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circuitpython/ports/rp2/machine_uart.c
robert-hh 2488311dc2 rp2/machine_uart: Implement uart.flush() and uart.txdone(). 
uart.flush()

flush() will wait until all characters have been sent. It may return
while the last character is sent. if needed, the calling code has to
add one character wait time. To avoid a permanent lock, a timeout
applies depending on the size of txbuf and the baud rate.

ret = uart.txdone()

ret is True if no transfer is in progress. It may return True if the
last byte of a transfer is sent.
ret is False otherwise.
2022-08-31 00:17:54 +10:00

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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"
#include "pico/mutex.h"
#define DEFAULT_UART_BAUDRATE (115200)
#define DEFAULT_UART_BITS (8)
#define DEFAULT_UART_STOP (1)
// UART 0 default pins
#if !defined(MICROPY_HW_UART0_TX)
#define MICROPY_HW_UART0_TX (0)
#define MICROPY_HW_UART0_RX (1)
#define MICROPY_HW_UART0_CTS (2)
#define MICROPY_HW_UART0_RTS (3)
#endif
// UART 1 default pins
#if !defined(MICROPY_HW_UART1_TX)
#define MICROPY_HW_UART1_TX (4)
#define MICROPY_HW_UART1_RX (5)
#define MICROPY_HW_UART1_CTS (6)
#define MICROPY_HW_UART1_RTS (7)
#endif
#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 IS_VALID_CTS(uart, pin) (((pin) & 3) == 2 && IS_VALID_PERIPH(uart, pin))
#define IS_VALID_RTS(uart, pin) (((pin) & 3) == 3 && 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)
#define UART_HWCONTROL_CTS (1)
#define UART_HWCONTROL_RTS (2)
STATIC mutex_t write_mutex_0;
STATIC mutex_t write_mutex_1;
STATIC mutex_t read_mutex_0;
STATIC mutex_t read_mutex_1;
auto_init_mutex(write_mutex_0);
auto_init_mutex(write_mutex_1);
auto_init_mutex(read_mutex_0);
auto_init_mutex(read_mutex_1);
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;
uint8_t cts;
uint8_t rts;
uint16_t timeout; // timeout waiting for first char (in ms)
uint16_t timeout_char; // timeout waiting between chars (in ms)
uint8_t invert;
uint8_t flow;
ringbuf_t read_buffer;
mutex_t *read_mutex;
ringbuf_t write_buffer;
mutex_t *write_mutex;
} 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,
MICROPY_HW_UART0_TX, MICROPY_HW_UART0_RX, MICROPY_HW_UART0_CTS, MICROPY_HW_UART0_RTS,
0, 0, 0, 0, {NULL, 1, 0, 0}, &read_mutex_0, {NULL, 1, 0, 0}, &write_mutex_0},
{{&machine_uart_type}, uart1, 1, 0, DEFAULT_UART_BITS, UART_PARITY_NONE, DEFAULT_UART_STOP,
MICROPY_HW_UART1_TX, MICROPY_HW_UART1_RX, MICROPY_HW_UART1_CTS, MICROPY_HW_UART1_RTS,
0, 0, 0, 0, {NULL, 1, 0, 0}, &read_mutex_1, {NULL, 1, 0, 0}, &write_mutex_1},
};
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
static inline bool write_mutex_try_lock(machine_uart_obj_t *u) {
return mutex_enter_timeout_ms(u->write_mutex, 0);
}
static inline void write_mutex_unlock(machine_uart_obj_t *u) {
mutex_exit(u->write_mutex);
}
static inline bool read_mutex_try_lock(machine_uart_obj_t *u) {
return mutex_enter_timeout_ms(u->read_mutex, 0);
}
static inline void read_mutex_unlock(machine_uart_obj_t *u) {
mutex_exit(u->read_mutex);
}
// take all bytes from the fifo and store them in the buffer
STATIC void uart_drain_rx_fifo(machine_uart_obj_t *self) {
if (read_mutex_try_lock(self)) {
while (uart_is_readable(self->uart) && ringbuf_free(&self->read_buffer) > 0) {
// get a byte from uart and put into the buffer
ringbuf_put(&(self->read_buffer), uart_get_hw(self->uart)->dr);
}
read_mutex_unlock(self);
}
}
// take bytes from the buffer and put them into the UART FIFO
// Re-entrancy: quit if an instance already running
STATIC void uart_fill_tx_fifo(machine_uart_obj_t *self) {
if (write_mutex_try_lock(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));
}
write_mutex_unlock(self);
}
}
STATIC inline void uart_service_interrupt(machine_uart_obj_t *self) {
if (uart_get_hw(self->uart)->mis & (UART_UARTMIS_RXMIS_BITS | UART_UARTMIS_RTMIS_BITS)) { // rx interrupt?
// clear all interrupt bits but tx
uart_get_hw(self->uart)->icr = UART_UARTICR_BITS & (~UART_UARTICR_TXIC_BITS);
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);
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 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_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_tx, ARG_rx, ARG_cts, ARG_rts,
ARG_timeout, ARG_timeout_char, ARG_invert, ARG_flow, ARG_txbuf, ARG_rxbuf};
static const mp_arg_t allowed_args[] = {
{ 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_cts, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_rts, 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_flow, 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(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// 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 CTS/RTS pins if configured.
if (args[ARG_cts].u_obj != mp_const_none) {
int cts = mp_hal_get_pin_obj(args[ARG_cts].u_obj);
if (!IS_VALID_CTS(self->uart_id, cts)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad CTS pin"));
}
self->cts = cts;
}
if (args[ARG_rts].u_obj != mp_const_none) {
int rts = mp_hal_get_pin_obj(args[ARG_rts].u_obj);
if (!IS_VALID_RTS(self->uart_id, rts)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad RTS pin"));
}
self->rts = rts;
}
// 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;
}
// Set hardware flow control if configured.
if (args[ARG_flow].u_int >= 0) {
if (args[ARG_flow].u_int & ~(UART_HWCONTROL_CTS | UART_HWCONTROL_RTS)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad hardware flow control mask"));
}
self->flow = args[ARG_flow].u_int;
}
// 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 > 0 || kw_args->used > 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);
}
// Set hardware flow control if configured.
if (self->flow & UART_HWCONTROL_CTS) {
gpio_set_function(self->cts, GPIO_FUNC_UART);
}
if (self->flow & UART_HWCONTROL_RTS) {
gpio_set_function(self->rts, GPIO_FUNC_UART);
}
uart_set_hw_flow(self->uart, self->flow & UART_HWCONTROL_CTS, self->flow & UART_HWCONTROL_RTS);
// Allocate the RX/TX buffers.
ringbuf_alloc(&(self->read_buffer), rxbuf_len + 1);
MP_STATE_PORT(rp2_uart_rx_buffer[self->uart_id]) = self->read_buffer.buf;
ringbuf_alloc(&(self->write_buffer), txbuf_len + 1);
MP_STATE_PORT(rp2_uart_tx_buffer[self->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);
}
}
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 UART bus.
int uart_id = mp_obj_get_int(args[0]);
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];
// Initialise the UART peripheral.
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 mp_obj_t machine_uart_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
// Initialise the UART peripheral.
machine_uart_init_helper(args[0], n_args - 1, args + 1, kw_args);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(machine_uart_init_obj, 1, machine_uart_init);
STATIC mp_obj_t machine_uart_deinit(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
uart_deinit(self->uart);
if (self->uart_id == 0) {
irq_set_enabled(UART0_IRQ, false);
} else {
irq_set_enabled(UART1_IRQ, false);
}
self->baudrate = 0;
MP_STATE_PORT(rp2_uart_rx_buffer[self->uart_id]) = NULL;
MP_STATE_PORT(rp2_uart_tx_buffer[self->uart_id]) = NULL;
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_deinit_obj, machine_uart_deinit);
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
uart_drain_rx_fifo(self);
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 mp_obj_t machine_uart_txdone(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
if (ringbuf_avail(&self->write_buffer) == 0 &&
uart_get_hw(self->uart)->fr & UART_UARTFR_TXFE_BITS) {
return mp_const_true;
} else {
return mp_const_false;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_txdone_obj, machine_uart_txdone);
STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_uart_init_obj) },
{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&machine_uart_deinit_obj) },
{ MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&machine_uart_any_obj) },
{ MP_ROM_QSTR(MP_QSTR_flush), MP_ROM_PTR(&mp_stream_flush_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_txdone), MP_ROM_PTR(&machine_uart_txdone_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) },
{ MP_ROM_QSTR(MP_QSTR_CTS), MP_ROM_INT(UART_HWCONTROL_CTS) },
{ MP_ROM_QSTR(MP_QSTR_RTS), MP_ROM_INT(UART_HWCONTROL_RTS) },
};
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 (uart_is_readable(self->uart)) {
// Force a few incoming bytes to the buffer
uart_drain_rx_fifo(self);
break;
}
if (time_us_64() > t) { // timed out
if (i <= 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
} else {
return i;
}
}
MICROPY_EVENT_POLL_HOOK
}
*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.
uart_fill_tx_fifo(self);
// 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;
uart_fill_tx_fifo(self);
}
// 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) && (uart_is_readable(self->uart) || 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 if (request == MP_STREAM_FLUSH) {
// The timeout is estimated using the buffer size and the baudrate.
// Take the worst case assumptions at 13 bit symbol size times 2.
uint64_t timeout = time_us_64() +
(uint64_t)(33 + self->write_buffer.size) * 13000000ll * 2 / self->baudrate;
do {
if (machine_uart_txdone((mp_obj_t)self) == mp_const_true) {
return 0;
}
MICROPY_EVENT_POLL_HOOK
} while (time_us_64() < timeout);
*errcode = MP_ETIMEDOUT;
ret = MP_STREAM_ERROR;
} 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,
};
MP_REGISTER_ROOT_POINTER(void *rp2_uart_rx_buffer[2]);
MP_REGISTER_ROOT_POINTER(void *rp2_uart_tx_buffer[2]);
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