[linux-2.6-block.git] / arch / arm / mach-realview / hotplug.c

/*
 *  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>
#include <asm/cp15.h>
#include <asm/smp_plat.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, #0x20\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)
	  : "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, #0x20\n"
	"	mcr	p15, 0, %0, c1, c0, 1\n"
	  : "=&r" (v)
	  : "Ir" (CR_C)
	  : "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_logical_map(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
97a63ecf RK	1	/*
	2	* linux/arch/arm/mach-realview/hotplug.c
	3	*
	4	* Copyright (C) 2002 ARM Ltd.
	5	* All Rights Reserved
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11	#include <linux/kernel.h>
	12	#include <linux/errno.h>
	13	#include <linux/smp.h>
97a63ecf	14
8aa2da87	15	#include <asm/cacheflush.h>
15d07dc9	16	#include <asm/cp15.h>
eb50439b	17	#include <asm/smp_plat.h>
8aa2da87	18
97a63ecf RK	19	extern volatile int pen_release;
97a63ecf RK	20
97a63ecf RK	21	static inline void cpu_enter_lowpower(void)
	22	{
	23	unsigned int v;
	24
8aa2da87 HF	25	flush_cache_all();
8aa2da87 HF	26	asm volatile(
97a63ecf RK	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"
	33	" bic %0, %0, #0x20\n"
	34	" mcr p15, 0, %0, c1, c0, 1\n"
	35	" mrc p15, 0, %0, c1, c0, 0\n"
e3d9c625	36	" bic %0, %0, %2\n"
97a63ecf RK	37	" mcr p15, 0, %0, c1, c0, 0\n"
97a63ecf RK	38	: "=&r" (v)
e3d9c625	39	: "r" (0), "Ir" (CR_C)
97a63ecf RK	40	: "cc");
	41	}
	42
	43	static inline void cpu_leave_lowpower(void)
	44	{
	45	unsigned int v;
	46
	47	asm volatile( "mrc p15, 0, %0, c1, c0, 0\n"
e3d9c625	48	" orr %0, %0, %1\n"
97a63ecf RK	49	" mcr p15, 0, %0, c1, c0, 0\n"
	50	" mrc p15, 0, %0, c1, c0, 1\n"
	51	" orr %0, %0, #0x20\n"
	52	" mcr p15, 0, %0, c1, c0, 1\n"
	53	: "=&r" (v)
e3d9c625	54	: "Ir" (CR_C)
97a63ecf RK	55	: "cc");
	56	}
	57
d4450261	58	static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
97a63ecf RK	59	{
	60	/*
	61	* there is no power-control hardware on this platform, so all
	62	* we can do is put the core into WFI; this is safe as the calling
	63	* code will have already disabled interrupts
	64	*/
	65	for (;;) {
	66	/*
	67	* here's the WFI
	68	*/
	69	asm(".word 0xe320f003\n"
	70	:
	71	:
	72	: "memory", "cc");
	73
4a139b64	74	if (pen_release == cpu_logical_map(cpu)) {
97a63ecf RK	75	/*
	76	* OK, proper wakeup, we're done
	77	*/
	78	break;
	79	}
	80
	81	/*
d4450261	82	* Getting here, means that we have come out of WFI without
97a63ecf RK	83	* having been woken up - this shouldn't happen
97a63ecf RK	84	*
d4450261 RK	85	* Just note it happening - when we're woken, we can report
d4450261 RK	86	* its occurrence.
97a63ecf	87	*/
d4450261	88	(*spurious)++;
97a63ecf RK	89	}
	90	}
	91
	92	int platform_cpu_kill(unsigned int cpu)
	93	{
3c030bea	94	return 1;
97a63ecf RK	95	}
	96
	97	/*
	98	* platform-specific code to shutdown a CPU
	99	*
	100	* Called with IRQs disabled
	101	*/
	102	void platform_cpu_die(unsigned int cpu)
	103	{
d4450261 RK	104	int spurious = 0;
d4450261 RK	105
97a63ecf RK	106	/*
	107	* we're ready for shutdown now, so do it
	108	*/
	109	cpu_enter_lowpower();
d4450261	110	platform_do_lowpower(cpu, &spurious);
97a63ecf RK	111
	112	/*
	113	* bring this CPU back into the world of cache
	114	* coherency, and then restore interrupts
	115	*/
	116	cpu_leave_lowpower();
d4450261 RK	117
	118	if (spurious)
	119	pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
97a63ecf RK	120	}
97a63ecf RK	121
8e2a43f5	122	int platform_cpu_disable(unsigned int cpu)
97a63ecf RK	123	{
	124	/*
	125	* we don't allow CPU 0 to be shutdown (it is still too special
	126	* e.g. clock tick interrupts)
	127	*/
	128	return cpu == 0 ? -EPERM : 0;
	129	}