diff options
| -rw-r--r-- | drivers/tty/serial/msm_serial.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index 19e897dad5fe..60a9c53fa7cb 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -606,7 +606,7 @@ static void msm_start_rx_dma(struct msm_port *msm_port) UARTDM_RX_SIZE, dma->dir); ret = dma_mapping_error(uart->dev, dma->phys); if (ret) - return; + goto sw_mode; dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys, UARTDM_RX_SIZE, DMA_DEV_TO_MEM, @@ -657,6 +657,22 @@ static void msm_start_rx_dma(struct msm_port *msm_port) return; unmap: dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir); + +sw_mode: + /* + * Switch from DMA to SW/FIFO mode. After clearing Rx BAM (UARTDM_DMEN), + * receiver must be reset. + */ + msm_write(uart, UART_CR_CMD_RESET_RX, UART_CR); + msm_write(uart, UART_CR_RX_ENABLE, UART_CR); + + msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR); + msm_write(uart, 0xFFFFFF, UARTDM_DMRX); + msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR); + + /* Re-enable RX interrupts */ + msm_port->imr |= (UART_IMR_RXLEV | UART_IMR_RXSTALE); + msm_write(uart, msm_port->imr, UART_IMR); } static void msm_stop_rx(struct uart_port *port) |