Add provision to extend CPU operations at more levels
Various CPU drivers in ARM Trusted Firmware register functions to handle
power-down operations. At present, separate functions are registered to
power down individual cores and clusters.
This scheme operates on the basis of core and cluster, and doesn't cater
for extending the hierarchy for power-down operations. For example,
future CPUs might support multiple threads which might need powering
down individually.
This patch therefore reworks the CPU operations framework to allow for
registering power down handlers on specific level basis. Henceforth:
- Generic code invokes CPU power down operations by the level
required.
- CPU drivers explicitly mention CPU_NO_RESET_FUNC when the CPU has no
reset function.
- CPU drivers register power down handlers as a list: a mandatory
handler for level 0, and optional handlers for higher levels.
All existing CPU drivers are adapted to the new CPU operations framework
without needing any functional changes within.
Also update firmware design guide.
Change-Id: I1826842d37a9e60a9e85fdcee7b4b8f6bc1ad043
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/lib/psci/aarch32/psci_helpers.S b/lib/psci/aarch32/psci_helpers.S
index 5a41ff3..9f991df 100644
--- a/lib/psci/aarch32/psci_helpers.S
+++ b/lib/psci/aarch32/psci_helpers.S
@@ -65,22 +65,13 @@
bl do_stack_maintenance
/* ---------------------------------------------
- * Determine how many levels of cache will be
- * subject to cache maintenance. Power level
- * 0 implies that only the cpu is being powered
- * down. Only the L1 data cache needs to be
- * flushed to the PoU in this case. For a higher
- * power level we are assuming that a flush
- * of L1 data and L2 unified cache is enough.
- * This information should be provided by the
- * platform.
+ * Invoke CPU-specifc power down operations for
+ * the appropriate level
* ---------------------------------------------
*/
- cmp r4, #PSCI_CPU_PWR_LVL
- pop {r4,lr}
-
- beq prepare_core_pwr_dwn
- b prepare_cluster_pwr_dwn
+ mov r0, r4
+ pop {r4, lr}
+ b prepare_cpu_pwr_dwn
endfunc psci_do_pwrdown_cache_maintenance