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| author | Huang Shijie <b32955@freescale.com> | 2013-10-11 18:30:58 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-10-16 13:19:54 -0700 |
| commit | eb56b7edae6ba2bfd3a07e59ea82195e2c1c28ec (patch) | |
| tree | 5fdaab8e8a4e33e2f4b63f6d82629e02a6a0a163 /drivers/tty/serial | |
| parent | fa2b5ea09e48186041f68649ab8192447b31bffc (diff) | |
| download | kernel-common-eb56b7edae6ba2bfd3a07e59ea82195e2c1c28ec.tar.gz kernel-common-eb56b7edae6ba2bfd3a07e59ea82195e2c1c28ec.tar.bz2 kernel-common-eb56b7edae6ba2bfd3a07e59ea82195e2c1c28ec.zip | |
serial: imx: implement the flush_buffer hook
The current driver does not implement the flush_buffer hook for
uart_ops. When we enable the DMA for the driver, and test it with Bluetooth,
we may meet the following bug for TX:
[1] User application may call the flush operation at any time.
The uart_flush_buffer() calls the uart_circ_clear() to set
the xmit->head and xmit->tail with 0.
[2] The TX DMA callback can be called at any time too.
The dma_tx_call() will update the xmit->tail.
If [2] occurs just after the [1], we will get the wrong xmit->tail.
This patch implements the flush_buffer hook to fix this issue.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
| -rw-r--r-- | drivers/tty/serial/imx.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index c07d9bb39695..708ba899258d 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1303,6 +1303,16 @@ static void imx_shutdown(struct uart_port *port) clk_disable_unprepare(sport->clk_ipg); } +static void imx_flush_buffer(struct uart_port *port) +{ + struct imx_port *sport = (struct imx_port *)port; + + if (sport->dma_is_enabled) { + sport->tx_bytes = 0; + dmaengine_terminate_all(sport->dma_chan_tx); + } +} + static void imx_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) @@ -1623,6 +1633,7 @@ static struct uart_ops imx_pops = { .break_ctl = imx_break_ctl, .startup = imx_startup, .shutdown = imx_shutdown, + .flush_buffer = imx_flush_buffer, .set_termios = imx_set_termios, .type = imx_type, .release_port = imx_release_port, |