[U-Boot] [linux-sunxi] Re: PSCI for H3

[Siarhei Siamashka <siarhei.siamashka@gmail.com>]

On Wed, 23 Dec 2015 22:36:19 +0800
Chen-Yu Tsai <wens@csie.org> wrote:

> On Wed, Dec 23, 2015 at 6:14 PM, Siarhei Siamashka
> <siarhei.siamashka@gmail.com> wrote:
> > On Tue, 17 Nov 2015 15:32:30 +0100
> > Jens Kuske <jenskuske@gmail.com> wrote:
> >  
> >> On 16/11/15 07:26, Chen-Yu Tsai wrote:  
> >> > Hi everyone,
> >> >
> >> > I got my Orange Pi PC booting U-boot now, using Hans' sunxi-wip branch that
> >> > includes Jens' patches.
> >> >
> >> > For PSCI and SMP, it seems the H3 follows the structure of previous sun8i SoCs.
> >> > The CPUCFG registers line up. The manual doesn't have the PRCM, so I'll have to
> >> > dig through the SDK.
> >> >
> >> > One other thing is the SMTA, or Secure Memory Touch Arbiter, which we last
> >> > encountered issues with on the A31s. This controls non-secure access to a whole
> >> > bunch of peripherals, which we'll need to enable for Linux to run non-secure.  
> >>
> >> There is also register 0x2f0 in the CCU, it defaults to disabling
> >> non-secure access to all clock registers.
> >>
> >> Jens
> >>  
> >
> > How about just enabling SMP on Allwinner H3 in an old unfashionable way
> > while all these non-secure access limiters are still being under
> > investigation?  
> 
> I'm not against it, though I was considering removing the SMP code.
> 
> BTW, without docs on the PRCM, do we know if the H3 has the same power clamps
> as the A31? FYI the A23 SMP code is the same as A31, just without the power
> clamps.

Yes. I inspected the kernel sources from the Allwinner SDK and it looks
like A31 and H3 are taking exactly the same code path (using the same
ifdef guards everywhere):
https://github.com/allwinner-zh/linux-3.4-sunxi/blob/55599b8209bb7150140e4d45ef460dbff6c876dd/arch/arm/mach-sunxi/include/mach/sun8i/platsmp.h#L124-L139

"SUN8IW1 = A31" and "SUN8IW7 = H3" according to
http://linux-sunxi.org/Allwinner_SoC_Family#2013_naming_scheme_change


I'll also try to see if I can get PSCI working on H3, but it seems to
be a real PITA to debug. Also some parts of the H3 documentation are
missing (PRCM is a good example) and if there happens to be an
undocumented configuration knob responsible to allowing non-secure
access to some important resource, then we hit a brick wall...

-- 
Best regards,
Siarhei Siamashka