Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Nico Pitre | 282 | 63.66% | 10 | 66.67% |
Dave P Martin | 151 | 34.09% | 3 | 20.00% |
Haojian Zhuang | 8 | 1.81% | 1 | 6.67% |
Thomas Gleixner | 2 | 0.45% | 1 | 6.67% |
Total | 443 | 15 |
/* SPDX-License-Identifier: GPL-2.0-only */ /* * arch/arm/include/asm/mcpm.h * * Created by: Nicolas Pitre, April 2012 * Copyright: (C) 2012-2013 Linaro Limited */ #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 #ifdef CONFIG_MCPM_QUAD_CLUSTER #define MAX_NR_CLUSTERS 4 #else #define MAX_NR_CLUSTERS 2 #endif #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); /* * This sets an early poke i.e a value to be poked into some address * from very early assembly code before the CPU is ungated. The * address must be physical, and if 0 then nothing will happen. */ void mcpm_set_early_poke(unsigned cpu, unsigned cluster, unsigned long poke_phys_addr, unsigned long poke_val); /* * CPU/cluster power operations API for higher subsystems to use. */ /** * mcpm_is_available - returns whether MCPM is initialized and available * * This returns true or false accordingly. */ bool mcpm_is_available(void); /** * 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. * * On success this does not return. Re-entry in the kernel is expected * via mcpm_entry_point. * * This will return if mcpm_platform_register() has not been called * previously in which case the caller should take appropriate action. * * On success, the CPU is not guaranteed to be truly halted until * mcpm_wait_for_cpu_powerdown() subsequently returns non-zero for the * specified cpu. Until then, other CPUs should make sure they do not * trash memory the target CPU might be executing/accessing. */ void mcpm_cpu_power_down(void); /** * mcpm_wait_for_cpu_powerdown - wait for a specified CPU to halt, and * make sure it is powered off * * @cpu: CPU number within given cluster * @cluster: cluster number for the CPU * * Call this function to ensure that a pending powerdown has taken * effect and the CPU is safely parked before performing non-mcpm * operations that may affect the CPU (such as kexec trashing the * kernel text). * * It is *not* necessary to call this function if you only need to * serialise a pending powerdown with mcpm_cpu_power_up() or a wakeup * event. * * Do not call this function unless the specified CPU has already * called mcpm_cpu_power_down() or has committed to doing so. * * @return: * - zero if the CPU is in a safely parked state * - nonzero otherwise (e.g., timeout) */ int mcpm_wait_for_cpu_powerdown(unsigned int cpu, unsigned int cluster); /** * mcpm_cpu_suspend - bring the calling CPU in a suspended state * * The calling CPU is suspended. This is similar to mcpm_cpu_power_down() * except for possible extra platform specific configuration steps to allow * an asynchronous wake-up e.g. with a pending interrupt. * * If this CPU is found to be the "last man standing" in the cluster * then the cluster may be prepared for power-down too. * * This must be called with interrupts disabled. * * On success this does not return. Re-entry in the kernel is expected * via mcpm_entry_point. * * This will return if mcpm_platform_register() has not been called * previously in which case the caller should take appropriate action. */ void mcpm_cpu_suspend(void); /** * 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 callbacks used in the implementation of the above API. * * cpu_powerup: * Make given CPU runable. Called with MCPM lock held and IRQs disabled. * The given cluster is assumed to be set up (cluster_powerup would have * been called beforehand). Must return 0 for success or negative error code. * * cluster_powerup: * Set up power for given cluster. Called with MCPM lock held and IRQs * disabled. Called before first cpu_powerup when cluster is down. Must * return 0 for success or negative error code. * * cpu_suspend_prepare: * Special suspend configuration. Called on target CPU with MCPM lock held * and IRQs disabled. This callback is optional. If provided, it is called * before cpu_powerdown_prepare. * * cpu_powerdown_prepare: * Configure given CPU for power down. Called on target CPU with MCPM lock * held and IRQs disabled. Power down must be effective only at the next WFI instruction. * * cluster_powerdown_prepare: * Configure given cluster for power down. Called on one CPU from target * cluster with MCPM lock held and IRQs disabled. A cpu_powerdown_prepare * for each CPU in the cluster has happened when this occurs. * * cpu_cache_disable: * Clean and disable CPU level cache for the calling CPU. Called on with IRQs * disabled only. The CPU is no longer cache coherent with the rest of the * system when this returns. * * cluster_cache_disable: * Clean and disable the cluster wide cache as well as the CPU level cache * for the calling CPU. No call to cpu_cache_disable will happen for this * CPU. Called with IRQs disabled and only when all the other CPUs are done * with their own cpu_cache_disable. The cluster is no longer cache coherent * with the rest of the system when this returns. * * cpu_is_up: * Called on given CPU after it has been powered up or resumed. The MCPM lock * is held and IRQs disabled. This callback is optional. * * cluster_is_up: * Called by the first CPU to be powered up or resumed in given cluster. * The MCPM lock is held and IRQs disabled. This callback is optional. If * provided, it is called before cpu_is_up for that CPU. * * wait_for_powerdown: * Wait until given CPU is powered down. This is called in sleeping context. * Some reasonable timeout must be considered. Must return 0 for success or * negative error code. */ struct mcpm_platform_ops { int (*cpu_powerup)(unsigned int cpu, unsigned int cluster); int (*cluster_powerup)(unsigned int cluster); void (*cpu_suspend_prepare)(unsigned int cpu, unsigned int cluster); void (*cpu_powerdown_prepare)(unsigned int cpu, unsigned int cluster); void (*cluster_powerdown_prepare)(unsigned int cluster); void (*cpu_cache_disable)(void); void (*cluster_cache_disable)(void); void (*cpu_is_up)(unsigned int cpu, unsigned int cluster); void (*cluster_is_up)(unsigned int cluster); int (*wait_for_powerdown)(unsigned int cpu, unsigned int cluster); }; /** * 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); /** * mcpm_sync_init - Initialize the cluster synchronization support * * @power_up_setup: platform specific function invoked during very * early CPU/cluster bringup stage. * * This prepares memory used by vlocks and the MCPM state machine used * across CPUs that may have their caches active or inactive. Must be * called only after a successful call to mcpm_platform_register(). * * The power_up_setup argument is a pointer to assembly code called when * the MMU and caches are still disabled during boot and no stack space is * available. The affinity level passed to that code corresponds to the * resource that needs to be initialized (e.g. 1 for cluster level, 0 for * CPU level). Proper exclusion mechanisms are already activated at that * point. */ int __init mcpm_sync_init( void (*power_up_setup)(unsigned int affinity_level)); /** * mcpm_loopback - make a run through the MCPM low-level code * * @cache_disable: pointer to function performing cache disabling * * This exercises the MCPM machinery by soft resetting the CPU and branching * to the MCPM low-level entry code before returning to the caller. * The @cache_disable function must do the necessary cache disabling to * let the regular kernel init code turn it back on as if the CPU was * hotplugged in. The MCPM state machine is set as if the cluster was * initialized meaning the power_up_setup callback passed to mcpm_sync_init() * will be invoked for all affinity levels. This may be useful to initialize * some resources such as enabling the CCI that requires the cache to be off, or simply for testing purposes. */ int __init mcpm_loopback(void (*cache_disable)(void)); void __init mcpm_smp_set_ops(void); /* * Synchronisation structures for coordinating safe cluster setup/teardown. * This is private to the MCPM core code and shared between C and assembly. * 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]; }; #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
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