From 22f08973f35d3413148168a0a622d7dcd2c2630b Mon Sep 17 00:00:00 2001
From: Soby Mathew <soby.mathew@arm.com>
Date: Tue, 6 Jan 2015 21:36:55 +0000
Subject: [PATCH] Return success if an interrupt is seen during PSCI
CPU_SUSPEND
This patch adds support to return SUCCESS if a pending interrupt is
detected during a CPU_SUSPEND call to a power down state. The check
is performed as late as possible without losing the ability to return
to the caller. This reduces the overhead incurred by a CPU in
undergoing a complete power cycle when a wakeup interrupt is already
pending.
Fixes ARM-Software/tf-issues#102
Change-Id: I1aff04a74b704a2f529734428030d1d10750fd4b
---
include/lib/aarch64/arch_helpers.h | 2 ++
services/std_svc/psci/psci_afflvl_off.c | 8 ++++++++
services/std_svc/psci/psci_afflvl_suspend.c | 14 ++++++++++++++
services/std_svc/psci/psci_main.c | 10 ----------
4 files changed, 24 insertions(+), 10 deletions(-)
diff --git a/include/lib/aarch64/arch_helpers.h b/include/lib/aarch64/arch_helpers.h
index 7d24a5378..65941e6cf 100644
--- a/include/lib/aarch64/arch_helpers.h
+++ b/include/lib/aarch64/arch_helpers.h
@@ -270,6 +270,8 @@ DEFINE_SYSREG_RW_FUNCS(cntvoff_el2)
DEFINE_SYSREG_RW_FUNCS(vpidr_el2)
DEFINE_SYSREG_RW_FUNCS(vmpidr_el2)
+DEFINE_SYSREG_READ_FUNC(isr_el1)
+
/* GICv3 System Registers */
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_sre_el1, ICC_SRE_EL1)
diff --git a/services/std_svc/psci/psci_afflvl_off.c b/services/std_svc/psci/psci_afflvl_off.c
index d1b7e88d7..ceb51f83e 100644
--- a/services/std_svc/psci/psci_afflvl_off.c
+++ b/services/std_svc/psci/psci_afflvl_off.c
@@ -236,5 +236,13 @@ exit:
end_afflvl,
mpidr_nodes);
+ /*
+ * Check if all actions needed to safely power down this cpu have
+ * successfully completed. Enter a wfi loop which will allow the
+ * power controller to physically power down this cpu.
+ */
+ if (rc == PSCI_E_SUCCESS)
+ psci_power_down_wfi();
+
return rc;
}
diff --git a/services/std_svc/psci/psci_afflvl_suspend.c b/services/std_svc/psci/psci_afflvl_suspend.c
index 35f9e4a5a..9ede65d01 100644
--- a/services/std_svc/psci/psci_afflvl_suspend.c
+++ b/services/std_svc/psci/psci_afflvl_suspend.c
@@ -257,6 +257,7 @@ void psci_afflvl_suspend(entry_point_info_t *ep,
int start_afflvl,
int end_afflvl)
{
+ int skip_wfi = 0;
mpidr_aff_map_nodes_t mpidr_nodes;
unsigned int max_phys_off_afflvl;
@@ -280,6 +281,16 @@ void psci_afflvl_suspend(entry_point_info_t *ep,
end_afflvl,
mpidr_nodes);
+ /*
+ * We check if there are any pending interrupts after the delay
+ * introduced by lock contention to increase the chances of early
+ * detection that a wake-up interrupt has fired.
+ */
+ if (read_isr_el1()) {
+ skip_wfi = 1;
+ goto exit;
+ }
+
/*
* Call the cpu suspend handler registered by the Secure Payload
* Dispatcher to let it do any bookeeping. If the handler encounters an
@@ -323,6 +334,7 @@ void psci_afflvl_suspend(entry_point_info_t *ep,
*/
psci_set_max_phys_off_afflvl(PSCI_INVALID_DATA);
+exit:
/*
* Release the locks corresponding to each affinity level in the
* reverse order to which they were acquired.
@@ -330,6 +342,8 @@ void psci_afflvl_suspend(entry_point_info_t *ep,
psci_release_afflvl_locks(start_afflvl,
end_afflvl,
mpidr_nodes);
+ if (!skip_wfi)
+ psci_power_down_wfi();
}
/*******************************************************************************
diff --git a/services/std_svc/psci/psci_main.c b/services/std_svc/psci/psci_main.c
index 7c686949f..91d16f46a 100644
--- a/services/std_svc/psci/psci_main.c
+++ b/services/std_svc/psci/psci_main.c
@@ -161,8 +161,6 @@ int psci_cpu_suspend(unsigned int power_state,
MPIDR_AFFLVL0,
target_afflvl);
- psci_power_down_wfi();
-
/* Reset PSCI power state parameter for the core. */
psci_set_suspend_power_state(PSCI_INVALID_DATA);
return PSCI_E_SUCCESS;
@@ -181,14 +179,6 @@ int psci_cpu_off(void)
*/
rc = psci_afflvl_off(MPIDR_AFFLVL0, target_afflvl);
- /*
- * Check if all actions needed to safely power down this cpu have
- * successfully completed. Enter a wfi loop which will allow the
- * power controller to physically power down this cpu.
- */
- if (rc == PSCI_E_SUCCESS)
- psci_power_down_wfi();
-
/*
* The only error cpu_off can return is E_DENIED. So check if that's
* indeed the case.
--
GitLab