| /* |
| * 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 |
| |
| #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 |