esp-idf/components/vfs/vfs_uart.c

96 wiersze
2.5 KiB
C
Czysty Zwykły widok Historia

#include <string.h>
#include "esp_vfs.h"
#include "esp_attr.h"
#include "sys/errno.h"
#include "sys/lock.h"
#include "soc/uart_struct.h"
static uart_dev_t* s_uarts[3] = {&UART0, &UART1, &UART2};
static int IRAM_ATTR 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
if (strcmp(path, "/0") == 0) {
return 0;
} else if (strcmp(path, "/1") == 0) {
return 1;
} else if (strcmp(path, "/2") == 0) {
return 2;
}
errno = ENOENT;
return -1;
}
static void IRAM_ATTR uart_tx_char(uart_dev_t* uart, int c)
{
while (uart->status.txfifo_cnt >= 127) {
;
}
uart->fifo.rw_byte = c;
}
static size_t IRAM_ATTR 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];
static _lock_t stdout_lock; /* lazily initialised */
/* Even though newlib does stream locking on stdout, we need
a dedicated stdout UART lock...
This is because each task has its own _reent structure with
unique FILEs for stdin/stdout/stderr, so these are
per-thread (lazily initialised by __sinit the first time a
stdio function is used, see findfp.c:235.
It seems like overkill to allocate a FILE-per-task and lock
a thread-local stream, but I see no easy way to fix this
(pre-__sinit_, tasks have "fake" FILEs ie __sf_fake_stdout
which aren't fully valid.)
*/
_lock_acquire_recursive(&stdout_lock);
for (size_t i = 0; i < size; i++) {
#if CONFIG_NEWLIB_STDOUT_ADDCR
if (data_c[i]=='\n') {
uart_tx_char(uart, '\r');
}
#endif
uart_tx_char(uart, data_c[i]);
}
_lock_release_recursive(&stdout_lock);
return size;
}
static int IRAM_ATTR 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)
{
assert(fd >=0 && fd < 3);
return 0;
}
void esp_vfs_dev_uart_register()
{
esp_vfs_t vfs = {
.fd_offset = 0,
.flags = ESP_VFS_FLAG_DEFAULT,
.write = &uart_write,
.open = &uart_open,
.fstat = &uart_fstat,
.close = &uart_close,
.read = NULL, // TODO: implement reading from UART
.stat = NULL,
.link = NULL,
.unlink = NULL,
.rename = NULL
};
ESP_ERROR_CHECK(esp_vfs_register("/dev/uart", &vfs, NULL));
}