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authorStefan Agner <stefan@agner.ch>2015-01-26 01:10:16 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-02-02 19:09:55 +0100
commitbfc2e07f910891516c8eeef61859fa17369fea9f (patch)
treedff78a4eb45e351e013a09253e06debddfcb1a81 /drivers/tty/serial/fsl_lpuart.c
parentserial: fsl-lpuart: disable interrupt when suspend (diff)
downloadlinux-bfc2e07f910891516c8eeef61859fa17369fea9f.tar.xz
linux-bfc2e07f910891516c8eeef61859fa17369fea9f.zip
tty: serial: fsl_lpuart: terminate DMA on buffer flush
On uart buffer flush, serial core resets the circular buffer. If a DMA transfer is in progress at that time, the callback lpuart_dma_tx_complete will move buffer's tail unconditionally, hence tail moves beyond head. Use the flush_buffer hook to terminate the DMA imeaditely and avoid lpuart_dma_tx_complete being called in this situation. This bug often showed up while shutdown and lead to duplicate serial console output. Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/fsl_lpuart.c')
-rw-r--r--drivers/tty/serial/fsl_lpuart.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index f196a33e619b..b1893f3f88f1 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -455,6 +455,15 @@ static int lpuart_dma_rx(struct lpuart_port *sport)
return 0;
}
+static void lpuart_flush_buffer(struct uart_port *port)
+{
+ struct lpuart_port *sport = container_of(port, struct lpuart_port, port);
+ if (sport->lpuart_dma_tx_use) {
+ dmaengine_terminate_all(sport->dma_tx_chan);
+ sport->dma_tx_in_progress = 0;
+ }
+}
+
static void lpuart_dma_rx_complete(void *arg)
{
struct lpuart_port *sport = arg;
@@ -1496,6 +1505,7 @@ static struct uart_ops lpuart_pops = {
.release_port = lpuart_release_port,
.config_port = lpuart_config_port,
.verify_port = lpuart_verify_port,
+ .flush_buffer = lpuart_flush_buffer,
};
static struct uart_ops lpuart32_pops = {
@@ -1514,6 +1524,7 @@ static struct uart_ops lpuart32_pops = {
.release_port = lpuart_release_port,
.config_port = lpuart_config_port,
.verify_port = lpuart_verify_port,
+ .flush_buffer = lpuart_flush_buffer,
};
static struct lpuart_port *lpuart_ports[UART_NR];