diff mbox series

[1/2] dt-bindings: clock: imx8m: introduce fsl,protected-clocks property

Message ID 20220815033632.1687854-2-peng.fan@oss.nxp.com
State New
Headers show
Series [1/2] dt-bindings: clock: imx8m: introduce fsl,protected-clocks property | expand

Commit Message

Peng Fan (OSS) Aug. 15, 2022, 3:36 a.m. UTC 
From: Peng Fan <peng.fan@nxp.com>

i.MX8M Linux run on top of Jailhouse hypervisor, the root cell Linux
should not disable clocks used by inmate. This would also benifit
AMP to avoid Linux disable clocks used by Cortex-M4/M7.

So introduce fsl,protected-clocks for above case.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 Documentation/devicetree/bindings/clock/imx8m-clock.yaml | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Peng Fan Aug. 16, 2022, 7:13 a.m. UTC | #1 
Hi Sascha,

> Subject: Re: [PATCH 1/2] dt-bindings: clock: imx8m: introduce fsl,protected-
> clocks property
> 
> Hi Peng,
> 
> On Mon, Aug 15, 2022 at 11:36:31AM +0800, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > i.MX8M Linux run on top of Jailhouse hypervisor, the root cell Linux
> > should not disable clocks used by inmate. This would also benifit AMP
> > to avoid Linux disable clocks used by Cortex-M4/M7.
> >
> > So introduce fsl,protected-clocks for above case.
> >
> > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > ---
> >  Documentation/devicetree/bindings/clock/imx8m-clock.yaml | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > index 458c7645ee68..0ec490ff9a09 100644
> > --- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > +++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > @@ -39,6 +39,10 @@ properties:
> >        ID in its "clocks" phandle cell. See include/dt-bindings/clock/imx8m-
> clock.h
> >        for the full list of i.MX8M clock IDs.
> >
> > +  fsl,protected-clocks:
> > +    description: List of the Protected clock.
> > +    $ref: /schemas/types.yaml#/definitions/uint32-array
> 
> There already is a generic protected-clocks property described in
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithu
> b.com%2Fdevicetree-org%2Fdt-
> schema%2Fblob%2F0d1b78cd0c3d9a3d523ced17d7da64b03f6c18ea%2Fdtsc
> hema%2Fschemas%2Fclock%2Fclock.yaml%23L131&amp;data=05%7C01%7
> Cpeng.fan%40nxp.com%7C5dbc72639c9147765af208da7ec63315%7C686ea
> 1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637961686968811809%7CUn
> known%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI
> 6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=D%2BfJA5h
> wblaX8VH%2BdQoN0pEFmCipfZHHf0ZVo07B4kg%3D&amp;reserved=0
> We probably shouldn't add a property with the same name but different
> meaning.
> 

Thanks for sharing the info. I should check the common bindings before
cook this patchset.

> I am not sure if we want to go the route of a fsl specific property, it looks
> like other SoCs could have similar problems and it might be worth solving
> this problem with a broader view.
> 

I see qcom just drop the clock entries before registering the clocks. But to
i.MX8M, it is not feasible to drop those clocks, unless check the
protected-clocks property before registering every clock. This is odd.

So here I just wanna let i.MX8M clk driver prepare enable the clocks listed
in protected-clocks property to avoid linux disable those clocks.
> Anyway, please add a description to the binding what this property actually
> does.
I will switch to use the common bindings.

Thanks,
Peng.
> 
> Sascha
> 
> --
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       |
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.
> pengutronix.de%2F&amp;data=05%7C01%7Cpeng.fan%40nxp.com%7C5dbc
> 72639c9147765af208da7ec63315%7C686ea1d3bc2b4c6fa92cd99c5c301635
> %7C0%7C0%7C637961686968811809%7CUnknown%7CTWFpbGZsb3d8eyJW
> IjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7
> C3000%7C%7C%7C&amp;sdata=7UqyWwDDhaze2qZJ%2FknZ6Am7Y%2Bs%
> 2Fbpyv9SITJHgsZPw%3D&amp;reserved=0  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
Sascha Hauer Aug. 16, 2022, 8:14 a.m. UTC | #2 
On Tue, Aug 16, 2022 at 07:13:27AM +0000, Peng Fan wrote:
> Hi Sascha,
> 
> > Subject: Re: [PATCH 1/2] dt-bindings: clock: imx8m: introduce fsl,protected-
> > clocks property
> > 
> > Hi Peng,
> > 
> > On Mon, Aug 15, 2022 at 11:36:31AM +0800, Peng Fan (OSS) wrote:
> > > From: Peng Fan <peng.fan@nxp.com>
> > >
> > > i.MX8M Linux run on top of Jailhouse hypervisor, the root cell Linux
> > > should not disable clocks used by inmate. This would also benifit AMP
> > > to avoid Linux disable clocks used by Cortex-M4/M7.
> > >
> > > So introduce fsl,protected-clocks for above case.
> > >
> > > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > > ---
> > >  Documentation/devicetree/bindings/clock/imx8m-clock.yaml | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > > b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > > index 458c7645ee68..0ec490ff9a09 100644
> > > --- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > > +++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> > > @@ -39,6 +39,10 @@ properties:
> > >        ID in its "clocks" phandle cell. See include/dt-bindings/clock/imx8m-
> > clock.h
> > >        for the full list of i.MX8M clock IDs.
> > >
> > > +  fsl,protected-clocks:
> > > +    description: List of the Protected clock.
> > > +    $ref: /schemas/types.yaml#/definitions/uint32-array
> > 
> > There already is a generic protected-clocks property described in
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithu
> > b.com%2Fdevicetree-org%2Fdt-
> > schema%2Fblob%2F0d1b78cd0c3d9a3d523ced17d7da64b03f6c18ea%2Fdtsc
> > hema%2Fschemas%2Fclock%2Fclock.yaml%23L131&amp;data=05%7C01%7
> > Cpeng.fan%40nxp.com%7C5dbc72639c9147765af208da7ec63315%7C686ea
> > 1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637961686968811809%7CUn
> > known%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI
> > 6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=D%2BfJA5h
> > wblaX8VH%2BdQoN0pEFmCipfZHHf0ZVo07B4kg%3D&amp;reserved=0
> > We probably shouldn't add a property with the same name but different
> > meaning.
> > 
> 
> Thanks for sharing the info. I should check the common bindings before
> cook this patchset.
> 
> > I am not sure if we want to go the route of a fsl specific property, it looks
> > like other SoCs could have similar problems and it might be worth solving
> > this problem with a broader view.
> > 
> 
> I see qcom just drop the clock entries before registering the clocks. But to
> i.MX8M, it is not feasible to drop those clocks, unless check the
> protected-clocks property before registering every clock. This is odd.
> 
> So here I just wanna let i.MX8M clk driver prepare enable the clocks listed
> in protected-clocks property to avoid linux disable those clocks.
> > Anyway, please add a description to the binding what this property actually
> > does.
> I will switch to use the common bindings.

There were cases when a property first started with a "soc," prefix and
later when people realized that it could be useful for other
drivers/SoCs as well, the prefix was removed. With that in mind I
would expect that a "fsl,protected-clocks" property behaves the same
as a "protected-clocks" property without the prefix.

If it doesn't please pick a different name. I didn't want to suggest
to just drop the "fsl," prefix and to use the generic property name
when the properties have a different meaning.

Sascha
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
index 458c7645ee68..0ec490ff9a09 100644
--- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
+++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
@@ -39,6 +39,10 @@  properties:
       ID in its "clocks" phandle cell. See include/dt-bindings/clock/imx8m-clock.h
       for the full list of i.MX8M clock IDs.
 
+  fsl,protected-clocks:
+    description: List of the Protected clock.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
 required:
   - compatible
   - reg