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
27 #include <linux/types.h>
28 #include <asm/cacheflush.h>
31 * Platform specific code should use this symbol to set up secondary
32 * entry location for processors to use when released from reset.
34 extern void mcpm_entry_point(void);
37 * This is used to indicate where the given CPU from given cluster should
38 * branch once it is ready to re-enter the kernel using ptr, or NULL if it
39 * should be gated. A gated CPU is held in a WFE loop until its vector
42 void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr);
45 * This sets an early poke i.e a value to be poked into some address
46 * from very early assembly code before the CPU is ungated. The
47 * address must be physical, and if 0 then nothing will happen.
49 void mcpm_set_early_poke(unsigned cpu, unsigned cluster,
50 unsigned long poke_phys_addr, unsigned long poke_val);
53 * CPU/cluster power operations API for higher subsystems to use.
57 * mcpm_cpu_power_up - make given CPU in given cluster runable
59 * @cpu: CPU number within given cluster
60 * @cluster: cluster number for the CPU
62 * The identified CPU is brought out of reset. If the cluster was powered
63 * down then it is brought up as well, taking care not to let the other CPUs
64 * in the cluster run, and ensuring appropriate cluster setup.
66 * Caller must ensure the appropriate entry vector is initialized with
67 * mcpm_set_entry_vector() prior to calling this.
69 * This must be called in a sleepable context. However, the implementation
70 * is strongly encouraged to return early and let the operation happen
71 * asynchronously, especially when significant delays are expected.
73 * If the operation cannot be performed then an error code is returned.
75 int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster);
78 * mcpm_cpu_power_down - power the calling CPU down
80 * The calling CPU is powered down.
82 * If this CPU is found to be the "last man standing" in the cluster
83 * then the cluster is prepared for power-down too.
85 * This must be called with interrupts disabled.
87 * On success this does not return. Re-entry in the kernel is expected
88 * via mcpm_entry_point.
90 * This will return if mcpm_platform_register() has not been called
91 * previously in which case the caller should take appropriate action.
93 * On success, the CPU is not guaranteed to be truly halted until
94 * mcpm_cpu_power_down_finish() subsequently returns non-zero for the
95 * specified cpu. Until then, other CPUs should make sure they do not
96 * trash memory the target CPU might be executing/accessing.
98 void mcpm_cpu_power_down(void);
101 * mcpm_cpu_power_down_finish - wait for a specified CPU to halt, and
102 * make sure it is powered off
104 * @cpu: CPU number within given cluster
105 * @cluster: cluster number for the CPU
107 * Call this function to ensure that a pending powerdown has taken
108 * effect and the CPU is safely parked before performing non-mcpm
109 * operations that may affect the CPU (such as kexec trashing the
112 * It is *not* necessary to call this function if you only need to
113 * serialise a pending powerdown with mcpm_cpu_power_up() or a wakeup
116 * Do not call this function unless the specified CPU has already
117 * called mcpm_cpu_power_down() or has committed to doing so.
120 * - zero if the CPU is in a safely parked state
121 * - nonzero otherwise (e.g., timeout)
123 int mcpm_cpu_power_down_finish(unsigned int cpu, unsigned int cluster);
126 * mcpm_cpu_suspend - bring the calling CPU in a suspended state
128 * @expected_residency: duration in microseconds the CPU is expected
129 * to remain suspended, or 0 if unknown/infinity.
131 * The calling CPU is suspended. The expected residency argument is used
132 * as a hint by the platform specific backend to implement the appropriate
133 * sleep state level according to the knowledge it has on wake-up latency
134 * for the given hardware.
136 * If this CPU is found to be the "last man standing" in the cluster
137 * then the cluster may be prepared for power-down too, if the expected
138 * residency makes it worthwhile.
140 * This must be called with interrupts disabled.
142 * On success this does not return. Re-entry in the kernel is expected
143 * via mcpm_entry_point.
145 * This will return if mcpm_platform_register() has not been called
146 * previously in which case the caller should take appropriate action.
148 void mcpm_cpu_suspend(u64 expected_residency);
151 * mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up
153 * This lets the platform specific backend code perform needed housekeeping
154 * work. This must be called by the newly activated CPU as soon as it is
155 * fully operational in kernel space, before it enables interrupts.
157 * If the operation cannot be performed then an error code is returned.
159 int mcpm_cpu_powered_up(void);
162 * Platform specific methods used in the implementation of the above API.
164 struct mcpm_platform_ops {
165 int (*power_up)(unsigned int cpu, unsigned int cluster);
166 void (*power_down)(void);
167 int (*power_down_finish)(unsigned int cpu, unsigned int cluster);
168 void (*suspend)(u64);
169 void (*powered_up)(void);
173 * mcpm_platform_register - register platform specific power methods
175 * @ops: mcpm_platform_ops structure to register
177 * An error is returned if the registration has been done previously.
179 int __init mcpm_platform_register(const struct mcpm_platform_ops *ops);
181 /* Synchronisation structures for coordinating safe cluster setup/teardown: */
184 * When modifying this structure, make sure you update the MCPM_SYNC_ defines
187 struct mcpm_sync_struct {
188 /* individual CPU states */
190 s8 cpu __aligned(__CACHE_WRITEBACK_GRANULE);
191 } cpus[MAX_CPUS_PER_CLUSTER];
194 s8 cluster __aligned(__CACHE_WRITEBACK_GRANULE);
196 /* inbound-side state */
197 s8 inbound __aligned(__CACHE_WRITEBACK_GRANULE);
201 struct mcpm_sync_struct clusters[MAX_NR_CLUSTERS];
204 extern unsigned long sync_phys; /* physical address of *mcpm_sync */
206 void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster);
207 void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster);
208 void __mcpm_outbound_leave_critical(unsigned int cluster, int state);
209 bool __mcpm_outbound_enter_critical(unsigned int this_cpu, unsigned int cluster);
210 int __mcpm_cluster_state(unsigned int cluster);
212 int __init mcpm_sync_init(
213 void (*power_up_setup)(unsigned int affinity_level));
215 void __init mcpm_smp_set_ops(void);
220 * asm-offsets.h causes trouble when included in .c files, and cacheflush.h
221 * cannot be included in asm files. Let's work around the conflict like this.
223 #include <asm/asm-offsets.h>
224 #define __CACHE_WRITEBACK_GRANULE CACHE_WRITEBACK_GRANULE
226 #endif /* ! __ASSEMBLY__ */
228 /* Definitions for mcpm_sync_struct */
229 #define CPU_DOWN 0x11
230 #define CPU_COMING_UP 0x12
232 #define CPU_GOING_DOWN 0x14
234 #define CLUSTER_DOWN 0x21
235 #define CLUSTER_UP 0x22
236 #define CLUSTER_GOING_DOWN 0x23
238 #define INBOUND_NOT_COMING_UP 0x31
239 #define INBOUND_COMING_UP 0x32
242 * Offsets for the mcpm_sync_struct members, for use in asm.
243 * We don't want to make them global to the kernel via asm-offsets.c.
245 #define MCPM_SYNC_CLUSTER_CPUS 0
246 #define MCPM_SYNC_CPU_SIZE __CACHE_WRITEBACK_GRANULE
247 #define MCPM_SYNC_CLUSTER_CLUSTER \
248 (MCPM_SYNC_CLUSTER_CPUS + MCPM_SYNC_CPU_SIZE * MAX_CPUS_PER_CLUSTER)
249 #define MCPM_SYNC_CLUSTER_INBOUND \
250 (MCPM_SYNC_CLUSTER_CLUSTER + __CACHE_WRITEBACK_GRANULE)
251 #define MCPM_SYNC_CLUSTER_SIZE \
252 (MCPM_SYNC_CLUSTER_INBOUND + __CACHE_WRITEBACK_GRANULE)