[V7,1/2] dt-bindings: firmware: bootstats: Add the dtschema

  Add the device tree bindings for boot stats. This has 2 properties
pre-abl-time and abl-time which records the timestamps for boot
stats.

Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
Link: https://lore.kernel.org/linux-arm-kernel/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/
---
 .../bindings/firmware/qcom,bootstats.yaml     | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml
  

On 05/07/2023 07:32, Souradeep Chowdhury wrote:
> Add the device tree bindings for boot stats. This has 2 properties
> pre-abl-time and abl-time which records the timestamps for boot
> stats.
> 
> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
> Link: https://lore.kernel.org/linux-arm-kernel/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/
> ---
>  .../bindings/firmware/qcom,bootstats.yaml     | 38 +++++++++++++++++++
>  1 file changed, 38 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml
> 
> diff --git a/Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml b/Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml
> new file mode 100644
> index 000000000000..22e697524058
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml
> @@ -0,0 +1,38 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/firmware/qcom,bootstats.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Boot Stats

This explains nothing...

> +
> +maintainers:
> +  - Souradeep Chowdhury <quic_schowdhu@quicinc.com>
> +
> +description: |

Drop |

> +    Qualcomm's proprietary Android boot-loaders capture boot time

Wrong indentation.

> +    stats, like the time when the bootloader started execution and
> +    at what point the bootloader handed over control to the kernel.
> +    This is captured in the unit of ms in devicetree property.
> +
> +properties:
> +  pre-abl-time:
> +    description: The property to store the starting point of abl in ms.

String instead of ms? No, this is the craziest idea I saw recently. Use
-ms suffix.

> +    $ref: /schemas/types.yaml#/definitions/string-array
> +
> +  abl-time:
> +    description: The property to store the duration of abl in ms.
> +    $ref: /schemas/types.yaml#/definitions/string-array

I have no clue what this entire binding is about. Nothing can bind to
it, no usage explained. Properties are not used to "store the duration".
This does not look like suitable for DT, drop entire binding.

> +
> +required:
> +  - pre-abl-time
> +  - abl-time
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    bootstats {
> +        pre-abl-time="17627";
> +        abl-time="26748";

Missing spaces. Open existing DTS and look at existing coding style.

Best regards,
Krzysztof
  

On 7/5/2023 11:47 AM, Krzysztof Kozlowski wrote:
> On 05/07/2023 07:32, Souradeep Chowdhury wrote:
>> Add the device tree bindings for boot stats. This has 2 properties
>> pre-abl-time and abl-time which records the timestamps for boot
>> stats.
>>
>> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
>> Link: https://lore.kernel.org/linux-arm-kernel/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/
>> ---
>>   .../bindings/firmware/qcom,bootstats.yaml     | 38 +++++++++++++++++++
>>   1 file changed, 38 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml b/Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml
>> new file mode 100644
>> index 000000000000..22e697524058
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/firmware/qcom,bootstats.yaml
>> @@ -0,0 +1,38 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/firmware/qcom,bootstats.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Boot Stats
> 
> This explains nothing...

Ack

> 
>> +
>> +maintainers:
>> +  - Souradeep Chowdhury <quic_schowdhu@quicinc.com>
>> +
>> +description: |
> 
> Drop |

Ack

> 
>> +    Qualcomm's proprietary Android boot-loaders capture boot time
> 
> Wrong indentation.

Ack
> 
>> +    stats, like the time when the bootloader started execution and
>> +    at what point the bootloader handed over control to the kernel.
>> +    This is captured in the unit of ms in devicetree property.
>> +
>> +properties:
>> +  pre-abl-time:
>> +    description: The property to store the starting point of abl in ms.
> 
> String instead of ms? No, this is the craziest idea I saw recently. Use
> -ms suffix.
> 
>> +    $ref: /schemas/types.yaml#/definitions/string-array
>> +
>> +  abl-time:
>> +    description: The property to store the duration of abl in ms.
>> +    $ref: /schemas/types.yaml#/definitions/string-array
> 
> I have no clue what this entire binding is about. Nothing can bind to
> it, no usage explained. Properties are not used to "store the duration".
> This does not look like suitable for DT, drop entire binding.

This binding was created as per the suggestion on version 6 of the patch 
by Arnd. The idea was that these 2 devicetree properties will be used to 
populate the bootstat values from the bootloader and exposed to the user 
via /sys/firmware/devicetree/ directly.

Details in the link below:-

https://lore.kernel.org/lkml/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/T/#mbdc9ad95fcbb5ad7b56c6996a3933899b42d982c

Can you suggest any alternative way to represent this as a binding?

> 
>> +
>> +required:
>> +  - pre-abl-time
>> +  - abl-time
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    bootstats {
>> +        pre-abl-time="17627";
>> +        abl-time="26748";
> 
> Missing spaces. Open existing DTS and look at existing coding style.

Ack

> 
> Best regards,
> Krzysztof
>
  

On 05/07/2023 10:33, Souradeep Chowdhury wrote:
>>> +    $ref: /schemas/types.yaml#/definitions/string-array
>>> +
>>> +  abl-time:
>>> +    description: The property to store the duration of abl in ms.
>>> +    $ref: /schemas/types.yaml#/definitions/string-array
>>
>> I have no clue what this entire binding is about. Nothing can bind to
>> it, no usage explained. Properties are not used to "store the duration".
>> This does not look like suitable for DT, drop entire binding.
> 
> This binding was created as per the suggestion on version 6 of the patch 
> by Arnd. The idea was that these 2 devicetree properties will be used to 
> populate the bootstat values from the bootloader and exposed to the user 
> via /sys/firmware/devicetree/ directly.
> 
> Details in the link below:-
> 
> https://lore.kernel.org/lkml/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/T/#mbdc9ad95fcbb5ad7b56c6996a3933899b42d982c
> 
> Can you suggest any alternative way to represent this as a binding?

Then you should clearly state in the binding how this is going to be
used and who is going to populate it. Not only in the binding but also
in commit msg which currently has 0 rationale and answers to "why". Your
commit msg explained only "what", which is usually obvious and much less
important. Your commit should stand on its own and should clearly
explain why we need this feature at all, what problem it solves.

And before you claim that there is some discussion under link or some
cover letter - these do not matter. Commit and bindings matter.

What's more, I don't think that Arnd's advice is correct here - DT is
suppose to describe hardware or firmware. These properties are coming
from firmware but they are not describing any firmware or hardware
characteristics. Instead they are debugging of current boot status.

I will leave the decision on that for Rob, however anyway binding is
very vague and incorrect, so I would expect he will come with the same
concerns regardless whether it is suitable to DT or is not.



Best regards,
Krzysztof
  

On Wed, Jul 05, 2023 at 11:34:35AM +0200, Krzysztof Kozlowski wrote:
> On 05/07/2023 10:33, Souradeep Chowdhury wrote:
> >>> +    $ref: /schemas/types.yaml#/definitions/string-array
> >>> +
> >>> +  abl-time:
> >>> +    description: The property to store the duration of abl in ms.
> >>> +    $ref: /schemas/types.yaml#/definitions/string-array
> >>
> >> I have no clue what this entire binding is about. Nothing can bind to
> >> it, no usage explained. Properties are not used to "store the duration".
> >> This does not look like suitable for DT, drop entire binding.
> > 
> > This binding was created as per the suggestion on version 6 of the patch 
> > by Arnd. The idea was that these 2 devicetree properties will be used to 
> > populate the bootstat values from the bootloader and exposed to the user 
> > via /sys/firmware/devicetree/ directly.
> > 
> > Details in the link below:-
> > 
> > https://lore.kernel.org/lkml/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/T/#mbdc9ad95fcbb5ad7b56c6996a3933899b42d982c
> > 
> > Can you suggest any alternative way to represent this as a binding?
> 
> Then you should clearly state in the binding how this is going to be
> used and who is going to populate it. Not only in the binding but also
> in commit msg which currently has 0 rationale and answers to "why". Your
> commit msg explained only "what", which is usually obvious and much less
> important. Your commit should stand on its own and should clearly
> explain why we need this feature at all, what problem it solves.
> 
> And before you claim that there is some discussion under link or some
> cover letter - these do not matter. Commit and bindings matter.
> 
> What's more, I don't think that Arnd's advice is correct here - DT is
> suppose to describe hardware or firmware. These properties are coming
> from firmware but they are not describing any firmware or hardware
> characteristics. Instead they are debugging of current boot status.
> 
> I will leave the decision on that for Rob, however anyway binding is
> very vague and incorrect, so I would expect he will come with the same
> concerns regardless whether it is suitable to DT or is not.

My main concern here is not so much having this info in DT, but whether 
it's just the start of various properties. Either because there's already 
more data and these are just the 2 things you care about now, or because 
once we enable this it's an invitation to add more properties.

Boot timing information seems like something multiple platforms might 
want and only having 2 stages isn't extensible.

Rob
  

On 05/07/2023 22:30, Rob Herring wrote:
> On Wed, Jul 05, 2023 at 11:34:35AM +0200, Krzysztof Kozlowski wrote:
>> On 05/07/2023 10:33, Souradeep Chowdhury wrote:
>>>>> +    $ref: /schemas/types.yaml#/definitions/string-array
>>>>> +
>>>>> +  abl-time:
>>>>> +    description: The property to store the duration of abl in ms.
>>>>> +    $ref: /schemas/types.yaml#/definitions/string-array
>>>>
>>>> I have no clue what this entire binding is about. Nothing can bind to
>>>> it, no usage explained. Properties are not used to "store the duration".
>>>> This does not look like suitable for DT, drop entire binding.
>>>
>>> This binding was created as per the suggestion on version 6 of the patch
>>> by Arnd. The idea was that these 2 devicetree properties will be used to
>>> populate the bootstat values from the bootloader and exposed to the user
>>> via /sys/firmware/devicetree/ directly.
>>>
>>> Details in the link below:-
>>>
>>> https://lore.kernel.org/lkml/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/T/#mbdc9ad95fcbb5ad7b56c6996a3933899b42d982c
>>>
>>> Can you suggest any alternative way to represent this as a binding?
>>
>> Then you should clearly state in the binding how this is going to be
>> used and who is going to populate it. Not only in the binding but also
>> in commit msg which currently has 0 rationale and answers to "why". Your
>> commit msg explained only "what", which is usually obvious and much less
>> important. Your commit should stand on its own and should clearly
>> explain why we need this feature at all, what problem it solves.
>>
>> And before you claim that there is some discussion under link or some
>> cover letter - these do not matter. Commit and bindings matter.
>>
>> What's more, I don't think that Arnd's advice is correct here - DT is
>> suppose to describe hardware or firmware. These properties are coming
>> from firmware but they are not describing any firmware or hardware
>> characteristics. Instead they are debugging of current boot status.
>>
>> I will leave the decision on that for Rob, however anyway binding is
>> very vague and incorrect, so I would expect he will come with the same
>> concerns regardless whether it is suitable to DT or is not.
> 
> My main concern here is not so much having this info in DT, but whether
> it's just the start of various properties. Either because there's already
> more data and these are just the 2 things you care about now, or because
> once we enable this it's an invitation to add more properties.
> 
> Boot timing information seems like something multiple platforms might
> want and only having 2 stages isn't extensible.

I preferred the previous implementation idea, where the Linux driver 
will parse firmware data, instead of bootloader doing something for us.

Not to mention that that approach would allow us to get boot time stats 
on older platforms, without waiting (indefinitely) for the platform 
vendor to update the bootloader.

> 
> Rob
  

On 7/6/2023 2:44 AM, Dmitry Baryshkov wrote:
> On 05/07/2023 22:30, Rob Herring wrote:
>> On Wed, Jul 05, 2023 at 11:34:35AM +0200, Krzysztof Kozlowski wrote:
>>> On 05/07/2023 10:33, Souradeep Chowdhury wrote:
>>>>>> +    $ref: /schemas/types.yaml#/definitions/string-array
>>>>>> +
>>>>>> +  abl-time:
>>>>>> +    description: The property to store the duration of abl in ms.
>>>>>> +    $ref: /schemas/types.yaml#/definitions/string-array
>>>>>
>>>>> I have no clue what this entire binding is about. Nothing can bind to
>>>>> it, no usage explained. Properties are not used to "store the 
>>>>> duration".
>>>>> This does not look like suitable for DT, drop entire binding.
>>>>
>>>> This binding was created as per the suggestion on version 6 of the 
>>>> patch
>>>> by Arnd. The idea was that these 2 devicetree properties will be 
>>>> used to
>>>> populate the bootstat values from the bootloader and exposed to the 
>>>> user
>>>> via /sys/firmware/devicetree/ directly.
>>>>
>>>> Details in the link below:-
>>>>
>>>> https://lore.kernel.org/lkml/7d397e67-5d56-4975-98af-1ac9746c07f4@app.fastmail.com/T/#mbdc9ad95fcbb5ad7b56c6996a3933899b42d982c
>>>>
>>>> Can you suggest any alternative way to represent this as a binding?
>>>
>>> Then you should clearly state in the binding how this is going to be
>>> used and who is going to populate it. Not only in the binding but also
>>> in commit msg which currently has 0 rationale and answers to "why". Your
>>> commit msg explained only "what", which is usually obvious and much less
>>> important. Your commit should stand on its own and should clearly
>>> explain why we need this feature at all, what problem it solves.
>>>
>>> And before you claim that there is some discussion under link or some
>>> cover letter - these do not matter. Commit and bindings matter.
>>>
>>> What's more, I don't think that Arnd's advice is correct here - DT is
>>> suppose to describe hardware or firmware. These properties are coming
>>> from firmware but they are not describing any firmware or hardware
>>> characteristics. Instead they are debugging of current boot status.
>>>
>>> I will leave the decision on that for Rob, however anyway binding is
>>> very vague and incorrect, so I would expect he will come with the same
>>> concerns regardless whether it is suitable to DT or is not.
>>
>> My main concern here is not so much having this info in DT, but whether
>> it's just the start of various properties. Either because there's already
>> more data and these are just the 2 things you care about now, or because
>> once we enable this it's an invitation to add more properties.
>>
>> Boot timing information seems like something multiple platforms might
>> want and only having 2 stages isn't extensible.
> 
> I preferred the previous implementation idea, where the Linux driver 
> will parse firmware data, instead of bootloader doing something for us.
> 
> Not to mention that that approach would allow us to get boot time stats 
> on older platforms, without waiting (indefinitely) for the platform 
> vendor to update the bootloader.
> 
>>
>> Rob

Hi Rob/Krzysztof/Arnd,

We will work on describing the bindings better but can you first give us
clarity on whether this is something that should be represented on the
devicetree and what should be the final approach we need to take for 
boot_stats?

Thanks,
Souradeep

>