LinuxLists.cc - [PATCH] arm64: dts: fix node name for the sysclk

2021-06-08 23:51:16

Subject: [PATCH] arm64: dts: fix node name for the sysclk

From: Vladimir Oltean <[email protected]>

U-Boot attempts to fix up the "clock-frequency" property of the "/sysclk" node:
https://elixir.bootlin.com/u-boot/v2021.04/source/arch/arm/cpu/armv8/fsl-layerscape/fdt.c#L512

but fails to do so:

## Booting kernel from Legacy Image at a1000000 ...
Image Name:
Created: 2021-06-08 10:31:38 UTC
Image Type: AArch64 Linux Kernel Image (gzip compressed)
Data Size: 15431370 Bytes = 14.7 MiB
Load Address: 80080000
Entry Point: 80080000
Verifying Checksum ... OK
## Flattened Device Tree blob at a0000000
Booting using the fdt blob at 0xa0000000
Uncompressing Kernel Image
Loading Device Tree to 00000000fbb19000, end 00000000fbb22717 ... OK
Unable to update property /sysclk:clock-frequency, err=FDT_ERR_NOTFOUND

Starting kernel ...

All Layerscape SoCs except LS1028A use "sysclk" as the node name, and
not "clock-sysclk". So change the node name of LS1028A accordingly.

Fixes: 8897f3255c9c ("arm64: dts: Add support for NXP LS1028A SoC")
Signed-off-by: Vladimir Oltean <[email protected]>
---
arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
index d0dddf19578a..03e1ca7fea9a 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
@@ -66,7 +66,7 @@ CPU_PW20: cpu-pw20 {
};
};

- sysclk: clock-sysclk {
+ sysclk: sysclk {
compatible = "fixed-clock";
#clock-cells = <0>;
clock-frequency = <100000000>;
--
2.25.1

2021-06-08 23:53:16

by Vladimir Oltean

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Subject: Re: [PATCH] arm64: dts: fix node name for the sysclk

I forgot to add "ls1028a: " to the commit prefix. Shawn, if there are no
objections to the patch, would you mind adding it when applying? Thanks!

2021-06-12 08:08:14

by Shawn Guo

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Subject: Re: [PATCH] arm64: dts: fix node name for the sysclk

On Tue, Jun 08, 2021 at 02:26:58PM +0300, Vladimir Oltean wrote:
> From: Vladimir Oltean <[email protected]>
>
> U-Boot attempts to fix up the "clock-frequency" property of the "/sysclk" node:
> https://elixir.bootlin.com/u-boot/v2021.04/source/arch/arm/cpu/armv8/fsl-layerscape/fdt.c#L512
>
> but fails to do so:
>
> ## Booting kernel from Legacy Image at a1000000 ...
> Image Name:
> Created: 2021-06-08 10:31:38 UTC
> Image Type: AArch64 Linux Kernel Image (gzip compressed)
> Data Size: 15431370 Bytes = 14.7 MiB
> Load Address: 80080000
> Entry Point: 80080000
> Verifying Checksum ... OK
> ## Flattened Device Tree blob at a0000000
> Booting using the fdt blob at 0xa0000000
> Uncompressing Kernel Image
> Loading Device Tree to 00000000fbb19000, end 00000000fbb22717 ... OK
> Unable to update property /sysclk:clock-frequency, err=FDT_ERR_NOTFOUND
>
> Starting kernel ...
>
> All Layerscape SoCs except LS1028A use "sysclk" as the node name, and
> not "clock-sysclk". So change the node name of LS1028A accordingly.

Wouldn't it more flexible to use alias/label for finding the node?
Using node name/path looks fragile.

Shawn

>
> Fixes: 8897f3255c9c ("arm64: dts: Add support for NXP LS1028A SoC")
> Signed-off-by: Vladimir Oltean <[email protected]>
> ---
> arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> index d0dddf19578a..03e1ca7fea9a 100644
> --- a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> +++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> @@ -66,7 +66,7 @@ CPU_PW20: cpu-pw20 {
> };
> };
>
> - sysclk: clock-sysclk {
> + sysclk: sysclk {
> compatible = "fixed-clock";
> #clock-cells = <0>;
> clock-frequency = <100000000>;
> --
> 2.25.1
>

2021-06-14 14:54:20

by Vladimir Oltean

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Subject: Re: [PATCH] arm64: dts: fix node name for the sysclk

Hello Shawn,

On Sat, Jun 12, 2021 at 03:53:47PM +0800, Shawn Guo wrote:
> On Tue, Jun 08, 2021 at 02:26:58PM +0300, Vladimir Oltean wrote:
> > From: Vladimir Oltean <[email protected]>
> >
> > U-Boot attempts to fix up the "clock-frequency" property of the "/sysclk" node:
> > https://elixir.bootlin.com/u-boot/v2021.04/source/arch/arm/cpu/armv8/fsl-layerscape/fdt.c#L512
> >
> > but fails to do so:
> >
> > ## Booting kernel from Legacy Image at a1000000 ...
> > Image Name:
> > Created: 2021-06-08 10:31:38 UTC
> > Image Type: AArch64 Linux Kernel Image (gzip compressed)
> > Data Size: 15431370 Bytes = 14.7 MiB
> > Load Address: 80080000
> > Entry Point: 80080000
> > Verifying Checksum ... OK
> > ## Flattened Device Tree blob at a0000000
> > Booting using the fdt blob at 0xa0000000
> > Uncompressing Kernel Image
> > Loading Device Tree to 00000000fbb19000, end 00000000fbb22717 ... OK
> > Unable to update property /sysclk:clock-frequency, err=FDT_ERR_NOTFOUND
> >
> > Starting kernel ...
> >
> > All Layerscape SoCs except LS1028A use "sysclk" as the node name, and
> > not "clock-sysclk". So change the node name of LS1028A accordingly.
>
> Wouldn't it more flexible to use alias/label for finding the node?
> Using node name/path looks fragile.

Thank you for the advice, I will keep it in mind next time when I design
my own bootloader device tree fixup scheme. However, in this case I did
not create it, and implementing your suggestion to find the sysclk node
through /aliases would require changes not only to the bootloader, but
to the Linux device tree still (and if we're modifying the Linux DT, why
not just go with this patch). So yes, the existing mechanism is more
fragile, but I am not sure if we gain anything by artificially creating
an additional dependency in the process.

2021-07-14 02:30:52

by Shawn Guo

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