Remove coherent stack usage from the cold boot path

This patch reworks the cold boot path across the BL1, BL2, BL3-1 and BL3-2 boot
loader stages to not use stacks allocated in coherent memory for early platform
setup and enabling the MMU. Stacks allocated in normal memory are used instead.

Attributes for stack memory change from nGnRnE when the MMU is disabled to
Normal WBWA Inner-shareable when the MMU and data cache are enabled. It is
possible for the CPU to read stale stack memory after the MMU is enabled from
another CPUs cache. Hence, it is unsafe to turn on the MMU and data cache while
using normal stacks when multiple CPUs are a part of the same coherency
domain. It is safe to do so in the cold boot path as only the primary cpu
executes it. The secondary cpus are in a quiescent state.

This patch does not remove the allocation of coherent stack memory. That is done
in a subsequent patch.

Change-Id: I12c80b7c7ab23506d425c5b3a8a7de693498f830
Make enablement of the MMU more flexible

This patch adds a 'flags' parameter to each exception level specific function
responsible for enabling the MMU. At present only a single flag which indicates
whether the data cache should also be enabled is implemented. Subsequent patches
will use this flag when enabling the MMU in the warm boot paths.

Change-Id: I0eafae1e678c9ecc604e680851093f1680e9cefa
Remove coherent stack usage from the warm boot path

This patch uses stacks allocated in normal memory to enable the MMU early in the
warm boot path thus removing the dependency on stacks allocated in coherent
memory. Necessary cache and stack maintenance is performed when a cpu is being
powered down and up. This avoids any coherency issues that can arise from
reading speculatively fetched stale stack memory from another CPUs cache. These
changes affect the warm boot path in both BL3-1 and BL3-2.

The EL3 system registers responsible for preserving the MMU state are not saved
and restored any longer. Static values are used to program these system
registers when a cpu is powered on or resumed from suspend.

Change-Id: I8357e2eb5eb6c5f448492c5094b82b8927603784
Remove the concept of coherent stacks

This patch removes the allocation of memory for coherent stacks, associated
accessor function and some dead code which called the accessor function. It also
updates the porting guide to remove the concept and the motivation behind using
stacks allocated in coherent memory.

Fixes ARM-software/tf-issues#198

Change-Id: I00ff9a04f693a03df3627ba39727e3497263fc38
Simplify management of SCTLR_EL3 and SCTLR_EL1

This patch reworks the manner in which the M,A, C, SA, I, WXN & EE bits of
SCTLR_EL3 & SCTLR_EL1 are managed. The EE bit is cleared immediately after reset
in EL3. The I, A and SA bits are set next in EL3 and immediately upon entry in
S-EL1. These bits are no longer managed in the blX_arch_setup() functions. They
do not have to be saved and restored either. The M, WXN and optionally the C
bit are set in the enable_mmu_elX() function. This is done during both the warm
and cold boot paths.

Fixes ARM-software/tf-issues#226

Change-Id: Ie894d1a07b8697c116960d858cd138c50bc7a069
Introduce asm console functions in TF

This patch replaces the pl011 console family of functions
with their equivalents defined in assembly. The baud rate is
defined by the PL011_BAUDRATE macro and IBRD and FBRD values
for pl011 are computed statically. This patch will enable
us to invoke the console functions without the C Runtime Stack.

Change-Id: Ic3f7b7370ded38bf9020bf746b362081b76642c7
Parametrize baudrate and UART clock during console_init()

This patch adds baud rate and UART clock frequency as parameters
to the pl011 driver api console_init(). This allows each platform
to specify UART clock and baud rate according to their specific
hardware implementation.

Fixes ARM-software/tf-issues#215

Change-Id: Id13eef70a1c530e709b34dd1e6eb84db0797ced2
Introduce crash console APIs for crash reporting

This patch introduces platform APIs to initialise and
print a character on a designated crash console.
For the FVP platform, PL011_UART0 is the designated
crash console. The platform porting guide is also updated
to document the new APIs.

Change-Id: I5e97d8762082e0c88c8c9bbb479353eac8f11a66
Implement an assert() callable from assembly code

The patch implements a macro ASM_ASSERT() which can
be invoked from assembly code. When assertion happens,
file name and line number of the check is written
to the crash console.

Fixes ARM-software/tf-issues#95

Change-Id: I6f905a068e1c0fa4f746d723f18df60daaa00a86
Rework the crash reporting in BL3-1 to use less stack

This patch reworks the crash reporting mechanism to further
optimise the stack and code size. The reporting makes use
of assembly console functions to avoid calling C Runtime
to report the CPU state. The crash buffer requirement is
reduced to 64 bytes with this implementation. The crash
buffer is now part of per-cpu data which makes retrieving
the crash buffer trivial.

Also now panic() will use crash reporting if
invoked from BL3-1.

Fixes ARM-software/tf-issues#199

Change-Id: I79d27a4524583d723483165dc40801f45e627da5
Add CPUECTLR_EL1 and Snoop Control register to crash reporting

This patch adds the CPUECTLR_EL1 register and the CCI Snoop Control
register to the list of registers being reported when an unhandled
exception occurs.

Change-Id: I2d997f2d6ef3d7fa1fad5efe3364dc9058f9f22c
Merge pull request #169 from achingupta/ag/tf-issues#198

Ag/tf issues#198
Merge pull request #170 from achingupta/ag/tf-issues#226

Simplify management of SCTLR_EL3 and SCTLR_EL1
Merge pull request #172 from soby-mathew/sm/asm_assert

Introduce asm assert and optimize crash reporting
Rework the TSPD setup code

There is no mechanism which allows the TSPD to specify what SPSR to
use when entering BL3-2 instead of BL3-3. This patch divides the
responsibility between tspd_setup() and tspd_init() for initializing
the TSPD and TSP to support the alternate BL3-2 initialization flow
where BL3-1 handsover control to BL3-2 instead of BL3-3.
SPSR generated by TSPD for TSP is preserved due the new division of
labour which fixes #174.

This patch also moves the cpu_context initialization code from
tspd_setup() to tspd_init() immediately before entering the TSP.
Instead tspd_setup() updates the BL3-2 entrypoint info structure
with the state required for initializing the TSP later.

Fixes  ARM-software/TF-issues#174

Change-Id: Ida0a8a48d466c71d5b07b8c7f2af169b73f96940
Support asynchronous method for BL3-2 initialization

This patch adds support for BL3-2 initialization by asynchronous
method where BL3-1 transfers control to BL3-2 using world switch.
After BL3-2 initialization, it transfers control to BL3-3 via SPD
service handler. The SPD service handler initializes the CPU context
to BL3-3 entrypoint depending on the return function indentifier from
TSP initialization.

Fixes ARM-software/TF-issues#184

Change-Id: I7b135c2ceeb356d3bb5b6a287932e96ac67c7a34