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micropython/ports/rp2/machine_uart.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020-2021 Damien P. George
*
* 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 "py/runtime.h"
#include "py/stream.h"
#include "py/mphal.h"
#include "py/mperrno.h"
#include "py/ringbuf.h"
#include "modmachine.h"
#include "hardware/irq.h"
#include "hardware/uart.h"
#include "hardware/regs/uart.h"
#define DEFAULT_UART_BAUDRATE (115200)
#define DEFAULT_UART_BITS (8)
#define DEFAULT_UART_STOP (1)
#define DEFAULT_UART0_TX (0)
#define DEFAULT_UART0_RX (1)
#define DEFAULT_UART1_TX (4)
#define DEFAULT_UART1_RX (5)
#define DEFAULT_BUFFER_SIZE (256)
#define MIN_BUFFER_SIZE (32)
#define MAX_BUFFER_SIZE (32766)
#define IS_VALID_PERIPH(uart, pin) (((((pin) + 4) & 8) >> 3) == (uart))
#define IS_VALID_TX(uart, pin) (((pin) & 3) == 0 && IS_VALID_PERIPH(uart, pin))
#define IS_VALID_RX(uart, pin) (((pin) & 3) == 1 && IS_VALID_PERIPH(uart, pin))
#define UART_INVERT_TX (1)
#define UART_INVERT_RX (2)
#define UART_INVERT_MASK (UART_INVERT_TX | UART_INVERT_RX)
typedef struct _machine_uart_obj_t {
mp_obj_base_t base;
uart_inst_t *const uart;
uint8_t uart_id;
uint32_t baudrate;
uint8_t bits;
uart_parity_t parity;
uint8_t stop;
uint8_t tx;
uint8_t rx;
uint16_t timeout; // timeout waiting for first char (in ms)
uint16_t timeout_char; // timeout waiting between chars (in ms)
uint8_t invert;
ringbuf_t read_buffer;
bool read_lock;
ringbuf_t write_buffer;
bool write_lock;
} machine_uart_obj_t;
STATIC machine_uart_obj_t machine_uart_obj[] = {
{{&machine_uart_type}, uart0, 0, 0, DEFAULT_UART_BITS, UART_PARITY_NONE, DEFAULT_UART_STOP,
DEFAULT_UART0_TX, DEFAULT_UART0_RX, 0, 0, 0, {NULL, 1, 0, 0}, 0, {NULL, 1, 0, 0}, 0},
{{&machine_uart_type}, uart1, 1, 0, DEFAULT_UART_BITS, UART_PARITY_NONE, DEFAULT_UART_STOP,
DEFAULT_UART1_TX, DEFAULT_UART1_RX, 0, 0, 0, {NULL, 1, 0, 0}, 0, {NULL, 1, 0, 0}, 0,},
};
STATIC const char *_parity_name[] = {"None", "0", "1"};
STATIC const char *_invert_name[] = {"None", "INV_TX", "INV_RX", "INV_TX|INV_RX"};
/******************************************************************************/
// IRQ and buffer handling
// take all bytes from the fifo and store them, if possible, in the buffer
STATIC void uart_drain_rx_fifo(machine_uart_obj_t *self) {
while (uart_is_readable(self->uart)) {
// try to write the data, ignore the fail
ringbuf_put(&(self->read_buffer), uart_get_hw(self->uart)->dr);
}
}
// take bytes from the buffer and put them into the UART FIFO
STATIC void uart_fill_tx_fifo(machine_uart_obj_t *self) {
while (uart_is_writable(self->uart) && ringbuf_avail(&self->write_buffer) > 0) {
// get a byte from the buffer and put it into the uart
uart_get_hw(self->uart)->dr = ringbuf_get(&(self->write_buffer));
}
}
STATIC inline void uart_service_interrupt(machine_uart_obj_t *self) {
if (uart_get_hw(self->uart)->mis & UART_UARTMIS_RXMIS_BITS) { // rx interrupt?
// clear all interrupt bits but tx
uart_get_hw(self->uart)->icr = UART_UARTICR_BITS & (~UART_UARTICR_TXIC_BITS);
if (!self->read_lock) {
uart_drain_rx_fifo(self);
}
}
if (uart_get_hw(self->uart)->mis & UART_UARTMIS_TXMIS_BITS) { // tx interrupt?
// clear all interrupt bits but rx
uart_get_hw(self->uart)->icr = UART_UARTICR_BITS & (~UART_UARTICR_RXIC_BITS);
if (!self->write_lock) {
uart_fill_tx_fifo(self);
}
}
}
STATIC void uart0_irq_handler(void) {
uart_service_interrupt(&machine_uart_obj[0]);
}
STATIC void uart1_irq_handler(void) {
uart_service_interrupt(&machine_uart_obj[1]);
}
/******************************************************************************/
// MicroPython bindings for UART
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);
mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, tx=%d, rx=%d, "
"txbuf=%d, rxbuf=%d, timeout=%u, timeout_char=%u, invert=%s)",
self->uart_id, self->baudrate, self->bits, _parity_name[self->parity],
self->stop, self->tx, self->rx, self->write_buffer.size - 1, self->read_buffer.size - 1,
self->timeout, self->timeout_char, _invert_name[self->invert]);
}
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 *all_args) {
enum { ARG_id, ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_tx, ARG_rx,
ARG_timeout, ARG_timeout_char, ARG_invert, ARG_txbuf, ARG_rxbuf};
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_baudrate, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_bits, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_parity, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_INT(-1)} },
{ MP_QSTR_stop, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_tx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_rx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_txbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_rxbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
};
// Parse args.
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// Get UART bus.
int uart_id = mp_obj_get_int(args[ARG_id].u_obj);
if (uart_id < 0 || uart_id >= MP_ARRAY_SIZE(machine_uart_obj)) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("UART(%d) doesn't exist"), uart_id);
}
// Get static peripheral object.
machine_uart_obj_t *self = (machine_uart_obj_t *)&machine_uart_obj[uart_id];
// Set baudrate if configured.
if (args[ARG_baudrate].u_int > 0) {
self->baudrate = args[ARG_baudrate].u_int;
}
// Set bits if configured.
if (args[ARG_bits].u_int > 0) {
self->bits = args[ARG_bits].u_int;
}
// Set parity if configured.
if (args[ARG_parity].u_obj != MP_OBJ_NEW_SMALL_INT(-1)) {
if (args[ARG_parity].u_obj == mp_const_none) {
self->parity = UART_PARITY_NONE;
} else if (mp_obj_get_int(args[ARG_parity].u_obj) & 1) {
self->parity = UART_PARITY_ODD;
} else {
self->parity = UART_PARITY_EVEN;
}
}
// Set stop bits if configured.
if (args[ARG_stop].u_int > 0) {
self->stop = args[ARG_stop].u_int;
}
// Set TX/RX pins if configured.
if (args[ARG_tx].u_obj != mp_const_none) {
int tx = mp_hal_get_pin_obj(args[ARG_tx].u_obj);
if (!IS_VALID_TX(self->uart_id, tx)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad TX pin"));
}
self->tx = tx;
}
if (args[ARG_rx].u_obj != mp_const_none) {
int rx = mp_hal_get_pin_obj(args[ARG_rx].u_obj);
if (!IS_VALID_RX(self->uart_id, rx)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad RX pin"));
}
self->rx = rx;
}
// Set timeout if configured.
if (args[ARG_timeout].u_int >= 0) {
self->timeout = args[ARG_timeout].u_int;
}
// Set timeout_char if configured.
if (args[ARG_timeout_char].u_int >= 0) {
self->timeout_char = args[ARG_timeout_char].u_int;
}
// Set line inversion if configured.
if (args[ARG_invert].u_int >= 0) {
if (args[ARG_invert].u_int & ~UART_INVERT_MASK) {
mp_raise_ValueError(MP_ERROR_TEXT("bad inversion mask"));
}
self->invert = args[ARG_invert].u_int;
}
self->read_lock = false;
// Set the RX buffer size if configured.
size_t rxbuf_len = DEFAULT_BUFFER_SIZE;
if (args[ARG_rxbuf].u_int > 0) {
rxbuf_len = args[ARG_rxbuf].u_int;
if (rxbuf_len < MIN_BUFFER_SIZE) {
rxbuf_len = MIN_BUFFER_SIZE;
} else if (rxbuf_len > MAX_BUFFER_SIZE) {
mp_raise_ValueError(MP_ERROR_TEXT("rxbuf too large"));
}
}
// Set the TX buffer size if configured.
size_t txbuf_len = DEFAULT_BUFFER_SIZE;
if (args[ARG_txbuf].u_int > 0) {
txbuf_len = args[ARG_txbuf].u_int;
if (txbuf_len < MIN_BUFFER_SIZE) {
txbuf_len = MIN_BUFFER_SIZE;
} else if (txbuf_len > MAX_BUFFER_SIZE) {
mp_raise_ValueError(MP_ERROR_TEXT("txbuf too large"));
}
}
// Initialise the UART peripheral if any arguments given, or it was not initialised previously.
if (n_args > 1 || n_kw > 0 || self->baudrate == 0) {
if (self->baudrate == 0) {
self->baudrate = DEFAULT_UART_BAUDRATE;
}
// Make sure timeout_char is at least as long as a whole character (13 bits to be safe).
uint32_t min_timeout_char = 13000 / self->baudrate + 1;
if (self->timeout_char < min_timeout_char) {
self->timeout_char = min_timeout_char;
}
uart_init(self->uart, self->baudrate);
uart_set_format(self->uart, self->bits, self->stop, self->parity);
uart_set_fifo_enabled(self->uart, true);
gpio_set_function(self->tx, GPIO_FUNC_UART);
gpio_set_function(self->rx, GPIO_FUNC_UART);
if (self->invert & UART_INVERT_RX) {
gpio_set_inover(self->rx, GPIO_OVERRIDE_INVERT);
}
if (self->invert & UART_INVERT_TX) {
gpio_set_outover(self->tx, GPIO_OVERRIDE_INVERT);
}
// Allocate the RX/TX buffers.
ringbuf_alloc(&(self->read_buffer), rxbuf_len + 1);
MP_STATE_PORT(rp2_uart_rx_buffer[uart_id]) = self->read_buffer.buf;
ringbuf_alloc(&(self->write_buffer), txbuf_len + 1);
MP_STATE_PORT(rp2_uart_tx_buffer[uart_id]) = self->write_buffer.buf;
// Set the irq handler.
if (self->uart_id == 0) {
irq_set_exclusive_handler(UART0_IRQ, uart0_irq_handler);
irq_set_enabled(UART0_IRQ, true);
} else {
irq_set_exclusive_handler(UART1_IRQ, uart1_irq_handler);
irq_set_enabled(UART1_IRQ, true);
}
// Enable the uart irq; this macro sets the rx irq level to 4.
uart_set_irq_enables(self->uart, true, true);
}
return MP_OBJ_FROM_PTR(self);
}
STATIC mp_obj_t machine_uart_any(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
// get all bytes from the fifo first
self->read_lock = true;
uart_drain_rx_fifo(self);
self->read_lock = false;
return MP_OBJ_NEW_SMALL_INT(ringbuf_avail(&self->read_buffer));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_any_obj, machine_uart_any);
STATIC mp_obj_t machine_uart_sendbreak(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
uart_set_break(self->uart, true);
mp_hal_delay_us(13000000 / self->baudrate + 1);
uart_set_break(self->uart, false);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_sendbreak_obj, machine_uart_sendbreak);
STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&machine_uart_any_obj) },
{ 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) },
{ MP_ROM_QSTR(MP_QSTR_sendbreak), MP_ROM_PTR(&machine_uart_sendbreak_obj) },
{ MP_ROM_QSTR(MP_QSTR_INV_TX), MP_ROM_INT(UART_INVERT_TX) },
{ MP_ROM_QSTR(MP_QSTR_INV_RX), MP_ROM_INT(UART_INVERT_RX) },
};
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);
uint64_t t = time_us_64() + (uint64_t)self->timeout * 1000;
uint64_t timeout_char_us = (uint64_t)self->timeout_char * 1000;
uint8_t *dest = buf_in;
for (size_t i = 0; i < size; i++) {
// Wait for the first/next character
while (ringbuf_avail(&self->read_buffer) == 0) {
if (time_us_64() > t) { // timed out
if (i <= 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
} else {
return i;
}
}
MICROPY_EVENT_POLL_HOOK
// Force a few incoming bytes to the buffer
self->read_lock = true;
uart_drain_rx_fifo(self);
self->read_lock = false;
}
*dest++ = ringbuf_get(&(self->read_buffer));
t = time_us_64() + timeout_char_us;
}
return size;
}
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);
uint64_t t = time_us_64() + (uint64_t)self->timeout * 1000;
uint64_t timeout_char_us = (uint64_t)self->timeout_char * 1000;
const uint8_t *src = buf_in;
size_t i = 0;
// Put as many bytes as possible into the transmit buffer.
while (i < size && ringbuf_free(&(self->write_buffer)) > 0) {
ringbuf_put(&(self->write_buffer), *src++);
++i;
}
// Kickstart the UART transmit.
self->write_lock = true;
uart_fill_tx_fifo(self);
self->write_lock = false;
// Send the next characters while busy waiting.
while (i < size) {
// Wait for the first/next character to be sent.
while (ringbuf_free(&(self->write_buffer)) == 0) {
if (time_us_64() > t) { // timed out
if (i <= 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
} else {
return i;
}
}
MICROPY_EVENT_POLL_HOOK
}
ringbuf_put(&(self->write_buffer), *src++);
++i;
t = time_us_64() + timeout_char_us;
self->write_lock = true;
uart_fill_tx_fifo(self);
self->write_lock = false;
}
// Just in case the fifo was drained during refill of the ringbuf.
return size;
}
STATIC mp_uint_t machine_uart_ioctl(mp_obj_t self_in, mp_uint_t request, mp_uint_t arg, int *errcode) {
machine_uart_obj_t *self = self_in;
mp_uint_t ret;
if (request == MP_STREAM_POLL) {
uintptr_t flags = arg;
ret = 0;
if ((flags & MP_STREAM_POLL_RD) && ringbuf_avail(&self->read_buffer) > 0) {
ret |= MP_STREAM_POLL_RD;
}
if ((flags & MP_STREAM_POLL_WR) && ringbuf_free(&self->write_buffer) > 0) {
ret |= MP_STREAM_POLL_WR;
}
} 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,
};
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