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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 | |
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18 | static inline void cpu_enter_lowpower(void) |
19 | { | |
20 | unsigned int v; | |
21 | ||
8aa2da87 | 22 | asm volatile( |
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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" |
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33 | " mcr p15, 0, %0, c1, c0, 0\n" |
34 | : "=&r" (v) | |
e3d9c625 | 35 | : "r" (0), "Ir" (CR_C) |
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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" |
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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) |
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51 | : "cc"); |
52 | } | |
53 | ||
d4450261 | 54 | static inline void platform_do_lowpower(unsigned int cpu, int *spurious) |
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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)) { |
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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 |
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79 | * having been woken up - this shouldn't happen |
80 | * | |
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81 | * Just note it happening - when we're woken, we can report |
82 | * its occurrence. | |
97a63ecf | 83 | */ |
d4450261 | 84 | (*spurious)++; |
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85 | } |
86 | } | |
87 | ||
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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 | { |
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95 | int spurious = 0; |
96 | ||
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97 | /* |
98 | * we're ready for shutdown now, so do it | |
99 | */ | |
100 | cpu_enter_lowpower(); | |
d4450261 | 101 | platform_do_lowpower(cpu, &spurious); |
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102 | |
103 | /* | |
104 | * bring this CPU back into the world of cache | |
105 | * coherency, and then restore interrupts | |
106 | */ | |
107 | cpu_leave_lowpower(); | |
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108 | |
109 | if (spurious) | |
110 | pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); | |
97a63ecf | 111 | } |