1 /* 2 * arch/arm/include/asm/mcpm.h 3 * 4 * Created by: Nicolas Pitre, April 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 12 #ifndef MCPM_H 13 #define MCPM_H 14 15 /* 16 * Maximum number of possible clusters / CPUs per cluster. 17 * 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. 21 */ 22 #define MAX_CPUS_PER_CLUSTER 4 23 #define MAX_NR_CLUSTERS 2 24 25 #ifndef __ASSEMBLY__ 26 27 #include <linux/types.h> 28 #include <asm/cacheflush.h> 29 30 /* 31 * Platform specific code should use this symbol to set up secondary 32 * entry location for processors to use when released from reset. 33 */ 34 extern void mcpm_entry_point(void); 35 36 /* 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 40 * becomes non NULL. 41 */ 42 void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr); 43 44 /* 45 * CPU/cluster power operations API for higher subsystems to use. 46 */ 47 48 /** 49 * mcpm_cpu_power_up - make given CPU in given cluster runable 50 * 51 * @cpu: CPU number within given cluster 52 * @cluster: cluster number for the CPU 53 * 54 * The identified CPU is brought out of reset. If the cluster was powered 55 * down then it is brought up as well, taking care not to let the other CPUs 56 * in the cluster run, and ensuring appropriate cluster setup. 57 * 58 * Caller must ensure the appropriate entry vector is initialized with 59 * mcpm_set_entry_vector() prior to calling this. 60 * 61 * This must be called in a sleepable context. However, the implementation 62 * is strongly encouraged to return early and let the operation happen 63 * asynchronously, especially when significant delays are expected. 64 * 65 * If the operation cannot be performed then an error code is returned. 66 */ 67 int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster); 68 69 /** 70 * mcpm_cpu_power_down - power the calling CPU down 71 * 72 * The calling CPU is powered down. 73 * 74 * If this CPU is found to be the "last man standing" in the cluster 75 * then the cluster is prepared for power-down too. 76 * 77 * This must be called with interrupts disabled. 78 * 79 * On success this does not return. Re-entry in the kernel is expected 80 * via mcpm_entry_point. 81 * 82 * This will return if mcpm_platform_register() has not been called 83 * previously in which case the caller should take appropriate action. 84 */ 85 void mcpm_cpu_power_down(void); 86 87 /** 88 * mcpm_cpu_suspend - bring the calling CPU in a suspended state 89 * 90 * @expected_residency: duration in microseconds the CPU is expected 91 * to remain suspended, or 0 if unknown/infinity. 92 * 93 * The calling CPU is suspended. The expected residency argument is used 94 * as a hint by the platform specific backend to implement the appropriate 95 * sleep state level according to the knowledge it has on wake-up latency 96 * for the given hardware. 97 * 98 * If this CPU is found to be the "last man standing" in the cluster 99 * then the cluster may be prepared for power-down too, if the expected 100 * residency makes it worthwhile. 101 * 102 * This must be called with interrupts disabled. 103 * 104 * On success this does not return. Re-entry in the kernel is expected 105 * via mcpm_entry_point. 106 * 107 * This will return if mcpm_platform_register() has not been called 108 * previously in which case the caller should take appropriate action. 109 */ 110 void mcpm_cpu_suspend(u64 expected_residency); 111 112 /** 113 * mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up 114 * 115 * This lets the platform specific backend code perform needed housekeeping 116 * work. This must be called by the newly activated CPU as soon as it is 117 * fully operational in kernel space, before it enables interrupts. 118 * 119 * If the operation cannot be performed then an error code is returned. 120 */ 121 int mcpm_cpu_powered_up(void); 122 123 /* 124 * Platform specific methods used in the implementation of the above API. 125 */ 126 struct mcpm_platform_ops { 127 int (*power_up)(unsigned int cpu, unsigned int cluster); 128 void (*power_down)(void); 129 void (*suspend)(u64); 130 void (*powered_up)(void); 131 }; 132 133 /** 134 * mcpm_platform_register - register platform specific power methods 135 * 136 * @ops: mcpm_platform_ops structure to register 137 * 138 * An error is returned if the registration has been done previously. 139 */ 140 int __init mcpm_platform_register(const struct mcpm_platform_ops *ops); 141 142 /* Synchronisation structures for coordinating safe cluster setup/teardown: */ 143 144 /* 145 * When modifying this structure, make sure you update the MCPM_SYNC_ defines 146 * to match. 147 */ 148 struct mcpm_sync_struct { 149 /* individual CPU states */ 150 struct { 151 s8 cpu __aligned(__CACHE_WRITEBACK_GRANULE); 152 } cpus[MAX_CPUS_PER_CLUSTER]; 153 154 /* cluster state */ 155 s8 cluster __aligned(__CACHE_WRITEBACK_GRANULE); 156 157 /* inbound-side state */ 158 s8 inbound __aligned(__CACHE_WRITEBACK_GRANULE); 159 }; 160 161 struct sync_struct { 162 struct mcpm_sync_struct clusters[MAX_NR_CLUSTERS]; 163 }; 164 165 extern unsigned long sync_phys; /* physical address of *mcpm_sync */ 166 167 void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster); 168 void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster); 169 void __mcpm_outbound_leave_critical(unsigned int cluster, int state); 170 bool __mcpm_outbound_enter_critical(unsigned int this_cpu, unsigned int cluster); 171 int __mcpm_cluster_state(unsigned int cluster); 172 173 int __init mcpm_sync_init( 174 void (*power_up_setup)(unsigned int affinity_level)); 175 176 void __init mcpm_smp_set_ops(void); 177 178 #else 179 180 /* 181 * asm-offsets.h causes trouble when included in .c files, and cacheflush.h 182 * cannot be included in asm files. Let's work around the conflict like this. 183 */ 184 #include <asm/asm-offsets.h> 185 #define __CACHE_WRITEBACK_GRANULE CACHE_WRITEBACK_GRANULE 186 187 #endif /* ! __ASSEMBLY__ */ 188 189 /* Definitions for mcpm_sync_struct */ 190 #define CPU_DOWN 0x11 191 #define CPU_COMING_UP 0x12 192 #define CPU_UP 0x13 193 #define CPU_GOING_DOWN 0x14 194 195 #define CLUSTER_DOWN 0x21 196 #define CLUSTER_UP 0x22 197 #define CLUSTER_GOING_DOWN 0x23 198 199 #define INBOUND_NOT_COMING_UP 0x31 200 #define INBOUND_COMING_UP 0x32 201 202 /* 203 * Offsets for the mcpm_sync_struct members, for use in asm. 204 * We don't want to make them global to the kernel via asm-offsets.c. 205 */ 206 #define MCPM_SYNC_CLUSTER_CPUS 0 207 #define MCPM_SYNC_CPU_SIZE __CACHE_WRITEBACK_GRANULE 208 #define MCPM_SYNC_CLUSTER_CLUSTER \ 209 (MCPM_SYNC_CLUSTER_CPUS + MCPM_SYNC_CPU_SIZE * MAX_CPUS_PER_CLUSTER) 210 #define MCPM_SYNC_CLUSTER_INBOUND \ 211 (MCPM_SYNC_CLUSTER_CLUSTER + __CACHE_WRITEBACK_GRANULE) 212 #define MCPM_SYNC_CLUSTER_SIZE \ 213 (MCPM_SYNC_CLUSTER_INBOUND + __CACHE_WRITEBACK_GRANULE) 214 215 #endif 216