rpi4: Determine BL33 entry point at runtime ...

Now that we have the armstub magic value in place, the GPU firmware will
write the kernel load address (and DTB address) into our special page,
so we can always easily access the actual location without hardcoding
any addresses into the BL31 image.

Make the compile-time defined PRELOADED_BL33_BASE macro optional, and
read the BL33 entry point from the magic location, if the macro was not
defined. We do the same for the DTB address.

This also splits the currently "common" definition of
plat_get_ns_image_entrypoint() to be separate between RPi3 and RPi4.

Change-Id: I6f26c0adc6fce2df47786b271c490928b4529abb
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Allow runtime determination of UART base clock rate ...

At the moment the UART input clock rate is hard coded at compile time.
This works as long as the GPU firmware always sets up the same rate,
which does not seem to be true for the Raspberry Pi 4.

In preparation for being able to change this at runtime, add a base
clock parameter to the console setup function. This is still hardcoded
for the Raspberry Pi 3.

Change-Id: I398bc2f1e9b46f7af9a84cb0b33cbe8e78f2d900
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Do prescaler and control setup in C ...

To initialise the arch timer configuration and some clock prescaler, we
need to do two MMIO access *once*, early during boot.

As tempting as it may sound, plat_reset_handler() is not the right place
to do this, as it will be called on every CPU coming up, both for
secondary cores as well as during warmboots. So this access will be done
multiple times, and even during a rich OS' runtime. Whether doing so anyway
is actually harmful is hard to say, but we should definitely avoid this if
possible.

Move the initialisation of these registers to C code in
bl1_early_platform_setup(), where it will still be executed early enough
(before enabling the console), but only once during the whole boot
process.

Change-Id: I081c41a5476d424411411488ff8f633e87d3bcc5
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Rename RPI3_IO_BASE to RPI_IO_BASE ...

The location of the MMIO window is different between a Raspberry Pi 3
and 4: the former has it just below 1GB, the latter below 4GB.
The relative location of the peripherals is mostly compatible though.

To allow sharing code between the two models, let's rename the symbol
used for the MMIO base to the more generic RPI_IO_BASE name.

Change-Id: I3c2762fb30fd56cca743348e79d72ef8c60ddb03
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Move shared rpi3 files into common directory ...

To be able to share code more easily between the existing Raspberry Pi 3
and the upcoming Raspberry Pi 4 platform, move some code which is not
board specific into a "common" directory.

Change-Id: I9211ab2d754b040128fac13c2f0a30a5cc8c7f2c
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Move rng driver to drivers ...

To allow sharing the driver between the RPi3 and RPi4, move the random
number generator driver into the generic driver directory.

Change-Id: Iae94d7cb22c6bce3af9bff709d76d4caf87b14d1
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Move VC mailbox driver into generic drivers directory ...

To allow sharing the driver between the RPi3 and RPi4, move the mailbox
driver into the generic driver directory.

Change-Id: I463e49acf82b02bf004f3d56482b7791f3020bc0
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Move rpi3_hw.h header file to include/rpi_hw.h ...

With the advent of Raspberry Pi 4 support, we need to separate some
board specific headers between the RPi3 and RPi4.
Rename and move the "rpi3_hw.h" header, so that .c files just include
rpi_hw.h, and automatically get the correct version.

Change-Id: I03b39063028d2bee1429bffccde71dddfe2dcde8
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

rpi3: Add "rpi" platform directory ...

With the incoming support for the Raspberry Pi 4 boards, one directory
to serve both versions will not end up well.

Create an additional layer by inserting a "rpi" directory betweeen /plat
and rpi3, so that we can more easily share or separate files between the
two later.

Change-Id: I75adbb054fe7902f34db0fd5e579a55612dd8a5f
Signed-off-by: Andre Przywara <andre.przywara@arm.com>