Non-Secure Interrupt support during Standard SMC processing in TSP ...

Implements support for Non Secure Interrupts preempting the
Standard SMC call in EL1. Whenever an IRQ is trapped in the
Secure world we securely handover to the Normal world
to process the interrupt. The normal world then issues
"resume" smc call to resume the previous interrupted SMC call.
Fixes ARM-software/tf-issues#105

Change-Id: I72b760617dee27438754cdfc9fe9bcf4cc024858

Add S-EL1 interrupt handling support in the TSPD ...

This patch adds support in the TSPD for registering a handler for
S-EL1 interrupts. This handler ferries the interrupts generated in the
non-secure state to the TSP at 'tsp_fiq_entry'. Support has been added
to the smc handler to resume execution in the non-secure state once
interrupt handling has been completed by the TSP.

There is also support for resuming execution in the normal world if
the TSP receives a EL3 interrupt. This code is currently unused.

Change-Id: I816732595a2635e299572965179f11aa0bf93b69

Rework 'state' field usage in per-cpu TSP context ...

This patch lays the foundation for using the per-cpu 'state' field in
the 'tsp_context' structure for other flags apart from the power state
of the TSP.

It allocates 2 bits for the power state, introduces the necessary
macros to manipulate the power state in the 'state' field and
accordingly reworks all use of the TSP_STATE_* states.

It also allocates a flag bit to determine if the TSP is handling a
standard SMC. If this flag is set then the TSP was interrupted due to
non-secure or EL3 interupt depending upon the chosen routing
model. Macros to get, set and clear this flag have been added as
well. This flag will be used by subsequent patches.

Change-Id: Ic6ee80bd5895812c83b35189cf2c3be70a9024a6

Reduce deep nesting of header files ...

Reduce the number of header files included from other header
files as much as possible without splitting the files. Use forward
declarations where possible. This allows removal of some unnecessary
"#ifndef __ASSEMBLY__" statements.

Also, review the .c and .S files for which header files really need
including and reorder the #include statements alphabetically.

Fixes ARM-software/tf-issues#31

Change-Id: Iec92fb976334c77453e010b60bcf56f3be72bd3e

Always use named structs in header files ...

Add tag names to all unnamed structs in header files. This
allows forward declaration of structs, which is necessary to
reduce header file nesting (to be implemented in a subsequent
commit).

Also change the typedef names across the codebase to use the _t
suffix to be more conformant with the Linux coding style. The
coding style actually prefers us not to use typedefs at all but
this is considered a step too far for Trusted Firmware.

Also change the IO framework structs defintions to use typedef'd
structs to be consistent with the rest of the codebase.

Change-Id: I722b2c86fc0d92e4da3b15e5cab20373dd26786f

Separate out CASSERT macro into own header ...

Separate out the CASSERT macro out of bl_common.h into its own
header to allow more efficient header inclusion.

Change-Id: I291be0b6b8f9879645e839a8f0dd1ec9b3db9639

Implement late binding for runtime hooks ...

At present SPD power management hooks and BL3-2 entry are implemented
using weak references. This would have the handlers bound and registered
with the core framework at build time, but leaves them dangling if a
service fails to initialize at runtime.

This patch replaces implementation by requiring runtime handlers to
register power management and deferred initialization hooks with the
core framework at runtime. The runtime services are to register the
hooks only as the last step, after having all states successfully
initialized.

Change-Id: Ibe788a2a381ef39aec1d4af5ba02376e67269782

Add Test Secure Payload Dispatcher (TSPD) service ...

This patch adds the TSPD service which is responsible for managing
communication between the non-secure state and the Test Secure Payload
(TSP) executing in S-EL1.

The TSPD does the following:

1. Determines the location of the TSP (BL3-2) image and passes control
   to it for initialization. This is done by exporting the 'bl32_init()'
   function.

2. Receives a structure containing the various entry points into the TSP
   image as a response to being initialized. The TSPD uses this
   information to determine how the TSP should be entered depending on
   the type of operation.

3. Implements a synchronous mechanism for entering into and returning
   from the TSP image. This mechanism saves the current C runtime
   context on top of the current stack and jumps to the TSP through an
   ERET instruction. The TSP issues an SMC to indicate completion of the
   previous request. The TSPD restores the saved C runtime context and
   resumes TSP execution.

This patch also introduces a Make variable 'SPD' to choose the specific
SPD to include in the build. By default, no SPDs are included in the
build.

Change-Id: I124da5695cdc510999b859a1bf007f4d049e04f3
Co-authored-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>