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: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell 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: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This reverts commit 9f85550347.
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:
|
| 5fbd036b55
| 2baab4e904
| e3831edd59
|
| What's even worse:
|
| git describe --contains 9f85550347 --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: Russell 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: Jonas Aaberg <jonas.aberg@stericsson.com>
Reviewed-by: Rickard Andersson <rickard.andersson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Conflicts:
arch/arm/mach-shmobile/timer.c
This resolves a nonobvious merge conflict between renesas
timer changes in the global timer changes with those
from the renesas soc branch and last minute bug fixes that
went into v3.3.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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: Marc 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: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Marc 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: Marc 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: Marc Zyngier <marc.zyngier@arm.com>
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: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell 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: Colin Cross <ccross@android.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell 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: Colin Cross <ccross@android.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell 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: Colin Cross <ccross@android.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell 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: David Brown <davidb@codeaurora.org>
Tested-by: David Brown <davidb@codeaurora.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Marc 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: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will 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: Vitaly Kuzmichev <vkuzmichev@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Ensure that the twd timer reload value is reprogrammed each time we
enter periodic mode. This ensures that the reload value is always
reset correctly.
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The fraction of MHz was not being displayed correctly as the calculation
was a factor of 10 out. Fix this.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
When a CPU is hot unplugged, the generic tick code cleans up the
clock event device, but fails to call down to the device's set_mode
function to actually shut the device down.
To work around this, we've historically had a local_timer_stop()
callback out of the hotplug code. However, this adds needless
complexity when we have the clock event device itself available.
Explicitly call the clock event device's set_mode function with
CLOCK_EVT_MODE_UNUSED, so that the hardware can be cleanly shutdown
without any special external callbacks. When/if the generic code
is fixed, percpu_timer_stop() can be killed off.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Avoid adding nasty genirq-specific code to local timers to enable PPI
interrupts. Instead, provide a gic function to do this.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The TWD local timers are unable to wake up the CPU when it is placed
into a low power mode, eg. C3. Therefore, we need to adapt things
such that the TWD code can cope with this.
We do this by always providing a broadcast tick function, and marking
the fact that the TWD local timer will stop in low power modes. This
means that when the CPU is placed into a low power mode, the core
timer code marks this fact, and allows an IPI to be given to the core.
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
This moves the TWD register set of MPcore to a common
existing file so that watchdog driver can access it
Signed-off-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since this IRQ descriptor doesn't have an action registered, it is
allowed for probing via probe_irq_on/off() and it will be disabled by
the latter function. This patch sets the IRQ_NOPROBE status bit for the
local timer descriptor.
Signed-off-by: Varun Swara <Varun.Swara@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fix:
WARNING: vmlinux.o(.text+0x247c): Section mismatch in reference from the function cpu_idle() to the function .cpuexit.text:cpu_die()
The function cpu_idle() references a function in an exit section.
Often the function cpu_die() has valid usage outside the exit section
and the fix is to remove the __cpuexit annotation of cpu_die.
WARNING: vmlinux.o(.cpuexit.text+0x3c): Section mismatch in reference from the function cpu_die() to the function .cpuinit.text:secondary_start_kernel()
The function __cpuexit cpu_die() references
a function __cpuinit secondary_start_kernel().
This is often seen when error handling in the exit function
uses functionality in the init path.
The fix is often to remove the __cpuinit annotation of
secondary_start_kernel() so it may be used outside an init section.
Sam says:
> The annotation of cpu_die() is wrong.
> To be annotated __cpuexit the function shall:
> - be used in exit context and only in exit context with HOTPLUG_CPU=n
> - be used outside exit context with HOTPLUG_CPU=y
So, this also means __cpu_disable(), __cpu_die() and twd_timer_stop() are
also wrong. However, removing __cpuexit from cpu_die() creates:
WARNING: vmlinux.o(.text+0x6834): Section mismatch in reference from the function cpu_die() to the function .cpuinit.text:secondary_start_kernel()
The function cpu_die() references
the function __cpuinit secondary_start_kernel().
This is often because cpu_die lacks a __cpuinit
annotation or the annotation of secondary_start_kernel is wrong.
so fix this using __ref.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Linus Walleij