|author||Achin Gupta <email@example.com>||2013-11-26 15:34:12 +0000|
|committer||Dan Handley <firstname.lastname@example.org>||2013-12-05 12:28:50 +0000|
psci: update docs with status of cpu_suspend api
This patch makes changes to the documents to reflect the current state of play of the psci cpu_suspend function. Change-Id: I086509fb75111b6e9f93b7f6dbcd33cc4591b9f3
2 files changed, 38 insertions, 8 deletions
diff --git a/docs/change-log.md b/docs/change-log.md
index 5a9bdb3..4e5b9aa 100644
@@ -59,6 +59,20 @@ Detailed changes since last release
* A restriction in the FVP code which did not allow the non-secure entrypoint
to lie outside the DRAM has been removed.
+* The PSCI CPU_SUSPEND api has been stabilised to an extent where it can be
+ used for entry into power down states with the following restrictions:
+ - Entry into standby states is not supported.
+ - The api is only supported on the AEMv8 Base FVP.
+* The PSCI AFFINITY_INFO api has undergone limited testing on the AEMv8 Base
+ FVP to allow experimental use.
+* Locks corresponding to each affinity level are acquired and released in
+ the correct sequence in the PSCI implementation. Invocation of the PSCI
+ CPU_SUSPEND and CPU_OFF apis simultaneously across cpus & clusters should
+ not result in unexpected behaviour.
ARM Trusted Firmware - version 0.2
diff --git a/docs/user-guide.md b/docs/user-guide.md
index 476fc00..e7efc40 100644
@@ -860,16 +860,32 @@ memory address populated by BL2.
+ - `CPU_SUSPEND`
- The `CPU_ON` and `CPU_OFF` functions implement the warm boot path in ARM
- Trusted Firmware. These are the only functions which have been tested.
- `AFFINITY_INFO` & `PSCI_VERSION` are present but completely untested in
- this version of the software.
- Unsupported PSCI functions that can return, return the `NOT_SUPPORTED`
- (`-1`) error code. Other unsupported PSCI functions that don't return,
- signal an assertion failure.
+ The `CPU_ON`, `CPU_OFF` and `CPU_SUSPEND` functions implement the warm boot
+ path in ARM Trusted Firmware. `CPU_ON` and `CPU_OFF` have undergone testing
+ on all the supported FVPs. `CPU_SUSPEND` & `AFFINITY_INFO` have undergone
+ testing only on the AEM v8 Base FVP. Support for `AFFINITY_INFO` is still
+ experimental. Support for `CPU_SUSPEND` is stable for entry into power down
+ states. Standby states are currently not supported. `PSCI_VERSION` is
+ present but completely untested in this version of the software.
+ Unsupported PSCI functions can be divided into ones that can return
+ execution to the caller and ones that cannot. The following functions
+ return with a error code as documented in the [Power State Coordination
+ Interface PDD] [PSCI].
+ - `MIGRATE` : -1 (NOT_SUPPORTED)
+ - `MIGRATE_INFO_TYPE` : 2 (Trusted OS is either not present or does not
+ require migration)
+ - `MIGRATE_INFO_UP_CPU` : 0 (Return value is UNDEFINED)
+ The following unsupported functions do not return and signal an assertion
+ failure if invoked.
+ - `SYSTEM_OFF`
+ - `SYSTEM_RESET`
BL3-1 returns the error code `-1` if an SMC is raised for any other runtime
service. This behavior is mandated by the [SMC calling convention PDD]