CSS: Allow system suspend only via PSCI SYSTEM_SUSPEND API
The CSS power management layer previously allowed to suspend system
power domain level via both PSCI CPU_SUSPEND and PSCI SYSTEM_SUSPEND
APIs. System suspend via PSCI CPU_SUSPEND was always problematic to
support because of issues with targeting wakeup interrupts to
suspended cores before the per-cpu GIC initialization is done. This
is not the case for PSCI SYSTEM_SUSPEND API because all the other
cores are expected to be offlined prior to issuing system suspend and
PSCI CPU_ON explicit calls will be made to power them on. Hence the Juno
platform used to downgrade the PSCI CPU_SUSPEND request for system
power domain level to cluster level by overriding the default
`plat_psci_pm_ops` exported by CSS layer.
Given the direction the new CSS platforms are evolving, it is best to
limit the system suspend only via PSCI SYSTEM_SUSPEND API for all
CSS platforms. This patch makes changes to allow system suspend
only via PSCI SYSTEM_SUSPEND API. The override of `plat_psci_ops`
for Juno is removed.
Change-Id: Idb30eaad04890dd46074e9e888caeedc50a4b533
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/plat/arm/css/common/css_pm.c b/plat/arm/css/common/css_pm.c
index d4dd0af..21ce865 100644
--- a/plat/arm/css/common/css_pm.c
+++ b/plat/arm/css/common/css_pm.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
@@ -75,6 +75,13 @@
CASSERT(PLAT_MAX_PWR_LVL >= ARM_PWR_LVL1,
assert_max_pwr_lvl_supported_mismatch);
+/*
+ * Ensure that the PLAT_MAX_PWR_LVL is not greater than CSS_SYSTEM_PWR_DMN_LVL
+ * assumed by the CSS layer.
+ */
+CASSERT(PLAT_MAX_PWR_LVL <= CSS_SYSTEM_PWR_DMN_LVL,
+ assert_max_pwr_lvl_higher_than_css_sys_lvl);
+
/*******************************************************************************
* Handler called when a power domain is about to be turned on. The
* level and mpidr determine the affinity instance.
@@ -243,7 +250,7 @@
* System Suspend is supported only if the system power domain node
* is implemented.
*/
- assert(PLAT_MAX_PWR_LVL >= ARM_PWR_LVL2);
+ assert(PLAT_MAX_PWR_LVL == CSS_SYSTEM_PWR_DMN_LVL);
for (i = ARM_PWR_LVL0; i <= PLAT_MAX_PWR_LVL; i++)
req_state->pwr_domain_state[i] = ARM_LOCAL_STATE_OFF;
@@ -257,6 +264,39 @@
return css_scp_get_power_state(mpidr, power_level);
}
+/*
+ * The system power domain suspend is only supported only via
+ * PSCI SYSTEM_SUSPEND API. PSCI CPU_SUSPEND request to system power domain
+ * will be downgraded to the lower level.
+ */
+static int css_validate_power_state(unsigned int power_state,
+ psci_power_state_t *req_state)
+{
+ int rc;
+ rc = arm_validate_power_state(power_state, req_state);
+
+ /*
+ * Ensure that the system power domain level is never suspended
+ * via PSCI CPU SUSPEND API. Currently system suspend is only
+ * supported via PSCI SYSTEM SUSPEND API.
+ */
+ req_state->pwr_domain_state[CSS_SYSTEM_PWR_DMN_LVL] = ARM_LOCAL_STATE_RUN;
+ return rc;
+}
+
+/*
+ * Custom `translate_power_state_by_mpidr` handler for CSS. Unlike in the
+ * `css_validate_power_state`, we do not downgrade the system power
+ * domain level request in `power_state` as it will be used to query the
+ * PSCI_STAT_COUNT/RESIDENCY at the system power domain level.
+ */
+static int css_translate_power_state_by_mpidr(u_register_t mpidr,
+ unsigned int power_state,
+ psci_power_state_t *output_state)
+{
+ return arm_validate_power_state(power_state, output_state);
+}
+
/*******************************************************************************
* Export the platform handlers via plat_arm_psci_pm_ops. The ARM Standard
* platform will take care of registering the handlers with PSCI.
@@ -270,7 +310,9 @@
.pwr_domain_suspend_finish = css_pwr_domain_suspend_finish,
.system_off = css_system_off,
.system_reset = css_system_reset,
- .validate_power_state = arm_validate_power_state,
+ .validate_power_state = css_validate_power_state,
.validate_ns_entrypoint = arm_validate_ns_entrypoint,
- .get_node_hw_state = css_node_hw_state
+ .translate_power_state_by_mpidr = css_translate_power_state_by_mpidr,
+ .get_node_hw_state = css_node_hw_state,
+ .get_sys_suspend_power_state = css_get_sys_suspend_power_state
};