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SubjectRe: [PATCH v3 5/9] mtd: pxa3xx_nand: add support for the Marvell Berlin nand controller
Thomas,

On Thu, Mar 05, 2015 at 02:00:00PM +0100, Thomas Petazzoni wrote:
> On Thu, 5 Mar 2015 12:31:21 +0100, Antoine Tenart wrote:
>
> > struct pxa3xx_nand_host {
> > @@ -253,6 +258,12 @@ static struct pxa3xx_nand_flash builtin_flash_types[] = {
> > { "512MiB 8-bit", 0xdc2c, 64, 2048, 8, 8, 4096 },
> > { "512MiB 16-bit", 0xcc2c, 64, 2048, 16, 16, 4096 },
> > { "256MiB 16-bit", 0xba20, 64, 2048, 16, 16, 2048 },
> > +{ }
> > +};
> > +
> > +static struct pxa3xx_nand_flash berlin_builtin_flash_types[] = {
> > +{ "4GiB 8-bit", 0xd7ec, 128, 8192, 8, 8, 4096 },
> > +{ },
>
> This looks fishy. You know have two different definitions for the exact
> same chip_id. In the builtin_flash_types[] array:
>
> { "4GiB 8-bit", 0xd7ec, 128, 4096, 8, 8, 8192 },
>
> and in your new berlin_builtin_flash_types[] array:
>
> { "4GiB 8-bit", 0xd7ec, 128, 8192, 8, 8, 4096 },
>
> So you have twice a big pages, and twice as less blocks. Are you sure
> about your definition of the 0xd7ec NAND chip_id ?
>
> Why cannot you use the same data for both the Berlin platform and the
> platforms already supported by the driver? Are you sure your NAND isn't
> using 4k pages ? Or maybe the 0xd7ec entry in builtin_flash_types[] is
> incorrect?
>
> Or maybe like
> http://lists.infradead.org/pipermail/linux-mtd/2010-June/031159.html,
> the NAND chip_id is the same, but the NAND ext id is different.
>
> Is there no common NAND mechanism to handle this, rather than having
> this specifically in the driver?

I totally agree, this is one more thing wrong with this driver. Using a
ext id would solve the issue here.

If a NULL table is given to the nand_get_flash_type() function, then the
nand_flash_ids is used. This should be handled this way.

Antoine

--
Antoine Ténart, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com


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