// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. #include "freertos/FreeRTOS.h" #include "freertos/portmacro.h" #include "freertos/task.h" #include "freertos/queue.h" #include "freertos/semphr.h" #include "esp_types.h" #include "esp_log.h" #include "esp_intr_alloc.h" #include "esp_pm.h" #include "esp_attr.h" #include "esp_heap_caps.h" #include "soc/dport_reg.h" #include "soc/can_struct.h" #include "driver/gpio.h" #include "driver/periph_ctrl.h" #include "driver/can.h" /* ---------------------------- Definitions --------------------------------- */ //Internal Macros #define CAN_CHECK(cond, ret_val) ({ \ if (!(cond)) { \ return (ret_val); \ } \ }) #define CAN_CHECK_FROM_CRIT(cond, ret_val) ({ \ if (!(cond)) { \ CAN_EXIT_CRITICAL(); \ return ret_val; \ } \ }) #define CAN_SET_FLAG(var, mask) ((var) |= (mask)) #define CAN_RESET_FLAG(var, mask) ((var) &= ~(mask)) #ifdef CONFIG_CAN_ISR_IN_IRAM #define CAN_INLINE_ATTR __attribute__((always_inline)) #define CAN_ISR_ATTR IRAM_ATTR #define CAN_MALLOC_CAPS (MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT) #else #define CAN_INLINE_ATTR #define CAN_TAG "CAN" #define CAN_ISR_ATTR #define CAN_MALLOC_CAPS MALLOC_CAP_DEFAULT #endif /* * Baud Rate Prescaler Divider config/values. The BRP_DIV bit is located in the * CAN interrupt enable register, and is only available in ESP32 Revision 2 or * later. Setting this bit will cause the APB clock to be prescaled (divided) by * a factor 2, before having the BRP applied. This will allow for lower bit rates * to be achieved. */ #define BRP_DIV_EN_THRESH 128 //A BRP config value large this this will need to enable brp_div #define BRP_DIV_EN_BIT 0x10 //Bit mask for brp_div in the interrupt register //When brp_div is enabled, the BRP config value must be any multiple of 4 between 132 and 256 #define BRP_CHECK_WITH_DIV(brp) ((brp) >= 132 && (brp) <= 256 && ((brp) & 0x3) == 0) //When brp_div is disabled, the BRP config value must be any even number between 2 to 128 #define BRP_CHECK_NO_DIV(brp) ((brp) >= 2 && (brp) <= 128 && ((brp) & 0x1) == 0) //Driver default config/values #define DRIVER_DEFAULT_EWL 96 //Default Error Warning Limit value #define DRIVER_DEFAULT_TEC 0 //TX Error Counter starting value #define DRIVER_DEFAULT_REC 0 //RX Error Counter starting value #define DRIVER_DEFAULT_CLKOUT_DIV 14 //APB CLK divided by two #define DRIVER_DEFAULT_INTERRUPTS 0xE7 //Exclude data overrun (bit[3]) and brp_div (bit[4]) #define DRIVER_DEFAULT_ERR_PASS_CNT 128 //Error counter threshold for error passive //Command Bit Masks #define CMD_TX_REQ 0x01 //Transmission Request #define CMD_ABORT_TX 0x02 //Abort Transmission #define CMD_RELEASE_RX_BUFF 0x04 //Release Receive Buffer #define CMD_CLR_DATA_OVRN 0x08 //Clear Data Overrun #define CMD_SELF_RX_REQ 0x10 //Self Reception Request #define CMD_TX_SINGLE_SHOT 0x03 //Single Shot Transmission #define CMD_SELF_RX_SINGLE_SHOT 0x12 //Single Shot Self Reception //Control flags #define CTRL_FLAG_STOPPED 0x001 //CAN peripheral in stopped state #define CTRL_FLAG_RECOVERING 0x002 //Bus is undergoing bus recovery #define CTRL_FLAG_ERR_WARN 0x004 //TEC or REC is >= error warning limit #define CTRL_FLAG_ERR_PASSIVE 0x008 //TEC or REC is >= 128 #define CTRL_FLAG_BUS_OFF 0x010 //Bus-off due to TEC >= 256 #define CTRL_FLAG_TX_BUFF_OCCUPIED 0x020 //Transmit buffer is occupied #define CTRL_FLAG_SELF_TEST 0x040 //Configured to Self Test Mode #define CTRL_FLAG_LISTEN_ONLY 0x080 //Configured to Listen Only Mode //Constants use for frame formatting and parsing #define FRAME_MAX_LEN 13 //EFF with 8 bytes of data #define FRAME_MAX_DATA_LEN 8 //Max data bytes allowed in CAN2.0 #define FRAME_EXTD_ID_LEN 4 //EFF ID requires 4 bytes (29bit) #define FRAME_STD_ID_LEN 2 //SFF ID requires 2 bytes (11bit) #define FRAME_INFO_LEN 1 //Frame info requires 1 byte #define ALERT_LOG_LEVEL_WARNING CAN_ALERT_ARB_LOST //Alerts above and including this level use ESP_LOGW #define ALERT_LOG_LEVEL_ERROR CAN_ALERT_TX_FAILED //Alerts above and including this level use ESP_LOGE /* ------------------ Typedefs, structures, and variables ------------------- */ /* Formatted frame structure has identical layout as TX/RX buffer registers. This allows for direct copy to/from TX/RX buffer. The two reserved bits in TX buffer are used in the frame structure to store the self_reception and single_shot flags. */ typedef union { struct { struct { uint8_t dlc: 4; //Data length code (0 to 8) of the frame uint8_t self_reception: 1; //This frame should be transmitted using self reception command uint8_t single_shot: 1; //This frame should be transmitted using single shot command uint8_t rtr: 1; //This frame is a remote transmission request uint8_t frame_format: 1; //Format of the frame (1 = extended, 0 = standard) }; union { struct { uint8_t id[FRAME_STD_ID_LEN]; //11 bit standard frame identifier uint8_t data[FRAME_MAX_DATA_LEN]; //Data bytes (0 to 8) uint8_t reserved8[2]; } standard; struct { uint8_t id[FRAME_EXTD_ID_LEN]; //29 bit extended frame identifier uint8_t data[FRAME_MAX_DATA_LEN]; //Data bytes (0 to 8) } extended; }; }; uint8_t bytes[FRAME_MAX_LEN]; } can_frame_t; //Control structure for CAN driver typedef struct { //Control and status members uint32_t control_flags; uint32_t rx_missed_count; uint32_t tx_failed_count; uint32_t arb_lost_count; uint32_t bus_error_count; intr_handle_t isr_handle; //TX and RX #ifdef CONFIG_CAN_ISR_IN_IRAM void *tx_queue_buff; void *tx_queue_struct; void *rx_queue_buff; void *rx_queue_struct; void *semphr_struct; #endif QueueHandle_t tx_queue; QueueHandle_t rx_queue; int tx_msg_count; int rx_msg_count; //Alerts SemaphoreHandle_t alert_semphr; uint32_t alerts_enabled; uint32_t alerts_triggered; #ifdef CONFIG_PM_ENABLE //Power Management esp_pm_lock_handle_t pm_lock; #endif } can_obj_t; static can_obj_t *p_can_obj = NULL; static portMUX_TYPE can_spinlock = portMUX_INITIALIZER_UNLOCKED; #define CAN_ENTER_CRITICAL_ISR() portENTER_CRITICAL_ISR(&can_spinlock) #define CAN_EXIT_CRITICAL_ISR() portEXIT_CRITICAL_ISR(&can_spinlock) #define CAN_ENTER_CRITICAL() portENTER_CRITICAL(&can_spinlock) #define CAN_EXIT_CRITICAL() portEXIT_CRITICAL(&can_spinlock) /* ------------------- Configuration Register Functions---------------------- */ static inline CAN_INLINE_ATTR esp_err_t can_enter_reset_mode() { /* Enter reset mode (required to write to configuration registers). Reset mode also prevents all CAN activity on the current module and is automatically set upon entering a BUS-OFF condition. */ CAN.mode_reg.reset = 1; //Set reset mode bit CAN_CHECK(CAN.mode_reg.reset == 1, ESP_ERR_INVALID_STATE); //Check bit was set return ESP_OK; } static inline esp_err_t can_exit_reset_mode() { /* Exiting reset mode will return the CAN module to operating mode. Reset mode must also be exited in order to trigger BUS-OFF recovery sequence. */ CAN.mode_reg.reset = 0; //Exit reset mode CAN_CHECK(CAN.mode_reg.reset == 0, ESP_ERR_INVALID_STATE); //Check bit was reset return ESP_OK; } static inline void can_config_pelican() { //Use PeliCAN address layout. Exposes extra registers CAN.clock_divider_reg.can_mode = 1; } static CAN_ISR_ATTR void can_config_mode(can_mode_t mode) { //Configure CAN mode of operation can_mode_reg_t mode_reg; mode_reg.val = CAN.mode_reg.val; //Get current value of mode register if (mode == CAN_MODE_NO_ACK) { mode_reg.self_test = 1; mode_reg.listen_only = 0; } else if (mode == CAN_MODE_LISTEN_ONLY) { mode_reg.self_test = 0; mode_reg.listen_only = 1; } else { //Default to normal operating mode mode_reg.self_test = 0; mode_reg.listen_only = 0; } CAN.mode_reg.val = mode_reg.val; //Write back modified value to register } static inline void can_config_interrupts(uint32_t interrupts) { //Enable interrupt sources CAN.interrupt_enable_reg.val = interrupts; } static inline void can_config_bus_timing(uint32_t brp, uint32_t sjw, uint32_t tseg_1, uint32_t tseg_2, bool triple_sampling) { /* Configure bus/bit timing of CAN peripheral. - BRP (even from 2 to 128) divide APB to CAN system clock (T_scl) - SJW (1 to 4) is number of T_scl to shorten/lengthen for bit synchronization - TSEG_1 (1 to 16) is number of T_scl in a bit time before sample point - TSEG_2 (1 to 8) is number of T_scl in a bit time after sample point - triple_sampling will cause each bit time to be sampled 3 times */ can_bus_tim_0_reg_t timing_reg_0; can_bus_tim_1_reg_t timing_reg_1; timing_reg_0.baud_rate_prescaler = (brp / 2) - 1; timing_reg_0.sync_jump_width = sjw - 1; timing_reg_1.time_seg_1 = tseg_1 - 1; timing_reg_1.time_seg_2 = tseg_2 - 1; timing_reg_1.sampling = triple_sampling; CAN.bus_timing_0_reg.val = timing_reg_0.val; CAN.bus_timing_1_reg.val = timing_reg_1.val; } static inline void can_config_error(int err_warn_lim, int rx_err_cnt, int tx_err_cnt) { /* Set error warning limit, RX error counter, and TX error counter. Note that forcibly setting RX/TX error counters will incur the expected status changes and interrupts as soon as reset mode exits. */ if (err_warn_lim >= 0 && err_warn_lim <= UINT8_MAX) { //Defaults to 96 after hardware reset. CAN.error_warning_limit_reg.byte = err_warn_lim; } if (rx_err_cnt >= 0 && rx_err_cnt <= UINT8_MAX) { //Defaults to 0 after hardware reset. CAN.rx_error_counter_reg.byte = rx_err_cnt; } if (tx_err_cnt >= 0 && tx_err_cnt <= UINT8_MAX) { //Defaults to 0 after hardware reset, and 127 after BUS-OFF event CAN.tx_error_counter_reg.byte = tx_err_cnt; } } static inline void can_config_acceptance_filter(uint32_t code, uint32_t mask, bool single_filter) { //Set filter mode CAN.mode_reg.acceptance_filter = (single_filter) ? 1 : 0; //Swap code and mask to match big endian registers uint32_t code_swapped = __builtin_bswap32(code); uint32_t mask_swapped = __builtin_bswap32(mask); for (int i = 0; i < 4; i++) { CAN.acceptance_filter.code_reg[i].byte = ((code_swapped >> (i * 8)) & 0xFF); CAN.acceptance_filter.mask_reg[i].byte = ((mask_swapped >> (i * 8)) & 0xFF); } } static inline void can_config_clk_out(uint32_t divider) { /* Configure CLKOUT. CLKOUT is a pre-scaled version of APB CLK. Divider can be 1, or any even number from 2 to 14. Set to out of range value (0) to disable CLKOUT. */ can_clk_div_reg_t clock_divider_reg; clock_divider_reg.val = CAN.clock_divider_reg.val; if (divider >= 2 && divider <= 14) { clock_divider_reg.clock_off = 0; clock_divider_reg.clock_divider = (divider / 2) - 1; } else if (divider == 1) { clock_divider_reg.clock_off = 0; clock_divider_reg.clock_divider = 7; } else { clock_divider_reg.clock_off = 1; clock_divider_reg.clock_divider = 0; } CAN.clock_divider_reg.val = clock_divider_reg.val; } /* ---------------------- Runtime Register Functions------------------------- */ static inline CAN_INLINE_ATTR void can_set_command(uint8_t commands) { CAN.command_reg.val = commands; } static CAN_ISR_ATTR void can_set_tx_buffer_and_transmit(can_frame_t *frame) { //Copy frame structure into TX buffer registers for (int i = 0; i < FRAME_MAX_LEN; i++) { CAN.tx_rx_buffer[i].val = frame->bytes[i]; } //Set correct transmit command uint8_t command; if (frame->self_reception) { command = (frame->single_shot) ? CMD_SELF_RX_SINGLE_SHOT : CMD_SELF_RX_REQ; } else { command = (frame->single_shot) ? CMD_TX_SINGLE_SHOT : CMD_TX_REQ; } can_set_command(command); } static inline CAN_INLINE_ATTR uint32_t can_get_status() { return CAN.status_reg.val; } static inline CAN_INLINE_ATTR uint32_t can_get_interrupt_reason() { return CAN.interrupt_reg.val; } static inline CAN_INLINE_ATTR uint32_t can_get_arbitration_lost_capture() { return CAN.arbitration_lost_captue_reg.val; //Todo: ALC read only to re-arm arb lost interrupt. Add function to decode ALC } static inline CAN_INLINE_ATTR uint32_t can_get_error_code_capture() { return CAN.error_code_capture_reg.val; //Todo: ECC read only to re-arm bus error interrupt. Add function to decode ECC } static inline CAN_INLINE_ATTR void can_get_error_counters(uint32_t *tx_error_cnt, uint32_t *rx_error_cnt) { if (tx_error_cnt != NULL) { *tx_error_cnt = CAN.tx_error_counter_reg.byte; } if (rx_error_cnt != NULL) { *rx_error_cnt = CAN.rx_error_counter_reg.byte; } } static CAN_ISR_ATTR void can_get_rx_buffer_and_clear(can_frame_t *frame) { //Copy RX buffer registers into frame structure for (int i = 0; i < FRAME_MAX_LEN; i++) { frame->bytes[i] = CAN.tx_rx_buffer[i].val; } //Clear RX buffer can_set_command(CMD_RELEASE_RX_BUFF); } static inline CAN_INLINE_ATTR uint32_t can_get_rx_message_counter() { return CAN.rx_message_counter_reg.val; } /* -------------------- Interrupt and Alert Handlers ------------------------ */ static CAN_ISR_ATTR void can_alert_handler(uint32_t alert_code, int *alert_req) { if (p_can_obj->alerts_enabled & alert_code) { //Signify alert has occurred CAN_SET_FLAG(p_can_obj->alerts_triggered, alert_code); *alert_req = 1; #ifndef CONFIG_CAN_ISR_IN_IRAM //Only log if ISR is not in IRAM if (p_can_obj->alerts_enabled & CAN_ALERT_AND_LOG) { if (alert_code >= ALERT_LOG_LEVEL_ERROR) { ESP_EARLY_LOGE(CAN_TAG, "Alert %d", alert_code); } else if (alert_code >= ALERT_LOG_LEVEL_WARNING) { ESP_EARLY_LOGW(CAN_TAG, "Alert %d", alert_code); } else { ESP_EARLY_LOGI(CAN_TAG, "Alert %d", alert_code); } } #endif } } static CAN_ISR_ATTR void can_intr_handler_err_warn(can_status_reg_t *status, BaseType_t *task_woken, int *alert_req) { if (status->bus) { if (status->error) { //Bus-Off condition. TEC should set and held at 127, REC should be 0, reset mode entered CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_BUS_OFF); /* Note: REC is still allowed to increase during bus-off. REC > err_warn can prevent "bus recovery complete" interrupt from occurring. Set to listen only mode to freeze REC. */ can_config_mode(CAN_MODE_LISTEN_ONLY); can_alert_handler(CAN_ALERT_BUS_OFF, alert_req); } else { //Bus-recovery in progress. TEC has dropped below error warning limit can_alert_handler(CAN_ALERT_RECOVERY_IN_PROGRESS, alert_req); } } else { if (status->error) { //TEC or REC surpassed error warning limit CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_ERR_WARN); can_alert_handler(CAN_ALERT_ABOVE_ERR_WARN, alert_req); } else if (p_can_obj->control_flags & CTRL_FLAG_RECOVERING) { //Bus recovery complete. esp_err_t err = can_enter_reset_mode(); assert(err == ESP_OK); //Reset and set flags to the equivalent of the stopped state CAN_RESET_FLAG(p_can_obj->control_flags, CTRL_FLAG_RECOVERING | CTRL_FLAG_ERR_WARN | CTRL_FLAG_ERR_PASSIVE | CTRL_FLAG_BUS_OFF | CTRL_FLAG_TX_BUFF_OCCUPIED); CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_STOPPED); can_alert_handler(CAN_ALERT_BUS_RECOVERED, alert_req); } else { //TEC and REC are both below error warning CAN_RESET_FLAG(p_can_obj->control_flags, CTRL_FLAG_ERR_WARN); can_alert_handler(CAN_ALERT_BELOW_ERR_WARN, alert_req); } } } static inline CAN_INLINE_ATTR void can_intr_handler_err_passive(int *alert_req) { uint32_t tec, rec; can_get_error_counters(&tec, &rec); if (tec >= DRIVER_DEFAULT_ERR_PASS_CNT || rec >= DRIVER_DEFAULT_ERR_PASS_CNT) { //Entered error passive CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_ERR_PASSIVE); can_alert_handler(CAN_ALERT_ERR_PASS, alert_req); } else { //Returned to error active CAN_RESET_FLAG(p_can_obj->control_flags, CTRL_FLAG_ERR_PASSIVE); can_alert_handler(CAN_ALERT_ERR_ACTIVE, alert_req); } } static inline CAN_INLINE_ATTR void can_intr_handler_bus_err(int *alert_req) { // ECC register is read to re-arm bus error interrupt. ECC is not used (void) can_get_error_code_capture(); p_can_obj->bus_error_count++; can_alert_handler(CAN_ALERT_BUS_ERROR, alert_req); } static inline CAN_INLINE_ATTR void can_intr_handler_arb_lost(int *alert_req) { //ALC register is read to re-arm arb lost interrupt. ALC is not used (void) can_get_arbitration_lost_capture(); p_can_obj->arb_lost_count++; can_alert_handler(CAN_ALERT_ARB_LOST, alert_req); } static inline CAN_INLINE_ATTR CAN_ISR_ATTR void can_intr_handler_rx(BaseType_t *task_woken, int *alert_req) { can_rx_msg_cnt_reg_t msg_count_reg; msg_count_reg.val = can_get_rx_message_counter(); for (int i = 0; i < msg_count_reg.rx_message_counter; i++) { can_frame_t frame; can_get_rx_buffer_and_clear(&frame); //Copy frame into RX Queue if (xQueueSendFromISR(p_can_obj->rx_queue, &frame, task_woken) == pdTRUE) { p_can_obj->rx_msg_count++; } else { p_can_obj->rx_missed_count++; can_alert_handler(CAN_ALERT_RX_QUEUE_FULL, alert_req); } } //Todo: Add Software Filters //Todo: Check for data overrun of RX FIFO, then trigger alert } static CAN_ISR_ATTR void can_intr_handler_tx(can_status_reg_t *status, int *alert_req) { //Handle previously transmitted frame if (status->tx_complete) { can_alert_handler(CAN_ALERT_TX_SUCCESS, alert_req); } else { p_can_obj->tx_failed_count++; can_alert_handler(CAN_ALERT_TX_FAILED, alert_req); } //Update TX message count p_can_obj->tx_msg_count--; assert(p_can_obj->tx_msg_count >= 0); //Sanity check //Check if there are more frames to transmit if (p_can_obj->tx_msg_count > 0 && p_can_obj->tx_queue != NULL) { can_frame_t frame; int res = xQueueReceiveFromISR(p_can_obj->tx_queue, &frame, NULL); if (res == pdTRUE) { can_set_tx_buffer_and_transmit(&frame); } else { assert(false && "failed to get a frame from TX queue"); } } else { //No more frames to transmit CAN_RESET_FLAG(p_can_obj->control_flags, CTRL_FLAG_TX_BUFF_OCCUPIED); can_alert_handler(CAN_ALERT_TX_IDLE, alert_req); } } static CAN_ISR_ATTR void can_intr_handler_main(void *arg) { BaseType_t task_woken = pdFALSE; int alert_req = 0; can_status_reg_t status; can_intr_reg_t intr_reason; CAN_ENTER_CRITICAL_ISR(); status.val = can_get_status(); intr_reason.val = (p_can_obj != NULL) ? can_get_interrupt_reason() : 0; //Incase intr occurs whilst driver is being uninstalled //Handle error counter related interrupts if (intr_reason.err_warn) { //Triggers when Bus-Status or Error-status bits change can_intr_handler_err_warn(&status, &task_woken, &alert_req); } if (intr_reason.err_passive) { //Triggers when entering/returning error passive/active state can_intr_handler_err_passive(&alert_req); } //Handle other error interrupts if (intr_reason.bus_err) { //Triggers when an error (Bit, Stuff, CRC, Form, ACK) occurs on the CAN bus can_intr_handler_bus_err(&alert_req); } if (intr_reason.arb_lost) { //Triggers when arbitration is lost can_intr_handler_arb_lost(&alert_req); } //Handle TX/RX interrupts if (intr_reason.rx) { //Triggers when RX buffer has one or more frames. Disabled if RX Queue length = 0 can_intr_handler_rx(&task_woken, &alert_req); } if (intr_reason.tx) { //Triggers when TX buffer becomes free after a transmission can_intr_handler_tx(&status, &alert_req); } /* Todo: Check possible bug where transmitting self reception request then clearing rx buffer will cancel the transmission. */ CAN_EXIT_CRITICAL_ISR(); if (p_can_obj->alert_semphr != NULL && alert_req) { //Give semaphore if alerts were triggered xSemaphoreGiveFromISR(p_can_obj->alert_semphr, &task_woken); } if (task_woken == pdTRUE) { portYIELD_FROM_ISR(); } } /* -------------------------- Helper functions ----------------------------- */ static void can_format_frame(uint32_t id, uint8_t dlc, const uint8_t *data, uint32_t flags, can_frame_t *tx_frame) { /* This function encodes a message into a frame structure. The frame structure has an identical layout to the TX buffer, allowing the frame structure to be directly copied into TX buffer. */ //Set frame information tx_frame->dlc = dlc; tx_frame->rtr = (flags & CAN_MSG_FLAG_RTR) ? 1 : 0; tx_frame->frame_format = (flags & CAN_MSG_FLAG_EXTD) ? 1 : 0; tx_frame->self_reception = (flags & CAN_MSG_FLAG_SELF) ? 1 : 0; tx_frame->single_shot = (flags & CAN_MSG_FLAG_SS) ? 1 : 0; //Set ID int id_len = (flags & CAN_MSG_FLAG_EXTD) ? FRAME_EXTD_ID_LEN : FRAME_STD_ID_LEN; uint8_t *id_buffer = (flags & CAN_MSG_FLAG_EXTD) ? tx_frame->extended.id : tx_frame->standard.id; //Split ID into 4 or 2 bytes, and turn into big-endian with left alignment (<< 3 or 5) uint32_t id_temp = (flags & CAN_MSG_FLAG_EXTD) ? __builtin_bswap32((id & CAN_EXTD_ID_MASK) << 3) : //((id << 3) >> 8*(3-i)) __builtin_bswap16((id & CAN_STD_ID_MASK) << 5); //((id << 5) >> 8*(1-i)) for (int i = 0; i < id_len; i++) { id_buffer[i] = (id_temp >> (8 * i)) & 0xFF; //Copy big-endian ID byte by byte } //Set Data. uint8_t *data_buffer = (flags & CAN_MSG_FLAG_EXTD) ? tx_frame->extended.data : tx_frame->standard.data; for (int i = 0; (i < dlc) && (i < FRAME_MAX_DATA_LEN); i++) { //Handle case where dlc is > 8 data_buffer[i] = data[i]; } } static void can_parse_frame(can_frame_t *rx_frame, uint32_t *id, uint8_t *dlc, uint8_t *data, uint32_t *flags) { //This function decodes a frame structure into it's constituent components. //Copy frame information *dlc = rx_frame->dlc; *flags = 0; *flags |= (rx_frame->dlc > FRAME_MAX_DATA_LEN) ? CAN_MSG_FLAG_DLC_NON_COMP : 0; *flags |= (rx_frame->rtr) ? CAN_MSG_FLAG_RTR : 0; *flags |= (rx_frame->frame_format) ? CAN_MSG_FLAG_EXTD : 0; //Copy ID int id_len = (rx_frame->frame_format) ? FRAME_EXTD_ID_LEN : FRAME_STD_ID_LEN; uint8_t *id_buffer = (rx_frame->frame_format) ? rx_frame->extended.id : rx_frame->standard.id; uint32_t id_temp = 0; for (int i = 0; i < id_len; i++) { id_temp |= id_buffer[i] << (8 * i); //Copy big-endian ID byte by byte } //Revert endianness of 4 or 2 byte ID, and shift into 29 or 11 bit ID id_temp = (rx_frame->frame_format) ? (__builtin_bswap32(id_temp) >> 3) : //((byte[i] << 8*(3-i)) >> 3) (__builtin_bswap16(id_temp) >> 5); //((byte[i] << 8*(1-i)) >> 5) *id = id_temp & ((rx_frame->frame_format) ? CAN_EXTD_ID_MASK : CAN_STD_ID_MASK); //Copy data uint8_t *data_buffer = (rx_frame->frame_format) ? rx_frame->extended.data : rx_frame->standard.data; for (int i = 0; (i < rx_frame->dlc) && (i < FRAME_MAX_DATA_LEN); i++) { data[i] = data_buffer[i]; } //Set remaining bytes of data to 0 for (int i = rx_frame->dlc; i < FRAME_MAX_DATA_LEN; i++) { data[i] = 0; } } static void can_configure_gpio(gpio_num_t tx, gpio_num_t rx, gpio_num_t clkout, gpio_num_t bus_status) { //Set TX pin gpio_set_pull_mode(tx, GPIO_FLOATING); gpio_matrix_out(tx, CAN_TX_IDX, false, false); gpio_pad_select_gpio(tx); //Set RX pin gpio_set_pull_mode(rx, GPIO_FLOATING); gpio_matrix_in(rx, CAN_RX_IDX, false); gpio_pad_select_gpio(rx); gpio_set_direction(rx, GPIO_MODE_INPUT); //Configure output clock pin (Optional) if (clkout >= 0 && clkout < GPIO_NUM_MAX) { gpio_set_pull_mode(clkout, GPIO_FLOATING); gpio_matrix_out(clkout, CAN_CLKOUT_IDX, false, false); gpio_pad_select_gpio(clkout); } //Configure bus status pin (Optional) if (bus_status >= 0 && bus_status < GPIO_NUM_MAX) { gpio_set_pull_mode(bus_status, GPIO_FLOATING); gpio_matrix_out(bus_status, CAN_BUS_OFF_ON_IDX, false, false); gpio_pad_select_gpio(bus_status); } } static void can_free_driver_obj(can_obj_t *p_obj) { //Free driver object and any dependent SW resources it uses (queues, semaphores etc) #ifdef CONFIG_PM_ENABLE if (p_obj->pm_lock != NULL) { ESP_ERROR_CHECK(esp_pm_lock_delete(p_obj->pm_lock)); } #endif //Delete queues and semaphores if (p_obj->tx_queue != NULL) { vQueueDelete(p_obj->tx_queue); } if (p_obj->rx_queue != NULL) { vQueueDelete(p_obj->rx_queue); } if (p_obj->alert_semphr != NULL) { vSemaphoreDelete(p_obj->alert_semphr); } #ifdef CONFIG_CAN_ISR_IN_IRAM //Free memory used by static queues and semaphores. free() allows freeing NULL pointers free(p_obj->tx_queue_buff); free(p_obj->tx_queue_struct); free(p_obj->rx_queue_buff); free(p_obj->rx_queue_struct); free(p_obj->semphr_struct); #endif //CONFIG_CAN_ISR_IN_IRAM free(p_obj); } static can_obj_t *can_alloc_driver_obj(uint32_t tx_queue_len, uint32_t rx_queue_len) { can_obj_t *p_obj = heap_caps_calloc(1, sizeof(can_obj_t), CAN_MALLOC_CAPS); if (p_obj == NULL) { return NULL; } #ifdef CONFIG_CAN_ISR_IN_IRAM //Allocate memory for queues and semaphores in DRAM if (tx_queue_len > 0) { p_obj->tx_queue_buff = heap_caps_calloc(tx_queue_len, sizeof(can_frame_t), CAN_MALLOC_CAPS); p_obj->tx_queue_struct = heap_caps_calloc(1, sizeof(StaticQueue_t), CAN_MALLOC_CAPS); if (p_obj->tx_queue_buff == NULL || p_obj->tx_queue_struct == NULL) { goto cleanup; } } p_obj->rx_queue_buff = heap_caps_calloc(rx_queue_len, sizeof(can_frame_t), CAN_MALLOC_CAPS); p_obj->rx_queue_struct = heap_caps_calloc(1, sizeof(StaticQueue_t), CAN_MALLOC_CAPS); p_obj->semphr_struct = heap_caps_calloc(1, sizeof(StaticSemaphore_t), CAN_MALLOC_CAPS); if (p_obj->rx_queue_buff == NULL || p_obj->rx_queue_struct == NULL || p_obj->semphr_struct == NULL) { goto cleanup; } //Create static queues and semaphores if (tx_queue_len > 0) { p_obj->tx_queue = xQueueCreateStatic(tx_queue_len, sizeof(can_frame_t), p_obj->tx_queue_buff, p_obj->tx_queue_struct); if (p_obj->tx_queue == NULL) { goto cleanup; } } p_obj->rx_queue = xQueueCreateStatic(rx_queue_len, sizeof(can_frame_t), p_obj->rx_queue_buff, p_obj->rx_queue_struct); p_obj->alert_semphr = xSemaphoreCreateBinaryStatic(p_obj->semphr_struct); if (p_obj->rx_queue == NULL || p_obj->alert_semphr == NULL) { goto cleanup; } #else //CONFIG_CAN_ISR_IN_IRAM if (tx_queue_len > 0) { p_obj->tx_queue = xQueueCreate(tx_queue_len, sizeof(can_frame_t)); } p_obj->rx_queue = xQueueCreate(rx_queue_len, sizeof(can_frame_t)); p_obj->alert_semphr = xSemaphoreCreateBinary(); if ((tx_queue_len > 0 && p_obj->tx_queue == NULL) || p_obj->rx_queue == NULL || p_obj->alert_semphr == NULL) { goto cleanup; } #endif //CONFIG_CAN_ISR_IN_IRAM #ifdef CONFIG_PM_ENABLE esp_err_t pm_err = esp_pm_lock_create(ESP_PM_APB_FREQ_MAX, 0, "can", &(p_obj->pm_lock)); if (pm_err != ESP_OK ) { goto cleanup; } #endif return p_obj; cleanup: can_free_driver_obj(p_obj); return NULL; } /* ---------------------------- Public Functions ---------------------------- */ esp_err_t can_driver_install(const can_general_config_t *g_config, const can_timing_config_t *t_config, const can_filter_config_t *f_config) { //Check arguments CAN_CHECK(g_config != NULL, ESP_ERR_INVALID_ARG); CAN_CHECK(t_config != NULL, ESP_ERR_INVALID_ARG); CAN_CHECK(f_config != NULL, ESP_ERR_INVALID_ARG); CAN_CHECK(g_config->rx_queue_len > 0, ESP_ERR_INVALID_ARG); CAN_CHECK(g_config->tx_io >= 0 && g_config->tx_io < GPIO_NUM_MAX, ESP_ERR_INVALID_ARG); CAN_CHECK(g_config->rx_io >= 0 && g_config->rx_io < GPIO_NUM_MAX, ESP_ERR_INVALID_ARG); #if (CONFIG_ESP32_REV_MIN >= 2) //ESP32 revision 2 or later chips have a brp_div bit. Check that the BRP config value is valid when brp_div is enabled or disabled CAN_CHECK(BRP_CHECK_WITH_DIV(t_config->brp) || BRP_CHECK_NO_DIV(t_config->brp), ESP_ERR_INVALID_ARG); #else CAN_CHECK(BRP_CHECK_NO_DIV(t_config->brp), ESP_ERR_INVALID_ARG); #endif #ifndef CONFIG_CAN_ISR_IN_IRAM CAN_CHECK(!(g_config->intr_flags & ESP_INTR_FLAG_IRAM), ESP_ERR_INVALID_ARG); #endif CAN_ENTER_CRITICAL(); CAN_CHECK_FROM_CRIT(p_can_obj == NULL, ESP_ERR_INVALID_STATE); CAN_EXIT_CRITICAL(); esp_err_t ret; can_obj_t *p_can_obj_dummy; //Create a CAN object (including queues and semaphores) p_can_obj_dummy = can_alloc_driver_obj(g_config->tx_queue_len, g_config->rx_queue_len); CAN_CHECK(p_can_obj_dummy != NULL, ESP_ERR_NO_MEM); //Initialize flags and variables. All other members are already set to zero by can_alloc_driver_obj() p_can_obj_dummy->control_flags = CTRL_FLAG_STOPPED; p_can_obj_dummy->control_flags |= (g_config->mode == CAN_MODE_NO_ACK) ? CTRL_FLAG_SELF_TEST : 0; p_can_obj_dummy->control_flags |= (g_config->mode == CAN_MODE_LISTEN_ONLY) ? CTRL_FLAG_LISTEN_ONLY : 0; p_can_obj_dummy->alerts_enabled = g_config->alerts_enabled; //Initialize CAN peripheral registers, and allocate interrupt CAN_ENTER_CRITICAL(); if (p_can_obj == NULL) { p_can_obj = p_can_obj_dummy; } else { //Check if driver is already installed CAN_EXIT_CRITICAL(); ret = ESP_ERR_INVALID_STATE; goto err; } periph_module_reset(PERIPH_CAN_MODULE); periph_module_enable(PERIPH_CAN_MODULE); //Enable APB CLK to CAN peripheral esp_err_t err = can_enter_reset_mode(); //Must enter reset mode to write to config registers assert(err == ESP_OK); can_config_pelican(); //Use PeliCAN addresses /* Note: REC is allowed to increase even in reset mode. Listen only mode will freeze REC. The desired mode will be set when can_start() is called. */ can_config_mode(CAN_MODE_LISTEN_ONLY); #if (CONFIG_ESP32_REV_MIN >= 2) //If the BRP config value is large enough, the brp_div bit must be enabled to achieve the same effective baud rate prescaler can_config_interrupts((t_config->brp > BRP_DIV_EN_THRESH) ? DRIVER_DEFAULT_INTERRUPTS | BRP_DIV_EN_BIT : DRIVER_DEFAULT_INTERRUPTS); can_config_bus_timing((t_config->brp > BRP_DIV_EN_THRESH) ? t_config->brp/2 : t_config->brp, t_config->sjw, t_config->tseg_1, t_config->tseg_2, t_config->triple_sampling); #else can_config_interrupts(DRIVER_DEFAULT_INTERRUPTS); can_config_bus_timing(t_config->brp, t_config->sjw, t_config->tseg_1, t_config->tseg_2, t_config->triple_sampling); #endif can_config_error(DRIVER_DEFAULT_EWL, DRIVER_DEFAULT_REC, DRIVER_DEFAULT_TEC); can_config_acceptance_filter(f_config->acceptance_code, f_config->acceptance_mask, f_config->single_filter); can_config_clk_out(g_config->clkout_divider); (void) can_get_interrupt_reason(); //Read interrupt reg to clear it before allocating ISR //Todo: Allow interrupt to be registered to specified CPU CAN_EXIT_CRITICAL(); //Allocate GPIO and Interrupts can_configure_gpio(g_config->tx_io, g_config->rx_io, g_config->clkout_io, g_config->bus_off_io); ESP_ERROR_CHECK(esp_intr_alloc(ETS_CAN_INTR_SOURCE, g_config->intr_flags, can_intr_handler_main, NULL, &p_can_obj->isr_handle)); #ifdef CONFIG_PM_ENABLE ESP_ERROR_CHECK(esp_pm_lock_acquire(p_can_obj->pm_lock)); //Acquire pm_lock to keep APB clock at 80MHz #endif return ESP_OK; //CAN module is still in reset mode, users need to call can_start() afterwards err: can_free_driver_obj(p_can_obj_dummy); return ret; } esp_err_t can_driver_uninstall() { can_obj_t *p_can_obj_dummy; CAN_ENTER_CRITICAL(); //Check state CAN_CHECK_FROM_CRIT(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK_FROM_CRIT(p_can_obj->control_flags & (CTRL_FLAG_STOPPED | CTRL_FLAG_BUS_OFF), ESP_ERR_INVALID_STATE); esp_err_t err = can_enter_reset_mode(); //Enter reset mode to stop any CAN bus activity assert(err == ESP_OK); //Clear registers by reading (void) can_get_interrupt_reason(); (void) can_get_arbitration_lost_capture(); (void) can_get_error_code_capture(); periph_module_disable(PERIPH_CAN_MODULE); //Disable CAN peripheral p_can_obj_dummy = p_can_obj; //Use dummy to shorten critical section p_can_obj = NULL; CAN_EXIT_CRITICAL(); ESP_ERROR_CHECK(esp_intr_free(p_can_obj_dummy->isr_handle)); //Free interrupt #ifdef CONFIG_PM_ENABLE //Release and delete power management lock ESP_ERROR_CHECK(esp_pm_lock_release(p_can_obj_dummy->pm_lock)); #endif can_free_driver_obj(p_can_obj_dummy); return ESP_OK; } esp_err_t can_start() { //Check state CAN_ENTER_CRITICAL(); CAN_CHECK_FROM_CRIT(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK_FROM_CRIT(p_can_obj->control_flags & CTRL_FLAG_STOPPED, ESP_ERR_INVALID_STATE); //Reset RX queue, and RX message count xQueueReset(p_can_obj->rx_queue); p_can_obj->rx_msg_count = 0; esp_err_t err = can_enter_reset_mode(); //Should already be in bus-off mode, set again to make sure assert(err == ESP_OK); //Currently in listen only mode, need to set to mode specified by configuration can_mode_t mode; if (p_can_obj->control_flags & CTRL_FLAG_SELF_TEST) { mode = CAN_MODE_NO_ACK; } else if (p_can_obj->control_flags & CTRL_FLAG_LISTEN_ONLY) { mode = CAN_MODE_LISTEN_ONLY; } else { mode = CAN_MODE_NORMAL; } can_config_mode(mode); //Set mode (void) can_get_interrupt_reason(); //Clear interrupt register err = can_exit_reset_mode(); assert(err == ESP_OK); CAN_RESET_FLAG(p_can_obj->control_flags, CTRL_FLAG_STOPPED); CAN_EXIT_CRITICAL(); return ESP_OK; } esp_err_t can_stop() { //Check state CAN_ENTER_CRITICAL(); CAN_CHECK_FROM_CRIT(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK_FROM_CRIT(!(p_can_obj->control_flags & (CTRL_FLAG_STOPPED | CTRL_FLAG_BUS_OFF)), ESP_ERR_INVALID_STATE); //Clear interrupts and reset flags esp_err_t err = can_enter_reset_mode(); assert(err == ESP_OK); (void) can_get_interrupt_reason(); //Read interrupt register to clear interrupts can_config_mode(CAN_MODE_LISTEN_ONLY); //Set to listen only mode to freeze REC CAN_RESET_FLAG(p_can_obj->control_flags, CTRL_FLAG_TX_BUFF_OCCUPIED); CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_STOPPED); //Reset TX Queue and message count if (p_can_obj->tx_queue != NULL) { xQueueReset(p_can_obj->tx_queue); } p_can_obj->tx_msg_count = 0; CAN_EXIT_CRITICAL(); return ESP_OK; } esp_err_t can_transmit(const can_message_t *message, TickType_t ticks_to_wait) { //Check arguments CAN_CHECK(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK(message != NULL, ESP_ERR_INVALID_ARG); CAN_CHECK((message->data_length_code <= FRAME_MAX_DATA_LEN) || (message->flags & CAN_MSG_FLAG_DLC_NON_COMP), ESP_ERR_INVALID_ARG); CAN_ENTER_CRITICAL(); //Check State CAN_CHECK_FROM_CRIT(!(p_can_obj->control_flags & CTRL_FLAG_LISTEN_ONLY), ESP_ERR_NOT_SUPPORTED); CAN_CHECK_FROM_CRIT(!(p_can_obj->control_flags & (CTRL_FLAG_STOPPED | CTRL_FLAG_BUS_OFF)), ESP_ERR_INVALID_STATE); //Format frame esp_err_t ret = ESP_FAIL; can_frame_t tx_frame; can_format_frame(message->identifier, message->data_length_code, message->data, message->flags, &tx_frame); //Check if frame can be sent immediately if ((p_can_obj->tx_msg_count == 0) && !(p_can_obj->control_flags & CTRL_FLAG_TX_BUFF_OCCUPIED)) { //No other frames waiting to transmit. Bypass queue and transmit immediately can_set_tx_buffer_and_transmit(&tx_frame); p_can_obj->tx_msg_count++; CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_TX_BUFF_OCCUPIED); ret = ESP_OK; } CAN_EXIT_CRITICAL(); if (ret != ESP_OK) { if (p_can_obj->tx_queue == NULL) { //TX Queue is disabled and TX buffer is occupied, message was not sent ret = ESP_FAIL; } else if (xQueueSend(p_can_obj->tx_queue, &tx_frame, ticks_to_wait) == pdTRUE) { //Copied to TX Queue CAN_ENTER_CRITICAL(); if (p_can_obj->control_flags & (CTRL_FLAG_STOPPED | CTRL_FLAG_BUS_OFF)) { //TX queue was reset (due to stop/bus_off), remove copied frame from queue to prevent transmission int res = xQueueReceive(p_can_obj->tx_queue, &tx_frame, 0); assert(res == pdTRUE); ret = ESP_ERR_INVALID_STATE; } else if ((p_can_obj->tx_msg_count == 0) && !(p_can_obj->control_flags & CTRL_FLAG_TX_BUFF_OCCUPIED)) { //TX buffer was freed during copy, manually trigger transmission int res = xQueueReceive(p_can_obj->tx_queue, &tx_frame, 0); assert(res == pdTRUE); can_set_tx_buffer_and_transmit(&tx_frame); p_can_obj->tx_msg_count++; CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_TX_BUFF_OCCUPIED); ret = ESP_OK; } else { //Frame was copied to queue, waiting to be transmitted p_can_obj->tx_msg_count++; ret = ESP_OK; } CAN_EXIT_CRITICAL(); } else { //Timed out waiting for free space on TX queue ret = ESP_ERR_TIMEOUT; } } return ret; } esp_err_t can_receive(can_message_t *message, TickType_t ticks_to_wait) { //Check arguments and state CAN_CHECK(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK(message != NULL, ESP_ERR_INVALID_ARG); //Get frame from RX Queue or RX Buffer can_frame_t rx_frame; if (xQueueReceive(p_can_obj->rx_queue, &rx_frame, ticks_to_wait) != pdTRUE) { return ESP_ERR_TIMEOUT; } CAN_ENTER_CRITICAL(); p_can_obj->rx_msg_count--; CAN_EXIT_CRITICAL(); //Decode frame can_parse_frame(&rx_frame, &(message->identifier), &(message->data_length_code), message->data, &(message->flags)); return ESP_OK; } esp_err_t can_read_alerts(uint32_t *alerts, TickType_t ticks_to_wait) { //Check arguments and state CAN_CHECK(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK(alerts != NULL, ESP_ERR_INVALID_ARG); //Wait for an alert to occur if (xSemaphoreTake(p_can_obj->alert_semphr, ticks_to_wait) == pdTRUE) { CAN_ENTER_CRITICAL(); *alerts = p_can_obj->alerts_triggered; p_can_obj->alerts_triggered = 0; //Clear triggered alerts CAN_EXIT_CRITICAL(); return ESP_OK; } else { *alerts = 0; return ESP_ERR_TIMEOUT; } } esp_err_t can_reconfigure_alerts(uint32_t alerts_enabled, uint32_t *current_alerts) { CAN_CHECK(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_ENTER_CRITICAL(); //Clear any unhandled alerts if (current_alerts != NULL) { *current_alerts = p_can_obj->alerts_triggered;; } p_can_obj->alerts_triggered = 0; p_can_obj->alerts_enabled = alerts_enabled; //Update enabled alerts CAN_EXIT_CRITICAL(); return ESP_OK; } esp_err_t can_initiate_recovery() { CAN_ENTER_CRITICAL(); //Check state CAN_CHECK_FROM_CRIT(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK_FROM_CRIT(p_can_obj->control_flags & CTRL_FLAG_BUS_OFF, ESP_ERR_INVALID_STATE); CAN_CHECK_FROM_CRIT(!(p_can_obj->control_flags & CTRL_FLAG_RECOVERING), ESP_ERR_INVALID_STATE); //Reset TX Queue/Counters if (p_can_obj->tx_queue != NULL) { xQueueReset(p_can_obj->tx_queue); } p_can_obj->tx_msg_count = 0; CAN_RESET_FLAG(p_can_obj->control_flags, CTRL_FLAG_TX_BUFF_OCCUPIED); CAN_SET_FLAG(p_can_obj->control_flags, CTRL_FLAG_RECOVERING); //Trigger start of recovery process esp_err_t err = can_exit_reset_mode(); assert(err == ESP_OK); CAN_EXIT_CRITICAL(); return ESP_OK; } esp_err_t can_get_status_info(can_status_info_t *status_info) { //Check parameters and state CAN_CHECK(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK(status_info != NULL, ESP_ERR_INVALID_ARG); CAN_ENTER_CRITICAL(); uint32_t tec, rec; can_get_error_counters(&tec, &rec); status_info->tx_error_counter = tec; status_info->rx_error_counter = rec; status_info->msgs_to_tx = p_can_obj->tx_msg_count; status_info->msgs_to_rx = p_can_obj->rx_msg_count; status_info->tx_failed_count = p_can_obj->tx_failed_count; status_info->rx_missed_count = p_can_obj->rx_missed_count; status_info->arb_lost_count = p_can_obj->arb_lost_count; status_info->bus_error_count = p_can_obj->bus_error_count; if (p_can_obj->control_flags & CTRL_FLAG_RECOVERING) { status_info->state = CAN_STATE_RECOVERING; } else if (p_can_obj->control_flags & CTRL_FLAG_BUS_OFF) { status_info->state = CAN_STATE_BUS_OFF; } else if (p_can_obj->control_flags & CTRL_FLAG_STOPPED) { status_info->state = CAN_STATE_STOPPED; } else { status_info->state = CAN_STATE_RUNNING; } CAN_EXIT_CRITICAL(); return ESP_OK; } esp_err_t can_clear_transmit_queue() { //Check State CAN_CHECK(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_CHECK(p_can_obj->tx_queue != NULL, ESP_ERR_NOT_SUPPORTED); CAN_ENTER_CRITICAL(); //If a message is currently undergoing transmission, the tx interrupt handler will decrement tx_msg_count p_can_obj->tx_msg_count = (p_can_obj->control_flags & CTRL_FLAG_TX_BUFF_OCCUPIED) ? 1 : 0; xQueueReset(p_can_obj->tx_queue); CAN_EXIT_CRITICAL(); return ESP_OK; } esp_err_t can_clear_receive_queue() { //Check State CAN_CHECK(p_can_obj != NULL, ESP_ERR_INVALID_STATE); CAN_ENTER_CRITICAL(); p_can_obj->rx_msg_count = 0; xQueueReset(p_can_obj->rx_queue); CAN_EXIT_CRITICAL(); return ESP_OK; }