linux-kernel - [PATCH 2/2] cpuidle : Add auto-promotion flag to cpuidle flags

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Date:   Fri, 22 Mar 2019 01:25:30 -0500
From:   Abhishek Goel <huntbag@...ux.vnet.ibm.com>
To:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-pm@...r.kernel.org
Cc:     rjw@...ysocki.net, daniel.lezcano@...aro.org, mpe@...erman.id.au,
        Abhishek Goel <huntbag@...ux.vnet.ibm.com>
Subject: [PATCH 2/2] cpuidle : Add auto-promotion flag to cpuidle flags

This patch sets up flags for the state which needs to be auto-promoted.
For powernv systems, lite states do not even lose user context. That
information has been used to set the flag for lite states.

Signed-off-by: Abhishek Goel <huntbag@...ux.vnet.ibm.com>
---
 arch/powerpc/include/asm/opal-api.h |  1 +
 drivers/cpuidle/Kconfig             |  4 ++++
 drivers/cpuidle/cpuidle-powernv.c   | 13 +++++++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 870fb7b23..735dec731 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -226,6 +226,7 @@
  */
 
 #define OPAL_PM_TIMEBASE_STOP		0x00000002
+#define OPAL_PM_LOSE_USER_CONTEXT	0x00001000
 #define OPAL_PM_LOSE_HYP_CONTEXT	0x00002000
 #define OPAL_PM_LOSE_FULL_CONTEXT	0x00004000
 #define OPAL_PM_NAP_ENABLED		0x00010000
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index 7e48eb5bf..0ece62684 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -26,6 +26,10 @@ config CPU_IDLE_GOV_MENU
 config DT_IDLE_STATES
 	bool
 
+config CPU_IDLE_AUTO_PROMOTION
+	bool
+	default y if PPC_POWERNV
+
 menu "ARM CPU Idle Drivers"
 depends on ARM || ARM64
 source "drivers/cpuidle/Kconfig.arm"
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 84b1ebe21..e351f5f9c 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -299,6 +299,7 @@ static int powernv_add_idle_states(void)
 	for (i = 0; i < dt_idle_states; i++) {
 		unsigned int exit_latency, target_residency;
 		bool stops_timebase = false;
+		bool lose_user_context = false;
 		struct pnv_idle_states_t *state = &pnv_idle_states[i];
 
 		/*
@@ -324,6 +325,9 @@ static int powernv_add_idle_states(void)
 		if (has_stop_states && !(state->valid))
 				continue;
 
+		if (state->flags & OPAL_PM_LOSE_USER_CONTEXT)
+			lose_user_context = true;
+
 		if (state->flags & OPAL_PM_TIMEBASE_STOP)
 			stops_timebase = true;
 
@@ -332,12 +336,17 @@ static int powernv_add_idle_states(void)
 			add_powernv_state(nr_idle_states, "Nap",
 					  CPUIDLE_FLAG_NONE, nap_loop,
 					  target_residency, exit_latency, 0, 0);
+		} else if (has_stop_states & !lose_user_context) {
+			add_powernv_state(nr_idle_states, state->name,
+					  CPUIDLE_FLAG_AUTO_PROMOTION,
+					  stop_loop, target_residency,
+					  exit_latency, state->psscr_val,
+					  state->psscr_mask);
 		} else if (has_stop_states && !stops_timebase) {
 			add_powernv_state(nr_idle_states, state->name,
 					  CPUIDLE_FLAG_NONE, stop_loop,
 					  target_residency, exit_latency,
-					  state->psscr_val,
-					  state->psscr_mask);
+					  state->psscr_val, state->psscr_mask);
 		}
 
 		/*
-- 
2.17.1