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_afflvl_suspend.c b/services/std_svc/psci/psci_afflvl_suspend.c
index 4fb640a..54f2634 100644
--- a/services/std_svc/psci/psci_afflvl_suspend.c
+++ b/services/std_svc/psci/psci_afflvl_suspend.c
@@ -193,10 +193,9 @@
/*
* Arch. management: Flush all levels of caches to PoC if the
- * cluster is to be shutdown
+ * cluster is to be shutdown.
*/
- if (plat_state == PSCI_STATE_OFF)
- dcsw_op_all(DCCISW);
+ psci_do_pwrdown_cache_maintenance(MPIDR_AFFLVL1);
/*
* Plat. Management. Allow the platform to do its cluster
@@ -242,6 +241,12 @@
plat_state = psci_get_phys_state(system_node);
/*
+ * Arch. management: Flush all levels of caches to PoC if the
+ * system is to be shutdown.
+ */
+ psci_do_pwrdown_cache_maintenance(MPIDR_AFFLVL2);
+
+ /*
* Plat. Management : Allow the platform to do its bookeeping
* at this affinity level
*/
@@ -333,6 +338,7 @@
{
int rc = PSCI_E_SUCCESS;
mpidr_aff_map_nodes_t mpidr_nodes;
+ unsigned int max_phys_off_afflvl;
/*
* Collect the pointers to the nodes in the topology tree for
@@ -365,6 +371,15 @@
end_afflvl,
mpidr_nodes,
PSCI_STATE_SUSPEND);
+
+ max_phys_off_afflvl = psci_find_max_phys_off_afflvl(start_afflvl,
+ end_afflvl,
+ mpidr_nodes);
+ assert(max_phys_off_afflvl != PSCI_INVALID_DATA);
+
+ /* Stash the highest affinity level that will be turned off */
+ psci_set_max_phys_off_afflvl(max_phys_off_afflvl);
+
/* Perform generic, architecture and platform specific handling */
rc = psci_call_suspend_handlers(mpidr_nodes,
start_afflvl,
@@ -374,6 +389,13 @@
power_state);
/*
+ * Invalidate the entry for the highest affinity level stashed earlier.
+ * This ensures that any reads of this variable outside the power
+ * up/down sequences return PSCI_INVALID_DATA.
+ */
+ psci_set_max_phys_off_afflvl(PSCI_INVALID_DATA);
+
+ /*
* Release the locks corresponding to each affinity level in the
* reverse order to which they were acquired.
*/