RE: [PATCH] arm64: dts: imx8mp: drop dmas property for uart console

From: Peng Fan
Date: Wed Jun 22 2022 - 18:34:08 EST


> Subject: Re: [PATCH] arm64: dts: imx8mp: drop dmas property for uart console
>
> On Wed, Jun 22, 2022 at 12:24 AM Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> wrote:
> >
> > +Cc Saravana Kannan <saravanak@xxxxxxxxxx>, the author of
> > +71066545b48e4
> >
> > On Wed, Jun 22, 2022 at 02:20:27PM +0800, Peng Fan (OSS) wrote:
> > > From: Peng Fan <peng.fan@xxxxxxx>
> > >
> > > Commit 71066545b48e4("driver core: Set fw_devlink.strict=1 by
> > > default") default set fw_devlink to true. This has a side effect to
> > > i.MX uart console. The sdma will make the i.MX8MP uart driver defer
> > > probe for some time (~10s with i.MX8MP-EVK board) until sdma ready,
> > > because sdma is a supplier with property dmas set in device tree node.
> >
> > I just tested this on an i.MX6 board and observed the same behaviour.
> > The same will happen on any other i.MX board as well. This will also
> > likely happen on any other SoC on which the UART driver uses dmaengine.
> >
> > >
> > > Since this uart is for console, we need log printed out as soon as
> > > possible, so remove the dmas property for the uart console node.
> >
> > Fixing this at board level is not really an option because that means
> > fixing each and every, at least i.MX board in the tree. Furthermore
> > this would mean to bring the deleted property back in and to remove
> > another dmas property should a user want to switch to another console
> > port.
> >
> > For what it's worth: NACK for 71066545b48e4.
>
> Peng, I sent a fix. Can you give it a shot please?

Thanks for the quick fix. I have replied your patch with my T-b.
My patch could be dropped.

Thanks,
Peng.

>
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> -Saravana
>
> >
> > Sascha
> >
> > >
> > > Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> > > ---
> > >
> > > V1:
> > > The upper set fw_devlink.strict=1 patch is in linux-next tree.
> > >
> > > arch/arm64/boot/dts/freescale/imx8mp-evk.dts | 2
> ++
> > > arch/arm64/boot/dts/freescale/imx8mp-icore-mx8mp-edimm2.2.dts | 2
> > > ++ arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-rdk.dts |
> 2 ++
> > > arch/arm64/boot/dts/freescale/imx8mp-venice-gw74xx.dts | 2
> ++
> > > 4 files changed, 8 insertions(+)
> > >
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > > b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > > index fb11c03bc8b1..3fdb38bc0069 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > > @@ -359,6 +359,8 @@ &uart2 {
> > > pinctrl-names = "default";
> > > pinctrl-0 = <&pinctrl_uart2>;
> > > status = "okay";
> > > + /delete-property/ dmas;
> > > + /delete-property/ dma-names;
> > > };
> > >
> > > &usb3_phy1 {
> > > diff --git
> > > a/arch/arm64/boot/dts/freescale/imx8mp-icore-mx8mp-edimm2.2.dts
> > > b/arch/arm64/boot/dts/freescale/imx8mp-icore-mx8mp-edimm2.2.dts
> > > index dd703b6a5e17..fb2b44e94482 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mp-icore-mx8mp-edimm2.2.dts
> > > +++
> b/arch/arm64/boot/dts/freescale/imx8mp-icore-mx8mp-edimm2.2.dts
> > > @@ -69,6 +69,8 @@ &uart2 {
> > > pinctrl-names = "default";
> > > pinctrl-0 = <&pinctrl_uart2>;
> > > status = "okay";
> > > + /delete-property/ dmas;
> > > + /delete-property/ dma-names;
> > > };
> > >
> > > &usb3_phy0 {
> > > diff --git
> > > a/arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-rdk.dts
> > > b/arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-rdk.dts
> > > index 6aa720bafe28..68a478151292 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-rdk.dts
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mp-phyboard-pollux-rdk.dts
> > > @@ -99,6 +99,8 @@ &uart1 {
> > > pinctrl-names = "default";
> > > pinctrl-0 = <&pinctrl_uart1>;
> > > status = "okay";
> > > + /delete-property/ dmas;
> > > + /delete-property/ dma-names;
> > > };
> > >
> > > /* SD-Card */
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mp-venice-gw74xx.dts
> > > b/arch/arm64/boot/dts/freescale/imx8mp-venice-gw74xx.dts
> > > index 521215520a0f..f90c1ac2791c 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mp-venice-gw74xx.dts
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mp-venice-gw74xx.dts
> > > @@ -554,6 +554,8 @@ &uart2 {
> > > pinctrl-names = "default";
> > > pinctrl-0 = <&pinctrl_uart2>;
> > > status = "okay";
> > > + /delete-property/ dmas;
> > > + /delete-property/ dma-names;
> > > };
> > >
> > > &uart4 {
> > > --
> > > 2.25.1
> > >
> > >
> >
> > --
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