Add documentation for Google Kinfo Pixel reserved memory area.
Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
---
.../reserved-memory/google,kinfo.yaml | 49 +++++++++++++++++++
MAINTAINERS | 5 ++
2 files changed, 54 insertions(+)
create mode 100644 Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
diff --git a/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
new file mode 100644
index 000000000000..12d0b2815c02
--- /dev/null
+++ b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/reserved-memory/google,kinfo.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Google Pixel Kinfo reserved memory
+
+maintainers:
+ - Eugen Hristev <eugen.hristev@linaro.org>
+
+description:
+ This binding describes the Google Pixel Kinfo reserved memory, a region
+ of reserved-memory used to store data for firmware/bootloader on the Pixel
+ platform. The data stored is debugging information on the running kernel.
+
+properties:
+ compatible:
+ items:
+ - const: google,kinfo
+
+ memory-region:
+ maxItems: 1
+ description: Reference to the reserved-memory for the data
+
+required:
+ - compatible
+ - memory-region
+
+additionalProperties: true
+
+examples:
+ - |
+ reserved-memory {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges;
+
+ kinfo_region: smem@fa00000 {
+ reg = <0xfa00000 0x1000>;
+ no-map;
+ };
+ };
+
+ debug-kinfo {
+ compatible = "google,debug-kinfo";
+
+ memory-region = <&kinfo_region>;
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 2cb2cc427c90..8034940d0b1e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16164,6 +16164,11 @@ F: Documentation/dev-tools/meminspect.rst
F: include/linux/meminspect.h
F: kernel/meminspect/*
+MEMINSPECT KINFO DRIVER
+M: Eugen Hristev <eugen.hristev@linaro.org>
+S: Maintained
+F: Documentation/devicetree/bindings/misc/google,kinfo.yaml
+
MEMBLOCK AND MEMORY MANAGEMENT INITIALIZATION
M: Mike Rapoport <rppt@kernel.org>
L: linux-mm@kvack.org
--
2.43.0On Wed, Nov 19, 2025 at 05:44:26PM +0200, Eugen Hristev wrote:
> Add documentation for Google Kinfo Pixel reserved memory area.
>
> Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
> ---
> .../reserved-memory/google,kinfo.yaml | 49 +++++++++++++++++++
> MAINTAINERS | 5 ++
> 2 files changed, 54 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
>
> diff --git a/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
> new file mode 100644
> index 000000000000..12d0b2815c02
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/reserved-memory/google,kinfo.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Google Pixel Kinfo reserved memory
> +
> +maintainers:
> + - Eugen Hristev <eugen.hristev@linaro.org>
> +
> +description:
> + This binding describes the Google Pixel Kinfo reserved memory, a region
> + of reserved-memory used to store data for firmware/bootloader on the Pixel
> + platform. The data stored is debugging information on the running kernel.
> +
> +properties:
> + compatible:
> + items:
> + - const: google,kinfo
> +
> + memory-region:
> + maxItems: 1
> + description: Reference to the reserved-memory for the data
> +
> +required:
> + - compatible
> + - memory-region
> +
> +additionalProperties: true
> +
> +examples:
> + - |
> + reserved-memory {
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges;
> +
> + kinfo_region: smem@fa00000 {
Just put the google,kinfo (or google,debug-kinfo??) compatible here and
that's it.
> + reg = <0xfa00000 0x1000>;
> + no-map;
You don't need to access the memory?
> + };
> + };
> +
> + debug-kinfo {
> + compatible = "google,debug-kinfo";
> +
> + memory-region = <&kinfo_region>;
> + };
On Wed, 19 Nov 2025 17:44:26 +0200, Eugen Hristev wrote: > Add documentation for Google Kinfo Pixel reserved memory area. > > Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org> > --- > .../reserved-memory/google,kinfo.yaml | 49 +++++++++++++++++++ > MAINTAINERS | 5 ++ > 2 files changed, 54 insertions(+) > create mode 100644 Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml > My bot found errors running 'make dt_binding_check' on your patch: yamllint warnings/errors: dtschema/dtc warnings/errors: Documentation/devicetree/bindings/reserved-memory/google,kinfo.example.dtb: /example-0/debug-kinfo: failed to match any schema with compatible: ['google,debug-kinfo'] doc reference errors (make refcheckdocs): Warning: MAINTAINERS references a file that doesn't exist: Documentation/devicetree/bindings/misc/google,kinfo.yaml MAINTAINERS: Documentation/devicetree/bindings/misc/google,kinfo.yaml See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20251119154427.1033475-26-eugen.hristev@linaro.org The base for the series is generally the latest rc1. A different dependency should be noted in *this* patch. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit after running the above command yourself. Note that DT_SCHEMA_FILES can be set to your schema file to speed up checking your schema. However, it must be unset to test all examples with your schema.
On 19/11/2025 16:44, Eugen Hristev wrote:
> Add documentation for Google Kinfo Pixel reserved memory area.
Above and commit msg describe something completely else than binding. In
the binding you described kinfo Linux driver, above you suggest this is
some sort of reserved memory.
>
> Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
> ---
> .../reserved-memory/google,kinfo.yaml | 49 +++++++++++++++++++
> MAINTAINERS | 5 ++
> 2 files changed, 54 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
>
> diff --git a/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
> new file mode 100644
> index 000000000000..12d0b2815c02
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/reserved-memory/google,kinfo.yaml#
Filename based on the compatible.
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Google Pixel Kinfo reserved memory
> +
> +maintainers:
> + - Eugen Hristev <eugen.hristev@linaro.org>
> +
> +description:
> + This binding describes the Google Pixel Kinfo reserved memory, a region
Don't use "This binding", but please describe here hardware.
> + of reserved-memory used to store data for firmware/bootloader on the Pixel
> + platform. The data stored is debugging information on the running kernel.
> +
> +properties:
> + compatible:
> + items:
> + - const: google,kinfo
> +
> + memory-region:
> + maxItems: 1
> + description: Reference to the reserved-memory for the data
This does not match description. Unfortunately it looks like you added a
node just to instantiate Linux driver and this is not allowed.
If this was some special reserved memory region, then it would be part
of reserved memory bindings - see reserved-memory directory.
Compatible suggests that it is purely Linux driver, so another hint.
Looks like this is a SoC specific thing, so maybe this should be folded
in some of the soc drivers.
> +
> +required:
> + - compatible
> + - memory-region
> +
> +additionalProperties: true
> +
> +examples:
> + - |
> + reserved-memory {
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges;
> +
> + kinfo_region: smem@fa00000 {
> + reg = <0xfa00000 0x1000>;
> + no-map;
> + };
> + };
Anyway, drop, not relevant.
> +
> + debug-kinfo {
> + compatible = "google,debug-kinfo";
Device node with only one phandle to reserved memory region is a proof
it is not a real device.
Also,
Please use scripts/get_maintainers.pl to get a list of necessary people
and lists to CC (and consider --no-git-fallback argument, so you will
not CC people just because they made one commit years ago). It might
happen, that command when run on an older kernel, gives you outdated
entries. Therefore please be sure you base your patches on recent Linux
kernel.
Tools like b4 or scripts/get_maintainer.pl provide you proper list of
people, so fix your workflow. Tools might also fail if you work on some
ancient tree (don't, instead use mainline) or work on fork of kernel
(don't, instead use mainline). Just use b4 and everything should be
fine, although remember about `b4 prep --auto-to-cc` if you added new
patches to the patchset.
Best regards,
Krzysztof
On 11/19/25 18:02, Krzysztof Kozlowski wrote:
> On 19/11/2025 16:44, Eugen Hristev wrote:
>> Add documentation for Google Kinfo Pixel reserved memory area.
>
> Above and commit msg describe something completely else than binding. In
> the binding you described kinfo Linux driver, above you suggest this is
> some sort of reserved memory.
>
>>
>> Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
>> ---
>> .../reserved-memory/google,kinfo.yaml | 49 +++++++++++++++++++
>> MAINTAINERS | 5 ++
>> 2 files changed, 54 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
>> new file mode 100644
>> index 000000000000..12d0b2815c02
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml
>> @@ -0,0 +1,49 @@
>> +# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/reserved-memory/google,kinfo.yaml#
>
> Filename based on the compatible.
>
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Google Pixel Kinfo reserved memory
>> +
>> +maintainers:
>> + - Eugen Hristev <eugen.hristev@linaro.org>
>> +
>> +description:
>> + This binding describes the Google Pixel Kinfo reserved memory, a region
>
> Don't use "This binding", but please describe here hardware.
>
>> + of reserved-memory used to store data for firmware/bootloader on the Pixel
>> + platform. The data stored is debugging information on the running kernel.
>> +
>> +properties:
>> + compatible:
>> + items:
>> + - const: google,kinfo
>> +
>> + memory-region:
>> + maxItems: 1
>> + description: Reference to the reserved-memory for the data
>
> This does not match description. Unfortunately it looks like you added a
> node just to instantiate Linux driver and this is not allowed.
>
> If this was some special reserved memory region, then it would be part
> of reserved memory bindings - see reserved-memory directory.
I sent this patch for reserved-memory directory, where all the
reserved-memory bindings reside. Or maybe I do not understand your
comment ?>
> Compatible suggests that it is purely Linux driver, so another hint.
This reserved memory area is used by both Linux and firmware. Linux
stores some information into this reserved memory to be used by the
firmware/bootloader in some specific scenarios (e.g. crash or recovery
situations)
As the firmware reserves this memory for this specific purpose, it is
natural to inform Linux that the memory should not be used by another
purpose, but by the purpose it was reserved for.
Which would be the best way to have Linux understand where is this
memory area so it could be handled?
>
> Looks like this is a SoC specific thing, so maybe this should be folded
> in some of the soc drivers.
>
Not really soc specific. Any soc who implements this at firmware level
can use it. The firmware can reserve some memory for this specific
purpose and then pass it to Linux, so Linux can fill it up.
It just happens that the Pixel phone has this implemented right now, but
it is not constrained to Pixel only.
Instantiating this driver with a call like platform_device_register_data
would make the driver unaware of where exactly the firmware looks for
the data. This is right now passed through the DT node. Do you have a
better suggestion on how to pass it ?
>
>
>> +
>> +required:
>> + - compatible
>> + - memory-region
>> +
>> +additionalProperties: true
>> +
>> +examples:
>> + - |
>> + reserved-memory {
>> + #address-cells = <1>;
>> + #size-cells = <1>;
>> + ranges;
>> +
>> + kinfo_region: smem@fa00000 {
>> + reg = <0xfa00000 0x1000>;
>> + no-map;
>> + };
>> + };
>
> Anyway, drop, not relevant.
>
>
>> +
>> + debug-kinfo {
>> + compatible = "google,debug-kinfo";
>
> Device node with only one phandle to reserved memory region is a proof
> it is not a real device.
>
> Also,
> Please use scripts/get_maintainers.pl to get a list of necessary people
> and lists to CC (and consider --no-git-fallback argument, so you will
> not CC people just because they made one commit years ago). It might
> happen, that command when run on an older kernel, gives you outdated
> entries. Therefore please be sure you base your patches on recent Linux
> kernel.
>
> Tools like b4 or scripts/get_maintainer.pl provide you proper list of
> people, so fix your workflow. Tools might also fail if you work on some
> ancient tree (don't, instead use mainline) or work on fork of kernel
> (don't, instead use mainline). Just use b4 and everything should be
> fine, although remember about `b4 prep --auto-to-cc` if you added new
> patches to the patchset.
>
Thanks for your review and suggestions
>
> Best regards,
> Krzysztof
>
On 19/11/2025 17:19, Eugen Hristev wrote: > > > On 11/19/25 18:02, Krzysztof Kozlowski wrote: >> On 19/11/2025 16:44, Eugen Hristev wrote: >>> Add documentation for Google Kinfo Pixel reserved memory area. >> >> Above and commit msg describe something completely else than binding. In >> the binding you described kinfo Linux driver, above you suggest this is >> some sort of reserved memory. >> >>> >>> Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org> >>> --- >>> .../reserved-memory/google,kinfo.yaml | 49 +++++++++++++++++++ >>> MAINTAINERS | 5 ++ >>> 2 files changed, 54 insertions(+) >>> create mode 100644 Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml >>> >>> diff --git a/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml >>> new file mode 100644 >>> index 000000000000..12d0b2815c02 >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/reserved-memory/google,kinfo.yaml >>> @@ -0,0 +1,49 @@ >>> +# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause >>> +%YAML 1.2 >>> +--- >>> +$id: http://devicetree.org/schemas/reserved-memory/google,kinfo.yaml# >> >> Filename based on the compatible. >> >>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >>> + >>> +title: Google Pixel Kinfo reserved memory >>> + >>> +maintainers: >>> + - Eugen Hristev <eugen.hristev@linaro.org> >>> + >>> +description: >>> + This binding describes the Google Pixel Kinfo reserved memory, a region >> >> Don't use "This binding", but please describe here hardware. >> >>> + of reserved-memory used to store data for firmware/bootloader on the Pixel >>> + platform. The data stored is debugging information on the running kernel. >>> + >>> +properties: >>> + compatible: >>> + items: >>> + - const: google,kinfo >>> + >>> + memory-region: >>> + maxItems: 1 >>> + description: Reference to the reserved-memory for the data >> >> This does not match description. Unfortunately it looks like you added a >> node just to instantiate Linux driver and this is not allowed. >> >> If this was some special reserved memory region, then it would be part >> of reserved memory bindings - see reserved-memory directory. > > I sent this patch for reserved-memory directory, where all the > reserved-memory bindings reside. Or maybe I do not understand your > comment ?> There is no ref to reserved memory here. Please look first how reserved memory bindings are written, >> Compatible suggests that it is purely Linux driver, so another hint. > > This reserved memory area is used by both Linux and firmware. Linux > stores some information into this reserved memory to be used by the > firmware/bootloader in some specific scenarios (e.g. crash or recovery > situations) > As the firmware reserves this memory for this specific purpose, it is > natural to inform Linux that the memory should not be used by another > purpose, but by the purpose it was reserved for. But you did not write bindings for it. You wrote bindings for Linux device driver, I already explained that last time. > Which would be the best way to have Linux understand where is this > memory area so it could be handled? > > >> >> Looks like this is a SoC specific thing, so maybe this should be folded >> in some of the soc drivers. >> > Not really soc specific. Any soc who implements this at firmware level > can use it. The firmware can reserve some memory for this specific > purpose and then pass it to Linux, so Linux can fill it up. > It just happens that the Pixel phone has this implemented right now, but > it is not constrained to Pixel only. > > Instantiating this driver with a call like platform_device_register_data > would make the driver unaware of where exactly the firmware looks for > the data. This is right now passed through the DT node. Do you have a > better suggestion on how to pass it ? I do not see how this question is relevant here. I don't care how you pass it to the driver, because we discuss bindings. You created bindings for Linux driver and that's a no. If you wanted that, I suggests that it could be instantiated by some other driver, but sure - we don't have to go that way, that was just an idea how to solve the problem bindings like this cannot be accepted. Best regards, Krzysztof
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