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e9882777 RK |
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 | ||
eb50439b | 15 | #include <asm/smp_plat.h> |
15d07dc9 | 16 | #include <asm/cp15.h> |
e9882777 | 17 | |
e9882777 RK |
18 | static inline void cpu_enter_lowpower(void) |
19 | { | |
20 | unsigned int v; | |
21 | ||
e9882777 RK |
22 | asm volatile( |
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, %3\n" | |
30 | " mcr p15, 0, %0, c1, c0, 1\n" | |
31 | " mrc p15, 0, %0, c1, c0, 0\n" | |
32 | " bic %0, %0, %2\n" | |
33 | " mcr p15, 0, %0, c1, c0, 0\n" | |
34 | : "=&r" (v) | |
35 | : "r" (0), "Ir" (CR_C), "Ir" (0x40) | |
36 | : "cc"); | |
37 | } | |
38 | ||
39 | static inline void cpu_leave_lowpower(void) | |
40 | { | |
41 | unsigned int v; | |
42 | ||
43 | asm volatile( | |
44 | "mrc p15, 0, %0, c1, c0, 0\n" | |
45 | " orr %0, %0, %1\n" | |
46 | " mcr p15, 0, %0, c1, c0, 0\n" | |
47 | " mrc p15, 0, %0, c1, c0, 1\n" | |
48 | " orr %0, %0, %2\n" | |
49 | " mcr p15, 0, %0, c1, c0, 1\n" | |
50 | : "=&r" (v) | |
51 | : "Ir" (CR_C), "Ir" (0x40) | |
52 | : "cc"); | |
53 | } | |
54 | ||
55 | static inline void platform_do_lowpower(unsigned int cpu, int *spurious) | |
56 | { | |
57 | /* | |
58 | * there is no power-control hardware on this platform, so all | |
59 | * we can do is put the core into WFI; this is safe as the calling | |
60 | * code will have already disabled interrupts | |
61 | */ | |
62 | for (;;) { | |
b3377d18 | 63 | wfi(); |
e9882777 | 64 | |
4a139b64 | 65 | if (pen_release == cpu_logical_map(cpu)) { |
e9882777 RK |
66 | /* |
67 | * OK, proper wakeup, we're done | |
68 | */ | |
69 | break; | |
70 | } | |
71 | ||
72 | /* | |
73 | * Getting here, means that we have come out of WFI without | |
74 | * having been woken up - this shouldn't happen | |
75 | * | |
76 | * Just note it happening - when we're woken, we can report | |
77 | * its occurrence. | |
78 | */ | |
79 | (*spurious)++; | |
80 | } | |
81 | } | |
82 | ||
e9882777 RK |
83 | /* |
84 | * platform-specific code to shutdown a CPU | |
85 | * | |
86 | * Called with IRQs disabled | |
87 | */ | |
b96fc2f3 | 88 | void vexpress_cpu_die(unsigned int cpu) |
e9882777 RK |
89 | { |
90 | int spurious = 0; | |
91 | ||
92 | /* | |
93 | * we're ready for shutdown now, so do it | |
94 | */ | |
95 | cpu_enter_lowpower(); | |
96 | platform_do_lowpower(cpu, &spurious); | |
97 | ||
98 | /* | |
99 | * bring this CPU back into the world of cache | |
100 | * coherency, and then restore interrupts | |
101 | */ | |
102 | cpu_leave_lowpower(); | |
103 | ||
104 | if (spurious) | |
105 | pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); | |
106 | } |