Le sam. 12 mai 2018 à 20:02, Boris Brezillon
<boris.brezillon@xxxxxxxxxxx> a écrit :
On Sat, 12 May 2018 19:42:49 +0200
Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote:
>> >> My motivation is to get rid of this (move it to devicetree):
>> >>
>> >>
>>
https://elixir.bootlin.com/linux/latest/source/arch/mips/jz4740/board-qi_lb60.c#L93
>> >> And enable the support of other boards with custom OOB
layouts.
>> >
>> > Can you list the different layouts you have? I'm pretty sure
>> there's a
>> > pattern. Maybe we can even deduce the layout from the page
size
>> or OOB
>> > size.
>>
>> This is the other layout I have for another ingenic device:
>>
>>
http://projects.qi-hardware.com/index.php/p/qi-kernel/source/tree/od-2011-09-18/arch/mips/jz4740/board-a320.c#L125
>>
>> Page size and OOB size are the same between these two devices.
>
> Indeed. Do you know if there are other kind of layouts in the
wild?
I'm getting a new board in a few weeks, I'll be able to check that
out.
> Note that <layout-id> can be a string, so if each each board is
> defining its own layout, you could specify the board name here.
> Otherwise, if you just have those 2 patterns, you can just name
them
> "contiguous" and "interleaved".
I don't like the idea of adding board-specific data inside the
driver...
I'd prefer to use the method I used in this patch, but inside the
jz4740-nand driver, if you're OK with it.
Please don't. Encoding such detailed description in the DT has almost
always proven to be poor choice. Also, people are likely to get it
wrong, and then you'll have to fix all DTs, while, with a single
unique
ID representing the layout, you can
- re-use existing layouts easily without having to describe everything
again in the DT
- fix the driver without getting in trouble with people who claim
that DT is a stable ABI and don't want to update their DT
So, please just pick user-friendly IDs and add layout definitions in
the driver. If you don't want to leak board info in the driver, then
don't name the layout with the board name. BTW, I still hope you'll
only
have 2 kind of layouts (contiguous and interleaved).
Alright. Thanks for the insights.
-Paul
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
