[PATCH] cpuidle: psci: Add trace for PSCI domain idle

[Keita Morisaki <keyz@google.com>]

The trace event cpu_idle provides insufficient information for debugging
PSCI requests due to lacking access to determined PSCI domain idle
states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
CPUidle states the power domain has.

Add a new trace named psci_domain_idle with a determined idle state info
before the state entry, and after the state exit.

This new trace event will help developers debug CPUidle issues on ARM
systems using PSCI by providing more detailed information about the
requested idle states.

Signed-off-by: Keita Morisaki <keyz@google.com>
---
 drivers/cpuidle/cpuidle-psci.c |  3 +++
 include/trace/events/power.h   | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 2562dc001fc1..5888d4511787 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -25,6 +25,7 @@
 #include <linux/syscore_ops.h>
 
 #include <asm/cpuidle.h>
+#include <trace/events/power.h>
 
 #include "cpuidle-psci.h"
 #include "dt_idle_states.h"
@@ -74,7 +75,9 @@ static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
 	if (!state)
 		state = states[idx];
 
+	trace_psci_domain_idle(dev->cpu, state, true, s2idle);
 	ret = psci_cpu_suspend_enter(state) ? -1 : idx;
+	trace_psci_domain_idle(dev->cpu, state, false, s2idle);
 
 	if (s2idle)
 		dev_pm_genpd_resume(pd_dev);
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index d2349b6b531a..82ad8bb1c477 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -62,6 +62,31 @@ TRACE_EVENT(cpu_idle_miss,
 		(unsigned long)__entry->state, (__entry->below)?"below":"above")
 );
 
+TRACE_EVENT(psci_domain_idle,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool enter, bool s2idle),
+
+	TP_ARGS(cpu_id, state, enter, s2idle),
+
+	TP_STRUCT__entry(
+		__field(u32,		cpu_id)
+		__field(u32,		state)
+		__field(bool,		enter)
+		__field(bool,		s2idle)
+	),
+
+	TP_fast_assign(
+		__entry->cpu_id = cpu_id;
+		__entry->state = state;
+		__entry->enter = enter;
+		__entry->s2idle = s2idle;
+	),
+
+	TP_printk("cpu_id=%lu state=0x%lx type=%s, is_s2idle=%s",
+		  (unsigned long)__entry->cpu_id, (unsigned long)__entry->state,
+		  (__entry->enter)?"enter":"exit", (__entry->s2idle)?"yes":"no")
+);
+
 TRACE_EVENT(powernv_throttle,
 
 	TP_PROTO(int chip_id, const char *reason, int pmax),

base-commit: 9bffa1ad25b8b3b95d8f463e5c24dabe3c87d54d
-- 
2.48.0.rc2.279.g1de40edade-goog