ARM: EXYNOS: Move code from hotplug.c to platsmp.c

Cleanup a little the SMP/hotplug code for Exynos by:
1. Moving completely all functions from hotplug.c into the platsmp.c;
2. Deleting the hotplug.c file.

After recent cleanups (e.g. 75ad2ab "ARM: EXYNOS: use
v7_exit_coherency_flush macro for cache disabling") there was only CPU
power down related code in hotplug.c file.

Rationale behind the code movement and benefits:
1. The file platsmp.c is the only user of code located in hotplug.c.
   Keeping code in hotplug.c required declaring exynos_cpu_die() in common.h.
   Such dependencies and mentioned exynos_cpu_die() declaration can be
   removed.
2. In next patches exynos_set_delayed_reset_assertion() will be
   introduced. This function will be called by:
    - cpu_leave_power (hotplug.c),
    - platform_do_lowpower (hotplug.c),
    - exynos_boot_secondary (platsmp.c).

Merging hotplug.c into platsmp.c leads to simpler and cleaner code with
less dependencies between files.

The commit only moves code around with one additional observable change:
the hotplug.c was compiled with custom CFLAGS (-march=armv7-a). These
CFLAGS are not necessary any more.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos/Makefile

@@ -16,9 +16,6 @@ obj-$(CONFIG_PM_GENERIC_DOMAINS) += pm_domains.o
 
 obj-$(CONFIG_SMP)		+= platsmp.o headsmp.o
 
-obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug.o
-CFLAGS_hotplug.o		+= -march=armv7-a
-
 plus_sec := $(call as-instr,.arch_extension sec,+sec)
 AFLAGS_exynos-smc.o		:=-Wa,-march=armv7-a$(plus_sec)
 

arch/arm/mach-exynos/common.h

@@ -130,8 +130,6 @@ extern void exynos_cpu_resume(void);
 
 extern struct smp_operations exynos_smp_ops;
 
-extern void exynos_cpu_die(unsigned int cpu);
-
 /* PMU(Power Management Unit) support */
 
 #define PMU_TABLE_END	(-1U)

arch/arm/mach-exynos/platsmp.c

@@ -22,6 +22,7 @@
 #include <linux/of_address.h>
 
 #include <asm/cacheflush.h>
+#include <asm/cp15.h>
 #include <asm/smp_plat.h>
 #include <asm/smp_scu.h>
 #include <asm/firmware.h>
@@ -33,6 +34,54 @@
 
 extern void exynos4_secondary_startup(void);
 
+#ifdef CONFIG_HOTPLUG_CPU
+static inline void cpu_leave_lowpower(void)
+{
+	unsigned int v;
+
+	asm volatile(
+	"mrc	p15, 0, %0, c1, c0, 0\n"
+	"	orr	%0, %0, %1\n"
+	"	mcr	p15, 0, %0, c1, c0, 0\n"
+	"	mrc	p15, 0, %0, c1, c0, 1\n"
+	"	orr	%0, %0, %2\n"
+	"	mcr	p15, 0, %0, c1, c0, 1\n"
+	  : "=&r" (v)
+	  : "Ir" (CR_C), "Ir" (0x40)
+	  : "cc");
+}
+
+static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
+{
+	u32 mpidr = cpu_logical_map(cpu);
+	u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+
+	for (;;) {
+
+		/* Turn the CPU off on next WFI instruction. */
+		exynos_cpu_power_down(core_id);
+
+		wfi();
+
+		if (pen_release == core_id) {
+			/*
+			 * OK, proper wakeup, we're done
+			 */
+			break;
+		}
+
+		/*
+		 * Getting here, means that we have come out of WFI without
+		 * having been woken up - this shouldn't happen
+		 *
+		 * Just note it happening - when we're woken, we can report
+		 * its occurrence.
+		 */
+		(*spurious)++;
+	}
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
 /**
  * exynos_core_power_down : power down the specified cpu
  * @cpu : the cpu to power down
@@ -318,6 +367,31 @@ static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ * Called with IRQs disabled
+ */
+static void __ref exynos_cpu_die(unsigned int cpu)
+{
+	int spurious = 0;
+
+	v7_exit_coherency_flush(louis);
+
+	platform_do_lowpower(cpu, &spurious);
+
+	/*
+	 * bring this CPU back into the world of cache
+	 * coherency, and then restore interrupts
+	 */
+	cpu_leave_lowpower();
+
+	if (spurious)
+		pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
 struct smp_operations exynos_smp_ops __initdata = {
 	.smp_init_cpus		= exynos_smp_init_cpus,
 	.smp_prepare_cpus	= exynos_smp_prepare_cpus,