Re: [PATCH v2 1/4] dt-bindings: firmware: qcom,scm: Add minidump SRAM property

[Krzysztof Kozlowski <krzk@kernel.org>]

On 22/05/2026 09:52, Mukesh Ojha wrote:
> On Wed, May 20, 2026 at 12:17:21PM +0200, Krzysztof Kozlowski wrote:
>> On Tue, May 19, 2026 at 10:44:39PM +0530, Mukesh Ojha wrote:
>>> On most Qualcomm SoCs where minidump is supported, a word in always-on
>>> SRAM is shared between the kernel and boot firmware. Before DDR is
>>> initialised on the warm reset following a crash, firmware reads this
>>> word to decide if minidump is enabled and collect a minidump and where
>>>  to deliver it (USB upload to a host, or save to local storage).
>>>
>>> Add a 'sram' property to the SCM binding to describe a region in
>>> always-on SRAM where the minidump download destination value could be
>>> written. Boot firmware reads it before DDR is initialised on a warm
>>> reset to decide where to store the minidump either to host PC or to
>>> on device storage.
>>>
>>> Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
>>> ---
>>>  .../devicetree/bindings/firmware/qcom,scm.yaml   | 16 ++++++++++++++++
>>>  1 file changed, 16 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/firmware/qcom,scm.yaml b/Documentation/devicetree/bindings/firmware/qcom,scm.yaml
>>> index 25f62bacbc91..27422d00b8fc 100644
>>> --- a/Documentation/devicetree/bindings/firmware/qcom,scm.yaml
>>> +++ b/Documentation/devicetree/bindings/firmware/qcom,scm.yaml
>>> @@ -129,6 +129,13 @@ properties:
>>>            - description: offset of the download mode control register
>>>      description: TCSR hardware block
>>>  
>>> +  sram:
>>> +    description:
>>> +      Phandle to a region in always-on SRAM used to store the download
>>> +      mode value for boot firmware to read before DDR is initialised on
>>> +      the next warm reset.
>>> +    maxItems: 1
>>> +
>>>  allOf:
>>>    # Clocks
>>>    - if:
>>> @@ -250,3 +257,12 @@ examples:
>>>              clock-names = "core", "bus", "iface";
>>>          };
>>>      };
>>> +
>>> +  - |
>>> +    firmware {
>>> +        scm {
>>> +            compatible = "qcom,scm-kaanapali", "qcom,scm";
>>
>> Incomplete, missing interrupts.
> 
> Interrupt number comes from firmware and has not even been described
> statically for SCM  for any SoC and so I am not sure to include it in
> the example. Perhaps I took the wrong example here and should have taken
> some pre-Gunyah Qualcomm SoC.

Then you do not need a new example. Difference in one property (reset
cells) does not justify new example.


Best regards,
Krzysztof