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Diffstat (limited to 'arch/arm/include/asm/mcpm.h')
| -rw-r--r-- | arch/arm/include/asm/mcpm.h | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h new file mode 100644 index 00000000000..0f7b7620e9a --- /dev/null +++ b/arch/arm/include/asm/mcpm.h @@ -0,0 +1,209 @@ +/* + * arch/arm/include/asm/mcpm.h + * + * Created by: Nicolas Pitre, April 2012 + * Copyright: (C) 2012-2013 Linaro Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef MCPM_H +#define MCPM_H + +/* + * Maximum number of possible clusters / CPUs per cluster. + * + * This should be sufficient for quite a while, while keeping the + * (assembly) code simpler. When this starts to grow then we'll have + * to consider dynamic allocation. + */ +#define MAX_CPUS_PER_CLUSTER 4 +#define MAX_NR_CLUSTERS 2 + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <asm/cacheflush.h> + +/* + * Platform specific code should use this symbol to set up secondary + * entry location for processors to use when released from reset. + */ +extern void mcpm_entry_point(void); + +/* + * This is used to indicate where the given CPU from given cluster should + * branch once it is ready to re-enter the kernel using ptr, or NULL if it + * should be gated. A gated CPU is held in a WFE loop until its vector + * becomes non NULL. + */ +void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr); + +/* + * CPU/cluster power operations API for higher subsystems to use. + */ + +/** + * mcpm_cpu_power_up - make given CPU in given cluster runable + * + * @cpu: CPU number within given cluster + * @cluster: cluster number for the CPU + * + * The identified CPU is brought out of reset. If the cluster was powered + * down then it is brought up as well, taking care not to let the other CPUs + * in the cluster run, and ensuring appropriate cluster setup. + * + * Caller must ensure the appropriate entry vector is initialized with + * mcpm_set_entry_vector() prior to calling this. + * + * This must be called in a sleepable context. However, the implementation + * is strongly encouraged to return early and let the operation happen + * asynchronously, especially when significant delays are expected. + * + * If the operation cannot be performed then an error code is returned. + */ +int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster); + +/** + * mcpm_cpu_power_down - power the calling CPU down + * + * The calling CPU is powered down. + * + * If this CPU is found to be the "last man standing" in the cluster + * then the cluster is prepared for power-down too. + * + * This must be called with interrupts disabled. + * + * This does not return. Re-entry in the kernel is expected via + * mcpm_entry_point. + */ +void mcpm_cpu_power_down(void); + +/** + * mcpm_cpu_suspend - bring the calling CPU in a suspended state + * + * @expected_residency: duration in microseconds the CPU is expected + * to remain suspended, or 0 if unknown/infinity. + * + * The calling CPU is suspended. The expected residency argument is used + * as a hint by the platform specific backend to implement the appropriate + * sleep state level according to the knowledge it has on wake-up latency + * for the given hardware. + * + * If this CPU is found to be the "last man standing" in the cluster + * then the cluster may be prepared for power-down too, if the expected + * residency makes it worthwhile. + * + * This must be called with interrupts disabled. + * + * This does not return. Re-entry in the kernel is expected via + * mcpm_entry_point. + */ +void mcpm_cpu_suspend(u64 expected_residency); + +/** + * mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up + * + * This lets the platform specific backend code perform needed housekeeping + * work. This must be called by the newly activated CPU as soon as it is + * fully operational in kernel space, before it enables interrupts. + * + * If the operation cannot be performed then an error code is returned. + */ +int mcpm_cpu_powered_up(void); + +/* + * Platform specific methods used in the implementation of the above API. + */ +struct mcpm_platform_ops { + int (*power_up)(unsigned int cpu, unsigned int cluster); + void (*power_down)(void); + void (*suspend)(u64); + void (*powered_up)(void); +}; + +/** + * mcpm_platform_register - register platform specific power methods + * + * @ops: mcpm_platform_ops structure to register + * + * An error is returned if the registration has been done previously. + */ +int __init mcpm_platform_register(const struct mcpm_platform_ops *ops); + +/* Synchronisation structures for coordinating safe cluster setup/teardown: */ + +/* + * When modifying this structure, make sure you update the MCPM_SYNC_ defines + * to match. + */ +struct mcpm_sync_struct { + /* individual CPU states */ + struct { + s8 cpu __aligned(__CACHE_WRITEBACK_GRANULE); + } cpus[MAX_CPUS_PER_CLUSTER]; + + /* cluster state */ + s8 cluster __aligned(__CACHE_WRITEBACK_GRANULE); + + /* inbound-side state */ + s8 inbound __aligned(__CACHE_WRITEBACK_GRANULE); +}; + +struct sync_struct { + struct mcpm_sync_struct clusters[MAX_NR_CLUSTERS]; +}; + +extern unsigned long sync_phys; /* physical address of *mcpm_sync */ + +void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster); +void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster); +void __mcpm_outbound_leave_critical(unsigned int cluster, int state); +bool __mcpm_outbound_enter_critical(unsigned int this_cpu, unsigned int cluster); +int __mcpm_cluster_state(unsigned int cluster); + +int __init mcpm_sync_init( + void (*power_up_setup)(unsigned int affinity_level)); + +void __init mcpm_smp_set_ops(void); + +#else + +/* + * asm-offsets.h causes trouble when included in .c files, and cacheflush.h + * cannot be included in asm files. Let's work around the conflict like this. + */ +#include <asm/asm-offsets.h> +#define __CACHE_WRITEBACK_GRANULE CACHE_WRITEBACK_GRANULE + +#endif /* ! __ASSEMBLY__ */ + +/* Definitions for mcpm_sync_struct */ +#define CPU_DOWN 0x11 +#define CPU_COMING_UP 0x12 +#define CPU_UP 0x13 +#define CPU_GOING_DOWN 0x14 + +#define CLUSTER_DOWN 0x21 +#define CLUSTER_UP 0x22 +#define CLUSTER_GOING_DOWN 0x23 + +#define INBOUND_NOT_COMING_UP 0x31 +#define INBOUND_COMING_UP 0x32 + +/* + * Offsets for the mcpm_sync_struct members, for use in asm. + * We don't want to make them global to the kernel via asm-offsets.c. + */ +#define MCPM_SYNC_CLUSTER_CPUS 0 +#define MCPM_SYNC_CPU_SIZE __CACHE_WRITEBACK_GRANULE +#define MCPM_SYNC_CLUSTER_CLUSTER \ + (MCPM_SYNC_CLUSTER_CPUS + MCPM_SYNC_CPU_SIZE * MAX_CPUS_PER_CLUSTER) +#define MCPM_SYNC_CLUSTER_INBOUND \ + (MCPM_SYNC_CLUSTER_CLUSTER + __CACHE_WRITEBACK_GRANULE) +#define MCPM_SYNC_CLUSTER_SIZE \ + (MCPM_SYNC_CLUSTER_INBOUND + __CACHE_WRITEBACK_GRANULE) + +#endif |