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2020-01-16clocksource/drivers/exynos_mct: Rename Exynos to lowercaseKrzysztof Kozlowski
Fix up inconsistent usage of upper and lowercase letters in "Exynos" name. "EXYNOS" is not an abbreviation but a regular trademarked name. Therefore it should be written with lowercase letters starting with capital letter. The lowercase "Exynos" name is promoted by its manufacturer Samsung Electronics Co., Ltd., in advertisement materials and on website. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20200104152107.11407-12-krzk@kernel.org
2019-07-03Merge branch 'timers/vdso' into timers/coreThomas Gleixner
so the hyper-v clocksource update can be applied.
2019-06-25clocksource/drivers/exynos_mct: Increase priority over ARM arch timerMarek Szyprowski
Exynos SoCs based on CA7/CA15 have 2 timer interfaces: custom Exynos MCT (Multi Core Timer) and standard ARM Architected Timers. There are use cases, where both timer interfaces are used simultanously. One of such examples is using Exynos MCT for the main system timer and ARM Architected Timers for the KVM and virtualized guests (KVM requires arch timers). Exynos Multi-Core Timer driver (exynos_mct) must be however started before ARM Architected Timers (arch_timer), because they both share some common hardware blocks (global system counter) and turning on MCT is needed to get ARM Architected Timer working properly. To ensure selecting Exynos MCT as the main system timer, increase MCT timer rating. To ensure proper starting order of both timers during suspend/resume cycle, increase MCT hotplug priority over ARM Archictected Timers. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
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>
2019-02-23clocksource/drivers/exynos_mct: Remove unused header includesKrzysztof Kozlowski
The driver does not use sched.h and platform_device.h. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2019-02-23clocksource/drivers/exynos_mct: Fix error path in timer resources initializationMarek Szyprowski
While freeing interrupt handlers in error path, don't assume that all requested interrupts are per-processor interrupts and properly release standard interrupts too. Reported-by: Krzysztof Kozlowski <krzk@kernel.org> Fixes: 56a94f13919c ("clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2019-02-23clocksource/drivers/exynos_mct: Remove dead codeMarek Szyprowski
Exynos Multi-Core Timer driver is used only on device-tree based systems, so remove non-dt related code. In case of !CONFIG_OF the code is anyway equal because of_irq_count() has a stub returning 0. Device node pointer is always provided when driver has been probed from device tree. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2019-02-23clocksource/drivers/exynos_mct: Clear timer interrupt when shutdownStuart Menefy
When shutting down the timer, ensure that after we have stopped the timer any pending interrupts are cleared. This fixes a problem when suspending, as interrupts are disabled before the timer is stopped, so the timer interrupt may still be asserted, preventing the system entering a low power state when the wfi is executed. Signed-off-by: Stuart Menefy <stuart.menefy@mathembedded.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Cc: <stable@vger.kernel.org> # v4.3+ Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2019-02-23clocksource/drivers/exynos_mct: Move one-shot check from tick clear to ISRStuart Menefy
When a timer tick occurs and the clock is in one-shot mode, the timer needs to be stopped to prevent it triggering subsequent interrupts. Currently this code is in exynos4_mct_tick_clear(), but as it is only needed when an ISR occurs move it into exynos4_mct_tick_isr(), leaving exynos4_mct_tick_clear() just doing what its name suggests it should. Signed-off-by: Stuart Menefy <stuart.menefy@mathembedded.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Cc: stable@vger.kernel.org # v4.3+ Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2017-06-14clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLAREDaniel Lezcano
The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the clocksource at early stage. However, this macro is also used to initialize the clockevent if any, or the clockevent only. It was originally suggested to declare another macro to initialize a clockevent, so in order to separate the two entities even they belong to the same IP. This was not accepted because of the impact on the DT where splitting a clocksource/clockevent definition does not make sense as it is a Linux concept not a hardware description. On the other side, the clocksource has not interrupt declared while the clockevent has, so it is easy from the driver to know if the description is for a clockevent or a clocksource, IOW it could be implemented at the driver level. So instead of dealing with a named clocksource macro, let's use a more generic one: TIMER_OF_DECLARE. The patch has not functional changes. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Matthias Brugger <matthias.bgg@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-01-17clocksource/exynos_mct: Clear interrupt when cpu is shut downJoonyoung Shim
When a CPU goes offline a potentially pending timer interrupt is not cleared. When the CPU comes online again then the pending interrupt is delivered before the per cpu clockevent device is initialized. As a consequence the tick interrupt handler dereferences a NULL pointer. [ 51.251378] Unable to handle kernel NULL pointer dereference at virtual address 00000040 [ 51.289348] task: ee942d00 task.stack: ee960000 [ 51.293861] PC is at tick_periodic+0x38/0xb0 [ 51.298102] LR is at tick_handle_periodic+0x1c/0x90 Clear the pending interrupt in the cpu dying path. Fixes: 56a94f13919c ("clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier") Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com> Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com> Cc: linux-samsung-soc@vger.kernel.org Cc: cw00.choi@samsung.com Cc: daniel.lezcano@linaro.org Cc: stable@vger.kernel.org Cc: javier@osg.samsung.com Cc: kgene@kernel.org Cc: krzk@kernel.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1484628876-22065-1-git-send-email-jy0922.shim@samsung.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-25Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer type cleanups from Thomas Gleixner: "This series does a tree wide cleanup of types related to timers/timekeeping. - Get rid of cycles_t and use a plain u64. The type is not really helpful and caused more confusion than clarity - Get rid of the ktime union. The union has become useless as we use the scalar nanoseconds storage unconditionally now. The 32bit timespec alike storage got removed due to the Y2038 limitations some time ago. That leaves the odd union access around for no reason. Clean it up. Both changes have been done with coccinelle and a small amount of manual mopping up" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ktime: Get rid of ktime_equal() ktime: Cleanup ktime_set() usage ktime: Get rid of the union clocksource: Use a plain u64 instead of cycle_t
2016-12-25clocksource: Use a plain u64 instead of cycle_tThomas Gleixner
There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org>
2016-12-25cpu/hotplug: Cleanup state namesThomas Gleixner
When the state names got added a script was used to add the extra argument to the calls. The script basically converted the state constant to a string, but the cleanup to convert these strings into meaningful ones did not happen. Replace all the useless strings with 'subsys/xxx/yyy:state' strings which are used in all the other places already. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Link: http://lkml.kernel.org/r/20161221192112.085444152@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-16clocksource: exynos_mct: Add the support for ARM64Chanwoo Choi
This patch allows building and compile-testing the driver also for ARM64. The delay_timer is only supported on ARMv7. Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kukjin Kim <kgene@kernel.org> Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> [k.kozlowski: Adjusted commit msg] Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
2016-07-15clocksource/exynos_mct: Convert to hotplug state machineRichard Cochran
Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Richard Cochran <rcochran@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com> Cc: Kukjin Kim <kgene@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-samsung-soc@vger.kernel.org Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153338.147940411@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-28clocksources: Switch back to the clksrc tableDaniel Lezcano
All the clocksource drivers's init function are now converted to return an error code. CLOCKSOURCE_OF_DECLARE is no longer used as well as the clksrc-of table. Let's convert back the names: - CLOCKSOURCE_OF_DECLARE_RET => CLOCKSOURCE_OF_DECLARE - clksrc-of-ret => clksrc-of Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> For exynos_mct and samsung_pwm_timer: Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> For arch/arc: Acked-by: Vineet Gupta <vgupta@synopsys.com> For mediatek driver: Acked-by: Matthias Brugger <matthias.bgg@gmail.com> For the Rockchip-part Acked-by: Heiko Stuebner <heiko@sntech.de> For STi : Acked-by: Patrice Chotard <patrice.chotard@st.com> For the mps2-timer.c and versatile.c changes: Acked-by: Liviu Dudau <Liviu.Dudau@arm.com> For the OXNAS part : Acked-by: Neil Armstrong <narmstrong@baylibre.com> For LPC32xx driver: Acked-by: Sylvain Lemieux <slemieux.tyco@gmail.com> For Broadcom Kona timer change: Acked-by: Ray Jui <ray.jui@broadcom.com> For Sun4i and Sun5i: Acked-by: Chen-Yu Tsai <wens@csie.org> For Meson6: Acked-by: Carlo Caione <carlo@caione.org> For Keystone: Acked-by: Santosh Shilimkar <ssantosh@kernel.org> For NPS: Acked-by: Noam Camus <noamca@mellanox.com> For bcm2835: Acked-by: Eric Anholt <eric@anholt.net>
2016-06-28clocksource/drivers/exynos_mct: Convert init function to return errorDaniel Lezcano
The init functions do not return any error. They behave as the following: - panic, thus leading to a kernel crash while another timer may work and make the system boot up correctly or - print an error and let the caller unaware if the state of the system Change that by converting the init functions to return an error conforming to the CLOCKSOURCE_OF_RET prototype. Proper error handling (rollback, errno value) will be changed later case by case, thus this change just return back an error or success in the init function. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
2016-02-25clockevents/drivers/exynos_mct: Implement ->set_state_oneshot_stopped()Viresh Kumar
set_state_oneshot_stopped() is called by the clkevt core, when the next event is required at an expiry time of 'KTIME_MAX'. This normally happens with NO_HZ_{IDLE|FULL} in both LOWRES/HIGHRES modes. This patch makes the clockevent device to stop on such an event, to avoid spurious interrupts, as explained by: commit 8fff52fd5093 ("clockevents: Introduce CLOCK_EVT_STATE_ONESHOT_STOPPED state"). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2015-10-15clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()Alexey Klimov
Since evt structure is embedded in per-CPU mevt structure it's definitely faster to use container_of() to get access to mevt if we have evt (for example as incoming function argument) instead of more expensive approach with this_cpu_ptr(&percpu_mct_tick). this_cpu_ptr() on per-CPU mevt structure leads to access to cp15 to get cpu id and arithmetic operations. Container_of() is cheaper since it's just one asm instruction. This should work if used evt pointer is correct and owned by local mevt structure. For example, before this patch set_state_shutdown() looks like: 4a4: e92d4010 push {r4, lr} 4a8: e3004000 movw r4, #0 4ac: ebfffffe bl 0 <debug_smp_processor_id> 4b0: e3003000 movw r3, #0 4b4: e3404000 movt r4, #0 4b8: e3403000 movt r3, #0 4bc: e7933100 ldr r3, [r3, r0, lsl #2] 4c0: e0844003 add r4, r4, r3 4c4: e59400c0 ldr r0, [r4, #192] ; 0xc0 4c8: ebffffd4 bl 420 <exynos4_mct_tick_stop.isra.1> 4cc: e3a00000 mov r0, #0 4d0: e8bd8010 pop {r4, pc} With this patch: 4a4: e92d4010 push {r4, lr} 4a8: e59000c0 ldr r0, [r0, #192] ; 0xc0 4ac: ebffffdb bl 420 <exynos4_mct_tick_stop.isra.1> 4b0: e3a00000 mov r0, #0 4b4: e8bd8010 pop {r4, pc} Also, for me size of exynos_mct.o decreased from 84588 bytes to 83956. Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
2015-08-10clockevents/drivers/exynos_mct: Migrate to new 'set-state' interfaceViresh Kumar
Migrate exynos_mct driver to the new 'set-state' interface provided by clockevents core, the earlier 'set-mode' interface is marked obsolete now. This also enables us to implement callbacks for new states of clockevent devices, for example: ONESHOT_STOPPED. Cc: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2015-08-10clockevents/drivers/exynos_mct: Remove unneeded container_of()Alexey Klimov
Patch removes unneeded container_of() macro in exynos4_local_timer_setup(). Instead let's pass mevt pointer to setup and stop functions from exynos4_mct_cpu_notify() and let them get evt pointer. Tested on odroid-xu3. Signed-off-by: Alexey Klimov <klimov.linux@gmail.com> Acked-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
2015-06-26clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifierDamian Eppel
Whilst testing cpu hotplug events on kernel configured with DEBUG_PREEMPT and DEBUG_ATOMIC_SLEEP we get following BUG message, caused by calling request_irq() and free_irq() in the context of hotplug notification (which is in this case atomic context). [ 40.785859] CPU1: Software reset [ 40.786660] BUG: sleeping function called from invalid context at mm/slub.c:1241 [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/1 [ 40.786678] Preemption disabled at:[< (null)>] (null) [ 40.786681] [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4-00024-g7dca860 #36 [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 40.786728] [<c0014a00>] (unwind_backtrace) from [<c0011980>] (show_stack+0x10/0x14) [ 40.786747] [<c0011980>] (show_stack) from [<c0449ba0>] (dump_stack+0x70/0xbc) [ 40.786767] [<c0449ba0>] (dump_stack) from [<c00c6124>] (kmem_cache_alloc+0xd8/0x170) [ 40.786785] [<c00c6124>] (kmem_cache_alloc) from [<c005d6f8>] (request_threaded_irq+0x64/0x128) [ 40.786804] [<c005d6f8>] (request_threaded_irq) from [<c0350b8c>] (exynos4_local_timer_setup+0xc0/0x13c) [ 40.786820] [<c0350b8c>] (exynos4_local_timer_setup) from [<c0350ca8>] (exynos4_mct_cpu_notify+0x30/0xa8) [ 40.786838] [<c0350ca8>] (exynos4_mct_cpu_notify) from [<c003b330>] (notifier_call_chain+0x44/0x84) [ 40.786857] [<c003b330>] (notifier_call_chain) from [<c0022fd4>] (__cpu_notify+0x28/0x44) [ 40.786873] [<c0022fd4>] (__cpu_notify) from [<c0013714>] (secondary_start_kernel+0xec/0x150) [ 40.786886] [<c0013714>] (secondary_start_kernel) from [<40008764>] (0x40008764) Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING notifications which run on the hotplugged cpu with interrupts and preemption disabled. To avoid the issue, request the interrupts for all possible cpus in the boot code. The interrupts are marked NO_AUTOENABLE to avoid a racy request_irq/disable_irq() sequence. The flag prevents the request_irq() code from enabling the interrupt immediately. The interrupt is then enabled in the CPU_STARTING notifier of the hotplugged cpu and again disabled with disable_irq_nosync() in the CPU_DYING notifier. [ tglx: Massaged changelog to match the patch ] Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq calls for local timer registration") Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Tested-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> Signed-off-by: Damian Eppel <d.eppel@samsung.com> Cc: m.szyprowski@samsung.com Cc: kyungmin.park@samsung.com Cc: daniel.lezcano@linaro.org Cc: kgene@kernel.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email-d.eppel@samsung.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org>
2015-06-02clocksource/drivers/exynos_mct: Remove old platform mct_init()Krzysztof Kozlowski
Since commit 228e3023eb04 ("Merge tag 'mct-exynos-for-v3.10' of ...") the mct_init() was superseded by mct_init_dt() and is not referenced anywhere. Remove it. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2015-06-02clocksource/drivers/exynos_mct: Staticize struct clocksourceKrzysztof Kozlowski
The struct clocksource 'mct_frc' is not exported and used outside so make it static. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2015-06-02clocksource/drivers/exynos_mct: Change exynos4_mct_tick_clear return type to ↵Krzysztof Kozlowski
void Return value of exynos4_mct_tick_clear() was never checked so it can be safely changed to void. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2015-01-05clocksource: exynos_mct: Fix bitmask regression for exynos4_mct_writeTobias Jakobi
EXYNOS4_MCT_L_MASK is defined as 0xffffff00, so applying this bitmask produces a number outside the range 0x00 to 0xff, which always results in execution of the default switch statement. Obviously this is wrong and git history shows that the bitmask inversion was incorrectly set during a refactoring of the MCT code. Fix this by putting the inversion at the correct position again. Cc: stable@vger.kernel.org Acked-by: Kukjin Kim <kgene.kim@samsung.com> Reported-by: GP Orcullo <kinsamanka@gmail.com> Reviewed-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2014-07-23clocksource: exynos_mct: Only use 32-bits where possibleDoug Anderson
The MCT has a nice 64-bit counter. That means that we _can_ register as a 64-bit clocksource and sched_clock. ...but that doesn't mean we should. The 64-bit counter is read by reading two 32-bit registers. That means reading needs to be something like: - Read upper half - Read lower half - Read upper half and confirm that it hasn't changed. That wouldn't be terrible, but: - THe MCT isn't very fast to access (hundreds of nanoseconds). - The clocksource is queried _all the time_. In total system profiles of real workloads on ChromeOS, we've seen exynos_frc_read() taking 2% or more of CPU time even after optimizing the 3 reads above to 2 (see below). The MCT is clocked at ~24MHz on all known systems. That means that the 32-bit half of the counter rolls over every ~178 seconds. This inspired an optimization in ChromeOS to cache the upper half between calls, moving 3 reads to 2. ...but we can do better! Having a 32-bit timer that flips every 178 seconds is more than sufficient for Linux. Let's just use the lower half of the MCT. Times on 5420 to do 1000000 gettimeofday() calls from userspace: * Original code: 1323852 us * ChromeOS cache upper half: 1173084 us * ChromeOS + ldmia to optimize: 1045674 us * Use lower 32-bit only (this code): 1014429 us As you can see, the time used doesn't increase linearly with the number of reads and we can make 64-bit work almost as fast as 32-bit with a bit of assembly code. But since there's no real gain for 64-bit, let's go with the simplest and fastest implementation. Note: with this change roughly half the time for gettimeofday() is spent in exynos_frc_read(). The rest is timer / system call overhead. Also note: this patch disables the use of the MCT on ARM64 systems until we've sorted out how to make "cycles_t" always 32-bit. Really ARM64 systems should be using arch timers anyway. Signed-off-by: Doug Anderson <dianders@chromium.org> Acked-by Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2014-07-23clocksource: exynos_mct: Use readl_relaxed/writel_relaxedDoug Anderson
Using the __raw functions is discouraged. Update the file to consistently use the proper functions. Signed-off-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2014-07-05clocksource: exynos_mct: Register the timer for stable udelayAmit Daniel Kachhap
This patch registers the exynos mct clocksource as the current timer as it has constant clock rate. This will generate correct udelay for the exynos platform and avoid using unnecessary calibrated jiffies. This change has been tested on exynos5420 based board and udelay is very close to expected. Without this patch udelay() on exynos5400 / exynos5800 is wildly inaccurate due to big.LITTLE not adjusting loops_per_jiffy correctly. Also without this patch udelay() on exynos5250 can be innacruate during transitions between frequencies < 800 MHz (you'll go 200 MHz -> 800 MHz -> 300 MHz and will run at 800 MHz for a time with the wrong loops_per_jiffy). [dianders: reworked and created version 3] Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com> Signed-off-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2014-07-05clocksource: exynos_mct: Fix ftraceDoug Anderson
In (93bfb76 clocksource: exynos_mct: register sched_clock callback) we supported using the MCT as a scheduler clock. We properly marked exynos4_read_sched_clock() as notrace. However, we then went and called another function that _wasn't_ notrace. That means if you do: cd /sys/kernel/debug/tracing/ echo function_graph > current_tracer You'll get a crash. Fix this (but still let other readers of the MCT be trace-enabled) by adding an extra function. It's important to keep other users of MCT traceable because the MCT is actually quite slow to access and we want exynos4_frc_read() to show up in ftrace profiles if it's the bottleneck. Signed-off-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2014-06-17clocksource: exynos_mct: Don't reset the counter during boot and resumeChirantan Ekbote
Unfortunately on some exynos systems, resetting the mct counter also resets the architected timer counter. This can cause problems if the architected timer driver has already been initialized because the kernel will think that the counter has wrapped around, causing a big jump in printk timestamps and delaying any scheduled clock events until the counter reaches the value it had before it was reset. The kernel code makes no assumptions about the initial value of the mct counter so there is no reason from a software perspective to clear the counter before starting it. This also fixes the problems described in the previous paragraph. Cc: Olof Johansson <olof@lixom.net> Cc: Tomasz Figa <tomasz.figa@gmail.com> Signed-off-by: Chirantan Ekbote <chirantan@chromium.org> Reviewed-by: Doug Anderson <dianders@chromium.org> Tested-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2014-05-21Merge tag 'samsung-drivers' of ↵Olof Johansson
http://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung into next/drivers Merge "Samsung driver update for 3.16" from Kukjin Kim: exynos_mct update for v3.16 - register sched_clock callback to use clocksource mct-frc * tag 'samsung-drivers' of http://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung: clocksource: exynos_mct: register sched_clock callback Signed-off-by: Olof Johansson <olof@lixom.net>
2014-05-02clocksource: exynos_mct: register sched_clock callbackVincent Guittot
Use the clocksource mct-frc for sched_clock Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Tomasz Figa <t.figa@samsung.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2014-04-17clocksource: Exynos_mct: Register clock event after request_irq()Krzysztof Kozlowski
After hotplugging CPU1 the first call of interrupt handler for CPU1 oneshot timer was called on CPU0 because it fired before setting IRQ affinity. Affected are SoCs where Multi Core Timer interrupts are shared (SPI), e.g. Exynos 4210. During setup of the MCT timers the clock event device should be registered after setting the affinity for interrupt. This will prevent starting the timer too early. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Tomasz Figa <t.figa@samsung.com>, Cc: Daniel Lezcano <daniel.lezcano@linaro.org>, Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143316.299247848@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-04-17clocksource: Exynos_mct: Use irq_force_affinity() in cpu bringupThomas Gleixner
The starting cpu is not yet in the online mask so irq_set_affinity() fails which results in per cpu timers for this cpu ending up on some other online cpu, ususally cpu 0. Use irq_force_affinity() which disables the online mask check and makes things work. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Tomasz Figa <t.figa@samsung.com>, Cc: Daniel Lezcano <daniel.lezcano@linaro.org>, Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143316.106665251@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-04-05Merge tag 'cleanup-3.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC cleanups from Arnd Bergmann: "These cleanup patches are mainly move stuff around and should all be harmless. They are mainly split out so that other branches can be based on top to avoid conflicts. Notable changes are: - We finally remove all mach/timex.h, after CLOCK_TICK_RATE is no longer used (Uwe Kleine-König) - The Qualcomm MSM platform is split out into legacy mach-msm and new-style mach-qcom, to allow easier maintainance of the new hardware support without regressions (Kumar Gala) - A rework of some of the Kconfig logic to simplify multiplatform support (Rob Herring) - Samsung Exynos gets closer to supporting multiplatform (Sachin Kamat and others) - mach-bcm3528 gets merged into mach-bcm (Stephen Warren) - at91 gains some common clock framework support (Alexandre Belloni, Jean-Jacques Hiblot and other French people)" * tag 'cleanup-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (89 commits) ARM: hisi: select HAVE_ARM_SCU only for SMP ARM: efm32: allow uncompress debug output ARM: prima2: build reset code standalone ARM: at91: add PWM clock ARM: at91: move sam9261 SoC to common clk ARM: at91: prepare common clk transition for sam9261 SoC ARM: at91: updated the at91_dt_defconfig with support for the ADS7846 ARM: at91: dt: sam9261: Device Tree support for the at91sam9261ek ARM: at91: dt: defconfig: Added the sam9261 to the list of DT-enabled SOCs ARM: at91: dt: Add at91sam9261 dt SoC support ARM: at91: switch sam9rl to common clock framework ARM: at91/dt: define main clk frequency of at91sam9rlek ARM: at91/dt: define at91sam9rl clocks ARM: at91: prepare common clk transition for sam9rl SoCs ARM: at91: prepare sam9 dt boards transition to common clk ARM: at91: dt: sam9rl: Device Tree for the at91sam9rlek ARM: at91/defconfig: Add the sam9rl to the list of DT-enabled SOCs ARM: at91: Add at91sam9rl DT SoC support ARM: at91: prepare at91sam9rl DT transition ARM: at91/defconfig: refresh at91sam9260_9g20_defconfig ...
2014-03-11clocksource: exynos_mct: silence a static checker warningDan Carpenter
My guess is we aren't going to have a 2 digit cpuid here any time soon but the static checkers don't know that and complain that the snprintf() could overflow. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2014-02-14clocksource: exynos_mct: remove unwanted header file inclusionPankaj Dubey
remove unwanted header file inclusion "asm/mach/time.h" from exynos_mct.c Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2013-12-16clocksource: mct: extend mct to support 8 local interrupts for Exynos5420Chander Kashyap
Exynos5420 is octa-core SoC from Samsung. Hence extend exynos-mct clocksource driver to support 8 local interrupts. Also extend dts entries for 8 interrupts. Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2013-09-26clocksource: exynos_mct: Set IRQ affinity when the CPU goes onlineTomasz Figa
Some variants of Exynos MCT, namely exynos4210-mct at the moment, use normal, shared interrupts for local timers. This means that each interrupt must have correct affinity set to fire only on CPU corresponding to given local timer. However after recent conversion of clocksource drivers to not use the local timer API for local timer initialization any more, the point of time when local timers get initialized changed and irq_set_affinity() fails because the CPU is not marked as online yet. This patch fixes this by moving the call to irq_set_affinity() to CPU_ONLINE notification, so the affinity is being set when the CPU goes online. This fixes a regression introduced by commit ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API which rendered all Exynos4210 based boards unbootable due to failing irq_set_affinity() making local timers inoperatible. Signed-off-by: Tomasz Figa <t.figa@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2013-07-23Merge tag 'remove-local-timers' of ↵Olof Johansson
git://git.kernel.org/pub/scm/linux/kernel/git/davidb/linux-msm into next/cleanup From Stephen Boyd: Now that we have a generic arch hook for broadcast we can remove the local timer API entirely. Doing so will reduce code in ARM core, reduce the architecture dependencies of our timer drivers, and simplify the code because we no longer go through an architecture layer that is essentially a hotplug notifier. * tag 'remove-local-timers' of git://git.kernel.org/pub/scm/linux/kernel/git/davidb/linux-msm: ARM: smp: Remove local timer API clocksource: time-armada-370-xp: Divorce from local timer API clocksource: time-armada-370-xp: Fix sparse warning ARM: msm: Divorce msm_timer from local timer API ARM: PRIMA2: Divorce timer-marco from local timer API ARM: EXYNOS4: Divorce mct from local timer API ARM: OMAP2+: Divorce from local timer API ARM: smp_twd: Divorce smp_twd from local timer API ARM: smp: Remove duplicate dummy timer implementation Resolved a large number of conflicts due to __cpuinit cleanups, etc. Signed-off-by: Olof Johansson <olof@lixom.net>
2013-07-14clocksource+irqchip: delete __cpuinit usage from all related filesPaul Gortmaker
The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. This removes all the drivers/clocksource and drivers/irqchip uses of the __cpuinit macros from all C files. [1] https://lkml.org/lkml/2013/5/20/589 Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-06-24ARM: EXYNOS4: Divorce mct from local timer APIStephen Boyd
Separate the mct local timers from the local timer API. This will allow us to remove ARM local timer support in the near future and gets us closer to moving this driver to drivers/clocksource. Acked-by: Kukjin Kim <kgene.kim@samsung.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Thomas Abraham <thomas.abraham@linaro.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-06-19clocksource: exynos_mct: use (request/free)_irq calls for local timer ↵Chander Kashyap
registration Replace the (setup/remove)_irq calls for local timer registration with (request/free)_irq calls. This generalizes the local timer registration API. Suggested by Mark Rutland. Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Tomasz Figa <t.figa@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2013-05-07Merge tag 'multiplatform-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull late ARM Exynos multiplatform changes from Arnd Bergmann: "These continue the multiplatform support for exynos, adding support for building most of the essential drivers (clocksource, clk, irqchip) when combined with other platforms. As a result, it should become really easy to add full multiplatform exynos support in 3.11, although we don't yet enable it for 3.10. The changes were not included in the earlier multiplatform series in order to avoid clashes with the other Exynos updates. This also includes work from Tomasz Figa to fix the pwm clocksource code on Exynos, which is not strictly required for multiplatform, but related to the other patches in this set and needed as a bug fix for at least one board." * tag 'multiplatform-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (22 commits) ARM: dts: exynops4210: really add universal_c210 dts ARM: dts: exynos4210: Add basic dts file for universal_c210 board ARM: dts: exynos4: Add node for PWM device ARM: SAMSUNG: Do not register legacy timer interrupts on Exynos clocksource: samsung_pwm_timer: Work around rounding errors in clockevents core clocksource: samsung_pwm_timer: Correct programming of clock events clocksource: samsung_pwm_timer: Use proper clockevents max_delta clocksource: samsung_pwm_timer: Add support for non-DT platforms clocksource: samsung_pwm_timer: Drop unused samsung_pwm struct clocksource: samsung_pwm_timer: Keep all driver data in a structure clocksource: samsung_pwm_timer: Make PWM spinlock global clocksource: samsung_pwm_timer: Let platforms select the driver Documentation: Add device tree bindings for Samsung PWM timers clocksource: add samsung pwm timer driver irqchip: exynos: look up irq using irq_find_mapping irqchip: exynos: pass irq_base from platform irqchip: exynos: localize irq lookup for ATAGS irqchip: exynos: allocate combiner_data dynamically irqchip: exynos: pass max combiner number to combiner_init ARM: exynos: add missing properties for combiner IRQs ...
2013-05-07Merge tag 'cleanup-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC late cleanups from Arnd Bergmann: "These are cleanups and smaller changes that either depend on earlier feature branches or came in late during the development cycle. We normally try to get all cleanups early, so these are the exceptions: - A follow-up on the clocksource reworks, hopefully the last time we need to merge clocksource subsystem changes through arm-soc. A first set of patches was part of the original 3.10 arm-soc cleanup series because of interdependencies with timer drivers now moved out of arch/arm. - Migrating the SPEAr13xx platform away from using auxdata for DMA channel descriptions towards using information in device tree, based on the earlier SPEAr multiplatform series - A few follow-ups on the Atmel SAMA5 support and other changes for Atmel at91 based on the larger at91 reworks. - Moving the armada irqchip implementation to drivers/irqchip - Several OMAP cleanups following up on the larger series already merged in 3.10." * tag 'cleanup-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (50 commits) ARM: OMAP4: change the device names in usb_bind_phy ARM: OMAP2+: Fix mismerge for timer.c between ff931c82 and da4a686a ARM: SPEAr: conditionalize SMP code ARM: arch_timer: Silence debug preempt warnings ARM: OMAP: remove unused variable serial: amba-pl011: fix !CONFIG_DMA_ENGINE case ata: arasan: remove the need for platform_data ARM: at91/sama5d34ek.dts: remove not needed compatibility string ARM: at91: dts: add MCI DMA support ARM: at91: dts: add i2c dma support ARM: at91: dts: set #dma-cells to the correct value ARM: at91: suspend both memory controllers on at91sam9263 irqchip: armada-370-xp: slightly cleanup irq controller driver irqchip: armada-370-xp: move IRQ handler to avoid forward declaration irqchip: move IRQ driver for Armada 370/XP ARM: mvebu: move L2 cache initialization in init_early() devtree: add binding documentation for sp804 ARM: integrator-cp: convert use CLKSRC_OF for timer init ARM: versatile: use OF init for sp804 timer ARM: versatile: add versatile dtbs to dtbs target ...
2013-04-19clocksource: exynos_mct: remove platform header dependencyArnd Bergmann
For the non-DT case, the mct_init() function requires access to a couple of platform specific constants, but cannot include the header files in case we are building for multiplatform. This changes the interface to the platform so we pass all the necessary data as arguments to mct_init. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org>
2013-04-19clocksource: exynos_mct: fix build error on non-DTArnd Bergmann
There is currently no alternative implementation for of_irq_count when the function is not defined, and the declaration is hidden, so this works around calling an undeclared function. It should really not be needed. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2013-04-17Merge tag 'clksrc-cleanup-for-3.10-part2' of ↵Olof Johansson
git://sources.calxeda.com/kernel/linux into late/clksrc This is the 2nd part of ARM timer clean-ups for 3.10. This series has the following changes: - Add sched_clock selection logic to select the highest frequency clock - Use full 64-bit arch timer counter for sched_clock - Convert arch timer, sp804 and integrator-cp timers to CLKSRC_OF and adapt all users to use clocksource_of_init * tag 'clksrc-cleanup-for-3.10-part2' of git://sources.calxeda.com/kernel/linux: devtree: add binding documentation for sp804 ARM: integrator-cp: convert use CLKSRC_OF for timer init ARM: versatile: use OF init for sp804 timer ARM: versatile: add versatile dtbs to dtbs target ARM: vexpress: remove extra timer-sp control register clearing ARM: dts: vexpress: disable CA9 core tile sp804 timer ARM: vexpress: remove sp804 OF init ARM: highbank: use OF init for sp804 timer ARM: timer-sp: convert to use CLKSRC_OF init OF: add empty of_device_is_available for !OF ARM: convert arm/arm64 arch timer to use CLKSRC_OF init ARM: make machine_desc->init_time default to clocksource_of_init ARM: arch_timer: use full 64-bit counter for sched_clock ARM: make sched_clock just call a function pointer ARM: sched_clock: allow changing to higher frequency counter Signed-off-by: Olof Johansson <olof@lixom.net> This has a nasty set of conflicts with the exynos MCT code, which was moved in a separate branch, and then fixed up when merged in, but still conflicts a bit here. It should have been sorted out by this merge though.