linux-kernel - [PATCH 05/10] cpuidle, ARM/imx6: Push RCU-idle into driver

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Date:   Fri, 3 Mar 2023 17:23:27 +0800
From:   Cheng-Jui Wang <cheng-jui.wang@...iatek.com>
To:     <stable@...r.kernel.org>, Russell King <linux@...linux.org.uk>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        "Pengutronix Kernel Team" <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        "NXP Linux Team" <linux-imx@....com>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Cheng-Jui Wang <cheng-jui.wang@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>
Subject: [PATCH 05/10] cpuidle, ARM/imx6: Push RCU-idle into driver

From: Peter Zijlstra <peterz@...radead.org>

commit b3f46658ce40a3467cda82f920dd9d5325ab0eaf upstream.

Doing RCU-idle outside the driver, only to then temporarily enable it
again, at least twice, before going idle is suboptimal.

Notably both cpu_pm_enter() and cpu_cluster_pm_enter() implicity
re-enable RCU.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Tested-by: Tony Lindgren <tony@...mide.com>
Tested-by: Ulf Hansson <ulf.hansson@...aro.org>
Reviewed-by: Frederic Weisbecker <frederic@...nel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Link: https://lore.kernel.org/r/20230112195539.821714572@infradead.org
Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
Signed-off-by: Cheng-Jui Wang <cheng-jui.wang@...iatek.com>
---
 arch/arm/mach-imx/cpuidle-imx6sx.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-imx/cpuidle-imx6sx.c b/arch/arm/mach-imx/cpuidle-imx6sx.c
index 74ea1720e3d8..1dc01f6b0f36 100644
--- a/arch/arm/mach-imx/cpuidle-imx6sx.c
+++ b/arch/arm/mach-imx/cpuidle-imx6sx.c
@@ -47,7 +47,9 @@ static int imx6sx_enter_wait(struct cpuidle_device *dev,
 		cpu_pm_enter();
 		cpu_cluster_pm_enter();
 
+		ct_idle_enter();
 		cpu_suspend(0, imx6sx_idle_finish);
+		ct_idle_exit();
 
 		cpu_cluster_pm_exit();
 		cpu_pm_exit();
@@ -87,7 +89,8 @@ static struct cpuidle_driver imx6sx_cpuidle_driver = {
 			 */
 			.exit_latency = 300,
 			.target_residency = 500,
-			.flags = CPUIDLE_FLAG_TIMER_STOP,
+			.flags = CPUIDLE_FLAG_TIMER_STOP |
+				 CPUIDLE_FLAG_RCU_IDLE,
 			.enter = imx6sx_enter_wait,
 			.name = "LOW-POWER-IDLE",
 			.desc = "ARM power off",
-- 
2.18.0