469 lines
13 KiB
C
469 lines
13 KiB
C
// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <string.h>
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#include <stdbool.h>
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#include <stdarg.h>
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#include <sys/errno.h>
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#include <sys/lock.h>
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#include <sys/fcntl.h>
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#include <sys/param.h>
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#include "esp_vfs.h"
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#include "esp_vfs_dev.h"
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#include "esp_attr.h"
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#include "soc/uart_struct.h"
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#include "driver/uart.h"
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#include "sdkconfig.h"
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#include "driver/uart_select.h"
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// TODO: make the number of UARTs chip dependent
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#define UART_NUM 3
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// Token signifying that no character is available
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#define NONE -1
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// UART write bytes function type
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typedef void (*tx_func_t)(int, int);
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// UART read bytes function type
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typedef int (*rx_func_t)(int);
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// Basic functions for sending and receiving bytes over UART
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static void uart_tx_char(int fd, int c);
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static int uart_rx_char(int fd);
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// Functions for sending and receiving bytes which use UART driver
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static void uart_tx_char_via_driver(int fd, int c);
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static int uart_rx_char_via_driver(int fd);
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// Pointers to UART peripherals
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static uart_dev_t* s_uarts[UART_NUM] = {&UART0, &UART1, &UART2};
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// per-UART locks, lazily initialized
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static _lock_t s_uart_read_locks[UART_NUM];
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static _lock_t s_uart_write_locks[UART_NUM];
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// One-character buffer used for newline conversion code, per UART
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static int s_peek_char[UART_NUM] = { NONE, NONE, NONE };
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// Per-UART non-blocking flag. Note: default implementation does not honor this
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// flag, all reads are non-blocking. This option becomes effective if UART
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// driver is used.
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static bool s_non_blocking[UART_NUM];
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/* Lock ensuring that uart_select is used from only one task at the time */
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static _lock_t s_one_select_lock;
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static SemaphoreHandle_t *_signal_sem = NULL;
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static fd_set *_readfds = NULL;
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static fd_set *_writefds = NULL;
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static fd_set *_errorfds = NULL;
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static fd_set *_readfds_orig = NULL;
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static fd_set *_writefds_orig = NULL;
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static fd_set *_errorfds_orig = NULL;
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// Newline conversion mode when transmitting
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static esp_line_endings_t s_tx_mode =
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#if CONFIG_NEWLIB_STDOUT_LINE_ENDING_CRLF
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ESP_LINE_ENDINGS_CRLF;
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#elif CONFIG_NEWLIB_STDOUT_LINE_ENDING_CR
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ESP_LINE_ENDINGS_CR;
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#else
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ESP_LINE_ENDINGS_LF;
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#endif
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// Newline conversion mode when receiving
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static esp_line_endings_t s_rx_mode =
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#if CONFIG_NEWLIB_STDIN_LINE_ENDING_CRLF
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ESP_LINE_ENDINGS_CRLF;
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#elif CONFIG_NEWLIB_STDIN_LINE_ENDING_CR
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ESP_LINE_ENDINGS_CR;
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#else
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ESP_LINE_ENDINGS_LF;
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#endif
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static void uart_end_select();
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// Functions used to write bytes to UART. Default to "basic" functions.
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static tx_func_t s_uart_tx_func[UART_NUM] = {
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&uart_tx_char, &uart_tx_char, &uart_tx_char
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};
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// Functions used to read bytes from UART. Default to "basic" functions.
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static rx_func_t s_uart_rx_func[UART_NUM] = {
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&uart_rx_char, &uart_rx_char, &uart_rx_char
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};
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static int uart_open(const char * path, int flags, int mode)
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{
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// this is fairly primitive, we should check if file is opened read only,
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// and error out if write is requested
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int fd = -1;
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if (strcmp(path, "/0") == 0) {
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fd = 0;
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} else if (strcmp(path, "/1") == 0) {
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fd = 1;
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} else if (strcmp(path, "/2") == 0) {
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fd = 2;
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} else {
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errno = ENOENT;
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return fd;
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}
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s_non_blocking[fd] = ((flags & O_NONBLOCK) == O_NONBLOCK);
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return fd;
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}
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static void uart_tx_char(int fd, int c)
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{
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uart_dev_t* uart = s_uarts[fd];
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while (uart->status.txfifo_cnt >= 127) {
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;
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}
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uart->fifo.rw_byte = c;
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}
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static void uart_tx_char_via_driver(int fd, int c)
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{
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char ch = (char) c;
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uart_write_bytes(fd, &ch, 1);
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}
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static int uart_rx_char(int fd)
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{
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uart_dev_t* uart = s_uarts[fd];
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if (uart->status.rxfifo_cnt == 0) {
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return NONE;
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}
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return uart->fifo.rw_byte;
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}
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static int uart_rx_char_via_driver(int fd)
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{
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uint8_t c;
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int timeout = s_non_blocking[fd] ? 0 : portMAX_DELAY;
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int n = uart_read_bytes(fd, &c, 1, timeout);
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if (n <= 0) {
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return NONE;
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}
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return c;
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}
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static ssize_t uart_write(int fd, const void * data, size_t size)
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{
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assert(fd >=0 && fd < 3);
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const char *data_c = (const char *)data;
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/* Even though newlib does stream locking on each individual stream, we need
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* a dedicated UART lock if two streams (stdout and stderr) point to the
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* same UART.
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*/
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_lock_acquire_recursive(&s_uart_write_locks[fd]);
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for (size_t i = 0; i < size; i++) {
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int c = data_c[i];
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if (c == '\n' && s_tx_mode != ESP_LINE_ENDINGS_LF) {
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s_uart_tx_func[fd](fd, '\r');
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if (s_tx_mode == ESP_LINE_ENDINGS_CR) {
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continue;
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}
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}
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s_uart_tx_func[fd](fd, c);
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}
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_lock_release_recursive(&s_uart_write_locks[fd]);
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return size;
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}
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/* Helper function which returns a previous character or reads a new one from
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* UART. Previous character can be returned ("pushed back") using
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* uart_return_char function.
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*/
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static int uart_read_char(int fd)
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{
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/* return character from peek buffer, if it is there */
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if (s_peek_char[fd] != NONE) {
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int c = s_peek_char[fd];
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s_peek_char[fd] = NONE;
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return c;
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}
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return s_uart_rx_func[fd](fd);
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}
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/* Push back a character; it will be returned by next call to uart_read_char */
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static void uart_return_char(int fd, int c)
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{
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assert(s_peek_char[fd] == NONE);
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s_peek_char[fd] = c;
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}
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static ssize_t uart_read(int fd, void* data, size_t size)
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{
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assert(fd >=0 && fd < 3);
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char *data_c = (char *) data;
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size_t received = 0;
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_lock_acquire_recursive(&s_uart_read_locks[fd]);
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while (received < size) {
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int c = uart_read_char(fd);
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if (c == '\r') {
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if (s_rx_mode == ESP_LINE_ENDINGS_CR) {
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c = '\n';
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} else if (s_rx_mode == ESP_LINE_ENDINGS_CRLF) {
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/* look ahead */
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int c2 = uart_read_char(fd);
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if (c2 == NONE) {
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/* could not look ahead, put the current character back */
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uart_return_char(fd, c);
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break;
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}
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if (c2 == '\n') {
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/* this was \r\n sequence. discard \r, return \n */
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c = '\n';
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} else {
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/* \r followed by something else. put the second char back,
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* it will be processed on next iteration. return \r now.
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*/
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uart_return_char(fd, c2);
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}
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}
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} else if (c == NONE) {
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break;
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}
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data_c[received] = (char) c;
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++received;
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if (c == '\n') {
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break;
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}
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}
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_lock_release_recursive(&s_uart_read_locks[fd]);
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if (received > 0) {
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return received;
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}
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errno = EWOULDBLOCK;
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return -1;
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}
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static int uart_fstat(int fd, struct stat * st)
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{
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assert(fd >=0 && fd < 3);
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st->st_mode = S_IFCHR;
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return 0;
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}
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static int uart_close(int fd)
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{
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assert(fd >=0 && fd < 3);
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return 0;
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}
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static int uart_fcntl(int fd, int cmd, va_list args)
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{
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assert(fd >=0 && fd < 3);
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int result = 0;
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if (cmd == F_GETFL) {
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if (s_non_blocking[fd]) {
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result |= O_NONBLOCK;
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}
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} else if (cmd == F_SETFL) {
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int arg = va_arg(args, int);
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s_non_blocking[fd] = (arg & O_NONBLOCK) != 0;
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} else {
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// unsupported operation
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result = -1;
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errno = ENOSYS;
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}
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return result;
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}
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static int uart_access(const char *path, int amode)
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{
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int ret = -1;
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if (strcmp(path, "/0") == 0 || strcmp(path, "/1") == 0 || strcmp(path, "/2") == 0) {
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if (F_OK == amode) {
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ret = 0; //path exists
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} else {
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if ((((amode & R_OK) == R_OK) || ((amode & W_OK) == W_OK)) && ((amode & X_OK) != X_OK)) {
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ret = 0; //path is readable and/or writable but not executable
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} else {
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errno = EACCES;
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}
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}
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} else {
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errno = ENOENT;
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}
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return ret;
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}
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static void select_notif_callback(uart_port_t uart_num, uart_select_notif_t uart_select_notif, BaseType_t *task_woken)
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{
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switch (uart_select_notif) {
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case UART_SELECT_READ_NOTIF:
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if (FD_ISSET(uart_num, _readfds_orig)) {
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FD_SET(uart_num, _readfds);
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esp_vfs_select_triggered_isr(_signal_sem, task_woken);
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}
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break;
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case UART_SELECT_WRITE_NOTIF:
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if (FD_ISSET(uart_num, _writefds_orig)) {
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FD_SET(uart_num, _writefds);
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esp_vfs_select_triggered_isr(_signal_sem, task_woken);
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}
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break;
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case UART_SELECT_ERROR_NOTIF:
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if (FD_ISSET(uart_num, _errorfds_orig)) {
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FD_SET(uart_num, _errorfds);
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esp_vfs_select_triggered_isr(_signal_sem, task_woken);
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}
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break;
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}
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}
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static esp_err_t uart_start_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, SemaphoreHandle_t *signal_sem)
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{
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if (_lock_try_acquire(&s_one_select_lock)) {
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return ESP_ERR_INVALID_STATE;
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}
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const int max_fds = MIN(nfds, UART_NUM);
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taskENTER_CRITICAL(uart_get_selectlock());
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if (_readfds || _writefds || _errorfds || _readfds_orig || _writefds_orig || _errorfds_orig || _signal_sem) {
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taskEXIT_CRITICAL(uart_get_selectlock());
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uart_end_select();
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return ESP_ERR_INVALID_STATE;
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}
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if ((_readfds_orig = malloc(sizeof(fd_set))) == NULL) {
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taskEXIT_CRITICAL(uart_get_selectlock());
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uart_end_select();
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return ESP_ERR_NO_MEM;
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}
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if ((_writefds_orig = malloc(sizeof(fd_set))) == NULL) {
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taskEXIT_CRITICAL(uart_get_selectlock());
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uart_end_select();
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return ESP_ERR_NO_MEM;
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}
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if ((_errorfds_orig = malloc(sizeof(fd_set))) == NULL) {
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taskEXIT_CRITICAL(uart_get_selectlock());
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uart_end_select();
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return ESP_ERR_NO_MEM;
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}
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//uart_set_select_notif_callback set the callbacks in UART ISR
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for (int i = 0; i < max_fds; ++i) {
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if (FD_ISSET(i, readfds) || FD_ISSET(i, writefds) || FD_ISSET(i, exceptfds)) {
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uart_set_select_notif_callback(i, select_notif_callback);
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}
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}
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_signal_sem = signal_sem;
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_readfds = readfds;
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_writefds = writefds;
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_errorfds = exceptfds;
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*_readfds_orig = *readfds;
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*_writefds_orig = *writefds;
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*_errorfds_orig = *exceptfds;
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FD_ZERO(readfds);
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FD_ZERO(writefds);
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FD_ZERO(exceptfds);
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taskEXIT_CRITICAL(uart_get_selectlock());
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// s_one_select_lock is not released on successfull exit - will be
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// released in uart_end_select()
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return ESP_OK;
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}
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static void uart_end_select()
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{
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taskENTER_CRITICAL(uart_get_selectlock());
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for (int i = 0; i < UART_NUM; ++i) {
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uart_set_select_notif_callback(i, NULL);
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}
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_signal_sem = NULL;
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_readfds = NULL;
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_writefds = NULL;
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_errorfds = NULL;
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if (_readfds_orig) {
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free(_readfds_orig);
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_readfds_orig = NULL;
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}
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if (_writefds_orig) {
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free(_writefds_orig);
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_writefds_orig = NULL;
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}
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if (_errorfds_orig) {
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free(_errorfds_orig);
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_errorfds_orig = NULL;
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}
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taskEXIT_CRITICAL(uart_get_selectlock());
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_lock_release(&s_one_select_lock);
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}
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void esp_vfs_dev_uart_register()
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{
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esp_vfs_t vfs = {
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.flags = ESP_VFS_FLAG_DEFAULT,
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.write = &uart_write,
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.open = &uart_open,
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.fstat = &uart_fstat,
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.close = &uart_close,
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.read = &uart_read,
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.fcntl = &uart_fcntl,
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.access = &uart_access,
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.start_select = &uart_start_select,
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.end_select = &uart_end_select,
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};
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ESP_ERROR_CHECK(esp_vfs_register("/dev/uart", &vfs, NULL));
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}
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void esp_vfs_dev_uart_set_rx_line_endings(esp_line_endings_t mode)
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{
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s_rx_mode = mode;
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}
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void esp_vfs_dev_uart_set_tx_line_endings(esp_line_endings_t mode)
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{
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s_tx_mode = mode;
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}
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void esp_vfs_dev_uart_use_nonblocking(int uart_num)
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{
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_lock_acquire_recursive(&s_uart_read_locks[uart_num]);
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_lock_acquire_recursive(&s_uart_write_locks[uart_num]);
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s_uart_tx_func[uart_num] = uart_tx_char;
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s_uart_rx_func[uart_num] = uart_rx_char;
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_lock_release_recursive(&s_uart_write_locks[uart_num]);
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_lock_release_recursive(&s_uart_read_locks[uart_num]);
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}
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void esp_vfs_dev_uart_use_driver(int uart_num)
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{
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_lock_acquire_recursive(&s_uart_read_locks[uart_num]);
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_lock_acquire_recursive(&s_uart_write_locks[uart_num]);
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s_uart_tx_func[uart_num] = uart_tx_char_via_driver;
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s_uart_rx_func[uart_num] = uart_rx_char_via_driver;
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_lock_release_recursive(&s_uart_write_locks[uart_num]);
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_lock_release_recursive(&s_uart_read_locks[uart_num]);
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}
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