linux-kernel - Re: [PATCH 03/11] dt-bindings: reset: mobileye,eyeq5-reset: add EyeQ6L and EyeQ6H

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a6f91997-bbaf-48fd-9b8d-2bb671cd026b@linaro.org>
Date: Thu, 11 Apr 2024 17:05:22 +0200
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Théo Lebrun <theo.lebrun@...tlin.com>,
 Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 Conor Dooley <conor+dt@...nel.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Philipp Zabel <p.zabel@...gutronix.de>,
 Linus Walleij <linus.walleij@...aro.org>
Cc: linux-mips@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
 linux-gpio@...r.kernel.org,
 Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>,
 Gregory CLEMENT <gregory.clement@...tlin.com>,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
 Tawfik Bayouk <tawfik.bayouk@...ileye.com>
Subject: Re: [PATCH 03/11] dt-bindings: reset: mobileye,eyeq5-reset: add
 EyeQ6L and EyeQ6H

On 11/04/2024 16:04, Théo Lebrun wrote:
> Hello,
> 
> On Thu Apr 11, 2024 at 8:14 AM CEST, Krzysztof Kozlowski wrote:
>> On 10/04/2024 19:12, Théo Lebrun wrote:
>>> Add bindings for EyeQ6L and EyeQ6H reset controllers.
>>>
>>> Some controllers host a single domain, meaning a single cell is enough.
>>> We do not enforce reg-names for such nodes.
>>>
>>> Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
>>> ---
>>>  .../bindings/reset/mobileye,eyeq5-reset.yaml       | 88 ++++++++++++++++++----
>>>  MAINTAINERS                                        |  1 +
>>>  2 files changed, 74 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml b/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml
>>> index 062b4518347b..799bcf15bed9 100644
>>> --- a/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml
>>> +++ b/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml
>>> @@ -4,11 +4,13 @@
>>>  $id: http://devicetree.org/schemas/reset/mobileye,eyeq5-reset.yaml#
>>>  $schema: http://devicetree.org/meta-schemas/core.yaml#
>>>  
>>> -title: Mobileye EyeQ5 reset controller
>>> +title: Mobileye EyeQ reset controller
>>>  
>>>  description:
>>> -  The EyeQ5 reset driver handles three reset domains. Its registers live in a
>>> -  shared region called OLB.
>>> +  EyeQ reset controller handles one or more reset domains. They live in shared
>>> +  regions called OLB. EyeQ5 and EyeQ6L host one OLB each, each with one reset
>>> +  instance. EyeQ6H hosts 7 OLB regions; three of those (west, east,
>>> +  accelerator) host reset controllers. West and east are duplicates.
>>>  
>>>  maintainers:
>>>    - Grégory Clement <gregory.clement@...tlin.com>
>>> @@ -17,27 +19,83 @@ maintainers:
>>>  
>>>  properties:
>>>    compatible:
>>> -    const: mobileye,eyeq5-reset
>>> +    enum:
>>> +      - mobileye,eyeq5-reset
>>> +      - mobileye,eyeq6l-reset
>>> +      - mobileye,eyeq6h-we-reset
>>> +      - mobileye,eyeq6h-acc-reset
>>>  
>>> -  reg:
>>> -    maxItems: 3
>>> +  reg: true
>>
>> Same mistakes. Please open existing bindings with multiple variants,
>> e.g. some Qualcomm, and take a look how it is done there.
> 
> Thanks for the pointer to good example, that is useful! So if we take
> one random binding matching
> Documentation/devicetree/bindings/clock/qcom,*.yaml and that contains
> the "reg-names" string, we see:
> 
>   reg:
>     items:
>       - description: LPASS qdsp6ss register
>       - description: LPASS top-cc register
> 
>   reg-names:
>     items:
>       - const: qdsp6ss
>       - const: top_cc
> 
> I don't understand one thing; this doesn't tell you:
> 
>    You can provide 2 MMIO blocks, which must be qdsp6ss and top_cc.

No, it tells you exactly this, with difference: s/can/must/

> 
> But it tells you:
> 
>    Block zero must be qdsp6ss.
>    Block one must be top_cc.
> 
> If we do that I do not get the point of reg-names; we put more
> information in our devicetree that is in any case imposed.

Same old argument. Order is not flexible. Order is fixed.

Why do you need names? I don't need, it's purely your optional choice.
Maybe you find it more readable, up to you.


> 
> This is why I went with a different approach looking like:
> 
>   reg:
>     minItems: 2
>     maxItems: 2
>   reg-names:
>     minItems: 2
>     maxItems: 2
>     items:
>       enum: [ d0, d1 ]

No, order is fixed.

> 
> I know this is not perfect, but at least you don't enforce an order for
> no reason. If "items: const..." approach should be taken, then I'll
> remove reg-names which bring no benefit.

You can remove it, you can keep it, whatever makes code more readable,
but order is fixed.

Best regards,
Krzysztof