linux-kernel - [PATCH v2 2/2] cpuidle : Add auto-promotion flag to cpuidle flags

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Date:   Fri,  5 Apr 2019 04:16:47 -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,
        ego@...ux.vnet.ibm.com, Abhishek Goel <huntbag@...ux.vnet.ibm.com>
Subject: [PATCH v2 2/2] cpuidle : Add auto-promotion flag to cpuidle flags

This patch sets up flags for the state which needs to be auto-promoted. On
POWERNV system, only lite states need to be autopromoted. We identify lite
states by those which do not 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 8caccbbd7..9b8e9b96a 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -35,6 +35,10 @@ config CPU_IDLE_GOV_TEO
 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..0dd767270 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