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

Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx> · Wed, 3 Jan 2024 14:47:08 +0100

On 02/01/2024 at 17:18, ezra@xxxxxxxx wrote:
From: Ezra Buehler <ezra.buehler@xxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxx>
Signed-off-by: Michael Zimmermann <michael.zimmermann@xxxxxxxxxxxxxxxx>
Signed-off-by: Ezra Buehler <ezra.buehler@xxxxxxxxxxxxxxxxxx>

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

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









