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 * This does not return. Re-entry in the kernel is expected via 80 * mcpm_entry_point. 81 */ 82 void mcpm_cpu_power_down(void); 83 84 /** 85 * mcpm_cpu_suspend - bring the calling CPU in a suspended state 86 * 87 * @expected_residency: duration in microseconds the CPU is expected 88 * to remain suspended, or 0 if unknown/infinity. 89 * 90 * The calling CPU is suspended. The expected residency argument is used 91 * as a hint by the platform specific backend to implement the appropriate 92 * sleep state level according to the knowledge it has on wake-up latency 93 * for the given hardware. 94 * 95 * If this CPU is found to be the "last man standing" in the cluster 96 * then the cluster may be prepared for power-down too, if the expected 97 * residency makes it worthwhile. 98 * 99 * This must be called with interrupts disabled. 100 * 101 * This does not return. Re-entry in the kernel is expected via 102 * mcpm_entry_point. 103 */ 104 void mcpm_cpu_suspend(u64 expected_residency); 105 106 /** 107 * mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up 108 * 109 * This lets the platform specific backend code perform needed housekeeping 110 * work. This must be called by the newly activated CPU as soon as it is 111 * fully operational in kernel space, before it enables interrupts. 112 * 113 * If the operation cannot be performed then an error code is returned. 114 */ 115 int mcpm_cpu_powered_up(void); 116 117 /* 118 * Platform specific methods used in the implementation of the above API. 119 */ 120 struct mcpm_platform_ops { 121 int (*power_up)(unsigned int cpu, unsigned int cluster); 122 void (*power_down)(void); 123 void (*suspend)(u64); 124 void (*powered_up)(void); 125 }; 126 127 /** 128 * mcpm_platform_register - register platform specific power methods 129 * 130 * @ops: mcpm_platform_ops structure to register 131 * 132 * An error is returned if the registration has been done previously. 133 */ 134 int __init mcpm_platform_register(const struct mcpm_platform_ops *ops); 135 136 /* Synchronisation structures for coordinating safe cluster setup/teardown: */ 137 138 /* 139 * When modifying this structure, make sure you update the MCPM_SYNC_ defines 140 * to match. 141 */ 142 struct mcpm_sync_struct { 143 /* individual CPU states */ 144 struct { 145 s8 cpu __aligned(__CACHE_WRITEBACK_GRANULE); 146 } cpus[MAX_CPUS_PER_CLUSTER]; 147 148 /* cluster state */ 149 s8 cluster __aligned(__CACHE_WRITEBACK_GRANULE); 150 151 /* inbound-side state */ 152 s8 inbound __aligned(__CACHE_WRITEBACK_GRANULE); 153 }; 154 155 struct sync_struct { 156 struct mcpm_sync_struct clusters[MAX_NR_CLUSTERS]; 157 }; 158 159 extern unsigned long sync_phys; /* physical address of *mcpm_sync */ 160 161 void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster); 162 void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster); 163 void __mcpm_outbound_leave_critical(unsigned int cluster, int state); 164 bool __mcpm_outbound_enter_critical(unsigned int this_cpu, unsigned int cluster); 165 int __mcpm_cluster_state(unsigned int cluster); 166 167 int __init mcpm_sync_init( 168 void (*power_up_setup)(unsigned int affinity_level)); 169 170 void __init mcpm_smp_set_ops(void); 171 172 #else 173 174 /* 175 * asm-offsets.h causes trouble when included in .c files, and cacheflush.h 176 * cannot be included in asm files. Let's work around the conflict like this. 177 */ 178 #include <asm/asm-offsets.h> 179 #define __CACHE_WRITEBACK_GRANULE CACHE_WRITEBACK_GRANULE 180 181 #endif /* ! __ASSEMBLY__ */ 182 183 /* Definitions for mcpm_sync_struct */ 184 #define CPU_DOWN 0x11 185 #define CPU_COMING_UP 0x12 186 #define CPU_UP 0x13 187 #define CPU_GOING_DOWN 0x14 188 189 #define CLUSTER_DOWN 0x21 190 #define CLUSTER_UP 0x22 191 #define CLUSTER_GOING_DOWN 0x23 192 193 #define INBOUND_NOT_COMING_UP 0x31 194 #define INBOUND_COMING_UP 0x32 195 196 /* 197 * Offsets for the mcpm_sync_struct members, for use in asm. 198 * We don't want to make them global to the kernel via asm-offsets.c. 199 */ 200 #define MCPM_SYNC_CLUSTER_CPUS 0 201 #define MCPM_SYNC_CPU_SIZE __CACHE_WRITEBACK_GRANULE 202 #define MCPM_SYNC_CLUSTER_CLUSTER \ 203 (MCPM_SYNC_CLUSTER_CPUS + MCPM_SYNC_CPU_SIZE * MAX_CPUS_PER_CLUSTER) 204 #define MCPM_SYNC_CLUSTER_INBOUND \ 205 (MCPM_SYNC_CLUSTER_CLUSTER + __CACHE_WRITEBACK_GRANULE) 206 #define MCPM_SYNC_CLUSTER_SIZE \ 207 (MCPM_SYNC_CLUSTER_INBOUND + __CACHE_WRITEBACK_GRANULE) 208 209 #endif 210