On Tue, Jul 16, 2013 at 02:55:31PM +0800, Huang Shijie wrote:
> The original DMA support works only when RTS/CTS is enabled.
What is original here?
> But after several patches, DMA support has lost this limit.
This is still misleading.
> This patch adds an optional property for the UART DT node
> which indicates the UART has RTS and CTS lines.
>
> This patch also adds a macro MXS_AUART_RTSCTS, and uses it to check
> RTS/CTS before we enable the DMA for the UART.
I still think this should go to stable. The options are:
a) also take patch 1 into stable
b) apply this patch without patch 1
I don't know if option a) is OK, b) is probably preferable. And as Greg
has much to do anyhow, better move this patch first. (Otherwise he will
probably only say: That patch doesn't apply, please help.)
> Signed-off-by: Huang Shijie <b32955@xxxxxxxxxxxxx>
> ---
> .../bindings/tty/serial/fsl-mxs-auart.txt | 4 ++++
> drivers/tty/serial/mxs-auart.c | 5 ++++-
> 2 files changed, 8 insertions(+), 1 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt b/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
> index 2c00ec6..59a40f1 100644
> --- a/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
> +++ b/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
> @@ -10,6 +10,10 @@ Required properties:
> Refer to dma.txt and fsl-mxs-dma.txt for details.
> - dma-names: "rx" for RX channel, "tx" for TX channel.
>
> +Optional properties:
> +- fsl,uart-has-rtscts : Indicate the UART has RTS and CTS lines,
> + it also means you enable the DMA support for this UART.
> +
> Example:
> auart0: serial@8006a000 {
> compatible = "fsl,imx28-auart", "fsl,imx23-auart";
> diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
> index 465ef0b..27532fd 100644
> --- a/drivers/tty/serial/mxs-auart.c
> +++ b/drivers/tty/serial/mxs-auart.c
> @@ -134,6 +134,7 @@ enum mxs_auart_type {
> struct mxs_auart_port {
> struct uart_port port;
>
> +#define MXS_AUART_RTSCTS 1
> #define MXS_AUART_DMA_ENABLED 0x2
> #define MXS_AUART_DMA_TX_SYNC 2 /* bit 2 */
> #define MXS_AUART_DMA_RX_READY 3 /* bit 3 */
> @@ -639,7 +640,7 @@ static void mxs_auart_settermios(struct uart_port *u,
> * we can only implement the DMA support for auart
> * in mx28.
> */
> - if (is_imx28_auart(s)) {
> + if (is_imx28_auart(s) && (s->flags & MXS_AUART_RTSCTS)) {
I thought you wanted to add a comment here. Without knowing the details
if (RTSCTS)
enable_dma();
looks strange.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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