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

1 files changed, 0 insertions, 51 deletions

diff --git a/docs/porting-guide.md b/docs/porting-guide.md
index 813d0be..2bd1b56 100644
--- a/docs/porting-guide.md
+++ b/docs/porting-guide.md
@@ -104,12 +104,6 @@ file is found in [plat/fvp/include/platform_def.h].
     by [plat/common/aarch64/platform_mp_stack.S] and
     [plat/common/aarch64/platform_up_stack.S].
 
-*   **#define : PCPU_DV_MEM_STACK_SIZE**
-
-    Defines the coherent stack memory available to each CPU. This constant is used
-    by [plat/common/aarch64/platform_mp_stack.S] and
-    [plat/common/aarch64/platform_up_stack.S].
-
 *   **#define : FIRMWARE_WELCOME_STR**
 
     Defines the character string printed by BL1 upon entry into the `bl1_main()`
@@ -395,31 +389,6 @@ maximum of 4 CPUs:
     cluster_id = 8-bit value in MPIDR at affinity level 1
 
 
-### Function : platform_set_coherent_stack()
-
-    Argument : unsigned long
-    Return   : void
-
-A platform may need stack memory that is coherent with main memory to perform
-certain operations like:
-
-*   Turning the MMU on, or
-*   Flushing caches prior to powering down a CPU or cluster.
-
-Each BL stage allocates this coherent stack memory for each CPU in the
-`tzfw_coherent_mem` section.
-
-This function sets the current stack pointer to the coherent stack that
-has been allocated for the CPU specified by MPIDR. For BL images that only
-require a stack for the primary CPU the parameter is ignored. The size of
-the stack allocated to each CPU is specified by the platform defined constant
-`PCPU_DV_MEM_STACK_SIZE`.
-
-Common implementations of this function for the UP and MP BL images are
-provided in [plat/common/aarch64/platform_up_stack.S] and
-[plat/common/aarch64/platform_mp_stack.S]
-
-
 ### Function : platform_is_primary_cpu()
 
     Argument : unsigned long
@@ -1116,11 +1085,6 @@ the calling CPU is the last powered on CPU in the cluster, after powering down
 affinity level 0 (CPU), the platform port should power down affinity level 1
 (the cluster) as well.
 
-This function is called with coherent stacks. This allows the PSCI
-implementation to flush caches at a given affinity level without running into
-stale stack state after turning off the caches. On ARMv8-A cache hits do not
-occur after the cache has been turned off.
-
 #### plat_pm_ops.affinst_suspend()
 
 Perform the platform specific setup to power off an affinity instance in the
@@ -1143,11 +1107,6 @@ case, the affinity instance is expected to save enough state so that it can
 resume execution by restoring this state when its powered on (see
 `affinst_suspend_finish()`).
 
-This function is called with coherent stacks. This allows the PSCI
-implementation to flush caches at a given affinity level without running into
-stale stack state after turning off the caches. On ARMv8-A cache hits do not
-occur after the cache has been turned off.
-
 #### plat_pm_ops.affinst_on_finish()
 
 This function is called by the PSCI implementation after the calling CPU is
@@ -1159,11 +1118,6 @@ services.
 The `MPIDR` (first argument), `affinity level` (second argument) and `state`
 (third argument) have a similar meaning as described in the previous operations.
 
-This function is called with coherent stacks. This allows the PSCI
-implementation to flush caches at a given affinity level without running into
-stale stack state after turning off the caches. On ARMv8-A cache hits do not
-occur after the cache has been turned off.
-
 #### plat_pm_ops.affinst_on_suspend()
 
 This function is called by the PSCI implementation after the calling CPU is
@@ -1176,11 +1130,6 @@ and also provide secure runtime firmware services.
 The `MPIDR` (first argument), `affinity level` (second argument) and `state`
 (third argument) have a similar meaning as described in the previous operations.
 
-This function is called with coherent stacks. This allows the PSCI
-implementation to flush caches at a given affinity level without running into
-stale stack state after turning off the caches. On ARMv8-A cache hits do not
-occur after the cache has been turned off.
-
 BL3-1 platform initialization code must also detect the system topology and
 the state of each affinity instance in the topology. This information is
 critical for the PSCI runtime service to function correctly. More details are