blob: 41c252de0215b3c66aaad2c7074d90230b431c19 [file] [log] [blame]
Jeff Ohlstein9f1890a52010-12-02 12:11:27 -08001/*
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
15extern volatile int pen_release;
16
17static 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
24static inline void cpu_leave_lowpower(void)
25{
26}
27
28static 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
Will Deacon1d3cfb32011-08-09 12:02:27 +010040 if (pen_release == cpu_logical_map(cpu)) {
Jeff Ohlstein9f1890a52010-12-02 12:11:27 -080041 /*
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
59int 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 */
69void 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
84int 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}