Re: [PATCH] arm, omap2, sram: On HS/EMU devices, only 64K internal SRAM is available.

[Heiko Schocher]

Hello Tony,

Am 14.10.2015 um 19:49 schrieb Tony Lindgren:
> * Heiko Schocher <hs@xxxxxxx> [151012 22:58]:
> > Of this, secure content (including PPA) uses initial
> > portion of the SRAM. This chunk is not (and shouldn't
> > be) accessible from the public code.
> >
> > The minimum size of this chunk (0x350) is used in this
> > patch. Available size is rounded off to 63K.
> >
> > Both values would require a change if size of secure
> > content grows beyond 0x350.
>
> Makes sense to me. And something similar is needed at least for
> dm814x to get rid of the imprecise abort during boot with
> commit bbeb92095159 ("ARM: 8422/1: enable imprecise aborts during
> early kernel startup") applied.
>
> Is this needed as a fix to the -rc cycle, or can this wait for
> v4.4?

I need it for an upcoming boards support, so 4.4 is fine for me,
thanks!

bye,
Heiko
> Regards,
>
> Tony
>
>
> > Signed-off-by: Heiko Schocher <hs@xxxxxxx>
> > Signed-off-by: Ayoub Zaki <Ayoub.Zaki@xxxxxxxxxxxx>
> > ---
> >
> >   arch/arm/mach-omap2/sram.c | 25 +++++++++++++++++++++++++
> >   1 file changed, 25 insertions(+)
> >
> > diff --git a/arch/arm/mach-omap2/sram.c b/arch/arm/mach-omap2/sram.c
> > index cd488b8..2e7c00f 100644
> > --- a/arch/arm/mach-omap2/sram.c
> > +++ b/arch/arm/mach-omap2/sram.c
> > @@ -47,6 +47,28 @@
> >
> >   #define GP_DEVICE		0x300
> >
> > +/**
> > + * Size of chunk used by secure content in the HS/EMU devices.
> > + *
> > + * This size is not fixed. It depends upon the implementation of PPA.
> > + * May need to be modified if the size grows.
> > + */
> > +#define AM33XX_HS_HEADER_SIZE   0x0350
> > +
> > +/**
> > + * Start of public SRAM on HS/EMU devices.
> > + */
> > +#define AM33XX_SRAM_PA		0x40300000
> > +#define AM33XX_SRAM_PUB_PA	(AM33XX_SRAM_PA + AM33XX_HS_HEADER_SIZE)
> > +
> > +/**
> > + * Size of public SRAM available on HS/EMU devices.
> > + *
> > + * This size also depends upon AM33XX_HS_HEADER_SIZE.
> > + * Current value is derived from nearest round-off.
> > + */
> > +#define AM33XX_SRAM_PUB_SIZE		0xfc00	/* 63K */
> > +
> >   #define ROUND_DOWN(value,boundary)	((value) & (~((boundary)-1)))
> >
> >   static unsigned long omap_sram_start;
> > @@ -99,6 +121,9 @@ static void __init omap_detect_sram(void)
> >   			} else {
> >   				omap_sram_size = 0x8000; /* 32K */
> >   			}
> > +		} else if (soc_is_am33xx()) {
> > +			omap_sram_start = AM33XX_SRAM_PUB_PA;
> > +			omap_sram_size  = AM33XX_SRAM_PUB_SIZE;
> >   		} else {
> >   			omap_sram_start = OMAP2_SRAM_PUB_PA;
> >   			omap_sram_size = 0x800; /* 2K */
> > --
> > 2.1.0

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