[U-Boot] (no subject)

[Stefan Roese]

Hi Wolfgang,

On Sunday 10 October 2010 10:35:36 Wolfgang Denk wrote:
> your commit
> 
> 	commit 8a805df13615667ebdcc9f3a3a6fbf6c7778a992
> 	Author: Stefan Roese <sr at denx.de>
> 	Date:   Thu Sep 16 14:01:53 2010 +0200
> 
> 	    ppc4xx/fdt/flash: Change fdt_fixup_nor_flash_node() to not
> 	    rely on cs size
> 
> breaks building allboards that have both
> CONFIG_FDT_FIXUP_NOR_FLASH_SIZE and CONFIG_SYS_NO_FLASH defined.
> 
> The reason is that CONFIG_FDT_FIXUP_NOR_FLASH_SIZE references
> flash_info[], which is not defined when CONFIG_SYS_NO_FLASH is set.
> 
> Currently this affects especially the sequoia_ramboot configuration.
> 
> In "include/configs/acadia.h" you fixed this like this:
> 
> 124 /*
> 125  * No NOR-flash on Acadia when NAND-booting. We need to undef the
> 126  * NOR device-tree fixup code as well, since flash_info is not defined
> 127  * in this case.
> 128  */
> 129 #define CONFIG_SYS_NO_FLASH             1
> 130 #undef CONFIG_FDT_FIXUP_NOR_FLASH_SIZE
> 131 #endif
> 
> We could obviously do the same for sequoia_ramboot, but I think the
> "fix" for the Acadia boar dis actually not a good idea.
> 
> Why would you completely disable access to the NOR flash just because
> somebody decides to boot fom NAND?

Because NOR is physically not available in this case (see below).

> I think this is a very bad idea.
> I know of many use cases where customers (espeically such without
> access to a BDI3000 like to keep copies of U-Boot both in NOR and in
> NAND, so they can use the altenative copy to recover the system in
> case they happen to corrupt on U-Boot image.
> 
> However, you cannot use the NAND booting version to restore U-Boot in
> Nor when you completely disable all NOR support.
> 
> This needs to be reworked, please.

Acadia is special in respect to NOR/NAND booting. In NAND boot mode NOR is not 
available. It's not accessible at all since the NOR chips select is not 
connected to the SoC in this case. This is different to the "other" APM eval 
boards with NOR & NAND support like Sequoia. Here both flash types are 
available regardless of the boot mode.

sequoia_ramboot definitely needs a different "fix". We do want to support NAND 
and NOR flash when booting from RAM (via debugger etc). I'll take a look at it 
soon.

Cheers,
Stefan

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