[U-Boot-Users] [PATCH 8/8] New board SIMPC8313 support: nand_boot.c, sdram.c, simpc8313.c

[Stefan Roese]

On Monday 02 June 2008, Scott Wood wrote:
> On Sat, May 31, 2008 at 03:11:27PM +0200, Stefan Roese wrote:
> > One advantage of the current nand_spl subsystem is that it uses the same
> > NAND board/platform driver as the "normal", full blown U-Boot NAND
> > subsystem does. So there is no need to maintain multiple NAND drivers for
> > one board/platform.
>
> The elbc nand driver alone is over 4K, so that's not going to work.  It
> could be cut down a bit by removing erase/program support, and only
> supporting the page size present on the target hardware,

Too bad.

> but even then I'd 
> rather use the space for things like SPD-based SDRAM initialization.

Are you talking about a full-blown I2C SPD DIMM detection and 
autoconfiguration? The code I know from 4xx is much too complicated and big 
for a 4k NAND booting image.

> > So again, please try to use the current nand_spl infrastructure. Or at
> > least explain why it doesn't work for you, so that we can work on these
> > problems.
>
> The NAND controller on the 8313 exposes a very different programming
> interface than what nand_spl expects.  I don't think there's much that
> could be re-used, other than the high-level functions like nand_load().

Isn't there a chance to change those NAND handling functions (like 
nand_read_page()) in nand_boot.c to be more flexible, that they can be used 
by "different" NAND drivers too? Could be that we need to simplify the 
current implementation somehow. Perhaps to use something as you did in your 
implementation like nand_read_next_block() instead of this nand_read_page(). 
Addressing arbitrary blocks/pages seems not needed and could cut down the 
current code quite a bit.

I would really like to avoid that all newer NAND booting platforms (and I 
expact there will come more and more in the near future), to implement their 
own NAND loading routines.

Best regards,
Stefan

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