Re: [PATCH] ARM: OMAP2+: l2c: squelch warning dump on power control setting

[Tony Lindgren <tony@atomide.com>]

* Russell King - ARM Linux <linux@arm.linux.org.uk> [140707 05:17]:
> On Mon, Jul 07, 2014 at 05:20:27PM +0530, Sekhar Nori wrote:
> > OMAP4430 had L2 cache controller version r2p0 (per the public TRM) which
> > does not have this register. So unless there is a ROM API that was
> > introduced after OMAP4430, this would not be there even for other
> > OMAP4s. Public TRM of OMAP4470 does not indicate an API for this.
> > 
> > Before creating the patch, I checked with ROM team handling AM437x and
> > they denied an API to write to this register was present in AM437x ROM.
> 
> Okay, so why are we trying to write to this register then...
> 
> Ah, we have a bug in cache-l2x0.c:
> 
> #define L2X0_CACHE_ID_PART_MASK         (0xf << 6)
> #define L2X0_CACHE_ID_RTL_MASK          0x3f
> #define L310_CACHE_ID_RTL_R3P0          0x05
> 
>         unsigned rev = readl_relaxed(base + L2X0_CACHE_ID) & L2X0_CACHE_ID_PART_MASK;
> 
>         if (rev >= L310_CACHE_ID_RTL_R2P0) {
> ...
>         if (rev >= L310_CACHE_ID_RTL_R3P0) {
>                 l2c_write_sec(L310_DYNAMIC_CLK_GATING_EN | L310_STNDBY_MODE_EN,
>                               base, L310_POWER_CTRL);
> 
> So, because we're masking the wrong bits, we end up with these tests
> always succeeding.
> 
> So that's a NACK for the original patch, it's the wrong fix.  The
> right fix is to avoid writing this register by fixing the RTL masking.

Okie dokie, dropping the omap specific fix.

Tony