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vfs: support for blocking reads, more newline conversion options

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Previously VFS driver for UART could only use simple non-blocking
functions to read from and write to the UART. UART driver provides more
complex blocking and interrupt-driven functions, which can be used
instead.
This commit adds optional support for using UART driver's functions.

Also added is a more flexible mechanism for configuring newline
conversion rules on input and output.

This commit also fixes a bug that all UARTs shared one static variable
used as a character buffer in newline conversion code. This variable is
changed to be per-UART.
This commit is contained in:
Ivan Grokhotkov
2017-08-15 16:23:23 +08:00
parent a8075ea140
commit 489c523870
4 changed files with 279 additions and 62 deletions
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222
components/vfs/vfs_uart.c
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@@ -1,4 +1,4 @@
// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
@@ -13,17 +13,74 @@
// limitations under the License.
#include <string.h>
#include <stdbool.h>
#include "esp_vfs.h"
#include "esp_vfs_dev.h"
#include "esp_attr.h"
#include "sys/errno.h"
#include "sys/lock.h"
#include "soc/uart_struct.h"
#include "driver/uart.h"
#include "sdkconfig.h"
static uart_dev_t* s_uarts[3] = {&UART0, &UART1, &UART2};
static _lock_t s_uart_locks[3]; // per-UART locks, lazily initialized
// TODO: make the number of UARTs chip dependent
#define UART_NUM 3
static int IRAM_ATTR uart_open(const char * path, int flags, int mode)
// Token signifying that no character is available
#define NONE -1
// UART write bytes function type
typedef void (*tx_func_t)(int, int);
// UART read bytes function type
typedef int (*rx_func_t)(int);
// Basic functions for sending and receiving bytes over UART
static void uart_tx_char(int fd, int c);
static int uart_rx_char(int fd);
// Functions for sending and receiving bytes which use UART driver
static void uart_tx_char_via_driver(int fd, int c);
static int uart_rx_char_via_driver(int fd);
// Pointers to UART peripherals
static uart_dev_t* s_uarts[UART_NUM] = {&UART0, &UART1, &UART2};
// per-UART locks, lazily initialized
static _lock_t s_uart_locks[UART_NUM];
// One-character buffer used for newline conversion code, per UART
static int s_peek_char[UART_NUM] = { NONE, NONE, NONE };
// Newline conversion mode when transmitting
static esp_line_endings_t s_tx_mode =
#if CONFIG_NEWLIB_STDOUT_LINE_ENDING_CRLF
ESP_LINE_ENDINGS_CRLF;
#elif CONFIG_NEWLIB_STDOUT_LINE_ENDING_CR
ESP_LINE_ENDINGS_CR;
#else
ESP_LINE_ENDINGS_LF;
#endif
// Newline conversion mode when receiving
static esp_line_endings_t s_rx_mode =
#if CONFIG_NEWLIB_STDIN_LINE_ENDING_CRLF
ESP_LINE_ENDINGS_CRLF;
#elif CONFIG_NEWLIB_STDIN_LINE_ENDING_CR
ESP_LINE_ENDINGS_CR;
#else
ESP_LINE_ENDINGS_LF;
#endif
// Functions used to write bytes to UART. Default to "basic" functions.
static tx_func_t s_uart_tx_func[UART_NUM] = {
&uart_tx_char, &uart_tx_char, &uart_tx_char
};
// Functions used to read bytes from UART. Default to "basic" functions.
static rx_func_t s_uart_rx_func[UART_NUM] = {
&uart_rx_char, &uart_rx_char, &uart_rx_char
};
static int uart_open(const char * path, int flags, int mode)
{
// this is fairly primitive, we should check if file is opened read only,
// and error out if write is requested
@@ -38,81 +95,120 @@ static int IRAM_ATTR uart_open(const char * path, int flags, int mode)
return -1;
}
static void IRAM_ATTR uart_tx_char(uart_dev_t* uart, int c)
static void uart_tx_char(int fd, int c)
{
uart_dev_t* uart = s_uarts[fd];
while (uart->status.txfifo_cnt >= 127) {
;
}
uart->fifo.rw_byte = c;
}
static void uart_tx_char_via_driver(int fd, int c)
{
char ch = (char) c;
uart_write_bytes(fd, &ch, 1);
}
static ssize_t IRAM_ATTR uart_write(int fd, const void * data, size_t size)
static int uart_rx_char(int fd)
{
uart_dev_t* uart = s_uarts[fd];
if (uart->status.rxfifo_cnt == 0) {
return NONE;
}
return uart->fifo.rw_byte;
}
static int uart_rx_char_via_driver(int fd)
{
uint8_t c;
int n = uart_read_bytes(fd, &c, 1, portMAX_DELAY);
if (n == 0) {
return NONE;
}
return c;
}
static ssize_t uart_write(int fd, const void * data, size_t size)
{
assert(fd >=0 && fd < 3);
const char *data_c = (const char *)data;
uart_dev_t* uart = s_uarts[fd];
/*
* Even though newlib does stream locking on each individual stream, we need
/* Even though newlib does stream locking on each individual stream, we need
* a dedicated UART lock if two streams (stdout and stderr) point to the
* same UART.
*/
_lock_acquire_recursive(&s_uart_locks[fd]);
for (size_t i = 0; i < size; i++) {
#if CONFIG_NEWLIB_STDOUT_ADDCR
if (data_c[i]=='\n') {
uart_tx_char(uart, '\r');
int c = data_c[i];
if (c == '\n' && s_tx_mode != ESP_LINE_ENDINGS_LF) {
s_uart_tx_func[fd](fd, '\r');
if (s_tx_mode == ESP_LINE_ENDINGS_CR) {
continue;
}
}
#endif
uart_tx_char(uart, data_c[i]);
s_uart_tx_func[fd](fd, c);
}
_lock_release_recursive(&s_uart_locks[fd]);
return size;
}
static ssize_t IRAM_ATTR uart_read(int fd, void* data, size_t size)
/* Helper function which returns a previous character or reads a new one from
* UART. Previous character can be returned ("pushed back") using
* uart_return_char function.
*/
static int uart_read_char(int fd)
{
/* return character from peek buffer, if it is there */
if (s_peek_char[fd] != NONE) {
int c = s_peek_char[fd];
s_peek_char[fd] = NONE;
return c;
}
return s_uart_rx_func[fd](fd);
}
/* Push back a character; it will be returned by next call to uart_read_char */
static void uart_return_char(int fd, int c)
{
assert(s_peek_char[fd] == NONE);
s_peek_char[fd] = c;
}
static ssize_t uart_read(int fd, void* data, size_t size)
{
assert(fd >=0 && fd < 3);
uint8_t *data_c = (uint8_t *) data;
uart_dev_t* uart = s_uarts[fd];
char *data_c = (char *) data;
size_t received = 0;
_lock_acquire_recursive(&s_uart_locks[fd]);
while (uart->status.rxfifo_cnt > 0 && received < size) {
uint8_t c = uart->fifo.rw_byte;
#if CONFIG_NEWLIB_STDOUT_ADDCR
/* Convert \r\n sequences to \n.
* If \r is received, it is put into 'buffered_char' until the next
* character is received. Then depending on the character, we either
* drop \r (if the next one is \n) or output \r and then proceed to output
* the new character.
*/
const int NONE = -1;
static int buffered_char = NONE;
if (buffered_char != NONE) {
if (buffered_char == '\r' && c == '\n') {
buffered_char = NONE;
} else {
data_c[received] = buffered_char;
buffered_char = NONE;
++received;
if (received == size) {
/* We have placed the buffered character into the output buffer
* but there won't be enough space for the newly received one.
* Keep the new character in buffered_char until read is called
* again.
*/
buffered_char = c;
while (received < size) {
int c = uart_read_char(fd);
if (c == '\r') {
if (s_rx_mode == ESP_LINE_ENDINGS_CR) {
c = '\n';
} else if (s_rx_mode == ESP_LINE_ENDINGS_CRLF) {
/* look ahead */
int c2 = uart_read_char(fd);
if (c2 == NONE) {
/* could not look ahead, put the current character back */
uart_return_char(fd, c);
break;
}
if (c2 == '\n') {
/* this was \r\n sequence. discard \r, return \n */
c = '\n';
} else {
/* \r followed by something else. put the second char back,
* it will be processed on next iteration. return \r now.
*/
uart_return_char(fd, c2);
}
}
}
if (c == '\r') {
buffered_char = c;
continue;
}
#endif //CONFIG_NEWLIB_STDOUT_ADDCR
data_c[received] = c;
data_c[received] = (char) c;
++received;
if (c == '\n') {
break;
}
}
_lock_release_recursive(&s_uart_locks[fd]);
if (received > 0) {
@@ -122,14 +218,14 @@ static ssize_t IRAM_ATTR uart_read(int fd, void* data, size_t size)
return -1;
}
static int IRAM_ATTR uart_fstat(int fd, struct stat * st)
static int uart_fstat(int fd, struct stat * st)
{
assert(fd >=0 && fd < 3);
st->st_mode = S_IFCHR;
return 0;
}
static int IRAM_ATTR uart_close(int fd)
static int uart_close(int fd)
{
assert(fd >=0 && fd < 3);
return 0;
@@ -153,3 +249,29 @@ void esp_vfs_dev_uart_register()
};
ESP_ERROR_CHECK(esp_vfs_register("/dev/uart", &vfs, NULL));
}
void esp_vfs_dev_uart_set_rx_line_endings(esp_line_endings_t mode)
{
s_rx_mode = mode;
}
void esp_vfs_dev_uart_set_tx_line_endings(esp_line_endings_t mode)
{
s_tx_mode = mode;
}
void esp_vfs_dev_uart_use_nonblocking(int fd)
{
_lock_acquire_recursive(&s_uart_locks[fd]);
s_uart_tx_func[fd] = uart_tx_char;
s_uart_rx_func[fd] = uart_rx_char;
_lock_release_recursive(&s_uart_locks[fd]);
}
void esp_vfs_dev_uart_use_driver(int fd)
{
_lock_acquire_recursive(&s_uart_locks[fd]);
s_uart_tx_func[fd] = uart_tx_char_via_driver;
s_uart_rx_func[fd] = uart_rx_char_via_driver;
_lock_release_recursive(&s_uart_locks[fd]);
}