Re: [PATCH v3 1/2] dt-bindings: mtd: amlogic,meson-nand: support fields for boot ROM code

[Arseniy Krasnov]

On 10.04.2024 18:00, Miquel Raynal wrote:
> Hi Arseniy,
> 
> avkrasnov@xxxxxxxxxxxxxxxxx wrote on Wed, 10 Apr 2024 17:48:02 +0300:
> 
>> Hi,
>>
>> On 10.04.2024 13:23, Miquel Raynal wrote:
>>> Hi Arseniy,
>>>
>>> avkrasnov@xxxxxxxxxxxxxxxxx wrote on Tue, 9 Apr 2024 21:10:24 +0300:
>>>   
>>>> Boot ROM code on Meson requires that some pages on NAND must be written
>>>> in special mode: "short" ECC mode where each block is 384 bytes and
>>>> scrambling mode is on. Such pages located with the specified interval
>>>> within specified offset. Both interval and offset are located in the
>>>> device tree and used by driver if 'nand-is-boot-medium' is set for
>>>> NAND chip.
>>>>
>>>> Signed-off-by: Arseniy Krasnov <avkrasnov@xxxxxxxxxxxxxxxxx>
>>>> ---
>>>>  .../bindings/mtd/amlogic,meson-nand.yaml           | 14 ++++++++++++++
>>>>  1 file changed, 14 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
>>>> index 57b6957c8415..b86a1953056b 100644
>>>> --- a/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
>>>> +++ b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
>>>> @@ -64,11 +64,25 @@ patternProperties:
>>>>          items:
>>>>            maximum: 0
>>>>  
>>>> +      amlogic,boot-page-last:
>>>> +        $ref: /schemas/types.yaml#/definitions/uint32
>>>> +        description:
>>>> +          The NFC driver needs this information to select ECC
>>>> +          algorithms supported by the boot ROM.  
>>>
>>> Shall we have a length rather than the last page?  
>>
>> You mean rename it to "amlogic,boot-pages-length" or something like that ? But I think
>> length in bytes is useless here:
>> 1) boot rom needs that only some single pages are written in special mode (and as I see in
>>    vendor's driver it also works in pages).
>> 2) NAND driver operates in pages during write/read such pages.
>>
>> So length in bytes will be converted to pages anyway.
>>
>> What do You think ?
> 
> I didn't talk about units :-)
> 
> Maybe: amlogic,boot-pages would make sense? But pointing at the last
> page seems weird.

Ah ok I see. Got it!

Thanks, Arseniy

> 
> Miquèl