allwinner: Unify platform.mk files ...

For the two different platforms we support in the Allwinner port we
mostly rely on header files covering the differences. This leads to the
platform.mk files in the respective directories to be almost identical.

To avoid further divergence and make sure that one platform doesn't
break accidentally, let's create a shared allwinner-common.mk file and
include that from the platform directory.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

allwinner: Remove references to removed build flags ...

Change-Id: I206478597dd9855d3fe1577e7e2c0fe6d2af1cc5
Tested-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

allwinner: implement system power down on H6 w/ AXP805 ...

The AXP805 PMIC used with H6 is capable of shutting down the system.

Add support for using it to shut down the system power.

The original placeholder power off code is moved to A64 code, as it's
still TODO to implement PMIC operations for A64.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>

allwinner: call PMIC setup code ...

As the ATF may need to do some power initialization on Allwinner
platform with AXP PMICs, call the PMIC setup code in BL31.

Stub of PMIC setup code is added, to prevent undefined reference.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>

allwinner: sun50i_a64: remove unneeded VER_REG offset ...

The relative VER_REG *offset* is the same across all known SoCs, so we
can define this offset near it's user.

Remove it from the memory map.

Reported-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

allwinner: Add security setup ...

Some peripherals are TrustZone aware, so they need to be configured to
be accessible from non-secure world, as we don't need any of them being
exclusive to the secure world.
This affects some clocks, DMA channels and the Secure Peripheral
Controller (SPC). The latter controls access to most devices, but is not
active unless booting with the secure boot fuse burnt.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

allwinner: Add functions to control CPU power/reset ...

sun50i_cpu_on will be used by the PSCI implementation to initialize
secondary cores for SMP. Unfortunately, sun50i_cpu_off is not usable by
PSCI directly, because it is not possible for a CPU to use this function
to power itself down. Power cannot be shut off until the outputs are
clamped, and MMIO does not work once the outputs are clamped.

But at least CPU0 can shutdown the other cores early in the BL31 boot
process and before shutting down the system.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

allwinner: Add Allwinner A64 support ...

The Allwinner A64 SoC is quite popular on single board computers.
It comes with four Cortex-A53 cores in a singe cluster and the usual
peripherals for set-top box/tablet SoC.

The ATF platform target is called "sun50i_a64".

[Andre: adapted to amended directory layout, removed unneeded definitions ]

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>