The plat_core_pos_by_mpidr() implementation for the Arm FPGA port has
some issues, which leads to problems when matching GICv3 redistributors
with cores:
- The power domain tree was not taking multithreading into account, so
  we ended up with the wrong mapping between MPIDRs and core IDs.
- Before even considering an MPIDR, we try to make sure Aff2 is 0.
  Unfortunately this is the cluster ID when the MT bit is set.
- We mask off the MT bit in MPIDR, before basing decisions on it.
- When detecting the MT bit, we are properly calculating the thread ID,
  but don't account for the shift in the core and cluster ID checks.

Those problems lead to early rejections of MPIDRs values, in particular
when called from the GIC code. As a result, CPU_ON for secondary cores
was failing for most of the cores.

Fix this by properly handling the MT bit in plat_core_pos_by_mpidr(),
also pulling in FPGA_MAX_PE_PER_CPU when populating the power domain
tree.

Change-Id: I71b2255fc0d27bfe5806511df479ab38e4e33fc4
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

This adds a basic PSCI implementation allow secondary CPUs to be
released from an initial state and continue through to the warm boot
entrypoint.

Each secondary CPU is kept in a holding pen, whereby it polls the value
representing its hold state, by reading this from an array that acts as
a table for all the PEs. The hold states are initially set to 0 for all
cores to indicate that the executing core should continue polling.
To prevent the secondary CPUs from interfering with the platform's
initialization, they are only updated by the primary CPU once the cold
boot sequence has completed and fpga_pwr_domain_on(mpidr) is called.
The polling target CPU will then read 1 (which indicates that it should
branch to the warm reset entrypoint) and then jump to that address
rather than continue polling.

In addition to the initial polling behaviour of the secondary CPUs
before their warm boot reset sequence, they are also placed in a
low-power wfe() state at the end of each poll; accordingly, the PSCI
fpga_pwr_domain_on(mpidr) function also signals an event to all cores
(after updating the target CPU's hold entry) to wake them from this
state, allowing any secondary CPUs that are still polling to check
their hold state again.
This method is in accordance with both the PSCI and Linux kernel
recommendations, as the lessened overhead reduces the energy
consumption associated with the busy-loop.

The table of hold entries is implemented by a global array as shared SRAM
(which is used by other platforms in similar implementations) is not
available on the FPGA images.

Signed-off-by: Oliver Swede <oli.swede@arm.com>
Change-Id: I65cfd1892f8be1dfcb285f0e1e94e7a9870cdf5a

This adds the minimal functions and definitions to create a basic
BL31 port for an initial FPGA image, in order for the port to be
uploaded to one the FPGA boards operated by an internal group within
Arm, such that BL31 runs as a payload for an image.

Future changes will enable the port for a wide range of system
configurations running on the FPGA boards to ensure compatibility with
multiple FPGA images.

It is expected that this will replace the FPGA fork of the Linux kernel
bootwrapper by performing similar secure-world initialization and setup
through the use of drivers and other well-established methods, before
passing control to the kernel, which will act as the BL33 payload and
run in EL2NS.

This change introduces a basic, loadable port with the console
initialized by setting the baud rate and base address of the UART as
configured by the Zeus image.

It is a BL31-only port, and RESET_TO_BL31 is enabled to reflect this.

Signed-off-by: Oliver Swede <oli.swede@arm.com>
Change-Id: I1817ad81be00afddcdbbda1ab70eb697203178e2