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

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Arseniy Krasnov <avkrasnov@salutedevices.com>
Cc: Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Jerome Brunet <jbrunet@baylibre.com>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	<linux-mtd@lists.infradead.org>, <devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-amlogic@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <oxffffaa@gmail.com>,
	<kernel@sberdevices.ru>
Subject: Re: [PATCH v3 1/2] dt-bindings: mtd: amlogic,meson-nand: support fields for boot ROM code
Date: Wed, 10 Apr 2024 17:00:40 +0200	[thread overview]
Message-ID: <20240410170040.37a59ff6@xps-13> (raw)
In-Reply-To: <588551c9-3426-e623-e2aa-70b040c9324a@salutedevices.com>

Hi Arseniy,

avkrasnov@salutedevices.com wrote on Wed, 10 Apr 2024 17:48:02 +0300:

> Hi,
> 
> On 10.04.2024 13:23, Miquel Raynal wrote:
> > Hi Arseniy,
> > 
> > avkrasnov@salutedevices.com 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@salutedevices.com>
> >> ---
> >>  .../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.

Miquèl

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