File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h
new file mode 100644
index 0000000..acd4983
--- /dev/null
+++ b/arch/arm/include/asm/mcpm.h
@@ -0,0 +1,341 @@
+/*
+ * 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