[PATCH v2 0/3] serial: mxs-auart: add RTS/CTS check for DMA support

[PATCH v2 0/3] serial: mxs-auart: add RTS/CTS check for DMA support

[Huang Shijie]

The original DMA support works only when RTS/CTS is enabled.
But after several patches, DMA support has lost this limit.
So a UART without the RTS/CTS lines may also enables the DMA support
for it, but it may does not work or works abnormally (since without the
RTS/CTS signals, the TX/RX may not works)		

This patch set remove the unnecessary macro MXS_AUART_DMA_CONFIG,
and adds an optional property "fsl,uart-has-rtscts" for the UART DT node
which indicates the UART has RTS and CTS lines.

This patch set also adds a macro MXS_AUART_RTSCTS, and uses it to check
RTS/CTS before we enable the DMA for the UART.

At last, enable the DMA support for auart0 in the imx28-evk boards.

v1 --> v2:
	[0] changed the comments.
	[1] fix the typos.

Huang Shijie (3):
  serial: mxs: remove the MXS_AUART_DMA_CONFIG
  serial: mxs: enable the DMA only when the RTS/CTS is valid
  ARM: dts: imx28-evk: add the RTS/CTS property for auart0

 .../bindings/tty/serial/fsl-mxs-auart.txt          |    4 ++++
 arch/arm/boot/dts/imx28-evk.dts                    |    1 +
 drivers/tty/serial/mxs-auart.c                     |    8 ++++----
 3 files changed, 9 insertions(+), 4 deletions(-)

[PATCH v2 1/3] serial: mxs: remove the MXS_AUART_DMA_CONFIG

[Huang Shijie]

The MXS_AUART_DMA_CONFIG is originally used to check if the DT node
is configured with the DMA property.

But now, the MXS_AUART_DMA_CONFIG is set unconditionally in the
serial_mxs_probe_dt(), so the check in the mxs_auart_settermios() is
not necessary anymore. This patch removes it.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 drivers/tty/serial/mxs-auart.c |    5 +----
 1 files changed, 1 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 4f5f161..465ef0b 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -134,7 +134,6 @@ enum mxs_auart_type {
 struct mxs_auart_port {
 	struct uart_port port;
 
-#define MXS_AUART_DMA_CONFIG	0x1
 #define MXS_AUART_DMA_ENABLED	0x2
 #define MXS_AUART_DMA_TX_SYNC	2  /* bit 2 */
 #define MXS_AUART_DMA_RX_READY	3  /* bit 3 */
@@ -640,7 +639,7 @@ 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) && (s->flags & MXS_AUART_DMA_CONFIG)) {
+		if (is_imx28_auart(s)) {
 			if (!mxs_auart_dma_init(s))
 				/* enable DMA tranfer */
 				ctrl2 |= AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE
@@ -1002,8 +1001,6 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
 	}
 	s->port.line = ret;
 
-	s->flags |= MXS_AUART_DMA_CONFIG;
-
 	return 0;
 }
 
-- 
1.7.1

[PATCH v2 2/3] serial: mxs: enable the DMA only when the RTS/CTS is valid

[Huang Shijie]

The original DMA support works only when RTS/CTS is enabled.
But after several patches, DMA support has lost this limit.

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.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 .../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 at 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)) {
 			if (!mxs_auart_dma_init(s))
 				/* enable DMA tranfer */
 				ctrl2 |= AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE
@@ -1001,6 +1002,8 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
 	}
 	s->port.line = ret;
 
+	if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
+		s->flags |= MXS_AUART_RTSCTS;
 	return 0;
 }
 
-- 
1.7.1

[PATCH v2 2/3] serial: mxs: enable the DMA only when the RTS/CTS is valid

[Uwe Kleine-König]

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@freescale.com>
> ---
>  .../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 at 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-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

[PATCH v2 2/3] serial: mxs: enable the DMA only when the RTS/CTS is valid

[Huang Shijie]

? 2013?07?16? 17:54, Uwe Kleine-K?nig ??:
> 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?
>
i will add more information for this in the next version.
>> 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
to Greg:

I think a) is ok to me. what's your opinion?


> 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@freescale.com>
>> ---
>>   .../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 at 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();
>
ok, no problem.


thanks
Huang Shijie

[PATCH v2 2/3] serial: mxs: enable the DMA only when the RTS/CTS is valid

[Greg KH]

On Wed, Jul 17, 2013 at 03:33:22PM +0800, Huang Shijie wrote:
> ? 2013?07?16? 17:54, Uwe Kleine-K?nig ??:
> >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?
> >
> i will add more information for this in the next version.
> >>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
> to Greg:
> 
> I think a) is ok to me. what's your opinion?

Please reorder them, making patch 2 first, and mark it for stable, then
do patch 1, and the rest, so I don't have to take non-needed patches
into the stable tree.

thanks,

greg k-h

[PATCH v2 3/3] ARM: dts: imx28-evk: add the RTS/CTS property for auart0

[Huang Shijie]

Add the RTS/CTS property for auart0 which means we enable the
DMA support for it.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 arch/arm/boot/dts/imx28-evk.dts |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/arm/boot/dts/imx28-evk.dts b/arch/arm/boot/dts/imx28-evk.dts
index e035f46..15715d9 100644
--- a/arch/arm/boot/dts/imx28-evk.dts
+++ b/arch/arm/boot/dts/imx28-evk.dts
@@ -220,6 +220,7 @@
 			auart0: serial at 8006a000 {
 				pinctrl-names = "default";
 				pinctrl-0 = <&auart0_pins_a>;
+				fsl,uart-has-rtscts;
 				status = "okay";
 			};
 
-- 
1.7.1