diff options
| -rw-r--r-- | drivers/serial/bfin_sport_uart.c | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/drivers/serial/bfin_sport_uart.c b/drivers/serial/bfin_sport_uart.c index b9938acb030..0b459cf1b2e 100644 --- a/drivers/serial/bfin_sport_uart.c +++ b/drivers/serial/bfin_sport_uart.c @@ -54,7 +54,7 @@ struct sport_uart_port { #endif }; -static void sport_uart_tx_chars(struct sport_uart_port *up); +static int sport_uart_tx_chars(struct sport_uart_port *up); static void sport_stop_tx(struct uart_port *port); static inline void tx_one_byte(struct sport_uart_port *up, unsigned int value) @@ -307,18 +307,24 @@ static int sport_startup(struct uart_port *port) return ret; } -static void sport_uart_tx_chars(struct sport_uart_port *up) +/* + * sport_uart_tx_chars + * + * ret 1 means need to enable sport. + * ret 0 means do nothing. + */ +static int sport_uart_tx_chars(struct sport_uart_port *up) { struct circ_buf *xmit = &up->port.state->xmit; if (SPORT_GET_STAT(up) & TXF) - return; + return 0; if (up->port.x_char) { tx_one_byte(up, up->port.x_char); up->port.icount.tx++; up->port.x_char = 0; - return; + return 1; } if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) { @@ -329,7 +335,7 @@ static void sport_uart_tx_chars(struct sport_uart_port *up) */ if (SPORT_GET_STAT(up) & TXHRE) sport_stop_tx(&up->port); - return; + return 0; } while(!(SPORT_GET_STAT(up) & TXF) && !uart_circ_empty(xmit)) { @@ -340,6 +346,8 @@ static void sport_uart_tx_chars(struct sport_uart_port *up) if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&up->port); + + return 1; } static unsigned int sport_tx_empty(struct uart_port *port) @@ -361,6 +369,9 @@ static void sport_stop_tx(struct uart_port *port) pr_debug("%s enter\n", __func__); + if (!(SPORT_GET_TCR1(up) & TSPEN)) + return; + /* Although the hold register is empty, last byte is still in shift * register and not sent out yet. So, put a dummy data into TX FIFO. * Then, sport tx stops when last byte is shift out and the dummy @@ -383,11 +394,12 @@ static void sport_start_tx(struct uart_port *port) pr_debug("%s enter\n", __func__); /* Write data into SPORT FIFO before enable SPROT to transmit */ - sport_uart_tx_chars(up); + if (sport_uart_tx_chars(up)) { + /* Enable transmit, then an interrupt will generated */ + SPORT_PUT_TCR1(up, (SPORT_GET_TCR1(up) | TSPEN)); + SSYNC(); + } - /* Enable transmit, then an interrupt will generated */ - SPORT_PUT_TCR1(up, (SPORT_GET_TCR1(up) | TSPEN)); - SSYNC(); pr_debug("%s exit\n", __func__); } |