On Thu, Jul 31, 2014 at 3:23 PM, Mark Rutland <mark.rutland@arm.com> wrote:

> On Thu, Jul 31, 2014 at 09:41:10AM +0100, Ganapatrao Kulkarni wrote:
> >    On Wed, Jul 30, 2014 at 9:16 PM, Mark Rutland <[1]
> mark.rutland@arm.com>
> >    wrote:
> >
> >      Hi,
> >      On Wed, Jul 30, 2014 at 04:06:31PM +0100, Robert Richter wrote:
> >      > From: Radha Mohan Chintakuntla <[2]rchintakuntla@cavium.com>
> >      >
> >      > Add initial device tree nodes for Cavium Thunder SoCs with
> support of
> >      > 48 cores and gicv3. The dts file requires further changes, esp.
> for
> >      > pci, gicv3-its and smmu. This changes will be added later together
> >      > with the device drivers.
> >      >
> >      > Signed-off-by: Radha Mohan Chintakuntla <[3]
> rchintakuntla@cavium.com>
> >      > Signed-off-by: Robert Richter <[4]rrichter@cavium.com>
> >      > ---
> >      >  arch/arm64/boot/dts/Makefile         |   1 +
> >      >  arch/arm64/boot/dts/thunder-88xx.dts | 387
> >      +++++++++++++++++++++++++++++++++++
> >      >  2 files changed, 388 insertions(+)
> >      >  create mode 100644 arch/arm64/boot/dts/thunder-88xx.dts
> >      >
> >      > diff --git a/arch/arm64/boot/dts/Makefile
> >      b/arch/arm64/boot/dts/Makefile
> >      > index c52bdb051f66..f8001a62029c 100644
> >      > --- a/arch/arm64/boot/dts/Makefile
> >      > +++ b/arch/arm64/boot/dts/Makefile
> >      > @@ -1,3 +1,4 @@
> >      > +dtb-$(CONFIG_ARCH_THUNDER) += thunder-88xx.dtb
> >      >  dtb-$(CONFIG_ARCH_VEXPRESS) += rtsm_ve-aemv8a.dtb
> foundation-v8.dtb
> >      >  dtb-$(CONFIG_ARCH_XGENE) += apm-mustang.dtb
> >      >
> >      > diff --git a/arch/arm64/boot/dts/thunder-88xx.dts
> >      b/arch/arm64/boot/dts/thunder-88xx.dts
> >      > new file mode 100644
> >      > index 000000000000..4cf20ac9138b
> >      > --- /dev/null
> >      > +++ b/arch/arm64/boot/dts/thunder-88xx.dts
> >      > @@ -0,0 +1,387 @@
> >      > +/*
> >      > + * Cavium Thunder DTS file
> >      > + *
> >      > + * Copyright (C) 2013, Cavium Inc.
> >      > + *
> >      > + * This program is free software; you can redistribute it and/or
> >      > + * modify it under the terms of the GNU General Public License as
> >      > + * published by the Free Software Foundation; either version 2 of
> >      > + * the License, or (at your option) any later version.
> >      > + */
> >      > +/dts-v1/;
> >      > +
> >      > +/* Reserving first 12MB of DDR for firmware */
> >      > +/memreserve/ 0x00000000 0x00c00000;
> >
> >      What exactly is this memreserve intended to protect at runtime?
> >      Yes, this 12 MB is reserved for ATF and UEFI boot and run-time
> services.
>
> If booted as an EFI application Linux will use the UEFI memory map.
> Anything UEFI needs to have kept around will be marked as such, so
> there's no need to memreserve that.
>
> We are loading ATF and UEFI from flash(which is not XIP) within 12MB of
DDR.
 I dont see UEFI stub freeing RAM address where UEFI  image is loaded.



> I was under the impression that the ARM Trusted Firmware didn't need
> anything resident on the non-secure side, so I don't see why that needs
> a memreserve -- Linux should not be able to address anything it has
> resident.
>
We mark RAM used by ATF as secure-RAM, however we don't support
secure/non-secure address aliasing.
i.e, a DRAM address that can be referenced from both a secure PA and a
non-secure PA is not allowed.



>
> >      The only item of runtime firmware I see in use below is PSCI on the
> >      secure side.
> >
> >      How is the kernel booted on this platform? UEFI?
> >
> >    Boot sequence tried is ATF->UEFI->Linux  and ATF->UEFI->GRUB->Linux
>
> As I've just had it explained to me, in either of those cases we should
> enter Linux via the EFI stub. So we should be using the UEFI memory map
> regardless.
>
> Thanks,
> Mark.
>