From bfc2e07f910891516c8eeef61859fa17369fea9f Mon Sep 17 00:00:00 2001 From: Stefan Agner Date: Mon, 26 Jan 2015 01:10:16 +0100 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/fsl_lpuart.c | 11 +++++++++++ 1 file changed, 11 insertions(+) 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]; -- 2.34.1