Add CPU specific power management operations
This patch adds CPU core and cluster power down sequences to the CPU specific
operations framework introduced in a earlier patch. Cortex-A53, Cortex-A57 and
generic AEM sequences have been added. The latter is suitable for the
Foundation and Base AEM FVPs. A pointer to each CPU's operations structure is
saved in the per-cpu data so that it can be easily accessed during power down
seqeunces.
An optional platform API has been introduced to allow a platform to disable the
Accelerator Coherency Port (ACP) during a cluster power down sequence. The weak
definition of this function (plat_disable_acp()) does not take any action. It
should be overriden with a strong definition if the ACP is present on a
platform.
Change-Id: I8d09bd40d2f528a28d2d3f19b77101178778685d
diff --git a/docs/porting-guide.md b/docs/porting-guide.md
index 262de73..0a07bff 100644
--- a/docs/porting-guide.md
+++ b/docs/porting-guide.md
@@ -473,6 +473,18 @@
The default implementation doesn't do anything.
+### Function : plat_disable_acp()
+
+ Argument : void
+ Return : void
+
+This api allows a platform to disable the Accelerator Coherency Port (if
+present) during a cluster power down sequence. The default weak implementation
+doesn't do anything. Since this api is called during the power down sequence,
+it has restrictions for stack usage and it can use the registers x0 - x17 as
+scratch registers. It should preserve the value in x18 register as it is used
+by the caller to store the return address.
+
3. Modifications specific to a Boot Loader stage
-------------------------------------------------