clocksource/drivers/exynos_mct: Explicitly return 0 for shared timer

For a shared timers, the mct_init_dt() should not initialize the clock
even with global comparator. This is not an error, thus the function
should simply return 0, not 'ret'.

This also fixes smatch warning:

drivers/clocksource/exynos_mct.c:635 mct_init_dt() warn: missing error code? 'ret'

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/202304021446.46XVKag0-lkp@intel.com/
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230403094017.9556-1-krzysztof.kozlowski@linaro.org

clocksource/drivers/exynos_mct: Support local-timers property

If the device tree indicates that the hardware requires that the
processor only use certain local timers, respect that.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220609112738.359385-4-vincent.whitchurch@axis.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Support frc-shared property

When the FRC is shared with another main processor, the other processor
is assumed to have started it and this processor should not write to the
global registers.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220609112738.359385-3-vincent.whitchurch@axis.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Increase the size of name array

Variable _name_ hold mct_tick number per cpu and it is currently
limited to 10. Which restrict the scalability of the MCT driver for
the SoC which has more local timers interrupts (>= 12).
Increase the length of it to make mct_tick printed correctly for
each local timer interrupts per CPU.

Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20220221174547.26176-3-alim.akhtar@samsung.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Bump up mct max irq number

Bump-up maximum number of MCT IRQ to match the binding
documentation. This make driver scalable for SoC which
has more than 12 timer irqs, like recently added FSD SoC.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20220221174547.26176-2-alim.akhtar@samsung.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Remove mct interrupt index enum

MCT driver define an enum which list global and local timer's
irq index. Most of them are not used but MCT_G0_IRQ and
MCT_L0_IRQ and these two are at a fixed offset/index.
Get rid of this enum and use a #define for the used irq index.

No functional changes expected.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20220221174547.26176-1-alim.akhtar@samsung.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Handle DTS with higher number of interrupts

The driver statically defines maximum number of interrupts it can
handle, however it does not respect that limit when configuring them.
When provided with a DTS with more interrupts than assumed, the driver
will overwrite static array mct_irqs leading to silent memory
corruption.

Validate the interrupts coming from DTS to avoid this. This does not
change the fact that such DTS might not boot at all, because it is
simply incompatible, however at least some warning will be printed.

Fixes: 36ba5d527e95 ("ARM: EXYNOS: add device tree support for MCT controller driver")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20220220103815.135380-1-krzysztof.kozlowski@canonical.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Fix silly typo resulting in checkpatch warning

Commit ae460fd9164b ("clocksource/drivers/exynos_mct: Prioritise Arm
arch timer on arm64") changed the rating of the MCT clockevents device
to be lower than the Arm architected timer and, in the process, replaced
a semicolon with a comma thanks to a silly copy-paste error.

Put the semicolon back so that the code looks more idiomatic and resolve
the SUSPECT_COMMA_SEMICOLON warning from checkpatch at the same time.

Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211103164804.30182-1-will@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Refactor resources allocation

Move interrupts allocation from exynos4_timer_resources() into separate
function together with the interrupt number parsing code from
mct_init_dt(), so the code for managing interrupts is kept together.
While touching exynos4_timer_resources() function, move of_iomap() to it.
No functional changes.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20211101193531.15078-2-semen.protsenko@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/exynos_mct: Mark MCT device as CLOCK_EVT_FEAT_PERCPU

The "mct_tick" is a per-cpu clockevents device. Set the
CLOCK_EVT_FEAT_PERCPU feature to prevent e.g. mct_tick0 being unsafely
designated as the global broadcast timer and instead treat the device as
a per-cpu wakeup timer.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210608154341.10794-3-will@kernel.org

clocksource/drivers/exynos_mct: Prioritise Arm arch timer on arm64

All arm64 CPUs feature an architected timer, which offers a relatively
low-latency interface to a per-cpu clocksource and timer. For the most
part, using this interface is a no-brainer, with the exception of SoCs
where it cannot be used to wake up from deep idle state (i.e.
CLOCK_EVT_FEAT_C3STOP is set).

On the contrary, the Exynos MCT is extremely slow to access yet can be
used as a wakeup source. In preparation for using the Exynos MCT as a
potential wakeup timer for the Arm architected timer, reduce its ratings
so that the architected timer is preferred.

This effectively reverts the decision made in 6282edb72bed
("clocksource/drivers/exynos_mct: Increase priority over ARM arch timer")
for arm64, as the reasoning for the original change was to work around
a 32-bit SoC design.

Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Will Deacon <will@kernel.org>
Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> # exynos-5422
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210608154341.10794-2-will@kernel.org

clocksource: Replace setup_irq() by request_irq()

request_irq() is preferred over setup_irq(). The early boot setup_irq()
invocations happen either via 'init_IRQ()' or 'time_init()', while
memory allocators are ready by 'mm_init()'.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

Seldom remove_irq() usage has been observed coupled with setup_irq(),
wherever that has been found, it too has been replaced by free_irq().

A build error that was reported by kbuild test robot <lkp@intel.com>
in the previous version of the patch also has been fixed.

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/91961c77c1cf93d41523f5e1ac52043f32f97077.1582799709.git.afzal.mohd.ma@gmail.com

clocksource/drivers/exynos_mct: Rename Exynos to lowercase

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

clocksource/drivers/exynos_mct: Increase priority over ARM arch timer

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>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

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>

clocksource/drivers/exynos_mct: Remove unused header includes

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>

clocksource/drivers/exynos_mct: Fix error path in timer resources initialization

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>

clocksource/drivers/exynos_mct: Remove dead code

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>

clocksource/drivers/exynos_mct: Clear timer interrupt when shutdown

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>

clocksource/drivers/exynos_mct: Move one-shot check from tick clear to ISR

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>

clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLARE

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>

clocksource/exynos_mct: Clear interrupt when cpu is shut down

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>

clocksource: Use a plain u64 instead of cycle_t

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>

cpu/hotplug: Cleanup state names

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>

clocksource: exynos_mct: Add the support for ARM64

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>

clocksource/exynos_mct: Convert to hotplug state machine

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>

clocksources: Switch back to the clksrc table

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>

clocksource/drivers/exynos_mct: Convert init function to return error

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>

clockevents/drivers/exynos_mct: Implement ->set_state_oneshot_stopped()

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>

clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()

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>

clockevents/drivers/exynos_mct: Migrate to new 'set-state' interface

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>

clockevents/drivers/exynos_mct: Remove unneeded container_of()

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>

clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier

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>

clocksource/drivers/exynos_mct: Remove old platform mct_init()

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>

clocksource/drivers/exynos_mct: Staticize struct clocksource

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>

clocksource/drivers/exynos_mct: Change exynos4_mct_tick_clear return type to 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>

clocksource: exynos_mct: Fix bitmask regression for exynos4_mct_write

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>

clocksource: exynos_mct: Only use 32-bits where possible

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>

clocksource: exynos_mct: Use readl_relaxed/writel_relaxed

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>

clocksource: exynos_mct: Register the timer for stable udelay

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>

clocksource: exynos_mct: Fix ftrace

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>

clocksource: exynos_mct: Don't reset the counter during boot and resume

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>

clocksource: exynos_mct: register sched_clock callback

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>

clocksource: Exynos_mct: Register clock event after request_irq()

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>

clocksource: Exynos_mct: Use irq_force_affinity() in cpu bringup

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>

clocksource: exynos_mct: silence a static checker warning

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>

clocksource: exynos_mct: remove unwanted header file inclusion

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>

clocksource: mct: extend mct to support 8 local interrupts for Exynos5420

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>

clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

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>

clocksource+irqchip: delete __cpuinit usage from all related files

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>

ARM: EXYNOS4: Divorce mct from local timer API

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>

clocksource: exynos_mct: use (request/free)_irq calls for local timer 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>

clocksource: exynos_mct: remove platform header dependency

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>

clocksource: exynos_mct: fix build error on non-DT

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>

clocksource: mct: Add terminating entry for exynos_mct_ids table

The of_device_id table is supposed to be zero-terminated.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

clocksource: mct: Add missing semicolons in exynos_mct.c

The CLOCKSOURCE_OF_DECLARE lines were added without a semicolon at the
end. On my system this causes a compile-time error that looks like:

drivers/clocksource/exynos_mct.c:557:202: warning: comparison of distinct pointer types lacks a cast [enabled by default]
drivers/clocksource/exynos_mct.c:558:1: error: expected ',' or ';' before 'static'

The error didn't show up till now because there was an extra semicolon
at end of the CLOCKSOURCE_OF_DECLARE definition that was removed by
Arnd Bergmann in "clocksource: make CLOCKSOURCE_OF_DECLARE type safe"

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

clocksource: mct: add support for mct clock setup

Add support for mct clock lookup and setup to ensure that the mct
clock is has been turned on.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

clocksource: mct: use fin_pll clock as the tick clock source for mct

With the migration of Exynos4 clocks to use common clock framework, the
old styled 'xtal' clock is not used anymore. Instead, the clock 'fin_pll'
is used as the tick clock for mct controller.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

ARM: EXYNOS: move mct driver to drivers/clocksource

Move the multi core timer (mct) driver to from mach-exynos
to drivers/clocksource and update the Kconfig and makefiles.

Cc: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>