serial: mxs-auart: add RTS/CTS check for DMA support

PATCH New Huang Shijie 3 participants 7 messages Jul 16, 2013 – Jul 26, 2013

Subsystems (3)

Device tree bindings Arm i.MX and Layerscape TTY layer and serial drivers

lore

Share & tools

lore

Huang Shijie

author

2013-07-16 06:55 UTC #0 lore raw

v2 cover serial: mxs-auart: add RTS/CTS check for DMA support

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(-)

Huang Shijie

author

2013-07-16 06:55 UTC #1 lore raw

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

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 <[email protected]>

---
 drivers/tty/serial/mxs-auart.c |    5 +----
 1 files changed, 1 insertions(+), 4 deletions(-)

drivers/tty/serial/mxs-auart.c +1 -4

index 4f5f161..465ef0b 100644
@@ -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;
 }

Signature · 1 line

1.7.1

Huang Shijie

author

2013-07-16 06:55 UTC #2 lore raw

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

In reply to 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 <[email protected]>

---
 .../bindings/tty/serial/fsl-mxs-auart.txt          |    4 ++++
 drivers/tty/serial/mxs-auart.c                     |    5 ++++-
 2 files changed, 8 insertions(+), 1 deletions(-)

Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt +4 -0

index 2c00ec6..59a40f1 100644
@@ -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";

drivers/tty/serial/mxs-auart.c +4 -1

index 465ef0b..27532fd 100644
@@ -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;
 }

Signature · 1 line

1.7.1

Uwe Kleine-König

2013-07-16 09:54 UTC #3 lore raw

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

Quoted 1 line · Huang Shijie

The original DMA support works only when RTS/CTS is enabled.

What is original here?

Quoted 1 line

But after several patches, DMA support has lost this limit.

This is still misleading.

Quoted 5 lines

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.)

Quoted 34 lines

Signed-off-by Huang Shijie <[email protected]>

---
 .../bindings/tty/serial/fsl-mxs-auart.txt          |    4 ++++
 drivers/tty/serial/mxs-auart.c                     |    5 ++++-
 2 files changed, 8 insertions(+), 1 deletions(-)

Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt +4 -0

index 2c00ec6..59a40f1 100644
@@ -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";

drivers/tty/serial/mxs-auart.c +1 -0

index 465ef0b..27532fd 100644
@@ -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 */

drivers/tty/serial/mxs-auart.c static void mxs_auart_settermios(struct uart_port *u, · line 643

Quoted 5 lines

drivers/tty/serial/mxs-auart.c +1 -1

@@ -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

Signature · 2 lines

Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Huang Shijie

author

2013-07-17 07:30 UTC #4 lore raw

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

Quoted 4 lines · Uwe Kleine-König

Quoted 1 line · Huang Shijie
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.

Quoted 6 lines

Quoted 1 line
But after several patches, DMA support has lost this limit.
This is still misleading.
Quoted 3 lines
This patch adds an optional property for the UART DT node which indicates the UART has RTS and CTS lines.

Quoted 8 lines

Quoted 2 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?

Quoted 44 lines

has much to do anyhow, better move this patch first. (Otherwise he will probably only say: That patch doesn't apply, please help.)

Quoted 34 lines

Signed-off-by Huang Shijie<[email protected]>

---
  .../bindings/tty/serial/fsl-mxs-auart.txt          |    4 ++++
  drivers/tty/serial/mxs-auart.c                     |    5 ++++-
  2 files changed, 8 insertions(+), 1 deletions(-)

Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt +4 -0

index 2c00ec6..59a40f1 100644
@@ -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";

drivers/tty/serial/mxs-auart.c +1 -0

index 465ef0b..27532fd 100644
@@ -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 */

drivers/tty/serial/mxs-auart.c static void mxs_auart_settermios(struct uart_port *u, · line 643

Quoted 5 lines

drivers/tty/serial/mxs-auart.c +1 -1

@@ -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

Quoted 3 lines

	if (RTSCTS)
		enable_dma();

ok, no problem.

thanks
Huang Shijie

--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html

Greg KH

maintainer

2013-07-26 23:10 UTC #5 lore raw

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

Quoted 16 lines · Huang Shijie

? 2013?07?16? 17:54, Uwe Kleine-K?nig ??:
Quoted 4 lines · Huang Shijie
Quoted 1 line
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.
Quoted 10 lines
Quoted 1 line
But after several patches, DMA support has lost this limit.
This is still misleading.
Quoted 5 lines
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:

Quoted 7 lines

Quoted 4 lines
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

Huang Shijie

author

2013-07-16 06:55 UTC #6 lore raw

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

In reply to Huang Shijie

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

Signed-off-by Huang Shijie <[email protected]>

---
 arch/arm/boot/dts/imx28-evk.dts |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

arch/arm/boot/dts/imx28-evk.dts +1 -0

index e035f46..15715d9 100644
@@ -220,6 +220,7 @@
 			auart0: serial at 8006a000 {
 				pinctrl-names = "default";
 				pinctrl-0 = <&auart0_pins_a>;
+				fsl,uart-has-rtscts;
 				status = "okay";
 			};

Signature · 1 line

1.7.1