From 24cd73a3942f3df214d7953f0cfd65d5085fa583 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Richard=20R=C3=B6jfors?= Date: Tue, 27 Apr 2010 14:16:34 -0700 Subject: [PATCH] serial: timbuart: make sure last byte is sent when port is closed MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Fix a problem in early versions of the FPGA IP. In certain situations the IP reports that the FIFO is empty, but a byte is still clocked out. If a flush is done at that point the currently clocked byte is canceled. This causes incompatibilities with the upper layers when a port is closed, it waits until the FIFO is empty and then closes the port. During close the FIFO is flushed -> the last byte is not sent properly. Now the FIFO is only flushed if it is reported to be non-empty. Which makes the currently clocked out byte to finish. [akpm@linux-foundation.org: fix build] Signed-off-by: Richard Röjfors Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/serial/timbuart.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/serial/timbuart.c b/drivers/serial/timbuart.c index 62f389fdc2a3..67ca642713b8 100644 --- a/drivers/serial/timbuart.c +++ b/drivers/serial/timbuart.c @@ -68,12 +68,22 @@ static void timbuart_start_tx(struct uart_port *port) tasklet_schedule(&uart->tasklet); } +static unsigned int timbuart_tx_empty(struct uart_port *port) +{ + u32 isr = ioread32(port->membase + TIMBUART_ISR); + + return (isr & TXBE) ? TIOCSER_TEMT : 0; +} + static void timbuart_flush_buffer(struct uart_port *port) { - u8 ctl = ioread8(port->membase + TIMBUART_CTRL) | TIMBUART_CTRL_FLSHTX; + if (!timbuart_tx_empty(port)) { + u8 ctl = ioread8(port->membase + TIMBUART_CTRL) | + TIMBUART_CTRL_FLSHTX; - iowrite8(ctl, port->membase + TIMBUART_CTRL); - iowrite32(TXBF, port->membase + TIMBUART_ISR); + iowrite8(ctl, port->membase + TIMBUART_CTRL); + iowrite32(TXBF, port->membase + TIMBUART_ISR); + } } static void timbuart_rx_chars(struct uart_port *port) @@ -195,13 +205,6 @@ void timbuart_tasklet(unsigned long arg) dev_dbg(uart->port.dev, "%s leaving\n", __func__); } -static unsigned int timbuart_tx_empty(struct uart_port *port) -{ - u32 isr = ioread32(port->membase + TIMBUART_ISR); - - return (isr & TXBE) ? TIOCSER_TEMT : 0; -} - static unsigned int timbuart_get_mctrl(struct uart_port *port) { u8 cts = ioread8(port->membase + TIMBUART_CTRL); -- 2.20.1