[PATCH v5 4/8] arm64: add PSCI CPU_SUSPEND based cpu_suspend support

Lorenzo Pieralisi
2014-06-25T14:10:17Z

This patch implements the cpu_suspend cpu operations method through
the PSCI CPU_SUSPEND API. The PSCI implementation translates the idle state
index passed by the cpu_suspend core call into a valid PSCI state according to
the PSCI states initialized at boot by the PSCI suspend backend.

Entry point is set to cpu_resume physical address, that represents the
default kernel execution address following a CPU reset.

Idle state indices missing a DT node description are initialized to power
state standby WFI so that if called by the idle driver they provide the
default behaviour.

Reviewed-by: Sebastian Capella <sebcape-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
---
arch/arm64/include/asm/psci.h | 4 ++
arch/arm64/kernel/psci.c | 103 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 107 insertions(+)

diff --git a/arch/arm64/include/asm/psci.h b/arch/arm64/include/asm/psci.h
index e5312ea..16c1351 100644
--- a/arch/arm64/include/asm/psci.h
+++ b/arch/arm64/include/asm/psci.h
@@ -14,6 +14,10 @@
#ifndef __ASM_PSCI_H
#define __ASM_PSCI_H

+struct cpuidle_driver;
int psci_init(void);

+int __init psci_dt_register_idle_states(struct cpuidle_driver *,
+ struct device_node *[]);
+
#endif /* __ASM_PSCI_H */
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index 9e9798f..f708bcc 100644
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -15,12 +15,14 @@

#define pr_fmt(fmt) "psci: " fmt

+#include <linux/cpuidle.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/smp.h>
#include <linux/reboot.h>
#include <linux/pm.h>
#include <linux/delay.h>
+#include <linux/slab.h>
#include <uapi/linux/psci.h>

#include <asm/compiler.h>
@@ -28,6 +30,7 @@
#include <asm/errno.h>
#include <asm/psci.h>
#include <asm/smp_plat.h>
+#include <asm/suspend.h>
#include <asm/system_misc.h>

#define PSCI_POWER_STATE_TYPE_STANDBY 0
@@ -65,6 +68,8 @@ enum psci_function {
PSCI_FN_MAX,
};

+static DEFINE_PER_CPU_READ_MOSTLY(struct psci_power_state *, psci_power_state);
+
static u32 psci_function_id[PSCI_FN_MAX];

static int psci_to_linux_errno(int errno)
@@ -93,6 +98,18 @@ static u32 psci_power_state_pack(struct psci_power_state state)
& PSCI_0_2_POWER_STATE_AFFL_MASK);
}

+static void psci_power_state_unpack(u32 power_state,
+ struct psci_power_state *state)
+{
+ state->id = (power_state & PSCI_0_2_POWER_STATE_ID_MASK) >>
+ PSCI_0_2_POWER_STATE_ID_SHIFT;
+ state->type = (power_state & PSCI_0_2_POWER_STATE_TYPE_MASK) >>
+ PSCI_0_2_POWER_STATE_TYPE_SHIFT;
+ state->affinity_level =
+ (power_state & PSCI_0_2_POWER_STATE_AFFL_MASK) >>
+ PSCI_0_2_POWER_STATE_AFFL_SHIFT;
+}
+
/*
* The following two functions are invoked via the invoke_psci_fn pointer
* and will not be inlined, allowing us to piggyback on the AAPCS.
@@ -199,6 +216,77 @@ static int psci_migrate_info_type(void)
return err;
}

+int __init psci_dt_register_idle_states(struct cpuidle_driver *drv,
+ struct device_node *state_nodes[])
+{
+ int cpu, i;
+ struct psci_power_state *psci_states;
+ const struct cpu_operations *cpu_ops_ptr;
+
+ if (!state_nodes)
+ return -EINVAL;
+ /*
+ * This is belt-and-braces: make sure that if the idle
+ * specified protocol is psci, the cpu_ops have been
+ * initialized to psci operations. Anything else is
+ * a recipe for mayhem.
+ */
+ for_each_cpu(cpu, drv->cpumask) {
+ cpu_ops_ptr = cpu_ops[cpu];
+ if (WARN_ON(!cpu_ops_ptr || strcmp(cpu_ops_ptr->name, "psci")))
+ return -EOPNOTSUPP;
+ }
+
+ psci_states = kcalloc(drv->state_count, sizeof(*psci_states),
+ GFP_KERNEL);
+
+ if (!psci_states) {
+ pr_warn("psci idle state allocation failed\n");
+ return -ENOMEM;
+ }
+
+ for_each_cpu(cpu, drv->cpumask) {
+ if (per_cpu(psci_power_state, cpu)) {
+ pr_warn("idle states already initialized on cpu %u\n",
+ cpu);
+ continue;
+ }
+ per_cpu(psci_power_state, cpu) = psci_states;
+ }
+
+
+ for (i = 0; i < drv->state_count; i++) {
+ u32 psci_power_state;
+
+ if (!state_nodes[i]) {
+ /*
+ * An index with a missing node pointer falls back to
+ * simple STANDBYWFI
+ */
+ psci_states[i].type = PSCI_POWER_STATE_TYPE_STANDBY;
+ continue;
+ }
+
+ if (of_property_read_u32(state_nodes[i], "entry-method-param",
+ &psci_power_state)) {
+ pr_warn(" * %s missing entry-method-param property\n",
+ state_nodes[i]->full_name);
+ /*
+ * If entry-method-param property is missing, fall
+ * back to STANDBYWFI state
+ */
+ psci_states[i].type = PSCI_POWER_STATE_TYPE_STANDBY;
+ continue;
+ }
+
+ pr_debug("psci-power-state %#x index %u\n", psci_power_state,
+ i);
+ psci_power_state_unpack(psci_power_state, &psci_states[i]);
+ }
+
+ return 0;
+}
+
static int get_set_conduit_method(struct device_node *np)
{
const char *method;
@@ -435,6 +523,18 @@ static int cpu_psci_cpu_kill(unsigned int cpu)
}
#endif

+#ifdef CONFIG_ARM64_CPU_SUSPEND
+static int cpu_psci_cpu_suspend(unsigned long index)
+{
+ struct psci_power_state *state = __get_cpu_var(psci_power_state);
+
+ if (!state)
+ return -EOPNOTSUPP;
+
+ return psci_ops.cpu_suspend(state[index], virt_to_phys(cpu_resume));
+}
+#endif
+
const struct cpu_operations cpu_psci_ops = {
.name = "psci",
.cpu_init = cpu_psci_cpu_init,
@@ -445,6 +545,9 @@ const struct cpu_operations cpu_psci_ops = {
.cpu_die = cpu_psci_cpu_die,
.cpu_kill = cpu_psci_cpu_kill,
#endif
+#ifdef CONFIG_ARM64_CPU_SUSPEND
+ .cpu_suspend = cpu_psci_cpu_suspend,
+#endif
};

#endif
--
1.9.1

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