[PATCH] MTD: OMAP2-NAND: Fix partition reading from board info

[Lennert Buytenhek]

On Mon, Aug 04, 2008 at 02:37:34PM -0700, David Brownell wrote:

> > I've never seen CPU endianity being hardwired in any ARM system ever
> > -- but maybe OMAP is different.
> 
> I'll let TI answer that one, since I'm not going to look at docs for
> all the ARM's I've ever used.
> 
> My observation stands *REGARDLESS* of whether endianness was fixed in
> hardware, bootloader, or kernel ... and in any case, with very few
> exceptions (not including OMAP), Linux uses ARMs in LE mode:
> 
>   ~/kernel/linux-2.6/arch/arm/configs$ grep ENDIAN * | egrep -v '#' |egrep -v OHCI
>   ixp2000_defconfig:CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y
>   ixp2000_defconfig:CONFIG_CPU_BIG_ENDIAN=y
>   ixp23xx_defconfig:CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y
>   ixp23xx_defconfig:CONFIG_CPU_BIG_ENDIAN=y
>   ixp4xx_defconfig:CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y
>   ixp4xx_defconfig:CONFIG_CPU_BIG_ENDIAN=y
>   ~/kernel/linux-2.6/arch/arm/configs$  ls | wc -l
>   105
>   ~/kernel/linux-2.6/arch/arm/configs$ 

That's just because not many people ask for BE or use BE -- not
because the LE'ness would be hardwired in hardware as you asserted
earlier.


> To repeat:  there's no point in having the words byteswapped when
> writing, then again when reading, like this driver does.  All that
> does is ensure slow I/O paths.  Were you disagreeing with that main
> point?  Or just quibbling about where any unusual big-endianness
> might come from?

I was responding to your statement that ARM CPU endianity is
hardwired when ARM cores are turned into silicon.