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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 | |
8aa2da87 | 15 | #include <asm/cacheflush.h> |
eb50439b | 16 | #include <asm/smp_plat.h> |
8aa2da87 | 17 | |
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18 | extern volatile int pen_release; |
19 | ||
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20 | static inline void cpu_enter_lowpower(void) |
21 | { | |
22 | unsigned int v; | |
23 | ||
8aa2da87 HF |
24 | flush_cache_all(); |
25 | asm volatile( | |
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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" | |
e3d9c625 | 35 | " bic %0, %0, %2\n" |
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36 | " mcr p15, 0, %0, c1, c0, 0\n" |
37 | : "=&r" (v) | |
e3d9c625 | 38 | : "r" (0), "Ir" (CR_C) |
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39 | : "cc"); |
40 | } | |
41 | ||
42 | static inline void cpu_leave_lowpower(void) | |
43 | { | |
44 | unsigned int v; | |
45 | ||
46 | asm volatile( "mrc p15, 0, %0, c1, c0, 0\n" | |
e3d9c625 | 47 | " orr %0, %0, %1\n" |
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48 | " mcr p15, 0, %0, c1, c0, 0\n" |
49 | " mrc p15, 0, %0, c1, c0, 1\n" | |
50 | " orr %0, %0, #0x20\n" | |
51 | " mcr p15, 0, %0, c1, c0, 1\n" | |
52 | : "=&r" (v) | |
e3d9c625 | 53 | : "Ir" (CR_C) |
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54 | : "cc"); |
55 | } | |
56 | ||
d4450261 | 57 | static inline void platform_do_lowpower(unsigned int cpu, int *spurious) |
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58 | { |
59 | /* | |
60 | * there is no power-control hardware on this platform, so all | |
61 | * we can do is put the core into WFI; this is safe as the calling | |
62 | * code will have already disabled interrupts | |
63 | */ | |
64 | for (;;) { | |
65 | /* | |
66 | * here's the WFI | |
67 | */ | |
68 | asm(".word 0xe320f003\n" | |
69 | : | |
70 | : | |
71 | : "memory", "cc"); | |
72 | ||
4a139b64 | 73 | if (pen_release == cpu_logical_map(cpu)) { |
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74 | /* |
75 | * OK, proper wakeup, we're done | |
76 | */ | |
77 | break; | |
78 | } | |
79 | ||
80 | /* | |
d4450261 | 81 | * Getting here, means that we have come out of WFI without |
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82 | * having been woken up - this shouldn't happen |
83 | * | |
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84 | * Just note it happening - when we're woken, we can report |
85 | * its occurrence. | |
97a63ecf | 86 | */ |
d4450261 | 87 | (*spurious)++; |
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88 | } |
89 | } | |
90 | ||
91 | int platform_cpu_kill(unsigned int cpu) | |
92 | { | |
3c030bea | 93 | return 1; |
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94 | } |
95 | ||
96 | /* | |
97 | * platform-specific code to shutdown a CPU | |
98 | * | |
99 | * Called with IRQs disabled | |
100 | */ | |
101 | void platform_cpu_die(unsigned int cpu) | |
102 | { | |
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103 | int spurious = 0; |
104 | ||
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105 | /* |
106 | * we're ready for shutdown now, so do it | |
107 | */ | |
108 | cpu_enter_lowpower(); | |
d4450261 | 109 | platform_do_lowpower(cpu, &spurious); |
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110 | |
111 | /* | |
112 | * bring this CPU back into the world of cache | |
113 | * coherency, and then restore interrupts | |
114 | */ | |
115 | cpu_leave_lowpower(); | |
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116 | |
117 | if (spurious) | |
118 | pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); | |
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119 | } |
120 | ||
8e2a43f5 | 121 | int platform_cpu_disable(unsigned int cpu) |
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122 | { |
123 | /* | |
124 | * we don't allow CPU 0 to be shutdown (it is still too special | |
125 | * e.g. clock tick interrupts) | |
126 | */ | |
127 | return cpu == 0 ? -EPERM : 0; | |
128 | } |