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OVMS3-idf/components/driver/can.c
Darian Leung 09ae962c33 can: Add support for lower bit rates 
This commit adds support for lower bit rates in the CAN Driver for
ESP32 Rev 2 or later chips.
2019-12-16 07:45:59 +00:00

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// 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 "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))
#define CAN_TAG "CAN"
/*
* 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
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() portENTER_CRITICAL(&can_spinlock)
#define CAN_EXIT_CRITICAL() portEXIT_CRITICAL(&can_spinlock)
/* ------------------- Configuration Register Functions---------------------- */
static inline 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 inline 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 void can_set_command(uint8_t commands)
{
CAN.command_reg.val = commands;
}
static 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 uint32_t can_get_status()
{
return CAN.status_reg.val;
}
static inline uint32_t can_get_interrupt_reason()
{
return CAN.interrupt_reg.val;
}
static inline 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 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 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 inline 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 uint32_t can_get_rx_message_counter()
{
return CAN.rx_message_counter_reg.val;
}
/* -------------------- Interrupt and Alert Handlers ------------------------ */
static 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;
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);
}
}
}
}
static 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 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 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 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 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);
}
}
}
static 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 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();
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);
}
//Todo: Check data overrun bug where interrupt does not trigger even when enabled
//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();
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();
}
}
/* ---------------------- Frame and GPIO 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);
}
}
/* ---------------------------- 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
esp_err_t ret;
can_obj_t *p_can_obj_dummy;
//Create a CAN object
p_can_obj_dummy = calloc(1, sizeof(can_obj_t));
CAN_CHECK(p_can_obj_dummy != NULL, ESP_ERR_NO_MEM);
//Initialize queues, semaphores, and power management locks
p_can_obj_dummy->tx_queue = (g_config->tx_queue_len > 0) ? xQueueCreate(g_config->tx_queue_len, sizeof(can_frame_t)) : NULL;
p_can_obj_dummy->rx_queue = xQueueCreate(g_config->rx_queue_len, sizeof(can_frame_t));
p_can_obj_dummy->alert_semphr = xSemaphoreCreateBinary();
if ((g_config->tx_queue_len > 0 && p_can_obj_dummy->tx_queue == NULL) ||
p_can_obj_dummy->rx_queue == NULL || p_can_obj_dummy->alert_semphr == NULL) {
ret = ESP_ERR_NO_MEM;
goto err;
}
#ifdef CONFIG_PM_ENABLE
esp_err_t pm_err = esp_pm_lock_create(ESP_PM_APB_FREQ_MAX, 0, "can", &(p_can_obj_dummy->pm_lock));
if (pm_err != ESP_OK ) {
ret = pm_err;
goto err;
}
#endif
//Initialize flags and variables
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->tx_msg_count = 0;
p_can_obj_dummy->rx_msg_count = 0;
p_can_obj_dummy->tx_failed_count = 0;
p_can_obj_dummy->rx_missed_count = 0;
p_can_obj_dummy->arb_lost_count = 0;
p_can_obj_dummy->bus_error_count = 0;
p_can_obj_dummy->alerts_enabled = g_config->alerts_enabled;
p_can_obj_dummy->alerts_triggered = 0;
//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);
//Allocate GPIO and Interrupts
can_configure_gpio(g_config->tx_io, g_config->rx_io, g_config->clkout_io, g_config->bus_off_io);
(void) can_get_interrupt_reason(); //Read interrupt reg to clear it before allocating ISR
ESP_ERROR_CHECK(esp_intr_alloc(ETS_CAN_INTR_SOURCE, 0, can_intr_handler_main, NULL, &p_can_obj->isr_handle));
//Todo: Allow interrupt to be registered to specified CPU
CAN_EXIT_CRITICAL();
#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:
//Cleanup CAN object and return error
if (p_can_obj_dummy != NULL) {
if (p_can_obj_dummy->tx_queue != NULL) {
vQueueDelete(p_can_obj_dummy->tx_queue);
p_can_obj_dummy->tx_queue = NULL;
}
if (p_can_obj_dummy->rx_queue != NULL) {
vQueueDelete(p_can_obj_dummy->rx_queue);
p_can_obj_dummy->rx_queue = NULL;
}
if (p_can_obj_dummy->alert_semphr != NULL) {
vSemaphoreDelete(p_can_obj_dummy->alert_semphr);
p_can_obj_dummy->alert_semphr = NULL;
}
#ifdef CONFIG_PM_ENABLE
if (p_can_obj_dummy->pm_lock != NULL) {
ESP_ERROR_CHECK(esp_pm_lock_delete(p_can_obj_dummy->pm_lock));
}
#endif
free(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();
ESP_ERROR_CHECK(esp_intr_free(p_can_obj->isr_handle)); //Free interrupt
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();
//Delete queues, semaphores, and power management locks
if (p_can_obj_dummy->tx_queue != NULL) {
vQueueDelete(p_can_obj_dummy->tx_queue);
}
vQueueDelete(p_can_obj_dummy->rx_queue);
vSemaphoreDelete(p_can_obj_dummy->alert_semphr);
#ifdef CONFIG_PM_ENABLE
//Release and delete power management lock
ESP_ERROR_CHECK(esp_pm_lock_release(p_can_obj_dummy->pm_lock));
ESP_ERROR_CHECK(esp_pm_lock_delete(p_can_obj_dummy->pm_lock));
#endif
free(p_can_obj_dummy); //Free can driver object
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();
uint32_t cur_alerts;
cur_alerts = can_read_alerts(&cur_alerts, 0); //Clear any unhandled alerts
p_can_obj->alerts_enabled = alerts_enabled; //Update enabled alerts
CAN_EXIT_CRITICAL();
if (current_alerts != NULL) {
*current_alerts = cur_alerts;
}
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;
}
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