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2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner1-4/+1
Based on 2 normalized pattern(s): 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 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 # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-06ARM: MCPM: remove residency argument from mcpm_cpu_suspend()Nicolas Pitre1-10/+5
This is currently unused. If a suspend must be limited to CPU level only by preventing the last man from triggering a cluster level suspend then this should be determined according to many other criteria the MCPM layer is currently not aware of. It is unlikely that mcpm_cpu_suspend() would be the proper conduit for that information anyway. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Dave Martin <Dave.Martin@arm.com>
2015-05-06ARM: MCPM: make internal helpers private to the core codeNicolas Pitre1-29/+23
This concerns the following helpers: __mcpm_cpu_going_down() __mcpm_cpu_down() __mcpm_outbound_enter_critical() __mcpm_outbound_leave_critical() __mcpm_cluster_state() They are and should only be used by the core code now. Therefore their declarations are removed from mcpm.h and their definitions are made static, hence the need to move them before their users which accounts for the bulk of this patch. This left the mcpm_sync_struct definition at an odd location, therefore it is moved as well with some comment clarifications. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Dave Martin <Dave.Martin@arm.com>
2015-05-06ARM: MCPM: remove backward compatibility codeNicolas Pitre1-6/+0
Now that no one uses the old callbacks anymore, let's remove them and associated support code. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Dave Martin <Dave.Martin@arm.com>
2015-04-03ARM: MCPM: move the algorithmic complexity to the core codeNicolas Pitre1-2/+63
All backends are reimplementing a variation of the same CPU reference count handling. They are also responsible for driving the MCPM special low-level locking. This is needless duplication, involving algorithmic requirements that are not necessarily obvious to the uninitiated. And from past code review experience, those were all initially implemented badly. After 3 years, it is time to refactor as much common code to the core MCPM facility to make the backends as simple as possible. To avoid a flag day, the new scheme is introduced in parallel to the existing backend interface. When all backends are converted over, the compatibility interface could be removed. The new MCPM backend interface implements simpler methods addressing very platform specific tasks performed under lock protection while keeping the algorithmic complexity and race avoidance local to the core code. Signed-off-by: Nicolas Pitre <nico@linaro.org> Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Olof Johansson <olof@lixom.net>
2014-12-03ARM: 8240/1: MCPM: document mcpm_sync_init()Nicolas Pitre1-0/+17
Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-03ARM: mcpm: support 4 clustersHaojian Zhuang1-0/+5
Add the CONFIG_MCPM_QUAD_CLUSTER configuration to enlarge cluster number from 2 to 4. Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Wei Xu <xuwei5@hisilicon.com>
2014-07-18ARM: 8081/1: MCPM: provide infrastructure to allow for MCPM loopbackNicolas Pitre1-0/+16
The kernel already has the responsibility to handle resources such as the CCI when hotplugging CPUs, during the booting of secondary CPUs, and when resuming from suspend/idle. It would be more coherent and less confusing if the CCI for the boot CPU (or cluster) was also initialized by the kernel rather than expecting the firmware/bootloader to do it and only in that case. After all, the kernel has all the necessary code already and the bootloader shouldn't have to care at all. The CCI may be turned on only when the cache is off. Leveraging the CPU suspend code to loop back through the low-level MCPM entry point is all that is needed to properly turn on the CCI from the kernel by using the same code as during secondary boot. Let's provide a generic MCPM loopback function that can be invoked by backend initialization code to set things (CCI or similar) on the boot CPU just as it is done for the other CPUs. Signed-off-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Kevin Hilman <khilman@linaro.org> Tested-by: Kevin Hilman <khilman@linaro.org> Tested-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-29ARM: 8080/1: mcpm.h: remove unused variable declarationNicolas Pitre1-2/+0
The sync_phys variable has been replaced by link time computation in mcpm_head.S before the code was submitted upstream. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-05Merge branches 'alignment', 'fixes', 'l2c' (early part) and 'misc' into for-nextRussell King1-4/+4
2014-05-26ARM: 8029/1: mcpm: Rename the power_down_finish() functions to be less confusingDave Martin1-4/+4
The name "power_down_finish" seems to be causing some confusion, because it suggests that this function is responsible for taking some action to cause the specified CPU to complete its power down. This patch renames the affected functions to "wait_for_powerdown" and similar, since this function's intended purpose is just to wait for the hardware to finish a powerdown initiated by a previous cpu_power_down. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-04-23ARM: 8032/1: bL_switcher: fix validation check before its activationNicolas Pitre1-0/+7
The switcher should not depend on MAX_CLUSTER to determine ifit should be activated or not. In a multiplatform kernel binary it is possible to have dual-cluster and quad-cluster platforms configured in. In that case MAX_CLUSTER which is a build time limit should be 4 and that shouldn't prevent the switcher from working if the kernel is booted on a b.L dual-cluster system. In bL_switcher_halve_cpus() we already have a runtime validation check to make sure we're dealing with only two clusters, so booting on a quad cluster system will be caught and switcher activation aborted. However, the b.L switcher must ensure the MCPM layer is initialized on the booted hardware before doing anything. The mcpm_is_available() function is added to that effect. Signed-off-by: Nicolas Pitre <nico@linaro.org> Tested-by: Abhilash Kesavan <kesavan.abhilash@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-11-12Merge branch 'devel-stable' into for-nextRussell King1-0/+8
Conflicts: arch/arm/include/asm/atomic.h arch/arm/include/asm/hardirq.h arch/arm/kernel/smp.c
2013-10-29ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdownDave Martin1-0/+31
CPU hotplug and kexec rely on smp_ops.cpu_kill(), which is supposed to wait for the CPU to park or power down, and perform the last rites (such as disabling clocks etc., where the platform doesn't do this automatically). kexec in particular is unsafe without performing this synchronisation to park secondaries. Without it, the secondaries might not be parked when kexec trashes the kernel. There is no generic way to do this synchronisation, so a new mcpm platform_ops method power_down_finish() is added by this patch. The new method is mandatory. A platform which provides no way to detect when CPUs are parked is likely broken. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-03ARM: 7842/1: MCPM: don't explode if invoked without being initialized firstNicolas Pitre1-4/+10
Currently mcpm_cpu_power_down() and mcpm_cpu_suspend() trigger BUG() if mcpm_platform_register() is not called beforehand. This may occur for many reasons such as some incomplete device tree passed to the kernel or the like. Let's be nicer to users and avoid killing the kernel if that happens by logging a warning and returning to the caller. The mcpm_cpu_suspend() user is already set to deal with this situation, and so is cpu_die() invoking mcpm_cpu_die(). The problematic case would have been the B.L switcher's usage of mcpm_cpu_power_down(), however it has to call mcpm_cpu_power_up() first which is already set to catch an error resulting from a missing mcpm_platform_register() call. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-09-24ARM: mcpm: add a simple poke mechanism to the early entry codeNicolas Pitre1-0/+8
This allows to poke a predetermined value into a specific address upon entering the early boot code in bL_head.S. Signed-off-by: Nicolas Pitre <nico@linaro.org>
2013-04-24ARM: mcpm: provide an interface to set the SMP ops at run timeNicolas Pitre1-0/+2
This is cleaner than exporting the mcpm_smp_ops structure. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Jon Medhurst <tixy@linaro.org>
2013-04-24ARM: mcpm: introduce helpers for platform coherency exit/setupDave Martin1-0/+73
This provides helper methods to coordinate between CPUs coming down and CPUs going up, as well as documentation on the used algorithms, so that cluster teardown and setup operations are not done for a cluster simultaneously. For use in the power_down() implementation: * __mcpm_cpu_going_down(unsigned int cluster, unsigned int cpu) * __mcpm_outbound_enter_critical(unsigned int cluster) * __mcpm_outbound_leave_critical(unsigned int cluster) * __mcpm_cpu_down(unsigned int cluster, unsigned int cpu) The power_up_setup() helper should do platform-specific setup in preparation for turning the CPU on, such as invalidating local caches or entering coherency. It must be assembler for now, since it must run before the MMU can be switched on. It is passed the affinity level for which initialization should be performed. Because the mcpm_sync_struct content is looked-up and modified with the cache enabled or disabled depending on the code path, it is crucial to always ensure proper cache maintenance to update main memory right away. The sync_cache_*() helpers are used to that end. Also, in order to prevent a cached writer from interfering with an adjacent non-cached writer, we ensure each state variable is located to a separate cache line. Thanks to Nicolas Pitre and Achin Gupta for the help with this patch. Signed-off-by: Dave Martin <dave.martin@linaro.org> Signed-off-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Will Deacon <will.deacon@arm.com>
2013-04-24ARM: mcpm: introduce the CPU/cluster power APINicolas Pitre1-0/+92
This is the basic API used to handle the powering up/down of individual CPUs in a (multi-)cluster system. The platform specific backend implementation has the responsibility to also handle the cluster level power as well when the first/last CPU in a cluster is brought up/down. Signed-off-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2013-04-24ARM: multi-cluster PM: secondary kernel entry codeNicolas Pitre1-0/+42
CPUs in cluster based systems, such as big.LITTLE, have special needs when entering the kernel due to a hotplug event, or when resuming from a deep sleep mode. This is vectorized so multiple CPUs can enter the kernel in parallel without serialization. The mcpm prefix stands for "multi cluster power management", however this is usable on single cluster systems as well. Only the basic structure is introduced here. This will be extended with later patches. In order not to complexify things more than they currently have to, the planned work to make runtime adjusted MPIDR based indexing and dynamic memory allocation for cluster states is postponed to a later cycle. The MAX_NR_CLUSTERS and MAX_CPUS_PER_CLUSTER static definitions should be sufficient for those systems expected to be available in the near future. Signed-off-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>