summaryrefslogtreecommitdiff
path: root/arch/arm/mach-exynos/hotplug.c
blob: 9c17a0a43858d84df39cab4ddc8d417ba1b644a5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
/* 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 <linux/io.h>

#include <asm/cacheflush.h>
#include <asm/cp15.h>
#include <asm/smp_plat.h>

#include <mach/regs-pmu.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)
{
	for (;;) {

		/* make cpu1 to be turned off at next WFI command */
		if (cpu == 1)
			__raw_writel(0, S5P_ARM_CORE1_CONFIGURATION);

		/*
		 * 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;
}