canio: implement for stm32f405

The has successfully run my loopback self-test program for CAN,
which tests transmission, reception, and filtering.  The 1M baud rate setting
was also verified on saleae to be accurate.

Author: jepler

lib/tinyusb

@@ -198,6 +198,10 @@ SRC_STM32 = $(addprefix $(HAL_DIR)/Src/stm32$(MCU_SERIES_LOWER)xx_,\
 	ll_utils.c \
 )
 
+ifeq ($(CIRCUITPY_CANIO),1)
+SRC_STM32 += $(HAL_DIR)/Src/stm32$(MCU_SERIES_LOWER)xx_hal_can.c
+endif
+
 # Need this to avoid UART linker problems. TODO: rewrite to use registered callbacks.
 # Does not exist for F4 and lower
 ifeq ($(MCU_VARIANT),$(filter $(MCU_VARIANT),STM32F765xx STM32F767xx STM32F769xx STM32H743xx))

ports/stm/Makefile

@@ -16,3 +16,5 @@ LD_DEFAULT = boards/STM32F405_default.ld
 # UF2 boot option
 LD_BOOT = boards/STM32F405_boot.ld
 UF2_OFFSET = 0x8010000
+
+CIRCUITPY_CANIO = 1

ports/stm/boards/feather_stm32f405_express/mpconfigboard.mk

@@ -47,5 +47,8 @@ STATIC const mp_rom_map_elem_t board_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_SDIO_CLOCK), MP_ROM_PTR(&pin_PC12) },
     { MP_ROM_QSTR(MP_QSTR_SDIO_COMMAND), MP_ROM_PTR(&pin_PD02) },
     { MP_ROM_QSTR(MP_QSTR_SDIO_DATA), MP_ROM_PTR(&sdio_data_tuple) },
+
+    { MP_OBJ_NEW_QSTR(MP_QSTR_CAN_RX),  MP_ROM_PTR(&pin_PB09) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_CAN_TX),  MP_ROM_PTR(&pin_PB08) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_module_globals_table);

ports/stm/boards/feather_stm32f405_express/pins.c

@@ -0,0 +1,279 @@
+/*
+ * 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) {
+    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;
+}
+
+
+__attribute__((optimize("O0")))
+void common_hal_canio_can_construct(canio_can_obj_t *self, mcu_pin_obj_t *tx, mcu_pin_obj_t *rx, int baudrate, bool loopback, bool silent)
+{
+#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) {
+        mp_raise_ValueError_varg(translate("Invalid %q pin selection"), 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) {
+        mp_raise_ValueError_varg(translate("Invalid %q pin selection"), MP_QSTR_rx);
+    }
+
+    if (reserved_can[periph_index]) {
+        mp_raise_ValueError(translate("Hardware busy, 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();
+
+    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),
+        .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;
+    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;
+}
+
+bool common_hal_canio_can_loopback_get(canio_can_obj_t *self)
+{
+    return self->loopback;
+}
+
+int common_hal_canio_can_baudrate_get(canio_can_obj_t *self)
+{
+    return self->baudrate;
+}
+
+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;
+}
+
+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;
+}
+
+int common_hal_canio_can_error_warning_state_count_get(canio_can_obj_t *self)
+{
+    return self->error_warning_state_count;
+}
+
+int common_hal_canio_can_error_passive_state_count_get(canio_can_obj_t *self)
+{
+    return self->error_passive_state_count;
+}
+
+int common_hal_canio_can_bus_off_state_count_get(canio_can_obj_t *self)
+{
+    return self->bus_off_state_count;
+}
+
+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)) {
+        HAL_CAN_Start(&self->handle);
+    }
+}
+
+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) {
+    if(value) {
+        SET_BIT(self->handle.Instance->MCR, CAN_MCR_ABOM);
+    } else {
+        CLEAR_BIT(self->handle.Instance->MCR, CAN_MCR_ABOM);
+    }
+}
+
+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,
+    };
+    HAL_StatusTypeDef status = HAL_CAN_AddTxMessage(&self->handle, &header, message->data, &mailbox);
+    if (status != HAL_OK) {
+        mp_raise_OSError(MP_ENOMEM);
+    }
+}
+
+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();
+    }
+}
+
+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) {
+    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;
+    }
+}

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

@@ -0,0 +1,60 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+#include "shared-bindings/canio/__init__.h"
+#include "shared-bindings/canio/CAN.h"
+#include "common-hal/microcontroller/Pin.h"
+#include "common-hal/canio/__init__.h"
+#include "shared-module/canio/Message.h"
+
+#include "stm32f4xx_hal.h"
+#include "stm32f4xx_hal_can.h"
+
+#define FILTER_BANK_COUNT (28)
+
+typedef struct canio_can_obj {
+    mp_obj_base_t base;
+    CAN_HandleTypeDef handle;
+    CAN_TypeDef *filter_hw;
+    volatile uint32_t error_warning_state_count;
+    volatile uint32_t error_passive_state_count;
+    volatile uint32_t bus_off_state_count;
+    int baudrate;
+    const mcu_pin_obj_t *rx_pin;
+    const mcu_pin_obj_t *tx_pin;
+    bool loopback:1;
+    bool silent:1;
+    bool auto_restart:1;
+    bool fifo0_in_use:1;
+    bool fifo1_in_use:1;
+    uint8_t periph_index:2;
+    uint8_t start_filter_bank;
+    uint8_t end_filter_bank;
+    long filter_in_use; // bitmask for the 28 filter banks
+} canio_can_obj_t;