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>
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index f196a33..b1893f3 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -455,6 +455,15 @@
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 @@
.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 @@
.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];