ARM: CPU hotplug: move cpu_killed completion to core code

We always need to wait for the dying CPU to reach a safe state before
taking it down, irrespective of the requirements of the platform.
Move the completion code into the ARM SMP hotplug code rather than
having each platform re-implement this.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/smp.c

@@ -24,6 +24,7 @@
 #include <linux/irq.h>
 #include <linux/percpu.h>
 #include <linux/clockchips.h>
+#include <linux/completion.h>
 
 #include <asm/atomic.h>
 #include <asm/cacheflush.h>
@@ -238,12 +239,20 @@ int __cpu_disable(void)
 	return 0;
 }
 
+static DECLARE_COMPLETION(cpu_died);
+
 /*
  * called on the thread which is asking for a CPU to be shutdown -
  * waits until shutdown has completed, or it is timed out.
  */
 void __cpu_die(unsigned int cpu)
 {
+	if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
+		pr_err("CPU%u: cpu didn't die\n", cpu);
+		return;
+	}
+	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
+
 	if (!platform_cpu_kill(cpu))
 		printk("CPU%u: unable to kill\n", cpu);
 }
@@ -263,9 +272,12 @@ void __ref cpu_die(void)
 	local_irq_disable();
 	idle_task_exit();
 
+	/* Tell __cpu_die() that this CPU is now safe to dispose of */
+	complete(&cpu_died);
+
 	/*
 	 * actual CPU shutdown procedure is at least platform (if not
-	 * CPU) specific
+	 * CPU) specific.
 	 */
 	platform_cpu_die(cpu);
 

arch/arm/mach-omap2/omap-hotplug.c

@@ -17,16 +17,13 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <linux/completion.h>
 
 #include <asm/cacheflush.h>
 #include <mach/omap4-common.h>
 
-static DECLARE_COMPLETION(cpu_killed);
-
 int platform_cpu_kill(unsigned int cpu)
 {
-	return wait_for_completion_timeout(&cpu_killed, 5000);
+	return 1;
 }
 
 /*
@@ -42,8 +39,7 @@ void platform_cpu_die(unsigned int cpu)
 			   this_cpu, cpu);
 		BUG();
 	}
-	pr_notice("CPU%u: shutdown\n", cpu);
-	complete(&cpu_killed);
+
 	flush_cache_all();
 	dsb();
 

arch/arm/mach-realview/hotplug.c

@@ -11,14 +11,11 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <linux/completion.h>
 
 #include <asm/cacheflush.h>
 
 extern volatile int pen_release;
 
-static DECLARE_COMPLETION(cpu_killed);
-
 static inline void cpu_enter_lowpower(void)
 {
 	unsigned int v;
@@ -95,7 +92,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
 
 int platform_cpu_kill(unsigned int cpu)
 {
-	return wait_for_completion_timeout(&cpu_killed, 5000);
+	return 1;
 }
 
 /*
@@ -115,9 +112,6 @@ void platform_cpu_die(unsigned int cpu)
 	}
 #endif
 
-	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
-	complete(&cpu_killed);
-
 	/*
 	 * we're ready for shutdown now, so do it
 	 */

arch/arm/mach-s5pv310/hotplug.c

@@ -13,14 +13,11 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <linux/completion.h>
 
 #include <asm/cacheflush.h>
 
 extern volatile int pen_release;
 
-static DECLARE_COMPLETION(cpu_killed);
-
 static inline void cpu_enter_lowpower(void)
 {
 	unsigned int v;
@@ -98,7 +95,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
 
 int platform_cpu_kill(unsigned int cpu)
 {
-	return wait_for_completion_timeout(&cpu_killed, 5000);
+	return 1;
 }
 
 /*
@@ -118,9 +115,6 @@ void platform_cpu_die(unsigned int cpu)
 	}
 #endif
 
-	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
-	complete(&cpu_killed);
-
 	/*
 	 * we're ready for shutdown now, so do it
 	 */

arch/arm/mach-tegra/hotplug.c

@@ -11,12 +11,9 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <linux/completion.h>
 
 #include <asm/cacheflush.h>
 
-static DECLARE_COMPLETION(cpu_killed);
-
 static inline void cpu_enter_lowpower(void)
 {
 	unsigned int v;
@@ -94,7 +91,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
 
 int platform_cpu_kill(unsigned int cpu)
 {
-	return wait_for_completion_timeout(&cpu_killed, 5000);
+	return 1;
 }
 
 /*
@@ -114,9 +111,6 @@ void platform_cpu_die(unsigned int cpu)
 	}
 #endif
 
-	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
-	complete(&cpu_killed);
-
 	/*
 	 * we're ready for shutdown now, so do it
 	 */

arch/arm/mach-ux500/hotplug.c

@@ -11,14 +11,11 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <linux/completion.h>
 
 #include <asm/cacheflush.h>
 
 extern volatile int pen_release;
 
-static DECLARE_COMPLETION(cpu_killed);
-
 static inline void platform_do_lowpower(unsigned int cpu)
 {
 	flush_cache_all();
@@ -38,7 +35,7 @@ static inline void platform_do_lowpower(unsigned int cpu)
 
 int platform_cpu_kill(unsigned int cpu)
 {
-	return wait_for_completion_timeout(&cpu_killed, 5000);
+	return 1;
 }
 
 /*
@@ -58,9 +55,6 @@ void platform_cpu_die(unsigned int cpu)
 	}
 #endif
 
-	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
-	complete(&cpu_killed);
-
 	/* directly enter low power state, skipping secure registers */
 	platform_do_lowpower(cpu);
 }