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: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Acked-by: NNeil Armstrong <narmstrong@baylibre.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NMatthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

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: NThomas 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.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Install the callbacks via the state machine. The callbacks won't be invoked on
already online CPUs.
Signed-off-by: NRichard Cochran <rcochran@linutronix.de>
Signed-off-by: NAnna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153336.881124821@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

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: NDaniel Lezcano <daniel.lezcano@linaro.org>

For exynos_mct and samsung_pwm_timer:
Acked-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>

For arch/arc:
Acked-by: NVineet Gupta <vgupta@synopsys.com>

For mediatek driver:
Acked-by: NMatthias Brugger <matthias.bgg@gmail.com>

For the Rockchip-part
Acked-by: NHeiko Stuebner <heiko@sntech.de>

For STi :
Acked-by: NPatrice Chotard <patrice.chotard@st.com>

For the mps2-timer.c and versatile.c changes:
Acked-by: NLiviu Dudau <Liviu.Dudau@arm.com>

For the OXNAS part :
Acked-by: NNeil Armstrong <narmstrong@baylibre.com>

For LPC32xx driver:
Acked-by: NSylvain Lemieux <slemieux.tyco@gmail.com>

For Broadcom Kona timer change:
Acked-by: NRay Jui <ray.jui@broadcom.com>

For Sun4i and Sun5i:
Acked-by: NChen-Yu Tsai <wens@csie.org>

For Meson6:
Acked-by: NCarlo Caione <carlo@caione.org>

For Keystone:
Acked-by: NSantosh Shilimkar <ssantosh@kernel.org>

For NPS:
Acked-by: NNoam Camus <noamca@mellanox.com>

For bcm2835:
Acked-by: NEric Anholt <eric@anholt.net>

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: NDaniel Lezcano <daniel.lezcano@linaro.org>

Rename feat_c3stop to twd_features to match the other variables in this
file.  Initialise it with the standard features that we always support,
and arrange to set the CLOCK_EVT_FEAT_C3STOP when appropriate.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

In 5388a6b2 ("ARM: SMP: Always enable clock event broadcast support")
Russell noted that "the TWD local timers are unable to wake up the CPU
when it is placed into a low power mode".

However, some platforms do not stop the TWD block in low-power mode,
and can thus use the TWD timer in one-shot mode, without setting up
a broadcast device.

Make the driver check for the "always-on" boolean property, and set
the CLOCK_EVT_FEAT_C3STOP flag accordingly.
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NMarc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This reverts commit 904464b9.

The problem pointed out by commit 904464b9 ("ARM: 7655/1:
smp_twd: make twd_local_timer_of_register() no-op for nosmp")
doesn't exist anymore.

We can safely boot with nosmp and the warning won't show up.

The other side benefit of this patch is that TWD has a chance
to probe on single-core A9 systems such as AM437x which sport
TWD.

While at that, also drop SMP dependency from TWD's Kconfig entry.

Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Dirk Behme <dirk.behme@de.bosch.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Migrate smp_twd 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: Russell King <linux@arm.linux.org.uk>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>

Convert many (but not all) printk(KERN_* to pr_* to simplify the code.
We take the opportunity to join some printk lines together so we don't
split the message across several lines, and we also add a few levels
to some messages which were previously missing them.
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Tested-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

__this_cpu_ptr is being phased out. So replace with raw_cpu_ptr.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Two cpufreq notifiers CPUFREQ_RESUMECHANGE and CPUFREQ_SUSPENDCHANGE have
not been used for some time, so remove them to clean up code a bit.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
[rjw: Changelog]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Ensure the twd driver uses the correct calls to access the hardware
to ensure that we do not end up with data in the wrong endian format.
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>

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 5e427ec2 ("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.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit  -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings.  In any case, they are temporary and harmless.

This removes all the ARM uses of the __cpuinit macros from C code,
and all __CPUINIT from assembly code.  It also had two ".previous"
section statements that were paired off against __CPUINIT
(aka .section ".cpuinit.text") that also get removed here.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

When the local timer freq changed, the twd_update_frequency function
should be run all the CPUs include itself, otherwise, the twd freq will
not get updated and the local timer will not run correcttly.

smp_call_function will run functions on all other CPUs, but not include
himself, this is not correct,use on_each_cpu instead to fix this issue.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NJason Liu <r64343@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Separate the smp_twd 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.
Tested-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

Now that we have OF based init with CLKSRC_OF, convert smp_twd init
function to use it and covert all callers of
twd_local_timer_of_register.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Viresh Kumar <viresh.linux@gmail.com>
Cc: Shiraz Hashim <shiraz.hashim@st.com>
Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-omap@vger.kernel.org
Cc: spear-devel@list.st.com
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>

When booting a SMP build kernel with nosmp on kernel cmdline, the
following fat warning will be hit.

------------[ cut here ]------------
WARNING: at arch/arm/kernel/smp_twd.c:345
twd_local_timer_of_register+0x7c/0x90()
twd_local_timer_of_register failed (-6)
Modules linked in:
Backtrace:
[<80011f14>] (dump_backtrace+0x0/0x10c) from [<8044dd30>]
(dump_stack+0x18/0x1c)
 r7:805e9f58 r6:805ba84c r5:80539331 r4:00000159
[<8044dd18>] (dump_stack+0x0/0x1c) from [<80020fbc>]
(warn_slowpath_common+0x54/0x6c)
[<80020f68>] (warn_slowpath_common+0x0/0x6c) from [<80021078>]
(warn_slowpath_fmt+0x38/0x40)
 r9:412fc09a r8:8fffffff r7:ffffffff r6:00000001 r5:80633b8c
r4:80b32da8
[<80021040>] (warn_slowpath_fmt+0x0/0x40) from [<805ba84]
(twd_local_timer_of_register+0x7c/0x90)
 r3:fffffffa r2:8053934b
[<805ba7d0>] (twd_local_timer_of_register+0x0/0x90) from [<805c0bec>]
(imx6q_timer_init+0x18/0x4c)
 r5:80633800 r4:8053b701
[<805c0bd4>] (imx6q_timer_init+0x0/0x4c) from [<805ba4e8>]
(time_init+0x28/0x38)
 r5:80633800 r4:805dc0f4
[<805ba4c0>] (time_init+0x0/0x38) from [<805b6854>]
(start_kernel+0x1a0/0x310)
[<805b66b4>] (start_kernel+0x0/0x310) from [<10008044>] (0x10008044)
 r8:1000406a r7:805f3f8c r6:805dc0c4 r5:805f0518 r4:10c5387d
---[ end trace 1b75b31a2719ed1c ]---

Check (!is_smp() || !setup_max_cpus) in twd_local_timer_of_register()
to make it be a no-op for the conditions, thus avoid above warning.
Reported-by: NDirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move clk setup to twd_local_timer_common_register and rely on
twd_timer_rate being 0 to force calibration if there is no clock.
Remove common_setup_called as it is no longer needed.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NMark Langsdorf <mark.langsdorf@calxeda.com>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Now that the GIC initialization sets up the handle_arch_irq pointer, we
can remove it for all machines and make it static.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Anton Vorontsov <avorontsov@mvista.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: David Brown <davidb@codeaurora.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Acked-by: NTony Lindgren <tony@atomide.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Dinh Nguyen <dinguyen@altera.com>
Cc: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: NStephen Warren <swarren@nvidia.com>
Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NKukjin Kim <kgene.kim@samsung.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Acked-by: NOlof Johansson <olof@lixom.net>
Acked-by: NArnd Bergmann <arnd@arndb.de>

0336517b "ARM: smp_twd: don't warn on no DT node" introduced
a silly build warning by returning an error from a void function.
This keeps the intention of that patch but fixes the warning by
removing the error code
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

It has been brought to my knowledge that the .setup()/.stop()
function pair in the SMP TWD is going to be called from atomic
contexts for CPUs coming and going, and then the
clk_prepare()/clk_unprepare() calls cannot be called
on subsequent .setup()/.stop() iterations. This is however
just the tip of an iceberg as the function pair is not
designed to be reentrant at all.

This change makes the SMP_TWD clock .setup()/.stop() pair reentrant
by splitting the .setup() function in three parts:

- One COMMON part that is executed the first time the first CPU
  in the TWD cluster is initialized. This will fetch the TWD
  clk for the cluster and prepare+enable it. If no clk is
  available it will calibrate the rate instead.

- One part that is executed the FIRST TIME a certain CPU is
  brought on-line. This initializes and sets up the clock event
  for a certain CPU.

- One part that is executed on every subsequent .setup() call.
  This will re-initialize the clock event. This is augmented
  to call the clk_enable()/clk_disable() pair properly.

Cc: Shawn Guo <shawn.guo@linaro.org>
Reported-by: NPeter Chen <peter.chen@freescale.com>
Reviewed-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

A minor code refactoring saving a few lines by merging prepare()
and enable() calls.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Not having a TWD is valid if we have multiple platforms with different
cores, so remove the warning message.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

The periodic mode is currently calculated by a simple division
but we should pay more attention to our integer arithmetics.
Also delete a comment that does not make any sense.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Running cpufreq driver on imx6q, the following warning is seen.

$ BUG: sleeping function called from invalid context at kernel/mutex.c:269

<snip>

stack backtrace:
Backtrace:
[<80011d64>] (dump_backtrace+0x0/0x10c) from [<803fc164>] (dump_stack+0x18/0x1c)
 r6:bf8142e0 r5:bf814000 r4:806ac794 r3:bf814000
[<803fc14c>] (dump_stack+0x0/0x1c) from [<803fd444>] (print_usage_bug+0x250/0x2b
8)
[<803fd1f4>] (print_usage_bug+0x0/0x2b8) from [<80060f90>] (mark_lock+0x56c/0x67
0)
[<80060a24>] (mark_lock+0x0/0x670) from [<80061a20>] (__lock_acquire+0x98c/0x19b
4)
[<80061094>] (__lock_acquire+0x0/0x19b4) from [<80062f14>] (lock_acquire+0x68/0x
7c)
[<80062eac>] (lock_acquire+0x0/0x7c) from [<80400f28>] (mutex_lock_nested+0x78/0
x344)
 r7:00000000 r6:bf872000 r5:805cc858 r4:805c2a04
[<80400eb0>] (mutex_lock_nested+0x0/0x344) from [<803089ac>] (clk_get_rate+0x1c/
0x58)
[<80308990>] (clk_get_rate+0x0/0x58) from [<80013c48>] (twd_update_frequency+0x1
8/0x50)
 r5:bf253d04 r4:805cadf4
[<80013c30>] (twd_update_frequency+0x0/0x50) from [<80068e20>] (generic_smp_call
_function_single_interrupt+0xd4/0x13c)
 r4:bf873ee0 r3:80013c30
[<80068d4c>] (generic_smp_call_function_single_interrupt+0x0/0x13c) from [<80013
34c>] (handle_IPI+0xc0/0x194)
 r8:00000001 r7:00000000 r6:80574e48 r5:bf872000 r4:80593958
[<8001328c>] (handle_IPI+0x0/0x194) from [<800084e8>] (gic_handle_irq+0x58/0x60)
 r8:00000000 r7:bf873f8c r6:bf873f58 r5:80593070 r4:f4000100
r3:00000005
[<80008490>] (gic_handle_irq+0x0/0x60) from [<8000e124>] (__irq_svc+0x44/0x60)
Exception stack(0xbf873f58 to 0xbf873fa0)
3f40:                                                       00000001 00000001
3f60: 00000000 bf814000 bf872000 805cab48 80405aa4 80597648 00000000 412fc09a
3f80: bf872000 bf873fac bf873f70 bf873fa0 80063844 8000f1f8 20000013 ffffffff
 r6:ffffffff r5:20000013 r4:8000f1f8 r3:bf814000
[<8000f1b8>] (default_idle+0x0/0x4c) from [<8000f428>] (cpu_idle+0x98/0x114)
[<8000f390>] (cpu_idle+0x0/0x114) from [<803f9834>] (secondary_start_kernel+0x11
c/0x140)
[<803f9718>] (secondary_start_kernel+0x0/0x140) from [<103f9234>] (0x103f9234)
 r6:10c03c7d r5:0000001f r4:4f86806a r3:803f921c

It looks that the warning is caused by that twd_update_frequency() gets
called from an atomic context while it calls clk_get_rate() where a
mutex gets held.

To fix the warning, let's convert common clk users over to clk notifiers
in place of CPUfreq notifiers.  This works out nicely for Cortex-A9
MPcore designs that scale all CPUs at the same frequency.

Platforms that have not been converted to the common clk framework and
support CPUfreq will rely on the old mechanism.  Once these platforms
are converted over fully then we can remove the CPUfreq-specific bits
for good.
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This reverts commit 9f855503.

Peter Zijlstra says:
| Argh, how did that ever make it upstream, please drop.
|
| Russell, please make that go away upstream.
|
| Like I said, this is both completely the wrong way to solve, and you're
| so not paying attention, see:
|
|   5fbd036b
|   2baab4e9
|   e3831edd
|
| What's even worse:
|
| git describe --contains 9f855503 --match "v*"
| v3.4-rc3~1^2~3
|
| that nonsense got merged long after those other commits.

Linus Walleij says:
| My bad, was because the initial patch was submitted march 9th before
| these fixes were merged:
| http://marc.info/?l=linux-arm-kernel&m=133159655513844&w=2
|
| It was pending for a while in Russell's patch tracker and I
| rebased it to -rc2 without paying enough attention to recent
| related scheduler fixes ... lesson learned.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

During booting of cpu1, there is a short window where cpu1
is online, but not active where cpu1 is occupied by waiting
to become active. If cpu0 then decides to schedule something
on cpu1 and wait for it to complete, before cpu0 has set
cpu1 active, we have a deadlock.

Typically it's this CPU frequency transition that happens at
this time, so let's just not wait for it to happen, it will
happen whenever the CPU eventually comes online instead.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: NJonas Aaberg <jonas.aberg@stericsson.com>
Reviewed-by: NRickard Andersson <rickard.andersson@stericsson.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Now that all users of the previous local timer interface
have been converted to the runtime registration API, make
this interface the only one supported for this driver.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Add bindings to support DT discovery of the ARM Timer Watchdog
(aka TWD). Only the timer side is converted by this patch.
Acked-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Add support for the new registration interface to smp_twd.
Platforms can populate a struct twd_local_timer with MMIO
and IRQ resources, and then call twd_local_timer_register()
to have the timer registered with the core.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

When CONFIG_HAVE_ARM_TWD is selected, local_timer_stop is a #define,
while all other local timers are using a real function.

Convert it to an alias of twd_timer_stop, as it helps converting
all local timers to another internal API in a sane way.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Current ARM local timer code registers CPUFREQ notifiers even in case
the twd_timer_setup() isn't called. That seems to be wrong and
would eventually lead to kernel crash on the CPU frequency transitions
on the SOCs where the local timer doesn't exist or broken because of
hardware BUG. Fix it by testing twd_evt and *__this_cpu_ptr(twd_evt).

The issue was observed with v3.3-rc3 and building an OMAP2+ kernel
on OMAP3 SOC which doesn't have TWD.

Below is the dump for reference :

 Unable to handle kernel paging request at virtual address 007e900
 pgd = cdc20000
 [007e9000] *pgd=00000000
 Internal error: Oops: 5 [#1] SMP
 Modules linked in:
 CPU: 0    Not tainted  (3.3.0-rc3-pm+debug+initramfs #9)
 PC is at twd_update_frequency+0x34/0x48
 LR is at twd_update_frequency+0x10/0x48
 pc : [<c001382c>]    lr : [<c0013808>]    psr: 60000093
 sp : ce311dd8  ip : 00000000  fp : 00000000
 r10: 00000000  r9 : 00000001  r8 : ce310000
 r7 : c0440458  r6 : c00137f8  r5 : 00000000  r4 : c0947a74
 r3 : 00000000  r2 : 007e9000  r1 : 00000000  r0 : 00000000
 Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment usr
 Control: 10c5387d  Table: 8dc20019  DAC: 00000015
 Process sh (pid: 599, stack limit = 0xce3102f8)
 Stack: (0xce311dd8 to 0xce312000)
 1dc0:                                                       6000c
 1de0: 00000001 00000002 00000000 00000000 00000000 00000000 00000
 1e00: ffffffff c093d8f0 00000000 ce311ebc 00000001 00000001 ce310
 1e20: c001386c c0437c4c c0e95b60 c0e95ba8 00000001 c0e95bf8 ffff4
 1e40: 00000000 00000000 c005ef74 ce310000 c0435cf0 ce311ebc 00000
 1e60: ce352b40 0007a120 c08d5108 c08ba040 c08ba040 c005f030 00000
 1e80: c08bc554 c032fe2c 0007a120 c08d4b64 ce352b40 c08d8618 ffff8
 1ea0: c08ba040 c033364c ce311ecc c0433b50 00000002 ffffffea c0330
 1ec0: 0007a120 0007a120 22222201 00000000 22222222 00000000 ce357
 1ee0: ce3d6000 cdc2aed8 ce352ba0 c0470164 00000002 c032f47c 00034
 1f00: c0331cac ce352b40 00000007 c032f6d0 ce352bbc 0003d090 c0930
 1f20: c093d8bc c03306a4 00000007 ce311f80 00000007 cdc2aec0 ce358
 1f40: ce8d20c0 00000007 b6fe5000 ce311f80 00000007 ce310000 0000c
 1f60: c000de74 ce987400 ce8d20c0 b6fe5000 00000000 00000000 0000c
 1f80: 00000000 00000000 001fbac8 00000000 00000007 001fbac8 00004
 1fa0: c000df04 c000dd60 00000007 001fbac8 00000001 b6fe5000 00000
 1fc0: 00000007 001fbac8 00000007 00000004 b6fe5000 00000000 00202
 1fe0: 00000000 beb565f8 00101ffc 00008e8c 60000010 00000001 00000
 [<c001382c>] (twd_update_frequency+0x34/0x48) from [<c008ac4c>] )
 [<c008ac4c>] (smp_call_function_single+0x17c/0x1c8) from [<c0013)
 [<c0013890>] (twd_cpufreq_transition+0x24/0x30) from [<c0437c4c>)
 [<c0437c4c>] (notifier_call_chain+0x44/0x84) from [<c005efe4>] ()
 [<c005efe4>] (__srcu_notifier_call_chain+0x70/0xa4) from [<c005f)
 [<c005f030>] (srcu_notifier_call_chain+0x18/0x20) from [<c032fe2)
 [<c032fe2c>] (cpufreq_notify_transition+0xc8/0x1b0) from [<c0333)
 [<c033364c>] (omap_target+0x1b4/0x28c) from [<c032f47c>] (__cpuf)
 [<c032f47c>] (__cpufreq_driver_target+0x50/0x64) from [<c0331d24)
 [<c0331d24>] (cpufreq_set+0x78/0x98) from [<c032f6d0>] (store_sc)
 [<c032f6d0>] (store_scaling_setspeed+0x5c/0x74) from [<c03306a4>)
 [<c03306a4>] (store+0x58/0x74) from [<c014d868>] (sysfs_write_fi)
 [<c014d868>] (sysfs_write_file+0x80/0xb4) from [<c00f2c2c>] (vfs)
 [<c00f2c2c>] (vfs_write+0xa8/0x138) from [<c00f2e9c>] (sys_write)
 [<c00f2e9c>] (sys_write+0x40/0x6c) from [<c000dd60>] (ret_fast_s)
 Code: e594300c e792210c e1a01000 e5840004 (e7930002)
 ---[ end trace 5da3b5167c1ecdda ]---
Reported-by: NKevin Hilman <khilman@ti.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Tested-by: NKevin Hilman <khilman@ti.com>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

On secondary CPUs, the Timer Control Register is not reset
to a sane value before the timer is registered, and the TRM
doesn't seem to indicate any reset value either. In some cases,
the kernel will take an interrupt too early, depending on what
junk was present in the registers at reset time.

The fix is to set the Timer Control Register to 0 before
registering the clock_event_device and enabling the interrupt.

Problem seen on VE (Cortex A5) and Tegra.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This break-out from Colin Cross' cpufreq-aware TWD patch
will handle the case when our localtimer's clock changes with
the cpu clock. A cpufreq transtion notifier will be registered
only if the platform has supplied a specified clock to the TWD.

After a cpufreq transition, update the clockevent's frequency
by fetching the new clock rate from the clock framework and
reprogram the next clock event.

The necessary changes in the clockevents framework was done by
Thomas Gleixner in kernel v3.0.

ChangeLog v1->v2:
- Replace IS_ERR_OR_NULL() with IS_ERR() in twd_clk check.
- Update code to use the already existing per-cpu array of TWD
  clockevents instead of adding cruft.

[Broke out, ifdef:ed CPUfreq stuff for non-cpufreq configs]
[Rebased to newer TWD base with per-CPU clock array]
Signed-off-by: NColin Cross <ccross@android.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NRob Herring <rob.herring@calxeda.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This break-out from Colin Cross' cpufreq-aware TWD patch will
optionally retrieve the clock rate of the TWD from an external
clock. A variant of this patch has been proposed by Rob Herring
as well.

The basic idea is to avoid recalibrating the rate of the clock
at boot if the platform already know what rate the clock to the
TWD block has.

ChangeLog v1->v2: added clk_[prepare|unprepare] calls.

[Broke out of larger SMP TWD patch]
Signed-off-by: NColin Cross <ccross@android.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NRob Herring <rob.herring@calxeda.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This break-out from Colin Cross' cpufreq-aware TWD patch will
just modernize the clock event registration code to use
clockevents_config_and_register().

[Broke out of larger SMP TWD patch]
Signed-off-by: NColin Cross <ccross@android.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NRob Herring <rob.herring@calxeda.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch remove the hardcoded link between local timers and PPIs,
and convert the PPI users (TWD, MCT and MSM timers) to the new
*_percpu_irq interface. Also some collateral cleanup
(local_timer_ack() is gone, and the interrupt handler is strictly
private to each driver).

PPIs are now useable for more than just the local timers.

Additional testing by David Brown (msm8250 and msm8660) and
Shawn Guo (imx6q).

Cc: David Brown <davidb@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The smp_twd clockevents driver currently enables the local timer PPI
before the clockevents device is registered. This can lead to a kernel
panic if a spurious timer interrupt is generated before registration
has completed since the kernel will treat it as an IPI timer.

This patch moves the clockevents device registration before the IRQ
unmasking so that we can always handle timer interrupts once they can
occur.
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

To get hundredths of MHz the rate needs to be divided by 10'000.
Here is an example:
 twd_timer_rate = 123456789
 Before the patch:
    twd_timer_rate / 1000000 = 123
    (twd_timer_rate / 1000000) % 100 = 23
    Result: 123.23MHz.
 After being fixed:
    twd_timer_rate / 1000000 = 123
    (twd_timer_rate / 10000) % 100 = 45
    Result: 123.45MHz.
Signed-off-by: NVitaly Kuzmichev <vkuzmichev@mvista.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>