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
136
137
138
139
140
141
142
143
144
|
/* linux arch/arm/mach-s5pv310/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/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(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;
}
|
