linux-kernel - [PATCH] ARM: imx: use generic function to exit coherency

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Date:   Thu, 11 Apr 2019 01:14:12 +0200
From:   Stefan Agner <stefan@...er.ch>
To:     shawnguo@...nel.org, s.hauer@...gutronix.de
Cc:     linux@...linux.org.uk, kernel@...gutronix.de, festevam@...il.com,
        linux-imx@....com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Stefan Agner <stefan@...er.ch>
Subject: [PATCH] ARM: imx: use generic function to exit coherency

The common ARM architecture code provides a generic function to exit
coherency called v7_exit_coherency_flush(). Replace the machine
specific implementation using the generic function.

Tested on a i.MX 6Dual by hotplugging the secondary CPU under load
through sysfs several 1000 times.

Tested-by: Stefan Agner <stefan@...er.ch>
Signed-off-by: Stefan Agner <stefan@...er.ch>
---
 arch/arm/mach-imx/hotplug.c | 24 ++----------------------
 1 file changed, 2 insertions(+), 22 deletions(-)

diff --git a/arch/arm/mach-imx/hotplug.c b/arch/arm/mach-imx/hotplug.c
index b35e99cc5e5b..7a74a9b89a49 100644
--- a/arch/arm/mach-imx/hotplug.c
+++ b/arch/arm/mach-imx/hotplug.c
@@ -12,32 +12,12 @@
 
 #include <linux/errno.h>
 #include <linux/jiffies.h>
+#include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include <asm/proc-fns.h>
 
 #include "common.h"
 
-static inline void cpu_enter_lowpower(void)
-{
-	unsigned int v;
-
-	asm volatile(
-		"mcr	p15, 0, %1, c7, c5, 0\n"
-	"	mcr	p15, 0, %1, c7, c10, 4\n"
-	/*
-	 * Turn off coherency
-	 */
-	"	mrc	p15, 0, %0, c1, c0, 1\n"
-	"	bic	%0, %0, %3\n"
-	"	mcr	p15, 0, %0, c1, c0, 1\n"
-	"	mrc	p15, 0, %0, c1, c0, 0\n"
-	"	bic	%0, %0, %2\n"
-	"	mcr	p15, 0, %0, c1, c0, 0\n"
-	  : "=&r" (v)
-	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
-	  : "cc");
-}
-
 /*
  * platform-specific code to shutdown a CPU
  *
@@ -45,7 +25,7 @@ static inline void cpu_enter_lowpower(void)
  */
 void imx_cpu_die(unsigned int cpu)
 {
-	cpu_enter_lowpower();
+	v7_exit_coherency_flush(louis);
 	/*
 	 * We use the cpu jumping argument register to sync with
 	 * imx_cpu_kill() which is running on cpu0 and waiting for
-- 
2.21.0