[U-Boot] [RFC PATCH 4/4 v3] mtd: sf: Add CONFIG_SPI_N25Q256A_RESET for software-reset

[Pavel Machek]

On Wed 2014-10-01 21:25:12, Stefan Roese wrote:
> On 01.10.2014 21:04, Jagan Teki wrote:
> >>>>This is needed for the SoCFPGA booting from SPI NOR flash
> >>>>e.g. (N25Q256A). With these changes, the SoCrates can boot and
> >>>>re-boot (reset) from SPI NOR flash without any problems.
> >>>
> >>>
> >>>Seems like your SPI NOR reset logic is buggy. Does any of [1] apply to
> >>>your
> >>>board please?
> >>>
> >>>[1] http://www.rocketboards.org/foswiki/Documentation/SocBoardQspiBoot
> >>
> >>
> >>Yes. This seems to be that case. But I can't change it right now. So this
> >>"solution" with the soft-reset is better than nothing.
> >
> >If this is some think that must require, any possibility to this
> >resetting prior to u-boot?
> >like preloader or in first stage boot loader or something.
> 
> Perhaps I was not clear with the intention of this patch. Its more to show
> how the problem with SPI flash on this platform / board (SoCrates in this
> case) can be solved. So that others have a reference. Thats why I marked it
> as RFC. Its not really meant for inclusion into mainline.
> 
> The real solution is a board rework. If not possible, the preloader should
> be changed. As I don't have access to the preloader code right now, this
> "solution" (I know, its more a hack) didn't seem too bad.

For the record, I do not think preloader is good place for such
workaround. Preloader works with SDRAM, and should load real u-boot as
fast as possible. If it does not need to touch SPI (it does not,
right?) it should not need to work around bugs there.

Actually, if SPI driver is not compiled into the u-boot, kernel will
have to do the workaround.

									Pavel
-- 
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