linux-toradex.git/drivers/clocksource/mips-gic-timer.c, branch v5.10-rc2

clocksource: mips-gic-timer: Mark GIC timer as unstable if ref clock changes

2020-05-22T22:03:16+00:00

Currently clocksource framework doesn't support the clocks with variable
frequency. Since MIPS GIC timer ticks rate might be unstable on some
platforms, we must make sure that it justifies the clocksource
requirements. MIPS GIC timer is incremented with the CPU cluster reference
clocks rate. So in case if CPU frequency changes, the MIPS GIC tick rate
changes synchronously. Due to this the clocksource subsystem can't rely on
the timer to measure system clocks anymore. This commit marks the MIPS GIC
based clocksource as unstable if reference clock (normally it's a CPU
reference clocks) rate changes. The clocksource will execute a watchdog
thread, which lowers the MIPS GIC timer rating to zero and fallbacks to a
new stable one.

Note we don't need to set the CLOCK_SOURCE_MUST_VERIFY flag to the MIPS
GIC clocksource since normally the timer is stable. The only reason why
it gets unstable is due to the ref clock rate change, which event we
detect here in the driver by means of the clocks event notifier.

Signed-off-by: Serge Semin 
Cc: Alexey Malahov 
Cc: Thomas Bogendoerfer 
Cc: Paul Burton 
Cc: Ralf Baechle 
Cc: Alessandro Zummo 
Cc: Alexandre Belloni 
Cc: Arnd Bergmann 
Cc: Rob Herring 
Cc: linux-mips@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Daniel Lezcano 
Link: https://lore.kernel.org/r/20200521204818.25436-9-Sergey.Semin@baikalelectronics.ru

clocksource: mips-gic-timer: Register as sched_clock

2020-05-22T22:03:08+00:00

The MIPS GIC timer is well suited for use as sched_clock, so register it
as such.

Whilst the existing gic_read_count() function matches the prototype
needed by sched_clock_register() already, we split it into 2 functions
in order to remove the need to evaluate the mips_cm_is64 condition
within each call since sched_clock should be as fast as possible.

Note the sched clock framework needs the clock source being stable in
order to rely on it. So we register the MIPS GIC timer as schedule clocks
only if it's, if either the system doesn't have CPU-frequency enabled or
the CPU frequency is changed by means of the CPC core clock divider
available on the platforms with CM3 or newer.

Signed-off-by: Paul Burton 
Co-developed-by: Serge Semin 
[Sergey.Semin@baikalelectronics.ru: Register sched-clock if CM3 or !CPU-freq]
Signed-off-by: Serge Semin 
Cc: Alexey Malahov 
Cc: Thomas Bogendoerfer 
Cc: Ralf Baechle 
Cc: Alessandro Zummo 
Cc: Alexandre Belloni 
Cc: Arnd Bergmann 
Cc: Rob Herring 
Cc: linux-mips@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Daniel Lezcano 
Link: https://lore.kernel.org/r/20200521204818.25436-8-Sergey.Semin@baikalelectronics.ru

mips: vdso: Use generic VDSO clock mode storage

2020-02-17T19:12:16+00:00

Switch to the generic VDSO clock mode storage.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Vincenzo Frascino 
Link: https://lkml.kernel.org/r/20200207124403.244684017@linutronix.de

clocksource/drivers/mips-gic-timer: Make gic_compare_irqaction static

2019-03-22T21:59:33+00:00

Fix sparse warning:

drivers/clocksource/mips-gic-timer.c:70:18: warning:
 symbol 'gic_compare_irqaction' was not declared. Should it be static?

Signed-off-by: YueHaibing 
Signed-off-by: Thomas Gleixner 
Cc: 
Link: https://lkml.kernel.org/r/20190322144359.19516-1-yuehaibing@huawei.com

clocksource/drivers/mips-gic-timer: Add pr_fmt and reword pr_* messages

2018-05-18T20:53:09+00:00

Several messages from the MIPS GIC driver include the text "GIC", "GIC
timer", etc, but the format is not standard. Add a pr_fmt of
"mips-gic-timer: " and reword the messages now that they will be
prefixed with the driver name.

Signed-off-by: Matt Redfearn 
Signed-off-by: Daniel Lezcano

clocksource/drivers/mips-gic-timer: Use correct shift count to extract data

2018-02-28T12:55:14+00:00

__gic_clocksource_init() extracts the GIC_CONFIG_COUNTBITS field from
read_gic_config() by right shifting the register value. The shift count is
determined by the most significant bit (__fls) of the bitmask which is
wrong as it shifts out the complete bitfield.

Use the least significant bit (__ffs) instead to shift the bitfield down to
bit 0.

Fixes: e07127a077c7 ("clocksource: mips-gic-timer: Use new GIC accessor functions")
Signed-off-by: Felix Fietkau 
Signed-off-by: Thomas Gleixner 
Cc: daniel.lezcano@linaro.org
Cc: paul.burton@imgtec.com
Link: https://lkml.kernel.org/r/20180228095610.50341-1-nbd@nbd.name

treewide/trivial: Remove ';;$' typo noise

2018-02-22T09:59:33+00:00

On lkml suggestions were made to split up such trivial typo fixes into per subsystem
patches:

  --- a/arch/x86/boot/compressed/eboot.c
  +++ b/arch/x86/boot/compressed/eboot.c
  @@ -439,7 +439,7 @@ setup_uga32(void **uga_handle, unsigned long size, u32 *width, u32 *height)
          struct efi_uga_draw_protocol *uga = NULL, *first_uga;
          efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
          unsigned long nr_ugas;
  -       u32 *handles = (u32 *)uga_handle;;
  +       u32 *handles = (u32 *)uga_handle;
          efi_status_t status = EFI_INVALID_PARAMETER;
          int i;

This patch is the result of the following script:

  $ sed -i 's/;;$/;/g' $(git grep -E ';;$'  | grep "\.[ch]:"  | grep -vwE 'for|ia64' | cut -d: -f1 | sort | uniq)

... followed by manual review to make sure it's all good.

Splitting this up is just crazy talk, let's get over with this and just do it.

Reported-by: Pavel Machek 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

clocksource/drivers/mips-gic-timer: Add fastpath for local timer updates

2017-10-19T21:51:31+00:00

Always accessing the compare register via the CM redirect region is
(relatively) slow. If the timer being updated is the current CPUs
then this can be shortcutted by writing to the CM VP local region.

Signed-off-by: Matt Redfearn 
Signed-off-by: Daniel Lezcano

clocksource/drivers/mips-gic-timer: Remove pointless irq_save,restore

2017-10-19T21:49:45+00:00

The function gic_next_event is always called with interrupts disabled, so
the local_irq_save / local_irq_restore are pointless - remove them.

[Daniel Lezcano: Fixed warning by removing unused variable 'flags']

Signed-off-by: Matt Redfearn 
Suggested-by: Daniel Lezcano 
Reported-by: Thomas Gleixner 
Signed-off-by: Daniel Lezcano

clocksource: mips-gic-timer: Use new GIC accessor functions

2017-08-30T12:30:07+00:00

Switch from calling functions exported by the GIC interrupt controller
to using new accessors provided by asm/mips-gic.h. This will allow the
counter-handling functionality to be removed from the interrupt
controller driver, where it doesn't really belong, and also allow for
inlining of the accesses to the GIC.

Signed-off-by: Paul Burton 
Acked-by: Thomas Gleixner 
Cc: Daniel Lezcano 
Cc: Jason Cooper 
Cc: Marc Zyngier 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17021/
Signed-off-by: Ralf Baechle