[mirror_ubuntu-zesty-kernel.git] / arch / arm / mach-exynos4 / hotplug.c

/* linux arch/arm/mach-exynos4/hotplug.c
 *
 *  Cloned from linux/arch/arm/mach-realview/hotplug.c
 *
 *  Copyright (C) 2002 ARM Ltd.
 *  All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/smp.h>

#include <asm/cacheflush.h>

extern volatile int pen_release;

static inline void cpu_enter_lowpower(void)
{
	unsigned int v;

	flush_cache_all();
	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");
}

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)
{
	/*
	 * there is no power-control hardware on this platform, so all
	 * we can do is put the core into WFI; this is safe as the calling
	 * code will have already disabled interrupts
	 */
	for (;;) {
		/*
		 * here's the WFI
		 */
		asm(".word	0xe320f003\n"
		    :
		    :
		    : "memory", "cc");

		if (pen_release == cpu) {
			/*
			 * 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)++;
	}
}

int platform_cpu_kill(unsigned int cpu)
{
	return 1;
}

/*
 * platform-specific code to shutdown a CPU
 *
 * Called with IRQs disabled
 */
void platform_cpu_die(unsigned int cpu)
{
	int spurious = 0;

	/*
	 * we're ready for shutdown now, so do it
	 */
	cpu_enter_lowpower();
	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);
}

int platform_cpu_disable(unsigned int cpu)
{
	/*
	 * we don't allow CPU 0 to be shutdown (it is still too special
	 * e.g. clock tick interrupts)
	 */
	return cpu == 0 ? -EPERM : 0;
}
Commit	Line	Data
7d30e8b3	1	/* linux arch/arm/mach-exynos4/hotplug.c
11adcc29 CY	2	*
	3	* Cloned from linux/arch/arm/mach-realview/hotplug.c
	4	*
	5	* Copyright (C) 2002 ARM Ltd.
	6	* All Rights Reserved
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/kernel.h>
	14	#include <linux/errno.h>
	15	#include <linux/smp.h>
11adcc29 CY	16
	17	#include <asm/cacheflush.h>
	18
	19	extern volatile int pen_release;
	20
11adcc29 CY	21	static inline void cpu_enter_lowpower(void)
	22	{
	23	unsigned int v;
	24
	25	flush_cache_all();
	26	asm volatile(
	27	" mcr p15, 0, %1, c7, c5, 0\n"
	28	" mcr p15, 0, %1, c7, c10, 4\n"
	29	/*
	30	* Turn off coherency
	31	*/
	32	" mrc p15, 0, %0, c1, c0, 1\n"
ad849a22	33	" bic %0, %0, %3\n"
11adcc29 CY	34	" mcr p15, 0, %0, c1, c0, 1\n"
11adcc29 CY	35	" mrc p15, 0, %0, c1, c0, 0\n"
30b99d07	36	" bic %0, %0, %2\n"
11adcc29 CY	37	" mcr p15, 0, %0, c1, c0, 0\n"
11adcc29 CY	38	: "=&r" (v)
ad849a22	39	: "r" (0), "Ir" (CR_C), "Ir" (0x40)
11adcc29 CY	40	: "cc");
	41	}
	42
	43	static inline void cpu_leave_lowpower(void)
	44	{
	45	unsigned int v;
	46
	47	asm volatile(
	48	"mrc p15, 0, %0, c1, c0, 0\n"
e3d9c625	49	" orr %0, %0, %1\n"
11adcc29 CY	50	" mcr p15, 0, %0, c1, c0, 0\n"
11adcc29 CY	51	" mrc p15, 0, %0, c1, c0, 1\n"
ad849a22	52	" orr %0, %0, %2\n"
11adcc29 CY	53	" mcr p15, 0, %0, c1, c0, 1\n"
11adcc29 CY	54	: "=&r" (v)
ad849a22	55	: "Ir" (CR_C), "Ir" (0x40)
11adcc29 CY	56	: "cc");
	57	}
	58
d4450261	59	static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
11adcc29 CY	60	{
	61	/*
	62	* there is no power-control hardware on this platform, so all
	63	* we can do is put the core into WFI; this is safe as the calling
	64	* code will have already disabled interrupts
	65	*/
	66	for (;;) {
	67	/*
	68	* here's the WFI
	69	*/
	70	asm(".word 0xe320f003\n"
	71	:
	72	:
	73	: "memory", "cc");
	74
	75	if (pen_release == cpu) {
	76	/*
	77	* OK, proper wakeup, we're done
	78	*/
	79	break;
	80	}
	81
	82	/*
d4450261	83	* Getting here, means that we have come out of WFI without
11adcc29 CY	84	* having been woken up - this shouldn't happen
11adcc29 CY	85	*
d4450261 RK	86	* Just note it happening - when we're woken, we can report
d4450261 RK	87	* its occurrence.
11adcc29	88	*/
d4450261	89	(*spurious)++;
11adcc29 CY	90	}
	91	}
	92
	93	int platform_cpu_kill(unsigned int cpu)
	94	{
3c030bea	95	return 1;
11adcc29 CY	96	}
	97
	98	/*
	99	* platform-specific code to shutdown a CPU
	100	*
	101	* Called with IRQs disabled
	102	*/
	103	void platform_cpu_die(unsigned int cpu)
	104	{
d4450261 RK	105	int spurious = 0;
d4450261 RK	106
11adcc29 CY	107	/*
	108	* we're ready for shutdown now, so do it
	109	*/
	110	cpu_enter_lowpower();
d4450261	111	platform_do_lowpower(cpu, &spurious);
11adcc29 CY	112
	113	/*
	114	* bring this CPU back into the world of cache
	115	* coherency, and then restore interrupts
	116	*/
	117	cpu_leave_lowpower();
d4450261 RK	118
	119	if (spurious)
	120	pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
11adcc29 CY	121	}
	122
	123	int platform_cpu_disable(unsigned int cpu)
	124	{
	125	/*
	126	* we don't allow CPU 0 to be shutdown (it is still too special
	127	* e.g. clock tick interrupts)
	128	*/
	129	return cpu == 0 ? -EPERM : 0;
	130	}