circuitpython/ports/zephyr/machine_uart.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Damien P. George
 * Copyright (c) 2020 Yonatan Schachter
 *
 * 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 <stdio.h>
#include <stdint.h>
#include <string.h>

#include <zephyr/zephyr.h>
#include <zephyr/drivers/uart.h>

#include "py/runtime.h"
#include "py/stream.h"
#include "py/mperrno.h"
#include "py/objstr.h"
#include "modmachine.h"

typedef struct _machine_uart_obj_t {
    mp_obj_base_t base;
    const struct device *dev;
    uint16_t timeout;       // timeout waiting for first char (in ms)
    uint16_t timeout_char;  // timeout waiting between chars (in ms)
} machine_uart_obj_t;

STATIC const char *_parity_name[] = {"None", "Odd", "Even", "Mark", "Space"};
STATIC const char *_stop_bits_name[] = {"0.5", "1", "1.5", "2"};
STATIC const char *_data_bits_name[] = {"5", "6", "7", "8", "9"};
STATIC const char *_flow_control_name[] = {"None", "RTS/CTS", "DTR/DSR"};

STATIC void machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
    struct uart_config config;
    uart_config_get(self->dev, &config);
    mp_printf(print, "UART(\"%s\", baudrate=%u, data_bits=%s, parity_bits=%s, stop_bits=%s, flow_control=%s, timeout=%u, timeout_char=%u)",
        self->dev->name, config.baudrate, _data_bits_name[config.data_bits],
        _parity_name[config.parity], _stop_bits_name[config.stop_bits], _flow_control_name[config.flow_ctrl],
        self->timeout, self->timeout_char);
}

STATIC void machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
    enum { ARG_timeout, ARG_timeout_char };
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
    };
    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

    self->timeout = args[ARG_timeout].u_int;
    self->timeout_char = args[ARG_timeout_char].u_int;
}

STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
    GET_STR_DATA_LEN(args[0], name, name_len);

    machine_uart_obj_t *self = mp_obj_malloc(machine_uart_obj_t, &machine_uart_type);
    self->dev = device_get_binding(name);
    if (!self->dev) {
        mp_raise_ValueError(MP_ERROR_TEXT("Bad device name"));
    }

    mp_map_t kw_args;
    mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
    machine_uart_init_helper(self, n_args - 1, args + 1, &kw_args);

    return MP_OBJ_FROM_PTR(self);
}

STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
    { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
    { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
    { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
    { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
};
STATIC MP_DEFINE_CONST_DICT(machine_uart_locals_dict, machine_uart_locals_dict_table);

STATIC mp_uint_t machine_uart_read(mp_obj_t self_in, void *buf_in, mp_uint_t size, int *errcode) {
    machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
    uint8_t *buffer = (uint8_t *)buf_in;
    uint8_t data;
    mp_uint_t bytes_read = 0;
    size_t elapsed_ms = 0;
    size_t time_to_wait = self->timeout;

    while ((elapsed_ms < time_to_wait) && (bytes_read < size)) {
        if (!uart_poll_in(self->dev, &data)) {
            buffer[bytes_read++] = data;
            elapsed_ms = 0;
            time_to_wait = self->timeout_char;
        } else {
            k_msleep(1);
            elapsed_ms++;
        }
    }
    return bytes_read;
}

STATIC mp_uint_t machine_uart_write(mp_obj_t self_in, const void *buf_in, mp_uint_t size, int *errcode) {
    machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
    uint8_t *buffer = (uint8_t *)buf_in;

    for (mp_uint_t i = 0; i < size; i++) {
        uart_poll_out(self->dev, buffer[i]);
    }

    return size;
}

STATIC mp_uint_t machine_uart_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {
    mp_uint_t ret;

    if (request == MP_STREAM_POLL) {
        ret = 0;
        // read is always blocking

        if (arg & MP_STREAM_POLL_WR) {
            ret |= MP_STREAM_POLL_WR;
        }
        return ret;
    } else {
        *errcode = MP_EINVAL;
        ret = MP_STREAM_ERROR;
    }
    return ret;
}

STATIC const mp_stream_p_t uart_stream_p = {
    .read = machine_uart_read,
    .write = machine_uart_write,
    .ioctl = machine_uart_ioctl,
    .is_text = false,
};

const mp_obj_type_t machine_uart_type = {
    { &mp_type_type },
    .name = MP_QSTR_UART,
    .print = machine_uart_print,
    .make_new = machine_uart_make_new,
    .getiter = mp_identity_getiter,
    .iternext = mp_stream_unbuffered_iter,
    .protocol = &uart_stream_p,
    .locals_dict = (mp_obj_dict_t *)&machine_uart_locals_dict,
};