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gerrit.openfyde.cn / github.com / raspberrypi / raspberrypi-kernel / 7c2b860534d02d11923dd0504b961f21508173f1 / . / arch / arm / common / mcpm_entry.c
blob: 5d72889a58a4cf2715b3f2f1b92e8a7a4e8fae9f [file] [log] [blame]
Nicolas Pitree8db2882012-04-12 02:45:22 -0400[diff] [blame]1/*
2 * arch/arm/common/mcpm_entry.c -- entry point for multi-cluster PM
3 *
4 * Created by: Nicolas Pitre, March 2012
5 * Copyright: (C) 2012-2013 Linaro Limited
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
Nicolas Pitre7c2b8602012-09-20 16:05:37 -0400[diff] [blame^]12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/irqflags.h>
15
Nicolas Pitree8db2882012-04-12 02:45:22 -0400[diff] [blame]16#include <asm/mcpm.h>
17#include <asm/cacheflush.h>
Nicolas Pitre7c2b8602012-09-20 16:05:37 -0400[diff] [blame^]18#include <asm/idmap.h>
Nicolas Pitree8db2882012-04-12 02:45:22 -0400[diff] [blame]19
20extern unsigned long mcpm_entry_vectors[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER];
21
22void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr)
23{
24 unsigned long val = ptr ? virt_to_phys(ptr) : 0;
25 mcpm_entry_vectors[cluster][cpu] = val;
26 sync_cache_w(&mcpm_entry_vectors[cluster][cpu]);
27}
Nicolas Pitre7c2b8602012-09-20 16:05:37 -0400[diff] [blame^]28
29static const struct mcpm_platform_ops *platform_ops;
30
31int __init mcpm_platform_register(const struct mcpm_platform_ops *ops)
32{
33 if (platform_ops)
34 return -EBUSY;
35 platform_ops = ops;
36 return 0;
37}
38
39int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster)
40{
41 if (!platform_ops)
42 return -EUNATCH; /* try not to shadow power_up errors */
43 might_sleep();
44 return platform_ops->power_up(cpu, cluster);
45}
46
47typedef void (*phys_reset_t)(unsigned long);
48
49void mcpm_cpu_power_down(void)
50{
51 phys_reset_t phys_reset;
52
53 BUG_ON(!platform_ops);
54 BUG_ON(!irqs_disabled());
55
56 /*
57 * Do this before calling into the power_down method,
58 * as it might not always be safe to do afterwards.
59 */
60 setup_mm_for_reboot();
61
62 platform_ops->power_down();
63
64 /*
65 * It is possible for a power_up request to happen concurrently
66 * with a power_down request for the same CPU. In this case the
67 * power_down method might not be able to actually enter a
68 * powered down state with the WFI instruction if the power_up
69 * method has removed the required reset condition. The
70 * power_down method is then allowed to return. We must perform
71 * a re-entry in the kernel as if the power_up method just had
72 * deasserted reset on the CPU.
73 *
74 * To simplify race issues, the platform specific implementation
75 * must accommodate for the possibility of unordered calls to
76 * power_down and power_up with a usage count. Therefore, if a
77 * call to power_up is issued for a CPU that is not down, then
78 * the next call to power_down must not attempt a full shutdown
79 * but only do the minimum (normally disabling L1 cache and CPU
80 * coherency) and return just as if a concurrent power_up request
81 * had happened as described above.
82 */
83
84 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
85 phys_reset(virt_to_phys(mcpm_entry_point));
86
87 /* should never get here */
88 BUG();
89}
90
91void mcpm_cpu_suspend(u64 expected_residency)
92{
93 phys_reset_t phys_reset;
94
95 BUG_ON(!platform_ops);
96 BUG_ON(!irqs_disabled());
97
98 /* Very similar to mcpm_cpu_power_down() */
99 setup_mm_for_reboot();
100 platform_ops->suspend(expected_residency);
101 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
102 phys_reset(virt_to_phys(mcpm_entry_point));
103 BUG();
104}
105
106int mcpm_cpu_powered_up(void)
107{
108 if (!platform_ops)
109 return -EUNATCH;
110 if (platform_ops->powered_up)
111 platform_ops->powered_up();
112 return 0;
113}