[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/cp15.h>
#include <asm/smp_plat.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, #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)++;
	}
}

/*
 * platform-specific code to shutdown a CPU
 *
 * Called with IRQs disabled
 */
void realview_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);
}
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
15d07dc9	15	#include <asm/cp15.h>
eb50439b	16	#include <asm/smp_plat.h>
8aa2da87	17
97a63ecf RK	18	static inline void cpu_enter_lowpower(void)
	19	{
	20	unsigned int v;
	21
8aa2da87	22	asm volatile(
97a63ecf RK	23	" mcr p15, 0, %1, c7, c5, 0\n"
	24	" mcr p15, 0, %1, c7, c10, 4\n"
	25	/*
	26	* Turn off coherency
	27	*/
	28	" mrc p15, 0, %0, c1, c0, 1\n"
	29	" bic %0, %0, #0x20\n"
	30	" mcr p15, 0, %0, c1, c0, 1\n"
	31	" mrc p15, 0, %0, c1, c0, 0\n"
e3d9c625	32	" bic %0, %0, %2\n"
97a63ecf RK	33	" mcr p15, 0, %0, c1, c0, 0\n"
97a63ecf RK	34	: "=&r" (v)
e3d9c625	35	: "r" (0), "Ir" (CR_C)
97a63ecf RK	36	: "cc");
	37	}
	38
	39	static inline void cpu_leave_lowpower(void)
	40	{
	41	unsigned int v;
	42
	43	asm volatile( "mrc p15, 0, %0, c1, c0, 0\n"
e3d9c625	44	" orr %0, %0, %1\n"
97a63ecf RK	45	" mcr p15, 0, %0, c1, c0, 0\n"
	46	" mrc p15, 0, %0, c1, c0, 1\n"
	47	" orr %0, %0, #0x20\n"
	48	" mcr p15, 0, %0, c1, c0, 1\n"
	49	: "=&r" (v)
e3d9c625	50	: "Ir" (CR_C)
97a63ecf RK	51	: "cc");
	52	}
	53
d4450261	54	static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
97a63ecf RK	55	{
	56	/*
	57	* there is no power-control hardware on this platform, so all
	58	* we can do is put the core into WFI; this is safe as the calling
	59	* code will have already disabled interrupts
	60	*/
	61	for (;;) {
	62	/*
	63	* here's the WFI
	64	*/
	65	asm(".word 0xe320f003\n"
	66	:
	67	:
	68	: "memory", "cc");
	69
4a139b64	70	if (pen_release == cpu_logical_map(cpu)) {
97a63ecf RK	71	/*
	72	* OK, proper wakeup, we're done
	73	*/
	74	break;
	75	}
	76
	77	/*
d4450261	78	* Getting here, means that we have come out of WFI without
97a63ecf RK	79	* having been woken up - this shouldn't happen
97a63ecf RK	80	*
d4450261 RK	81	* Just note it happening - when we're woken, we can report
d4450261 RK	82	* its occurrence.
97a63ecf	83	*/
d4450261	84	(*spurious)++;
97a63ecf RK	85	}
	86	}
	87
97a63ecf RK	88	/*
	89	* platform-specific code to shutdown a CPU
	90	*
	91	* Called with IRQs disabled
	92	*/
b96fc2f3	93	void realview_cpu_die(unsigned int cpu)
97a63ecf	94	{
d4450261 RK	95	int spurious = 0;
d4450261 RK	96
97a63ecf RK	97	/*
	98	* we're ready for shutdown now, so do it
	99	*/
	100	cpu_enter_lowpower();
d4450261	101	platform_do_lowpower(cpu, &spurious);
97a63ecf RK	102
	103	/*
	104	* bring this CPU back into the world of cache
	105	* coherency, and then restore interrupts
	106	*/
	107	cpu_leave_lowpower();
d4450261 RK	108
	109	if (spurious)
	110	pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
97a63ecf	111	}