[U-Boot] [PATCH] arm: socfpga: Fix cache configuration

[Marek Vasut <marex@denx.de>]

On Tuesday, December 08, 2015 at 12:13:23 PM, Pavel Machek wrote:

[...]

> > > Thanks for the pointers.
> > > 
> > > I checked the source and enabled the debug message. Noticed my failure
> > > is due to small LEB and PEB size. It was set to 4k which is the sub
> > > -sector erase size of NOR flash. I suspect you didn't hit this as you
> > > generate ubinized image which is 64kB erase size.
> > > 
> > > I will continue to dig more. Need to ensure it works when user create
> > > UBI part in U-Boot on top of serial NOR flash (which is commonly 4kB
> > > erase size). Hopefully existing U-Boot already have source taking care
> > > this :)
> > 
> > I am tempted to revert this patch, since it breaks USB and UBI for me
> > on two different boards though.
> 
> It caused regressions it was not supposed to change. That means
> revert...

I found the bug, it's not a bug in this patch, but it's even broader issue.

Look at arch/arm/lib/cache-cp15.c , the file checks for CONFIG_ARMV7 and only
ifdef CONFIG_ARMV7, then it configures TTBR0. If CONFIG_ARMV7 is not set, it 
configures nothing. But, I cannot find any place for any ARMV7 machine which 
would actually set the CONFIG_ARMV7 option.

I verified this on SoCFPGA and indeed, CONFIG_ARMV7 is not set, so this piece
of code is never executed and thus my cache misbehaves.

I guess the right way to fix this would be to replace #ifdef CONFIG_ARMV7 with
CONFIG_CPU_V7 ? Or shall we add new symbol, CONFIG_ARMV7 and make CONFIG_CPU_V7
select CONFIG_ARMV7 to avoid changing the system.h header, which is most likely
taken from Linux ?

Best regards,
Marek Vasut