PSCI: Add SYSTEM_SUSPEND API support

This patch adds support for SYSTEM_SUSPEND API as mentioned in the PSCI 1.0
specification. This API, on being invoked on the last running core on a
supported platform, will put the system into a low power mode with memory
retention.

The psci_afflvl_suspend() internal API has been reused as most of the actions
to suspend a system are the same as invoking the PSCI CPU_SUSPEND API with the
target affinity level as 'system'. This API needs the 'power state' parameter
for the target low power state. This parameter is not passed by the caller of
the SYSTEM_SUSPEND API. Hence, the platform needs to implement the
get_sys_suspend_power_state() platform function to provide this information.
Also, the platform also needs to add support for suspending the system to the
existing 'plat_pm_ops' functions: affinst_suspend() and
affinst_suspend_finish().

Change-Id: Ib6bf10809cb4e9b92f463755608889aedd83cef5

1 files changed, 20 insertions, 11 deletions

diff --git a/docs/porting-guide.md b/docs/porting-guide.md
index 1e49deb8..c09c2656 100644
--- a/docs/porting-guide.md
+++ b/docs/porting-guide.md
@@ -1211,8 +1211,8 @@ affinity level 0 (CPU), the platform port should power down affinity level 1
 #### plat_pm_ops.affinst_suspend()
 
 Perform the platform specific setup to power off an affinity instance of the
-calling CPU. It is called by the PSCI `CPU_SUSPEND` API
-implementation.
+calling CPU. It is called by the PSCI `CPU_SUSPEND` API and `SYSTEM_SUSPEND`
+API implementation
 
 The `affinity level` (second argument) and `state` (third argument) have a
 similar meaning as described in the `affinst_on()` operation. They are used to
@@ -1241,14 +1241,14 @@ The `affinity level` (first argument) and `state` (second argument) have a
 similar meaning as described in the previous operations. The generic code
 expects the handler to succeed.
 
-#### plat_pm_ops.affinst_on_suspend()
+#### plat_pm_ops.affinst_suspend_finish()
 
 This function is called by the PSCI implementation after the calling CPU is
 powered on and released from reset in response to an asynchronous wakeup
 event, for example a timer interrupt that was programmed by the CPU during the
-`CPU_SUSPEND` call. It performs the platform-specific setup required to
-restore the saved state for this CPU to resume execution in the normal world
-and also provide secure runtime firmware services.
+`CPU_SUSPEND` call or `SYSTEM_SUSPEND` call. It performs the platform-specific
+setup required to restore the saved state for this CPU to resume execution
+in the normal world and also provide secure runtime firmware services.
 
 The `affinity level` (first argument) and `state` (second argument) have a
 similar meaning as described in the previous operations. The generic code
@@ -1264,11 +1264,20 @@ world PSCI client.
 
 #### plat_pm_ops.validate_ns_entrypoint()
 
-This function is called by the PSCI implementation during the `CPU_SUSPEND`
-and `CPU_ON` calls to validate the non-secure `entry_point` parameter passed
-by the normal world. If the `entry_point` is known to be invalid, the platform
-must return PSCI_E_INVALID_PARAMS as error, which is propagated back to the
-normal world PSCI client.
+This function is called by the PSCI implementation during the `CPU_SUSPEND`,
+`SYSTEM_SUSPEND` and `CPU_ON` calls to validate the non-secure `entry_point`
+parameter passed by the normal world. If the `entry_point` is known to be
+invalid, the platform must return PSCI_E_INVALID_PARAMS as error, which is
+propagated back to the normal world PSCI client.
+
+#### plat_pm_ops.get_sys_suspend_power_state()
+
+This function is called by the PSCI implementation during the `SYSTEM_SUSPEND`
+call to return the `power_state` parameter. This allows the platform to encode
+the appropriate State-ID field within the `power_state` parameter which can be
+utilized in `affinst_suspend()` to suspend to system affinity level. The
+`power_state` parameter should be in the same format as specified by the
+PSCI specification for the CPU_SUSPEND API.
 
 BL3-1 platform initialization code must also detect the system topology and
 the state of each affinity instance in the topology. This information is