ticks to wait before this function times out.
* @return true if data was copied.
* @return false if data was not copied.
*/
bool dmx_sniffer_get_data(dmx_port_t dmx_num, dmx_sniffer_data_t *sniffer_data,
TickType_t timeout);
TickType_t wait_ticks);

/**
* @brief Sets the DMX baud rate. The baud rate will be clamped to DMX
Expand Down Expand Up @@ -280,9 +280,9 @@ int dmx_write_slot(dmx_port_t dmx_num, size_t slot_num, uint8_t value);

/**
* @brief Receives a DMX packet from the DMX bus. This is a blocking function.
* This function first blocks indefinitely until the DMX driver is idle and then
* it blocks using a timeout until a packet is received. This function will
* timeout early according to RDM specification if an RDM packet is expected.
* This function first blocks until the DMX driver is idle and then it blocks
* using a timeout until a packet is received. This function will timeout early
* according to RDM specification if an RDM packet is expected.
*
* @note This function uses FreeRTOS direct-to-task notifications to block and
* unblock. Using task notifications on the same task that calls this function
Expand All @@ -291,10 +291,11 @@ int dmx_write_slot(dmx_port_t dmx_num, size_t slot_num, uint8_t value);
* @param dmx_num The DMX port number.
* @param[out] event An optional pointer to a dmx_event_t which contains
* information about the received DMX packet.
* @param timeout The number of ticks to wait before this function times out.
* @param wait_ticks The number of ticks to wait before this function times out.
* @return The size of the received DMX packet or 0 if no packet was received.
*/
size_t dmx_receive(dmx_port_t dmx_num, dmx_event_t *event, TickType_t timeout);
size_t dmx_receive(dmx_port_t dmx_num, dmx_event_t *event,
TickType_t wait_ticks);

/**
* @brief Sends a DMX packet on the DMX bus. This function blocks indefinitely
Expand Down Expand Up @@ -322,11 +323,11 @@ size_t dmx_send(dmx_port_t dmx_num, size_t size);
* can lead to undesired behavior and program instability.
*
* @param dmx_num The DMX port number.
* @param timeout The number of ticks to wait before this function times out.
* @param wait_ticks The number of ticks to wait before this function times out.
* @retval true if the DMX driver is done sending.
* @retval false if the function timed out.
*/
bool dmx_wait_sent(dmx_port_t dmx_num, TickType_t timeout);
bool dmx_wait_sent(dmx_port_t dmx_num, TickType_t wait_ticks);

#ifdef __cplusplus
}
Expand Down

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