From e726c122b5ff6bf95356932ec2495132dd95c023 Mon Sep 17 00:00:00 2001
From: Achin Gupta <achin.gupta@arm.com>
Date: Tue, 12 Aug 2014 14:13:31 +0100
Subject: [PATCH] Juno: Add support for PSCI cpu_suspend api
This patch adds support for the PSCI cpu_suspend api to allow entry
into low power states until affinity level 1 i.e. cluster. It mainly
ensures that a consolidated power off command which specifies the
level to which each affinity level should be powered down is sent to
the SCP.
Change-Id: I84201f5c06e9c41c9e1fbc6438d12ab5f65ee429
---
plat/juno/plat_pm.c | 147 +++++++++++++++++++++++++++++++++++++-------
1 file changed, 126 insertions(+), 21 deletions(-)
diff --git a/plat/juno/plat_pm.c b/plat/juno/plat_pm.c
index 54ae303b9..2951459e5 100644
--- a/plat/juno/plat_pm.c
+++ b/plat/juno/plat_pm.c
@@ -28,6 +28,7 @@
* POSSIBILITY OF SUCH DAMAGE.
*/
+#include <assert.h>
#include <arch_helpers.h>
#include <cci400.h>
#include <platform.h>
@@ -37,6 +38,13 @@
#include "juno_private.h"
#include "scpi.h"
+typedef struct {
+ /* Align the suspend level to allow per-cpu lockless access */
+ uint32_t state[MPIDR_MAX_AFFLVL] __aligned(CACHE_WRITEBACK_GRANULE);
+} scp_pstate;
+
+static scp_pstate target_pstate[PLATFORM_CORE_COUNT];
+
int pm_on(unsigned long mpidr,
unsigned long sec_entrypoint,
unsigned long ns_entrypoint,
@@ -90,6 +98,16 @@ int pm_on_finish(unsigned long mpidr, unsigned int afflvl, unsigned int state)
/* Juno todo: Is this setup only needed after a cold boot? */
gic_pcpu_distif_setup(GICD_BASE);
+ /*
+ * Clear the mailbox for each cpu
+ */
+ unsigned long *mbox = (unsigned long *)(unsigned long)(
+ TRUSTED_MAILBOXES_BASE +
+ (platform_get_core_pos(mpidr) << TRUSTED_MAILBOX_SHIFT)
+ );
+ *mbox = 0;
+ flush_dcache_range((unsigned long)mbox, sizeof(*mbox));
+
break;
}
@@ -97,23 +115,34 @@ int pm_on_finish(unsigned long mpidr, unsigned int afflvl, unsigned int state)
}
/*******************************************************************************
- * Handler called when an affinity instance is about to be turned off. The
- * level and mpidr determine the affinity instance. The 'state' arg. allows the
- * platform to decide whether the cluster is being turned off and take apt
- * actions.
+ * Common function called while turning a cpu off or suspending it. It is called
+ * for each affinity level until the target affinity level. It keeps track of
+ * the power state that needs to be programmed through the SCP firmware for each
+ * affinity level. Once the target affinity level is reached it uses the MHU
+ * channel to ask the SCP to perform the power operations for each affinity
+ * level accumulated so far.
*
* CAUTION: There is no guarantee that caches will remain turned on across calls
* to this function as each affinity level is dealt with. So do not write & read
* global variables across calls. It will be wise to do flush a write to the
* global to prevent unpredictable results.
******************************************************************************/
-int pm_off(unsigned long mpidr, unsigned int afflvl, unsigned int state)
+static int juno_power_down_common(unsigned long mpidr,
+ unsigned int linear_id,
+ unsigned int cur_afflvl,
+ unsigned int tgt_afflvl,
+ unsigned int state)
{
- /* We're only interested in power off states */
- if (state != PSCI_STATE_OFF)
- return PSCI_E_SUCCESS;
+ /* Record which power state this affinity level is supposed to enter */
+ if (state == PSCI_STATE_OFF) {
+ target_pstate[linear_id].state[cur_afflvl] = scpi_power_off;
+ } else {
+ assert(cur_afflvl != MPIDR_AFFLVL0);
+ target_pstate[linear_id].state[cur_afflvl] = scpi_power_on;
+ goto exit;
+ }
- switch (afflvl) {
+ switch (cur_afflvl) {
case MPIDR_AFFLVL1:
/* Cluster is to be turned off, so disable coherency */
cci_disable_coherency(mpidr);
@@ -127,30 +156,106 @@ int pm_off(unsigned long mpidr, unsigned int afflvl, unsigned int state)
/* Prevent interrupts from spuriously waking up this cpu */
gic_cpuif_deactivate(GICC_BASE);
- /*
- * Ask SCP to power down CPU.
- *
- * Note, we also ask for cluster power down as well because we
- * know the SCP will only actually do that if this is the last
- * CPU going down, and also, that final power down won't happen
- * until this CPU executes the WFI instruction after the PSCI
- * framework has done it's thing.
- */
- scpi_set_css_power_state(mpidr, scpi_power_off, scpi_power_off,
- scpi_power_retention);
break;
}
+exit:
+ /*
+ * If this is the target affinity level then we need to ask the SCP
+ * to power down the appropriate components depending upon their state
+ */
+ if (cur_afflvl == tgt_afflvl) {
+ scpi_set_css_power_state(mpidr,
+ target_pstate[linear_id].state[MPIDR_AFFLVL0],
+ target_pstate[linear_id].state[MPIDR_AFFLVL1],
+ scpi_power_on);
+
+ /* Reset the states */
+ target_pstate[linear_id].state[MPIDR_AFFLVL0] = scpi_power_on;
+ target_pstate[linear_id].state[MPIDR_AFFLVL1] = scpi_power_on;
+ }
+
return PSCI_E_SUCCESS;
}
+/*******************************************************************************
+ * Handler called when an affinity instance is about to be turned off. The
+ * level and mpidr determine the affinity instance. The 'state' arg. allows the
+ * platform to decide whether the cluster is being turned off and take apt
+ * actions.
+ *
+ * CAUTION: There is no guarantee that caches will remain turned on across calls
+ * to this function as each affinity level is dealt with. So do not write & read
+ * global variables across calls. It will be wise to do flush a write to the
+ * global to prevent unpredictable results.
+ ******************************************************************************/
+int pm_off(unsigned long mpidr, unsigned int afflvl, unsigned int state)
+{
+ return juno_power_down_common(mpidr,
+ platform_get_core_pos(mpidr),
+ afflvl,
+ plat_get_max_afflvl(),
+ state);
+}
+
+/*******************************************************************************
+ * Handler called when an affinity instance is about to be suspended. The
+ * level and mpidr determine the affinity instance. The 'state' arg. allows the
+ * platform to decide whether the cluster is being turned off and take apt
+ * actions. The 'sec_entrypoint' determines the address in BL3-1 from where
+ * execution should resume.
+ *
+ * CAUTION: There is no guarantee that caches will remain turned on across calls
+ * to this function as each affinity level is dealt with. So do not write & read
+ * global variables across calls. It will be wise to do flush a write to the
+ * global to prevent unpredictable results.
+ ******************************************************************************/
+int pm_suspend(unsigned long mpidr,
+ unsigned long sec_entrypoint,
+ unsigned long ns_entrypoint,
+ unsigned int afflvl,
+ unsigned int state)
+{
+ uint32_t tgt_afflvl;
+
+ tgt_afflvl = psci_get_suspend_afflvl(mpidr);
+ assert(tgt_afflvl != PSCI_INVALID_DATA);
+
+ /*
+ * Setup mailbox with address for CPU entrypoint when it next powers up
+ */
+ if (afflvl == MPIDR_AFFLVL0) {
+ unsigned long *mbox = (unsigned long *)(unsigned long)(
+ TRUSTED_MAILBOXES_BASE +
+ (platform_get_core_pos(mpidr) << TRUSTED_MAILBOX_SHIFT)
+ );
+ *mbox = sec_entrypoint;
+ flush_dcache_range((unsigned long)mbox, sizeof(*mbox));
+ }
+
+ return juno_power_down_common(mpidr,
+ platform_get_core_pos(mpidr),
+ afflvl,
+ tgt_afflvl,
+ state);
+}
+
+int pm_suspend_finish(unsigned long mpidr,
+ unsigned int afflvl,
+ unsigned int state)
+{
+ return pm_on_finish(mpidr, afflvl, state);
+}
+
/*******************************************************************************
* Export the platform handlers to enable psci to invoke them
******************************************************************************/
static const plat_pm_ops_t pm_ops = {
.affinst_on = pm_on,
.affinst_on_finish = pm_on_finish,
- .affinst_off = pm_off
+ .affinst_off = pm_off,
+ .affinst_suspend = pm_suspend,
+ .affinst_suspend_finish = pm_suspend_finish
};
/*******************************************************************************
--
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