Support PSCI SYSTEM SUSPEND on Juno
This patch adds the capability to power down at system power domain level
on Juno via the PSCI SYSTEM SUSPEND API. The CSS power management helpers
are modified to add support for power management operations at system
power domain level. A new helper for populating `get_sys_suspend_power_state`
handler in plat_psci_ops is defined. On entering the system suspend state,
the SCP powers down the SYSTOP power domain on the SoC and puts the memory
into retention mode. On wakeup from the power down, the system components
on the CSS will be reinitialized by the platform layer and the PSCI client
is responsible for restoring the context of these system components.
According to PSCI Specification, interrupts targeted to cores in PSCI CPU
SUSPEND should be able to resume it. On Juno, when the system power domain
is suspended, the GIC is also powered down. The SCP resumes the final core
to be suspend when an external wake-up event is received. But the other
cores cannot be woken up by a targeted interrupt, because GIC doesn't
forward these interrupts to the SCP. Due to this hardware limitation,
we down-grade PSCI CPU SUSPEND requests targeted to the system power domain
level to cluster power domain level in `juno_validate_power_state()`
and the CSS default `plat_arm_psci_ops` is overridden in juno_pm.c.
A system power domain resume helper `arm_system_pwr_domain_resume()` is
defined for ARM standard platforms which resumes/re-initializes the
system components on wakeup from system suspend. The security setup also
needs to be done on resume from system suspend, which means
`plat_arm_security_setup()` must now be included in the BL3-1 image in
addition to previous BL images if system suspend need to be supported.
Change-Id: Ie293f75f09bad24223af47ab6c6e1268f77bcc47
diff --git a/plat/arm/board/juno/juno_pm.c b/plat/arm/board/juno/juno_pm.c
new file mode 100644
index 0000000..4b956d2
--- /dev/null
+++ b/plat/arm/board/juno/juno_pm.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2015, 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:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <css_pm.h>
+#include <plat_arm.h>
+
+/*
+ * Custom `validate_power_state` handler for Juno. According to PSCI
+ * Specification, interrupts targeted to cores in PSCI CPU SUSPEND should
+ * be able to resume it. On Juno, when the system power domain is suspended,
+ * the GIC is also powered down. The SCP resumes the final core to be suspend
+ * when an external wake-up event is received. But the other cores cannot be
+ * woken up by a targeted interrupt, because GIC doesn't forward these
+ * interrupts to the SCP. Due to this hardware limitation, we down-grade PSCI
+ * CPU SUSPEND requests targeted to the system power domain level
+ * to cluster power domain level.
+ *
+ * The system power domain suspend on Juno is only supported only via
+ * PSCI SYSTEM SUSPEND API.
+ */
+static int juno_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[ARM_PWR_LVL2] = ARM_LOCAL_STATE_RUN;
+ return rc;
+}
+
+/*******************************************************************************
+ * Export the platform handlers via plat_arm_psci_pm_ops. The ARM Standard
+ * platform will take care of registering the handlers with PSCI.
+ ******************************************************************************/
+const plat_psci_ops_t plat_arm_psci_pm_ops = {
+ .pwr_domain_on = css_pwr_domain_on,
+ .pwr_domain_on_finish = css_pwr_domain_on_finish,
+ .pwr_domain_off = css_pwr_domain_off,
+ .cpu_standby = css_cpu_standby,
+ .pwr_domain_suspend = css_pwr_domain_suspend,
+ .pwr_domain_suspend_finish = css_pwr_domain_suspend_finish,
+ .system_off = css_system_off,
+ .system_reset = css_system_reset,
+ .validate_power_state = juno_validate_power_state,
+ .validate_ns_entrypoint = arm_validate_ns_entrypoint,
+ .get_sys_suspend_power_state = css_get_sys_suspend_power_state
+};
diff --git a/plat/arm/board/juno/platform.mk b/plat/arm/board/juno/platform.mk
index b80cfb3..0dde4d7 100644
--- a/plat/arm/board/juno/platform.mk
+++ b/plat/arm/board/juno/platform.mk
@@ -38,7 +38,9 @@
BL2_SOURCES += plat/arm/board/juno/juno_security.c \
BL31_SOURCES += lib/cpus/aarch64/cortex_a53.S \
- lib/cpus/aarch64/cortex_a57.S
+ lib/cpus/aarch64/cortex_a57.S \
+ plat/arm/board/juno/juno_pm.c \
+ plat/arm/board/juno/juno_security.c
# Enable workarounds for selected Cortex-A57 erratas.
ERRATA_A57_806969 := 0