Remove concept of top/bottom image loading

This concept is no longer required since we now support loading of
images at fixed addresses only.

The image loader now automatically detects the position of the image
inside the current memory layout and updates the layout such that
memory fragmentation is minimised.

The 'attr' field of the meminfo data structure, which used to hold
the bottom/top loading information, has been removed. Also the 'next'
field has been removed as it wasn't used anywhere.

The 'init_bl2_mem_layout()' function has been moved out of common
code and put in BL1-specific code. It has also been renamed into
'bl1_init_bl2_mem_layout'.

Fixes ARM-software/tf-issues#109

Change-Id: I3f54642ce7b763d5ee3b047ad0ab59eabbcf916d
fvp: Properly detect the location of BL1 R/W data

There was already a rudimentary mechanism to detect whether BL1
R/W data was loaded at the top or bottom of memory. Basically,
 - either BL1 was loaded at the very end of the trusted RAM
 - in all other cases BL1 was considered sitting at the bottom of
   the memory and the memory usage structure was updated accordingly,
   potentially resulting in critical memory waste.
For instance, if BL1 R/W base address was set to
(TZRAM_END - 4096 - bl1_size), it would virtually occupy the whole
memory.

This patch improves the mechanism to detect the location of BL1
to avoid such scenarios.

Change-Id: I224a9edf0fe8d34208545d84b28b63f2bb830d03
Calculate TCR bits based on VA and PA

Currently the TCR bits are hardcoded in xlat_tables.c. In order to
map higher physical address into low virtual address, the TCR bits
need to be configured accordingly.

This patch is to save the max VA and PA and calculate the TCR.PS/IPS
and t0sz bits in init_xlat_tables function.

Change-Id: Ia7a58e5372b20200153057d457f4be5ddbb7dae4
Refactor fvp_config into common platform header

Changed the fvp_config array in fvp_common.c into a struct and
moved into a new optional common platform header,
include/plat/common/plat_config.h. Removed the config definitions
in fvp_def.h and updated all references to the platform config.

This makes the interface to the platform config cleaner and uses
a little less RAM.

Fixes ARM-software/tf-issues#180

Change-Id: I58dd7b3c150f24f7ee230a26fd57c827853ba803
Refactor fvp gic code to be a generic driver

Refactor the FVP gic code in plat/fvp/fvp_gic.c to be a generic ARM
GIC driver in drivers/arm/gic/arm_gic.c. Provide the platform
specific inputs in the arm_gic_setup() function so that the driver
has no explicit dependency on platform code.

Provide weak implementations of the platform interrupt controller
API in a new file, plat/common/plat_gic.c. These simply call through
to the ARM GIC driver.

Move the only remaining FVP GIC function, fvp_gic_init() to
plat/fvp/aarch64/fvp_common.c and remove plat/fvp/fvp_gic.c

Fixes ARM-software/tf-issues#182

Change-Id: Iea82fe095fad62dd33ba9efbddd48c57717edd21
Allow FP register context to be optional at build time

CTX_INCLUDE_FPREGS make variable allows us to include or exclude FP
registers from context structure, in case FP is not used by TSPD.

Fixes ARM-software/tf-issues#194

Change-Id: Iee41af382d691340c7ae21830ad1bbf95dad1f4b
Merge pull request #161 from danh-arm/lm/calc-tcr-bits

Calculate TCR bits based on VA and PA
Merge pull request #146 from danh-arm/dh/refactor-fvp-gic

Refactor fvp config and gic code
Merge pull request #157 from sandrine-bailleux/sb/tf-issue-109

TF issue 109
fvp: Reuse BL1 and BL2 memory through image overlaying

This patch re-organizes the memory layout on FVP as to give the
BL3-2 image as much memory as possible.

Considering these two facts:
 - not all images need to live in memory at the same time. Once
   in BL3-1, the memory used by BL1 and BL2 can be reclaimed.
 - when BL2 loads the BL3-1 and BL3-2 images, it only considers the
   PROGBITS sections of those 2 images. The memory occupied by the
   NOBITS sections will be touched only at execution of the BL3-x
   images;
Then it is possible to choose the different base addresses such that
the NOBITS sections of BL3-1 and BL3-2 overlay BL1 and BL2.

On FVP we choose to put:
 - BL1 and BL3-1 at the top of the Trusted RAM, with BL3-1 NOBITS
   sections overlaying BL1;
 - BL3-2 at the bottom of the Trusted RAM, with its NOBITS sections
   overlaying BL2;

This is illustrated by the following diagram:

0x0404_0000 ------------    ------------------
            |   BL1    | <= |  BL3-1 NOBITS  |
            ------------ <= ------------------
            |          | <= | BL3-1 PROGBITS |
            ------------    ------------------
            |   BL2    | <= |  BL3-2 NOBITS  |
            ------------ <= ------------------
            |          | <= | BL3-2 PROGBITS |
0x0400_0000 ------------    ------------------

New platform-specific constants have been introduced to easily check
at link time that BL3-1 and BL3-2 PROGBITS sections don't overwrite
BL1 and BL2. These are optional and the platform code is free to define
them or not. If not defined, the linker won't attempt to check
image overlaying.

Fixes ARM-software/tf-issues#117

Change-Id: I5981d1c3d66ee70eaac8bd052630c9ac6dd8b042
Add support for BL3-0 image

 - Add support for loading a BL3-0 image in BL2. Information about
   memory extents is populated by platform-specific code. Subsequent
   handling of BL3-0 is also platform specific.
   The BL2 main function has been broken down to improve readability.
   The BL3-2 image is now loaded before the BL3-3 image to align with
   the boot flow.

 - Build system: Add support for specifying a BL3-0 image that will be
   included into the FIP image.

 - IO FIP driver: Add support for identifying a BL3-0 image inside a
   FIP image.

 - Update the documentation to reflect the above changes.

Change-Id: I067c184afd52ccaa86569f13664757570c86fc48
Update the documentation about the memory layout on FVP

Update the "Memory layout on FVP platforms" section in the Firmware
Design document to reflect the overlaying of BL1 and BL2 images
by BL3-1 and BL3-2.

Also update the Porting Guide document to mention the
BL31_PROGBITS_LIMIT and BL32_PROGBITS_LIMIT constants.

Change-Id: I0b23dae5b5b4490a01be7ff7aa80567cff34bda8
Merge pull request #163 from sandrine-bailleux/sb/tf-issue-117-v2

fvp: Reuse BL1 and BL2 memory through image overlaying (v2)
Merge pull request #164 from sandrine-bailleux/sb/bl30-support-v2

Add support for BL3-0 image (v2)
Merge pull request #162 from jcastillo-arm/jc/tf-issues/194

Allow FP register context to be optional at build time