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Commit 24cd73a3 authored by Richard Röjfors's avatar Richard Röjfors Committed by Greg Kroah-Hartman
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serial: timbuart: make sure last byte is sent when port is closed 



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: default avatarRichard Röjfors <richard.rojfors@pelagicore.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 44051996

drivers/serial/timbuart.c

+13 −10
Original line number Diff line number Diff line
@@ -68,13 +68,23 @@ 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);

	}

}



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);