diff options
Diffstat (limited to 'arch/arm/include/asm/mcpm.h')
| -rw-r--r-- | arch/arm/include/asm/mcpm.h | 203 |
1 files changed, 166 insertions, 37 deletions
diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h index 0f7b7620e9a5..755c97de348c 100644 --- a/arch/arm/include/asm/mcpm.h +++ b/arch/arm/include/asm/mcpm.h @@ -1,12 +1,9 @@ +/* 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 - * - * 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 @@ -20,7 +17,12 @@ * 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__ @@ -42,10 +44,25 @@ extern void mcpm_entry_point(void); 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 @@ -76,32 +93,63 @@ int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster); * * This must be called with interrupts disabled. * - * This does not return. Re-entry in the kernel is expected via - * mcpm_entry_point. + * 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_cpu_suspend - bring the calling CPU in a suspended state + * mcpm_wait_for_cpu_powerdown - wait for a specified CPU to halt, and + * make sure it is powered off * - * @expected_residency: duration in microseconds the CPU is expected - * to remain suspended, or 0 if unknown/infinity. + * @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. 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. + * 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, if the expected - * residency makes it worthwhile. + * then the cluster may be 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. + * 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(u64 expected_residency); +void mcpm_cpu_suspend(void); /** * mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up @@ -115,13 +163,69 @@ void mcpm_cpu_suspend(u64 expected_residency); int mcpm_cpu_powered_up(void); /* - * Platform specific methods used in the implementation of the above API. + * 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 (*power_up)(unsigned int cpu, unsigned int cluster); - void (*power_down)(void); - void (*suspend)(u64); - void (*powered_up)(void); + 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); }; /** @@ -133,9 +237,47 @@ struct mcpm_platform_ops { */ int __init mcpm_platform_register(const struct mcpm_platform_ops *ops); -/* Synchronisation structures for coordinating safe cluster setup/teardown: */ +/** + * 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. */ @@ -156,19 +298,6 @@ 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 /* |