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sys: newlib: use double-lock scheme for uart ringbuffer

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This commit is contained in:
Kaspar Schleiser 2015-05-04 11:08:16 +02:00
parent fecc105063
commit be50f8b9f9
1 changed files with 13 additions and 14 deletions
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27
sys/newlib/syscalls.c
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@ -54,7 +54,7 @@ caddr_t heap_top = (caddr_t)&_sheap + 4;
/**
* @brief use mutex for waiting on incoming UART chars
*/
static mutex_t uart_rx_mutex;
static mutex_t uart_rx_mutex = MUTEX_INIT;
static char rx_buf_mem[STDIO_RX_BUFSIZE];
static ringbuffer_t rx_buf;
#endif
@ -65,16 +65,14 @@ static ringbuffer_t rx_buf;
void rx_cb(void *arg, char data)
{
(void)arg;
#ifdef MODULE_UART0
if (uart0_handler_pid) {
uart0_handle_incoming(data);
uart0_notify_thread();
}
#else
#ifndef MODULE_UART0
ringbuffer_add_one(&rx_buf, data);
mutex_unlock(&uart_rx_mutex);
#else
if (uart0_handler_pid) {
uart0_handle_incoming(data);
uart0_notify_thread();
}
#endif
}
@ -84,7 +82,7 @@ void rx_cb(void *arg, char data)
void _init(void)
{
#ifndef MODULE_UART0
mutex_init(&uart_rx_mutex);
mutex_lock(&uart_rx_mutex);
ringbuffer_init(&rx_buf, rx_buf_mem, STDIO_RX_BUFSIZE);
#endif
uart_init(STDIO, STDIO_BAUDRATE, rx_cb, 0, 0);
@ -205,10 +203,11 @@ int _open_r(struct _reent *r, const char *name, int mode)
int _read_r(struct _reent *r, int fd, void *buffer, unsigned int count)
{
#ifndef MODULE_UART0
while (rx_buf.avail == 0) {
mutex_lock(&uart_rx_mutex);
}
return ringbuffer_get(&rx_buf, (char*)buffer, rx_buf.avail);
mutex_lock(&uart_rx_mutex);
count = count < rx_buf.avail ? count : rx_buf.avail;
return ringbuffer_get(&rx_buf, (char*)buffer, count);
#else
char *res = (char*)buffer;
res[0] = (char)uart0_readc();