[PATCH] arm64: psci: Support generic pm suspend withtout CPUIDLE subsystem's help.

[Jonghwa Lee]

Current psci's cpu_suspend callback can be used only when common cpu idle
configuration is enabled. However, it's also needed for system which only
uses generic pm suspend not cpu idle. This patch modifies psci driver to
support both of cases.

Signed-off-by: Jonghwa Lee <jonghwa3.lee at samsung.com>
---
 arch/arm64/kernel/psci.c |   41 +++++++++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index f1dbca7..06d5527 100644
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -35,6 +35,13 @@
 #define PSCI_POWER_STATE_TYPE_STANDBY		0
 #define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
 
+enum psci_affinity_level {
+	PSCI_AFFINITY_LEVEL_0,
+	PSCI_AFFINITY_LEVEL_1,
+	PSCI_AFFINITY_LEVEL_2,
+	PSCI_AFFINITY_LEVEL_3,
+};
+
 struct psci_power_state {
 	u16	id;
 	u8	type;
@@ -513,27 +520,37 @@ static int psci_suspend_finisher(unsigned long index)
 {
 	struct psci_power_state *state = __this_cpu_read(psci_power_state);
 
+	/* Generic PM suspend without CPUIDLE functionality */
+	if (!state) {
+		struct psci_power_state s = {
+			.affinity_level = PSCI_AFFINITY_LEVEL_3,
+			.type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
+		};
+		return psci_ops.cpu_suspend(s, virt_to_phys(cpu_resume));
+	}
+
 	return psci_ops.cpu_suspend(state[index - 1],
 				    virt_to_phys(cpu_resume));
 }
 
 static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
 {
-	int ret;
 	struct psci_power_state *state = __this_cpu_read(psci_power_state);
-	/*
-	 * idle state index 0 corresponds to wfi, should never be called
-	 * from the cpu_suspend operations
-	 */
-	if (WARN_ON_ONCE(!index))
-		return -EINVAL;
 
-	if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
-		ret = psci_ops.cpu_suspend(state[index - 1], 0);
-	else
-		ret = __cpu_suspend(index, psci_suspend_finisher);
+	if (state) {
+		if (WARN_ON_ONCE(!index))
+			return -EINVAL;
+
+		/*
+		 * If idle state initialization is successfully done,
+		 * idle state index 0 corresponds to wfi, should never be
+		 * called from the cpu_suspend operations
+		 */
+		if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
+			return psci_ops.cpu_suspend(state[index - 1], 0);
+	}
 
-	return ret;
+	return __cpu_suspend(index, psci_suspend_finisher);
 }
 
 const struct cpu_operations cpu_psci_ops = {
-- 
1.7.9.5