[linux-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 <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;

	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, #0x04\n"
	"	mcr	p15, 0, %0, c1, c0, 0\n"
	  : "=&r" (v)
	  : "r" (0)
	  : "cc");
}

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

	asm volatile(	"mrc	p15, 0, %0, c1, c0, 0\n"
	"	orr	%0, %0, #0x04\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)
	  :
	  : "cc");
}

static inline void platform_do_lowpower(unsigned int cpu)
{
	/*
	 * 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
		 *
		 * The trouble is, letting people know about this is not really
		 * possible, since we are currently running incoherently, and
		 * therefore cannot safely call printk() or anything else
		 */
#ifdef DEBUG
		printk("CPU%u: spurious wakeup call\n", cpu);
#endif
	}
}

int platform_cpu_kill(unsigned int cpu)
{
	return wait_for_completion_timeout(&cpu_killed, 5000);
}

/*
 * platform-specific code to shutdown a CPU
 *
 * Called with IRQs disabled
 */
void platform_cpu_die(unsigned int cpu)
{
#ifdef DEBUG
	unsigned int this_cpu = hard_smp_processor_id();

	if (cpu != this_cpu) {
		printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n",
			   this_cpu, cpu);
		BUG();
	}
#endif

	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
	complete(&cpu_killed);

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

	/*
	 * bring this CPU back into the world of cache
	 * coherency, and then restore interrupts
	 */
	cpu_leave_lowpower();
}

int mach_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>
	14	#include <linux/completion.h>
	15
8aa2da87 HF	16	#include <asm/cacheflush.h>
8aa2da87 HF	17
97a63ecf RK	18	extern volatile int pen_release;
	19
	20	static DECLARE_COMPLETION(cpu_killed);
	21
	22	static inline void cpu_enter_lowpower(void)
	23	{
	24	unsigned int v;
	25
8aa2da87 HF	26	flush_cache_all();
8aa2da87 HF	27	asm volatile(
97a63ecf RK	28	" mcr p15, 0, %1, c7, c5, 0\n"
	29	" mcr p15, 0, %1, c7, c10, 4\n"
	30	/*
	31	* Turn off coherency
	32	*/
	33	" mrc p15, 0, %0, c1, c0, 1\n"
	34	" bic %0, %0, #0x20\n"
	35	" mcr p15, 0, %0, c1, c0, 1\n"
	36	" mrc p15, 0, %0, c1, c0, 0\n"
	37	" bic %0, %0, #0x04\n"
	38	" mcr p15, 0, %0, c1, c0, 0\n"
	39	: "=&r" (v)
	40	: "r" (0)
	41	: "cc");
	42	}
	43
	44	static inline void cpu_leave_lowpower(void)
	45	{
	46	unsigned int v;
	47
	48	asm volatile( "mrc p15, 0, %0, c1, c0, 0\n"
	49	" orr %0, %0, #0x04\n"
	50	" mcr p15, 0, %0, c1, c0, 0\n"
	51	" mrc p15, 0, %0, c1, c0, 1\n"
	52	" orr %0, %0, #0x20\n"
	53	" mcr p15, 0, %0, c1, c0, 1\n"
	54	: "=&r" (v)
	55	:
	56	: "cc");
	57	}
	58
	59	static inline void platform_do_lowpower(unsigned int cpu)
	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	/*
	83	* getting here, means that we have come out of WFI without
	84	* having been woken up - this shouldn't happen
	85	*
	86	* The trouble is, letting people know about this is not really
	87	* possible, since we are currently running incoherently, and
	88	* therefore cannot safely call printk() or anything else
	89	*/
	90	#ifdef DEBUG
	91	printk("CPU%u: spurious wakeup call\n", cpu);
92	#endif
93	}
94	}
95
96	int platform_cpu_kill(unsigned int cpu)
97	{
98	return wait_for_completion_timeout(&cpu_killed, 5000);
99	}
100
101	/*
102	* platform-specific code to shutdown a CPU
103	*
104	* Called with IRQs disabled
105	*/
106	void platform_cpu_die(unsigned int cpu)
107	{
108	#ifdef DEBUG
109	unsigned int this_cpu = hard_smp_processor_id();
110
111	if (cpu != this_cpu) {
112	printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n",
113	this_cpu, cpu);
114	BUG();
115	}
116	#endif
117
118	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
119	complete(&cpu_killed);
120
121	/*
122	* we're ready for shutdown now, so do it
123	*/
124	cpu_enter_lowpower();
125	platform_do_lowpower(cpu);
126
127	/*
128	* bring this CPU back into the world of cache
129	* coherency, and then restore interrupts
130	*/
131	cpu_leave_lowpower();
132	}
133
134	int mach_cpu_disable(unsigned int cpu)
135	{
136	/*
137	* we don't allow CPU 0 to be shutdown (it is still too special
138	* e.g. clock tick interrupts)
139	*/
140	return cpu == 0 ? -EPERM : 0;
141	}