refactor(psci): absorb psci_power_down_wfi() into common code
The AArch64 and AArch32 variants are not that different so there is no
need for them to be in assembly. They should also not be called from
non-PSCI code as PSCI is smart enough to handle this after platform
hooks. So absorb the functions into common code.
This allows for a tiny bit of optimisation: there will be no branch
(that can be missed or non-cached) to a non-inlineable function. Then in
the terminal case we can call wfi() directly with the application of the
erratum before the loop. And finally in the wakeup case, we don't have
to explicitly clear the errata as that will happen automatically on the
second call of prepare_cpu_pwr_dwn().
The A510 erratum requires a tsb csync before the dsb+wfi combo to turn
the core off. We can do this a little bit earlier in the cpu hook and
relieve common code from the responsibility. EL3 is always a prohibited
region so the buffer will stay empty.
Change-Id: I5f950df3fb7b0736df4ce25a21f78b29896de215
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
diff --git a/lib/psci/psci_common.c b/lib/psci/psci_common.c
index 1021ef6..7c83a79 100644
--- a/lib/psci/psci_common.c
+++ b/lib/psci/psci_common.c
@@ -14,6 +14,7 @@
#include <common/debug.h>
#include <context.h>
#include <drivers/delay_timer.h>
+#include <lib/cpus/cpu_ops.h>
#include <lib/el3_runtime/context_mgmt.h>
#include <lib/extensions/spe.h>
#include <lib/pmf/pmf.h>
@@ -1257,6 +1258,9 @@
}
#endif /* ERRATA_SME_POWER_DOWN */
+ /* ensure write buffer empty */
+ dsbsy();
+
/*
* Execute a wfi which, in most cases, will allow the power controller
* to physically power down this cpu. Under some circumstances that may
@@ -1264,7 +1268,7 @@
* power down.
*/
for (int i = 0; i < 32; i++)
- psci_power_down_wfi();
+ wfi();
/* Wake up wasn't transient. System is probably in a bad state. */
ERROR("Could not power off CPU.\n");
@@ -1278,11 +1282,14 @@
void psci_pwrdown_cpu_end_wakeup(unsigned int power_level)
{
+ /* ensure write buffer empty */
+ dsbsy();
+
/*
- * Usually, will be terminal. In some circumstances the powerdown will
- * be denied and we'll need to unwind
+ * Turn the core off. Usually, will be terminal. In some circumstances
+ * the powerdown will be denied and we'll need to unwind.
*/
- psci_power_down_wfi();
+ wfi();
/*
* Waking up does not require hardware-assisted coherency, but that is
@@ -1290,7 +1297,7 @@
* coherency code from powerdown is a non-trivial effort which isn't
* needed for our purposes.
*/
-#if !FEAT_PABANDON
+#if !FEAT_PABANDON || !defined(__aarch64__)
ERROR("Systems without FEAT_PABANDON shouldn't wake up.\n");
panic();
#else /* FEAT_PABANDON */