Add APIs to preserve highest affinity level in OFF state
This patch adds APIs to find, save and retrieve the highest affinity level which
will enter or exit from the physical OFF state during a PSCI power management
operation. The level is stored in per-cpu data.
It then reworks the PSCI implementation to perform cache maintenance only
when the handler for the highest affinity level to enter/exit the OFF state is
called.
For example. during a CPU_SUSPEND operation, state management is done prior to
calling the affinity level specific handlers. The highest affinity level which
will be turned off is determined using the psci_find_max_phys_off_afflvl()
API. This level is saved using the psci_set_max_phys_off_afflvl() API. In the
code that does generic handling for each level, prior to performing cache
maintenance it is first determined if the current affinity level matches the
value returned by psci_get_max_phys_off_afflvl(). Cache maintenance is done if
the values match.
This change allows the last CPU in a cluster to perform cache maintenance
independently. Earlier, cache maintenance was started in the level 0 handler and
finished in the level 1 handler. This change in approach will facilitate
implementation of tf-issues#98.
Change-Id: I57233f0a27b3ddd6ddca6deb6a88b234525b0ae6
diff --git a/services/std_svc/psci/psci_setup.c b/services/std_svc/psci/psci_setup.c
index 9e4955d..b49b6e8 100644
--- a/services/std_svc/psci/psci_setup.c
+++ b/services/std_svc/psci/psci_setup.c
@@ -201,6 +201,15 @@
psci_svc_cpu_data.power_state,
PSCI_INVALID_DATA);
+ /*
+ * There is no state associated with the current execution
+ * context so ensure that any reads of the highest affinity
+ * level in a powered down state return PSCI_INVALID_DATA.
+ */
+ set_cpu_data_by_index(linear_id,
+ psci_svc_cpu_data.max_phys_off_afflvl,
+ PSCI_INVALID_DATA);
+
cm_set_context_by_mpidr(mpidr,
(void *) &psci_ns_context[linear_id],
NON_SECURE);