Commit | Line | Data |
---|---|---|
9f1890a5 JO |
1 | /* |
2 | * Copyright (C) 2002 ARM Ltd. | |
3 | * All Rights Reserved | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/errno.h> | |
11 | #include <linux/smp.h> | |
12 | ||
13 | #include <asm/cacheflush.h> | |
14 | ||
15 | extern volatile int pen_release; | |
16 | ||
17 | static inline void cpu_enter_lowpower(void) | |
18 | { | |
19 | /* Just flush the cache. Changing the coherency is not yet | |
20 | * available on msm. */ | |
21 | flush_cache_all(); | |
22 | } | |
23 | ||
24 | static inline void cpu_leave_lowpower(void) | |
25 | { | |
26 | } | |
27 | ||
28 | static inline void platform_do_lowpower(unsigned int cpu) | |
29 | { | |
30 | /* Just enter wfi for now. TODO: Properly shut off the cpu. */ | |
31 | for (;;) { | |
32 | /* | |
33 | * here's the WFI | |
34 | */ | |
35 | asm("wfi" | |
36 | : | |
37 | : | |
38 | : "memory", "cc"); | |
39 | ||
40 | if (pen_release == cpu) { | |
41 | /* | |
42 | * OK, proper wakeup, we're done | |
43 | */ | |
44 | break; | |
45 | } | |
46 | ||
47 | /* | |
48 | * getting here, means that we have come out of WFI without | |
49 | * having been woken up - this shouldn't happen | |
50 | * | |
51 | * The trouble is, letting people know about this is not really | |
52 | * possible, since we are currently running incoherently, and | |
53 | * therefore cannot safely call printk() or anything else | |
54 | */ | |
55 | pr_debug("CPU%u: spurious wakeup call\n", cpu); | |
56 | } | |
57 | } | |
58 | ||
59 | int platform_cpu_kill(unsigned int cpu) | |
60 | { | |
61 | return 1; | |
62 | } | |
63 | ||
64 | /* | |
65 | * platform-specific code to shutdown a CPU | |
66 | * | |
67 | * Called with IRQs disabled | |
68 | */ | |
69 | void platform_cpu_die(unsigned int cpu) | |
70 | { | |
71 | /* | |
72 | * we're ready for shutdown now, so do it | |
73 | */ | |
74 | cpu_enter_lowpower(); | |
75 | platform_do_lowpower(cpu); | |
76 | ||
77 | /* | |
78 | * bring this CPU back into the world of cache | |
79 | * coherency, and then restore interrupts | |
80 | */ | |
81 | cpu_leave_lowpower(); | |
82 | } | |
83 | ||
84 | int platform_cpu_disable(unsigned int cpu) | |
85 | { | |
86 | /* | |
87 | * we don't allow CPU 0 to be shutdown (it is still too special | |
88 | * e.g. clock tick interrupts) | |
89 | */ | |
90 | return cpu == 0 ? -EPERM : 0; | |
91 | } |