linux-kernel - Re: [PATCH v2 01/16] dt-bindings: dma: qcom,bam: Add bam pipe lock

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Message-ID: <c2292ef2-e93e-4ca3-bcd3-542bd27526ad@kernel.org>
Date: Thu, 22 Aug 2024 08:27:44 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Md Sadre Alam <quic_mdalam@...cinc.com>, vkoul@...nel.org,
 robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
 andersson@...nel.org, konradybcio@...nel.org, thara.gopinath@...il.com,
 herbert@...dor.apana.org.au, davem@...emloft.net, gustavoars@...nel.org,
 u.kleine-koenig@...gutronix.de, kees@...nel.org, agross@...nel.org,
 linux-arm-msm@...r.kernel.org, dmaengine@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-crypto@...r.kernel.org
Cc: quic_srichara@...cinc.com, quic_varada@...cinc.com,
 quic_utiwari@...cinc.com
Subject: Re: [PATCH v2 01/16] dt-bindings: dma: qcom,bam: Add bam pipe lock

On 21/08/2024 18:34, Md Sadre Alam wrote:
> 
> 
> On 8/17/2024 2:38 PM, Krzysztof Kozlowski wrote:
>> On 15/08/2024 10:57, Md Sadre Alam wrote:
>>> BAM having pipe locking mechanism. The Lock and Un-Lock bit
>>> should be set on CMD descriptor only. Upon encountering a
>>> descriptor with Lock bit set, the BAM will lock all other
>>> pipes not related to the current pipe group, and keep
>>> handling the current pipe only until it sees the Un-Lock
>>> set.
>>
>> Please wrap commit message according to Linux coding style / submission
>> process (neither too early nor over the limit):
>> https://elixir.bootlin.com/linux/v6.4-rc1/source/Documentation/process/submitting-patches.rst#L597
>    Ok , will update in next patch.
>>
>>>
>>> Signed-off-by: Md Sadre Alam <quic_mdalam@...cinc.com>
>>> ---
>>>
>>> Change in [v2]
>>>
>>> * Added initial support for dt-binding
>>>
>>> Change in [v1]
>>>
>>> * This patch was not included in [v1]
>>>
>>>   Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml | 8 ++++++++
>>>   1 file changed, 8 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml b/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml
>>> index 3ad0d9b1fbc5..91cc2942aa62 100644
>>> --- a/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml
>>> +++ b/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml
>>> @@ -77,6 +77,12 @@ properties:
>>>         Indicates that the bam is powered up by a remote processor but must be
>>>         initialized by the local processor.
>>>   
>>> +  qcom,bam_pipe_lock:
>>
>> Please follow DTS coding style.
>    Ok
>>
>>> +    type: boolean
>>> +    description:
>>> +      Indicates that the bam pipe needs locking or not based on client driver
>>> +      sending the LOCK or UNLOK bit set on command descriptor.
>>
>> You described the desired Linux feature or behavior, not the actual
>> hardware. The bindings are about the latter, so instead you need to
>> rephrase the property and its description to match actual hardware
>> capabilities/features/configuration etc.
>    Ok, will update in next patch.
>>
>>> +
>>>     reg:
>>>       maxItems: 1
>>>   
>>> @@ -92,6 +98,8 @@ anyOf:
>>>         - qcom,powered-remotely
>>>     - required:
>>>         - qcom,controlled-remotely
>>> +  - required:
>>> +      - qcom,bam_pipe_lock
>>
>> Why is it here? What do you want to achieve?
>    This property added to achieve locking/unlocking
>    of BAM pipe groups for mutual exclusion of resources
>    that can be used across multiple EE's

This explains me nothing. I am questioning the anyOf block. Why this is
the fourth method of controlling BAM? Anyway, if it is, then explain
this in commit msg.

Best regards,
Krzysztof