[PATCH 4/4] ARM: dt: mvebu: ix4-300d: Add ECC properties to NAND flash

Hi Sebastian,
 
 On lun., nov. 30 2015, Sebastian Hesselbarth [off-list ref] wrote:

On 29.11.2015 15:35, Thomas Petazzoni wrote:

quoted

Adding Ezequiel Garcia in Cc.

On Sat, 28 Nov 2015 12:14:08 +0100, Sebastian Hesselbarth wrote:

quoted

The NAND device found on Lenovo ix4-300d uses 4-bit BCH ECC protection.
Add the corresponding properties to the NAND node.

If the ONFI information from the NAND flash say that it requires 4 bits
per 512, then there should be no need to add this information to the
Device Tree as the pxa3xx_nand driver by default uses the ONFI
information.

Thomas,

as said in the cover letter, this is also DT cleanup with barebox
bootloader in mind. I do not accept what Linux' pxa3xx_nand driver
is doing as a reference here ;)

quoted

Those properties are only needed when for some reason the vendor has
chosen to use a ECC strength that doesn't match with the one advertised
by the flash in its ONFI information (either stronger or weaker). But
in this case, your commit log is confusing, because it says that the
"NAND device ... uses 4-bit BCH ECC protection". If it really does,
then the patch is not needed :-)

I agree that if ONFI is already advertising 4/512 ECC (and it is), we
do not need the properties. Anyway, IIRC barebox does not yet properly
parse ONFI or at least it does not derive minimum ECC settings from it.

I'll have to have a closer look at barebox' ONFI parsing capabilites
and can live with this patch not applied even though it does no harm.

So for now, I don't apply it.

Thanks,

Gregory

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com