2 * arch/arm/include/asm/mcpm.h
4 * Created by: Nicolas Pitre, April 2012
5 * Copyright: (C) 2012-2013 Linaro Limited
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.
16 * Maximum number of possible clusters / CPUs per cluster.
18 * This should be sufficient for quite a while, while keeping the
19 * (assembly) code simpler. When this starts to grow then we'll have
20 * to consider dynamic allocation.
22 #define MAX_CPUS_PER_CLUSTER 4
23 #define MAX_NR_CLUSTERS 2
28 * Platform specific code should use this symbol to set up secondary
29 * entry location for processors to use when released from reset.
31 extern void mcpm_entry_point(void);
34 * This is used to indicate where the given CPU from given cluster should
35 * branch once it is ready to re-enter the kernel using ptr, or NULL if it
36 * should be gated. A gated CPU is held in a WFE loop until its vector
39 void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr);
42 * CPU/cluster power operations API for higher subsystems to use.
46 * mcpm_cpu_power_up - make given CPU in given cluster runable
48 * @cpu: CPU number within given cluster
49 * @cluster: cluster number for the CPU
51 * The identified CPU is brought out of reset. If the cluster was powered
52 * down then it is brought up as well, taking care not to let the other CPUs
53 * in the cluster run, and ensuring appropriate cluster setup.
55 * Caller must ensure the appropriate entry vector is initialized with
56 * mcpm_set_entry_vector() prior to calling this.
58 * This must be called in a sleepable context. However, the implementation
59 * is strongly encouraged to return early and let the operation happen
60 * asynchronously, especially when significant delays are expected.
62 * If the operation cannot be performed then an error code is returned.
64 int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster);
67 * mcpm_cpu_power_down - power the calling CPU down
69 * The calling CPU is powered down.
71 * If this CPU is found to be the "last man standing" in the cluster
72 * then the cluster is prepared for power-down too.
74 * This must be called with interrupts disabled.
76 * This does not return. Re-entry in the kernel is expected via
79 void mcpm_cpu_power_down(void);
82 * mcpm_cpu_suspend - bring the calling CPU in a suspended state
84 * @expected_residency: duration in microseconds the CPU is expected
85 * to remain suspended, or 0 if unknown/infinity.
87 * The calling CPU is suspended. The expected residency argument is used
88 * as a hint by the platform specific backend to implement the appropriate
89 * sleep state level according to the knowledge it has on wake-up latency
90 * for the given hardware.
92 * If this CPU is found to be the "last man standing" in the cluster
93 * then the cluster may be prepared for power-down too, if the expected
94 * residency makes it worthwhile.
96 * This must be called with interrupts disabled.
98 * This does not return. Re-entry in the kernel is expected via
101 void mcpm_cpu_suspend(u64 expected_residency);
104 * mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up
106 * This lets the platform specific backend code perform needed housekeeping
107 * work. This must be called by the newly activated CPU as soon as it is
108 * fully operational in kernel space, before it enables interrupts.
110 * If the operation cannot be performed then an error code is returned.
112 int mcpm_cpu_powered_up(void);
115 * Platform specific methods used in the implementation of the above API.
117 struct mcpm_platform_ops {
118 int (*power_up)(unsigned int cpu, unsigned int cluster);
119 void (*power_down)(void);
120 void (*suspend)(u64);
121 void (*powered_up)(void);
125 * mcpm_platform_register - register platform specific power methods
127 * @ops: mcpm_platform_ops structure to register
129 * An error is returned if the registration has been done previously.
131 int __init mcpm_platform_register(const struct mcpm_platform_ops *ops);
133 #endif /* ! __ASSEMBLY__ */