[PATCH v1 0/2] ARM: dts: at91: gardena-smart-gateway: Use DMA for serial ports

[PATCH v1 0/2] ARM: dts: at91: gardena-smart-gateway: Use DMA for serial ports

[ezra]

From: Ezra Buehler <ezra.buehler@husqvarnagroup.com>

On our AT91SAM9G25-based GARDENA smart Gateway we have been experiencing
various problems which we were able to trace back to unreliable UART
communication. Enabling DMA for the serial ports resolved these issues.

Ezra Buehler (2):
  ARM: dts: at91: at91sam9x5ek: Use DMA for DBGU serial port
  ARM: dts: at91: gardena-smart-gateway: Use DMA for USART3

 .../boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts    | 2 ++
 arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi                   | 2 ++
 2 files changed, 4 insertions(+)

--
2.39.2

[PATCH v1 1/2] ARM: dts: at91: at91sam9x5ek: Use DMA for DBGU serial port

[ezra]

From: Ezra Buehler <ezra.buehler@husqvarnagroup.com>

The UART controller does not seem to be fast enough to receive data (at
115200 baud) without dropping bytes when DMA is disabled.

This has often been noticed when pasting SSH keys into the serial
console (ttyS0). Only after multiple tries, the long strings would be
successfully transferred without missing characters.

Co-Developed-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
Signed-off-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
Signed-off-by: Ezra Buehler <ezra.buehler@husqvarnagroup.com>
---
 arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi b/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi
index 5f4eaa618ab4..9618b8d965b0 100644
--- a/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi
+++ b/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi
@@ -39,6 +39,8 @@ &adc0 {
 };
 
 &dbgu {
+	atmel,use-dma-rx;
+	atmel,use-dma-tx;
 	status = "okay";
 };
 
-- 
2.39.2

[PATCH v1 2/2] ARM: dts: at91: gardena-smart-gateway: Use DMA for USART3

[ezra]

From: Ezra Buehler <ezra.buehler@husqvarnagroup.com>

The AT91SAM9G25-based GARDENA smart Gateway uses USART3 (ttyS1) to
communicate (over PPP, at 115200 baud) with the radio module.

We have been experiencing packet loss and seeing errors on the ppp0
interface. Enabling DMA for the serial interface resolves the issues.

Co-Developed-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
Signed-off-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
Signed-off-by: Ezra Buehler <ezra.buehler@husqvarnagroup.com>
---
 .../boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts    | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts b/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts
index 92f2c05c873f..af70eb8a3a02 100644
--- a/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts
+++ b/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts
@@ -121,6 +121,8 @@ &usart2 {
 };
 
 &usart3 {
+	atmel,use-dma-rx;
+	atmel,use-dma-tx;
 	status = "okay";
 
 	pinctrl-0 = <&pinctrl_usart3
-- 
2.39.2

Re: [PATCH v1 1/2] ARM: dts: at91: at91sam9x5ek: Use DMA for DBGU serial port

[Nicolas Ferre]

On 02/01/2024 at 17:18, ezra@easyb.ch wrote:
> From: Ezra Buehler <ezra.buehler@husqvarnagroup.com>
> 
> The UART controller does not seem to be fast enough to receive data (at
> 115200 baud) without dropping bytes when DMA is disabled.
> 
> This has often been noticed when pasting SSH keys into the serial
> console (ttyS0). Only after multiple tries, the long strings would be
> successfully transferred without missing characters.
> 
> Co-Developed-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
> Signed-off-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
> Signed-off-by: Ezra Buehler <ezra.buehler@husqvarnagroup.com>

Fine with me:
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>

Thanks for your patch. Best regards,
   Nicolas

> ---
>   arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi b/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi
> index 5f4eaa618ab4..9618b8d965b0 100644
> --- a/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi
> +++ b/arch/arm/boot/dts/microchip/at91sam9x5ek.dtsi
> @@ -39,6 +39,8 @@ &adc0 {
>   };
> 
>   &dbgu {
> +       atmel,use-dma-rx;
> +       atmel,use-dma-tx;
>          status = "okay";
>   };
> 
> --
> 2.39.2
> 

Re: [PATCH v1 2/2] ARM: dts: at91: gardena-smart-gateway: Use DMA for USART3

[Nicolas Ferre]

On 02/01/2024 at 17:18, ezra@easyb.ch wrote:
> From: Ezra Buehler <ezra.buehler@husqvarnagroup.com>
> 
> The AT91SAM9G25-based GARDENA smart Gateway uses USART3 (ttyS1) to
> communicate (over PPP, at 115200 baud) with the radio module.
> 
> We have been experiencing packet loss and seeing errors on the ppp0
> interface. Enabling DMA for the serial interface resolves the issues.
> 
> Co-Developed-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
> Signed-off-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>
> Signed-off-by: Ezra Buehler <ezra.buehler@husqvarnagroup.com>

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Thanks!

Best regards,
   Nicolas

> ---
>   .../boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts    | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts b/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts
> index 92f2c05c873f..af70eb8a3a02 100644
> --- a/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts
> +++ b/arch/arm/boot/dts/microchip/at91sam9g25-gardena-smart-gateway.dts
> @@ -121,6 +121,8 @@ &usart2 {
>   };
> 
>   &usart3 {
> +       atmel,use-dma-rx;
> +       atmel,use-dma-tx;
>          status = "okay";
> 
>          pinctrl-0 = <&pinctrl_usart3
> --
> 2.39.2
> 

Re: [PATCH v1 0/2] ARM: dts: at91: gardena-smart-gateway: Use DMA for serial ports

[claudiu beznea]

On 02.01.2024 18:18, ezra@easyb.ch wrote:
> From: Ezra Buehler <ezra.buehler@husqvarnagroup.com>
> 
> On our AT91SAM9G25-based GARDENA smart Gateway we have been experiencing
> various problems which we were able to trace back to unreliable UART
> communication. Enabling DMA for the serial ports resolved these issues.
> 
> Ezra Buehler (2):
>   ARM: dts: at91: at91sam9x5ek: Use DMA for DBGU serial port
>   ARM: dts: at91: gardena-smart-gateway: Use DMA for USART3

Applied to at91-dt, thank you!