This change disables the DMA support (RX/TX) on the NXP's fsl_lpuart
driver - the PIO mode is used instead. This change is necessary for better
robustness of BK4's device use cases with many potentially interrupted
short serial transfers.
Without it the driver hangs when some distortion happens on UART lines.
Signed-off-by: Lukasz Majewski <[email protected]>
Suggested-by: Robin Murphy <[email protected]>
---
Changes for v2:
- Use /delete-property/dma-names; instead of dma-names = "","";
---
arch/arm/boot/dts/vf610-bk4.dts | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm/boot/dts/vf610-bk4.dts b/arch/arm/boot/dts/vf610-bk4.dts
index 0f3870d3b099..830c85476b3d 100644
--- a/arch/arm/boot/dts/vf610-bk4.dts
+++ b/arch/arm/boot/dts/vf610-bk4.dts
@@ -259,24 +259,28 @@
&uart0 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart0>;
+ /delete-property/dma-names;
status = "okay";
};
&uart1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart1>;
+ /delete-property/dma-names;
status = "okay";
};
&uart2 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart2>;
+ /delete-property/dma-names;
status = "okay";
};
&uart3 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart3>;
+ /delete-property/dma-names;
status = "okay";
};
--
2.20.1
On Thu, Oct 10, 2019 at 11:08:02AM +0200, Lukasz Majewski wrote:
> This change disables the DMA support (RX/TX) on the NXP's fsl_lpuart
> driver - the PIO mode is used instead. This change is necessary for better
> robustness of BK4's device use cases with many potentially interrupted
> short serial transfers.
>
> Without it the driver hangs when some distortion happens on UART lines.
>
> Signed-off-by: Lukasz Majewski <[email protected]>
> Suggested-by: Robin Murphy <[email protected]>
Subject prefix should be 'ARM: dts: ...'. I fixed it up and applied the
patch.
Shawn
Hi Shawn,
> On Thu, Oct 10, 2019 at 11:08:02AM +0200, Lukasz Majewski wrote:
> > This change disables the DMA support (RX/TX) on the NXP's fsl_lpuart
> > driver - the PIO mode is used instead. This change is necessary for
> > better robustness of BK4's device use cases with many potentially
> > interrupted short serial transfers.
> >
> > Without it the driver hangs when some distortion happens on UART
> > lines.
> >
> > Signed-off-by: Lukasz Majewski <[email protected]>
> > Suggested-by: Robin Murphy <[email protected]>
>
> Subject prefix should be 'ARM: dts: ...'. I fixed it up and applied
> the patch.
>
> Shawn
Thanks :-)
Best regards,
Lukasz Majewski
--
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