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psci: update docs with status of cpu_suspend api

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This patch makes changes to the documents to reflect the current
state of play of the psci cpu_suspend function.

Change-Id: I086509fb75111b6e9f93b7f6dbcd33cc4591b9f3
This commit is contained in:
Achin Gupta 2013-11-26 15:34:12 +00:00 • committed by Dan Handley
parent 0959db5c99
commit dc98e5370a
2 changed files with 37 additions and 7 deletions
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14
docs/change-log.md
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@ -59,6 +59,20 @@ Detailed changes since last release
* A restriction in the FVP code which did not allow the non-secure entrypoint * A restriction in the FVP code which did not allow the non-secure entrypoint
to lie outside the DRAM has been removed. 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 ARM Trusted Firmware - version 0.2
================================== ==================================

30
docs/user-guide.md
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@ -860,16 +860,32 @@ memory address populated by BL2.
- `PSCI_VERSION` - `PSCI_VERSION`
- `CPU_OFF` - `CPU_OFF`
- `CPU_ON` - `CPU_ON`
- `CPU_SUSPEND`
- `AFFINITY_INFO` - `AFFINITY_INFO`
The `CPU_ON` and `CPU_OFF` functions implement the warm boot path in ARM The `CPU_ON`, `CPU_OFF` and `CPU_SUSPEND` functions implement the warm boot
Trusted Firmware. These are the only functions which have been tested. path in ARM Trusted Firmware. `CPU_ON` and `CPU_OFF` have undergone testing
`AFFINITY_INFO` & `PSCI_VERSION` are present but completely untested in on all the supported FVPs. `CPU_SUSPEND` & `AFFINITY_INFO` have undergone
this version of the software. 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 that can return, return the `NOT_SUPPORTED` Unsupported PSCI functions can be divided into ones that can return
(`-1`) error code. Other unsupported PSCI functions that don't return, execution to the caller and ones that cannot. The following functions
signal an assertion failure. 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 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] service. This behavior is mandated by the [SMC calling convention PDD]