[deliverable/linux.git] / arch / arm / mach-tegra / 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>

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(KERN_WARN "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 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
1cea7326 CC	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
	16	#include <asm/cacheflush.h>
	17
	18	static DECLARE_COMPLETION(cpu_killed);
	19
	20	static inline void cpu_enter_lowpower(void)
	21	{
	22	unsigned int v;
	23
	24	flush_cache_all();
	25	asm volatile(
	26	" mcr p15, 0, %1, c7, c5, 0\n"
	27	" mcr p15, 0, %1, c7, c10, 4\n"
	28	/*
	29	* Turn off coherency
	30	*/
	31	" mrc p15, 0, %0, c1, c0, 1\n"
	32	" bic %0, %0, #0x20\n"
	33	" mcr p15, 0, %0, c1, c0, 1\n"
	34	" mrc p15, 0, %0, c1, c0, 0\n"
	35	" bic %0, %0, #0x04\n"
	36	" mcr p15, 0, %0, c1, c0, 0\n"
	37	: "=&r" (v)
	38	: "r" (0)
	39	: "cc");
	40	}
	41
	42	static inline void cpu_leave_lowpower(void)
	43	{
	44	unsigned int v;
	45
	46	asm volatile(
	47	"mrc p15, 0, %0, c1, c0, 0\n"
	48	" orr %0, %0, #0x04\n"
	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)
	54	:
	55	: "cc");
	56	}
	57
	58	static inline void platform_do_lowpower(unsigned int cpu)
	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
74	/if (pen_release == cpu) {/
75	/*
76	* OK, proper wakeup, we're done
77	*/
78	break;
79	/}/
80
81	/*
82	* getting here, means that we have come out of WFI without
83	* having been woken up - this shouldn't happen
84	*
85	* The trouble is, letting people know about this is not really
86	* possible, since we are currently running incoherently, and
87	* therefore cannot safely call printk() or anything else
88	*/
89	#ifdef DEBUG
90	printk(KERN_WARN "CPU%u: spurious wakeup call\n", cpu);
91	#endif
92	}
93	}
94
95	int platform_cpu_kill(unsigned int cpu)
96	{
97	return wait_for_completion_timeout(&cpu_killed, 5000);
98	}
99
100	/*
101	* platform-specific code to shutdown a CPU
102	*
103	* Called with IRQs disabled
104	*/
105	void platform_cpu_die(unsigned int cpu)
106	{
107	#ifdef DEBUG
108	unsigned int this_cpu = hard_smp_processor_id();
109
110	if (cpu != this_cpu) {
111	printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n",
112	this_cpu, cpu);
113	BUG();
114	}
115	#endif
116
117	printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
118	complete(&cpu_killed);
119
120	/*
121	* we're ready for shutdown now, so do it
122	*/
123	cpu_enter_lowpower();
124	platform_do_lowpower(cpu);
125
126	/*
127	* bring this CPU back into the world of cache
128	* coherency, and then restore interrupts
129	*/
130	cpu_leave_lowpower();
131	}
132
133	int platform_cpu_disable(unsigned int cpu)
134	{
135	/*
136	* we don't allow CPU 0 to be shutdown (it is still too special
137	* e.g. clock tick interrupts)
138	*/
139	return cpu == 0 ? -EPERM : 0;
140	}