Fix broken standby state implementation in PSCI

This patch fixes the broken support for entry into standby states
introduced under commit-id 'd118f9f864' (tf-issues#94). Upon exit from
the platform defined standby state instead of returning to the caller
of the SMC, execution would get stuck in the wfi instruction meant for
entering a power down state. This patch ensures that exit from a
standby state and entry into a power down state do not interfere with
each other.

Fixes ARM-software/tf-issues#154

Change-Id: I56e5df353368e44d6eefc94ffedefe21929f5cfe
Set SCR_EL3.RW correctly before exiting bl31_main

SCR_EL3.RW was not updated immediately before exiting bl31_main() and
running BL3-3. If a AArch32 Secure-EL1 Payload had just been
initialised, then the SCR_EL3.RW bit would be left indicating a
32-bit BL3-3, which may not be correct.

This patch explicitly sets SCR_EL3.RW appropriately based on the
provided SPSR_EL3 value for the BL3-3 image.

Fixes ARM-software/tf-issues#126

Change-Id: Ic7716fe8bc87e577c4bfaeb46702e88deedd9895
Introduce convenience functions to build

This patch introduces two convenience functions to the build system:

  - assert_boolean: asserts that a given option is assigned either 0 or
    1 as values

  - add_define: helps add/append macro definitions to build tool command
    line. This also introduces the variable DEFINES which is used to
    collect and pass all relevant configurations to build tools

Change-Id: I3126894b034470d39858ebb3bd183bda681c7126
Reorganize build options

At present, various build options are initialized at various places in
the Makefile. This patch gathers all build option declarations at the
top of the Makefile and assigns them default values.

Change-Id: I9f527bc8843bf69c00cb754dc60377bdb407a951
Document summary of build options in user guide

Change-Id: I6bd077955bf3780168a874705974bbe72ea0f5f1
Add build configuration for timer save/restore

At present, non-secure timer register contents are saved and restored as
part of world switch by BL3-1. This effectively means that the
non-secure timer stops, and non-secure timer interrupts are prevented
from asserting until BL3-1 switches back, introducing latency for
non-secure services. Often, secure world might depend on alternate
sources for secure interrupts (secure timer or platform timer) instead
of non-secure timers, in which case this save and restore is
unnecessary.

This patch introduces a boolean build-time configuration NS_TIMER_SWITCH
to choose whether or not to save and restore non-secure timer registers
upon world switch. The default choice is made not to save and restore
them.

Fixes ARM-software/tf-issues#148

Change-Id: I1b9d623606acb9797c3e0b02fb5ec7c0a414f37e
Merge pull request #78 from jeenuv:tf-issues-148
Improve BL3-0 documentation

Provide some information about the expected use of BL3-0.

Fixes ARM-software/tf-issues#144

Change-Id: I5c8d59a675578394be89481ae4ec39ca37522750
Address issue 156: 64-bit addresses get truncated
Addresses were declared as "unsigned int" in drivers/arm/peripherals/pl011/pl011.h and in function init_xlation_table. Changed to use "unsigned long" instead
Fixes ARM-software/tf-issues#156
Merge pull request #85 from hliebel/hl/bl30-doc

Improve BL3-0 documentation
Merge pull request #83 from athoelke/at/tf-issues-126

Set SCR_EL3.RW correctly before exiting bl31_main
Merge pull request #91 from linmaonly/lin_dev

Address issue 156: 64-bit addresses get truncated
Introduce macros to manipulate the SPSR

This patch introduces macros (SPSR_64 and SPSR_32) to
create a SPSR for both aarch32 and aarch64 execution
states. These macros allow the user to set fields
in the SPSR depending upon its format.
The make_spsr() function which did not allow
manipulation of all the fields in the aarch32 SPSR
has been replaced by these new macros.

Change-Id: I9425dda0923e8d5f03d03ddb8fa0e28392c4c61e
Rework handover interface between BL stages

This patch reworks the handover interface from: BL1 to BL2 and
BL2 to BL3-1. It removes the raise_el(), change_el(), drop_el()
and run_image() functions as they catered for code paths that were
never exercised.
BL1 calls bl1_run_bl2() to jump into BL2 instead of doing the same
by calling run_image(). Similarly, BL2 issues the SMC to transfer
execution to BL3-1 through BL1 directly. Only x0 and x1 are used
to pass arguments to BL31. These arguments and parameters for
running BL3-1 are passed through a reference to a
'el_change_info_t' structure. They were being passed value in
general purpose registers earlier.

Change-Id: Id4fd019a19a9595de063766d4a66295a2c9307e1
Populate BL31 input parameters as per new spec

This patch is based on spec published at
https://github.com/ARM-software/tf-issues/issues/133

It rearranges the bl31_args struct into
bl31_params and bl31_plat_params which provide the
information needed for Trusted firmware and platform
specific data via x0 and x1

On the FVP platform BL3-1 params and BL3-1 plat params
and its constituents are stored at the start of TZDRAM.

The information about memory availability and size for
BL3-1, BL3-2 and BL3-3 is moved into platform specific data.

Change-Id: I8b32057a3d0dd3968ea26c2541a0714177820da9
Rework memory information passing to BL3-x images

The issues addressed in this patch are:

1. Remove meminfo_t from the common interfaces in BL3-x,
expecting that platform code will find a suitable mechanism
to determine the memory extents in these images and provide
it to the BL3-x images.

2. Remove meminfo_t and bl31_plat_params_t from all FVP BL3-x
code as the images use link-time information to determine
memory extents.

meminfo_t is still used by common interface in BL1/BL2 for
loading images

Change-Id: I4e825ebf6f515b59d84dc2bdddf6edbf15e2d60f
Add support for BL3-1 as a reset vector

This change adds optional reset vector support to BL3-1
which means BL3-1 entry point can detect cold/warm boot,
initialise primary cpu, set up cci and mail box.

When using BL3-1 as a reset vector it is assumed that
the BL3-1 platform code can determine the location of
the BL3-2 images, or load them as there are no parameters
that can be passed to BL3-1 at reset.

It also fixes the incorrect initialisation of mailbox
registers on the FVP platform

This feature can be enabled by building the code with
make variable RESET_TO_BL31 set as 1

Fixes ARM-software/TF-issues#133
Fixes ARM-software/TF-issues#20

Change-Id: I4e23939b1c518614b899f549f1e8d412538ee570
Reserve some DDR DRAM for secure use on FVP platforms

TZC-400 is configured to set the last 16MB of DRAM1 as secure memory and
the rest of DRAM as non-secure. Non-secure software must not attempt to
access the 16MB secure area.

Device tree files (sources and binaries) have been updated to match this
configuration, removing that memory from the Linux physical memory map.

To use UEFI and Linux with this patch, the latest version of UEFI and
the updated device tree files are required. Check the user guide in the
documentation for more details.

Replaced magic numbers with #define for memory region definition in the
platform security initialization function.

Fixes ARM-software/tf-issues#149

Change-Id: Ia5d070244aae6c5288ea0e6c8e89d92859522bfe
TSP: Let the platform decide which secure memory to use

The TSP's linker script used to assume that the TSP would
execute from secure DRAM. Although it is currently the case
on FVPs, platforms are free to use any secure memory they wish.

This patch introduces the flexibility to load the TSP into any
secure memory. The platform code gets to specify the extents of
this memory in the platform header file, as well as the BL3-2 image
limit address. The latter definition allows to check in a generic way
that the BL3-2 image fits in its bounds.

Change-Id: I9450f2d8b32d74bd00b6ce57a0a1542716ab449c
fvp: Move TSP from Secure DRAM to Secure SRAM

The TSP used to execute from secure DRAM on the FVPs because there was
not enough space in Trusted SRAM to fit it in. Thanks to recent RAM
usage enhancements being implemented, we have made enough savings for
the TSP to execute in SRAM.

However, there is no contiguous free chunk of SRAM big enough to hold
the TSP. Therefore, the different bootloader images need to be moved
around to reduce memory fragmentation. This patch keeps the overall
memory layout (i.e. keeping BL1 R/W at the bottom, BL2 at the top and
BL3-1 in between) but moves the base addresses of all the bootloader
images in such a way that:
 - memory fragmentation is reduced enough to fit BL3-2 in;
 - new base addresses are suitable for release builds as well as debug
   ones;
 - each image has a few extra kilobytes for future growth.
   BL3-1 and BL3-2 are the images which received the biggest slice
   of the cake since they will most probably grow the most.

A few useful numbers for reference (valid at the time of this patch):
        |-----------------------|-------------------------------
        |  image size (debug)   |  extra space for the future
--------|-----------------------|-------------------------------
BL1 R/W |         20 KB         |            4 KB
BL2     |         44 KB         |            4 KB
BL3-1   |        108 KB         |           12 KB
BL3-2   |         56 KB         |            8 KB
--------|-----------------------|-------------------------------
Total   |        228 KB         |           28 KB       = 256 KB
--------|-----------------------|-------------------------------

Although on FVPs the TSP now executes from Trusted SRAM by default,
this patch keeps the option to execute it from Trusted DRAM. This is
controlled by the build configuration 'TSP_RAM_LOCATION'.

Fixes ARM-Software/tf-issues#81

Change-Id: Ifb9ef2befa9a2d5ac0813f7f79834df7af992b94