macronix ONFI nand flash OTP support

[Belisko Marek]

Hi Miquel,

On Thu, Nov 23, 2017 at 10:30 AM, Miquel RAYNAL
<miquel.raynal at free-electrons.com> wrote:
> Hi Marek,
>
>> >>
>> >> I did check nand_do_read_ops function but it's not sending e.g.
>> >> 0x30 which should be at the end of command. I'm using 4.1 kernel
>> >> but checked also 4.14 and no such functionality is added even
>> >> there. Nobody is using OTP area in nand flashes ;) ? Thanks for
>> >> any pointers.
>> >
>> > I suppose you added some tweaks to enable OTP and use
>> > nand_do_read_ops, because there is currently no implementation for
>> > that in the NAND framework (I think there is something in MTD layer
>> > though). But must importantly, nand_do_read_ops basically calls
>> > chip->ecc.read*() which is handled by the controller driver, so
>> > what driver are you using ?
>> >
>> > How (where) did you trace the commands sent to the NAND chip ? For
>> > instance, if you just looked at the arguments of ->cmdfunc(), it is
>> > normal not to see any READSTART (0x30) command as it should be added
>> > automatically later in the function. If the driver implements
>> > ->cmd_ctrl(), you may see there what exactly is sent to the
>> > device.
>> Yes I checked ->cmdfunc() output. I think my changes would be
>> beneficial for other so I'll cook some patches and post for review
>> here.
>
> Can you just tell us what controller driver are you using ?
I'm using omap2 controller (hope that is right answer :))
>
> You may want to have a look at [1], which hare the MTD hooks that I
> guess you could fill with you OTP related read/writes. I think you
> will also need some tweaks in nanddump (or a nandotpdump thing) to
> ease the validation of the implementation.
Yes I know about that. I saw that but implementation for NAND is
missing so maybe make sense to fill it so it will work out of the box?
>
> [1]
> http://elixir.free-electrons.com/linux/latest/source/include/linux/mtd/mtd.h#L314
>
> Thank you,
> Miquèl
>

BR,

marek

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Marek Belisko - OPEN-NANDRA
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