circuitpython/ports/stm/common-hal/canio/CAN.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020 Jeff Epler for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* 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 <string.h>
#include "py/runtime.h"
#include "py/mperrno.h"
#include "common-hal/canio/CAN.h"
#include "peripherals/periph.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "shared-bindings/util.h"
#include "supervisor/port.h"
STATIC bool reserved_can[MP_ARRAY_SIZE(mcu_can_banks)];
STATIC const mcu_periph_obj_t *find_pin_function(const mcu_periph_obj_t *table, size_t sz, const mcu_pin_obj_t *pin, int periph_index) {
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for (size_t i = 0; i < sz; i++, table++) {
if (periph_index != -1 && periph_index != table->periph_index) {
continue;
}
if (pin == table->pin) {
return table;
}
}
return NULL;
}
void common_hal_canio_can_construct(canio_can_obj_t *self, const mcu_pin_obj_t *tx, const mcu_pin_obj_t *rx, int baudrate, bool loopback, bool silent) {
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#define DIV_ROUND(a, b) (((a) + (b) / 2) / (b))
#define DIV_ROUND_UP(a, b) (((a) + (b) - 1) / (b))
const uint8_t can_tx_len = MP_ARRAY_SIZE(mcu_can_tx_list);
const uint8_t can_rx_len = MP_ARRAY_SIZE(mcu_can_rx_list);
const mcu_periph_obj_t *mcu_tx = find_pin_function(mcu_can_tx_list, can_tx_len, tx, -1);
if (!mcu_tx) {
raise_ValueError_invalid_pin_name(MP_QSTR_tx);
}
int periph_index = mcu_tx->periph_index;
const mcu_periph_obj_t *mcu_rx = find_pin_function(mcu_can_rx_list, can_rx_len, rx, periph_index);
if (!mcu_rx) {
raise_ValueError_invalid_pin_name(MP_QSTR_rx);
}
if (reserved_can[periph_index]) {
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mp_raise_ValueError(translate("Hardware in use, try alternative pins"));
}
const uint32_t can_frequency = 42000000;
uint32_t clocks_per_bit = DIV_ROUND(can_frequency, baudrate);
uint32_t clocks_to_sample = DIV_ROUND(clocks_per_bit * 7, 8);
uint32_t clocks_after_sample = clocks_per_bit - clocks_to_sample;
uint32_t divisor = MAX(DIV_ROUND_UP(clocks_to_sample, 16), DIV_ROUND_UP(clocks_after_sample, 8));
const uint32_t sjw = 3;
uint32_t tq_per_bit = DIV_ROUND(clocks_per_bit, divisor);
uint32_t tq_to_sample = DIV_ROUND(clocks_to_sample, divisor);
uint32_t tq_after_sample = tq_per_bit - tq_to_sample;
if (divisor > 1023) {
mp_raise_OSError(MP_EINVAL); // baudrate cannot be attained (16kHz or something is lower bound, should never happen)
}
{
GPIO_InitTypeDef GPIO_InitStruct = {
.Pin = pin_mask(tx->number),
.Speed = GPIO_SPEED_FREQ_VERY_HIGH,
.Mode = GPIO_MODE_AF_PP,
.Pull = GPIO_PULLUP,
.Alternate = mcu_tx->altfn_index,
};
HAL_GPIO_Init(pin_port(tx->port), &GPIO_InitStruct);
GPIO_InitStruct.Pin = pin_mask(rx->number);
GPIO_InitStruct.Alternate = mcu_rx->altfn_index;
HAL_GPIO_Init(pin_port(rx->port), &GPIO_InitStruct);
}
CAN_TypeDef *hw = mcu_can_banks[periph_index - 1];
// CAN2 shares resources with CAN1. So we always enable CAN1, then split
// the filter banks equally between them.
__HAL_RCC_CAN1_CLK_ENABLE();
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if (hw == CAN2) {
__HAL_RCC_CAN2_CLK_ENABLE();
self->start_filter_bank = 14;
self->end_filter_bank = 28;
self->filter_hw = CAN1;
} else {
self->start_filter_bank = 0;
self->end_filter_bank = 14;
self->filter_hw = hw;
}
CAN_InitTypeDef init = {
.AutoRetransmission = ENABLE,
.AutoBusOff = ENABLE,
.Prescaler = divisor,
.Mode = (loopback ? CAN_MODE_LOOPBACK : 0) | (silent ? CAN_MODE_SILENT_LOOPBACK : 0),
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.SyncJumpWidth = (sjw - 1) << CAN_BTR_SJW_Pos,
.TimeSeg1 = (tq_to_sample - 2) << CAN_BTR_TS1_Pos,
.TimeSeg2 = (tq_after_sample - 1) << CAN_BTR_TS2_Pos,
};
self->periph_index = periph_index;
self->silent = silent;
self->loopback = loopback;
self->baudrate = baudrate;
self->handle.Instance = hw;
self->handle.Init = init;
self->handle.State = HAL_CAN_STATE_RESET;
HAL_CAN_Init(&self->handle);
// Set the filter split as 14:14
// COULDDO(@jepler): Dynamically allocate filter banks between CAN1/2
self->filter_hw->FMR |= CAN_FMR_FINIT;
self->filter_hw->FMR = CAN_FMR_FINIT | (14 << CAN_FMR_CAN2SB_Pos);
// Clear every filter enable bit for this can HW
uint32_t fa1r = self->filter_hw->FA1R;
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for (int i = self->start_filter_bank; i < self->end_filter_bank; i++) {
fa1r &= ~(1 << i);
}
self->filter_hw->FA1R = fa1r;
CLEAR_BIT(self->filter_hw->FMR, CAN_FMR_FINIT);
HAL_CAN_Start(&self->handle);
reserved_can[periph_index] = true;
}
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bool common_hal_canio_can_loopback_get(canio_can_obj_t *self) {
return self->loopback;
}
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int common_hal_canio_can_baudrate_get(canio_can_obj_t *self) {
return self->baudrate;
}
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int common_hal_canio_can_transmit_error_count_get(canio_can_obj_t *self) {
return (self->handle.Instance->ESR & CAN_ESR_TEC) >> CAN_ESR_TEC_Pos;
}
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int common_hal_canio_can_receive_error_count_get(canio_can_obj_t *self) {
return (self->handle.Instance->ESR & CAN_ESR_REC) >> CAN_ESR_REC_Pos;
}
canio_bus_state_t common_hal_canio_can_state_get(canio_can_obj_t *self) {
uint32_t esr = self->handle.Instance->ESR;
if (READ_BIT(esr, CAN_ESR_BOFF)) {
return BUS_STATE_OFF;
}
if (READ_BIT(esr, CAN_ESR_EPVF)) {
return BUS_STATE_ERROR_PASSIVE;
}
if (READ_BIT(esr, CAN_ESR_EWGF)) {
return BUS_STATE_ERROR_WARNING;
}
return BUS_STATE_ERROR_ACTIVE;
}
void common_hal_canio_can_restart(canio_can_obj_t *self) {
if (!common_hal_canio_can_auto_restart_get(self)) {
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// "If ABOM is cleared, the software must initiate the recovering
// sequence by requesting bxCAN to enter and to leave initialization
// mode."
self->handle.Instance->MCR |= CAN_MCR_INRQ;
while ((self->handle.Instance->MSR & CAN_MSR_INAK) == 0) {
}
self->handle.Instance->MCR &= ~CAN_MCR_INRQ;
while ((self->handle.Instance->MSR & CAN_MSR_INAK)) {
}
}
}
bool common_hal_canio_can_auto_restart_get(canio_can_obj_t *self) {
return READ_BIT(self->handle.Instance->MCR, CAN_MCR_ABOM);
}
void common_hal_canio_can_auto_restart_set(canio_can_obj_t *self, bool value) {
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if (value) {
SET_BIT(self->handle.Instance->MCR, CAN_MCR_ABOM);
} else {
CLEAR_BIT(self->handle.Instance->MCR, CAN_MCR_ABOM);
}
}
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void common_hal_canio_can_send(canio_can_obj_t *self, mp_obj_t message_in) {
canio_message_obj_t *message = message_in;
uint32_t mailbox;
bool rtr = message->base.type == &canio_remote_transmission_request_type;
CAN_TxHeaderTypeDef header = {
.StdId = message->id,
.ExtId = message->id,
.IDE = message->extended ? CAN_ID_EXT : CAN_ID_STD,
.RTR = rtr ? CAN_RTR_REMOTE : CAN_RTR_DATA,
.DLC = message->size,
};
uint32_t free_level = HAL_CAN_GetTxMailboxesFreeLevel(&self->handle);
if (free_level == 0) {
// There's no free Tx mailbox. We need to cancel some message without
// transmitting it, because once the bus returns to active state it's
// preferable to transmit the newest messages instead of older messages.
//
// We don't strictly guarantee that we abort the oldest Tx request,
// rather we just abort a different index each time. This permits us
// to just track a single cancel index
HAL_CAN_AbortTxRequest(&self->handle, 1 << (self->cancel_mailbox));
self->cancel_mailbox = (self->cancel_mailbox + 1) % 3;
// The abort request may not have completed immediately, so wait for
// the Tx mailbox to become free
do {
free_level = HAL_CAN_GetTxMailboxesFreeLevel(&self->handle);
} while (!free_level);
}
HAL_StatusTypeDef status = HAL_CAN_AddTxMessage(&self->handle, &header, message->data, &mailbox);
if (status != HAL_OK) {
// this is a "shouldn't happen" condition. we don't throw because the
// contract of send() is that it queues the packet to be sent if
// possible and does not signal success or failure to actually send.
return;
}
// wait 8ms (hard coded for now) for TX to occur
uint64_t deadline = port_get_raw_ticks(NULL) + 8;
while (port_get_raw_ticks(NULL) < deadline && HAL_CAN_IsTxMessagePending(&self->handle, 1 << mailbox)) {
RUN_BACKGROUND_TASKS;
}
}
bool common_hal_canio_can_silent_get(canio_can_obj_t *self) {
return self->silent;
}
bool common_hal_canio_can_deinited(canio_can_obj_t *self) {
return !self->handle.Instance;
}
void common_hal_canio_can_check_for_deinit(canio_can_obj_t *self) {
if (common_hal_canio_can_deinited(self)) {
raise_deinited_error();
}
}
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void common_hal_canio_can_deinit(canio_can_obj_t *self) {
if (self->handle.Instance) {
SET_BIT(self->handle.Instance->MCR, CAN_MCR_RESET);
while (READ_BIT(self->handle.Instance->MCR, CAN_MCR_RESET)) {
}
reserved_can[self->periph_index] = 0;
}
self->handle.Instance = NULL;
}
void common_hal_canio_reset(void) {
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for (size_t i = 0; i < MP_ARRAY_SIZE(mcu_can_banks); i++) {
SET_BIT(mcu_can_banks[i]->MCR, CAN_MCR_RESET);
reserved_can[i] = 0;
}
}