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  1. 20 10月, 2017 3 次提交
  3. 15 4月, 2017 1 次提交
    • N
      clockevents/drivers/sh_cmt: Set ->min_delta_ticks and ->max_delta_ticks · bb2e94ac
      由 Nicolai Stange 提交于 
      In preparation for making the clockevents core NTP correction aware,
all clockevent device drivers must set ->min_delta_ticks and
->max_delta_ticks rather than ->min_delta_ns and ->max_delta_ns: a
clockevent device's rate is going to change dynamically and thus, the
ratio of ns to ticks ceases to stay invariant.

Make the sh_cmt clockevent driver initialize these fields properly.

This patch alone doesn't introduce any change in functionality as the
clockevents core still looks exclusively at the (untouched) ->min_delta_ns
and ->max_delta_ns. As soon as this has changed, a followup patch will
purge the initialization of ->min_delta_ns and ->max_delta_ns from this
driver.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NNicolai Stange <nicstange@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
      bb2e94ac
  5. 24 3月, 2017 1 次提交
    • N
      clocksource: sh_cmt: Compute rate before registration again · 890f423b
      由 Nicolai Stange 提交于 
      With the upcoming NTP correction related rate adjustments to be implemented
in the clockevents core, the latter needs to get informed about every rate
change of a clockevent device made after its registration.

Currently, sh_cmt violates this requirement in that it registers its
clockevent device with a dummy rate and sets its final ->mult and ->shift
values from its ->set_state_oneshot() and ->set_state_periodic() functions
respectively.

This patch moves the setting of the clockevent device's ->mult and ->shift
values to before its registration.

Note that there has been some back and forth regarding this question with
respect to the clocksource also provided by this driver:
  commit f4d7c356 ("clocksource: sh_cmt: compute mult and shift before
                        registration")
moves the rate determination from the clocksource's ->enable() function to
before its registration. OTOH, the later
  commit 3593f5fe ("clocksource: sh_cmt: __clocksource_updatefreq_hz()
                        update")
basically reverts this, saying
  "Without this patch the old code uses clocksource_register() together
   with a hack that assumes a never changing clock rate."

However, I checked all current sh_cmt users in arch/sh as well as in
arch/arm/mach-shmobile carefully and right now, none of them changes any
rate in any clock tree relevant to sh_cmt after their respective
time_init(). Since all sh_cmt instances are created after time_init(), none
of them should ever observe any clock rate changes.

What's more, both, a clocksource as well as a clockevent device, can
immediately get selected for use at their registration and thus, enabled
at this point already. So it's probably safer to assume a "never changing
clock rate" here.

- Move the struct sh_cmt_channel's ->rate member to struct sh_cmt_device:
  it's a property of the underlying clock which is in turn specific to
  the sh_cmt_device.
- Determine the ->rate value in sh_cmt_setup() at device probing rather
  than at first usage.
- Set the clockevent device's ->mult and ->shift values right before its
  registration.
- Although not strictly necessary for the upcoming clockevent core changes,
  set the clocksource's rate at its registration for consistency.
Signed-off-by: NNicolai Stange <nicstange@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
      890f423b
  7. 25 12月, 2016 1 次提交
  9. 15 10月, 2015 1 次提交
  11. 10 8月, 2015 4 次提交
  13. 08 8月, 2015 1 次提交
    • G
      clockevents/drivers/sh_cmt: Only perform clocksource suspend/resume if enabled · 54d46b7f
      由 Geert Uytterhoeven 提交于 
      Currently the sh_cmt clocksource timer is disabled or enabled
unconditionally on clocksource suspend resp. resume, even if a
better clocksource is present (e.g. arch_sys_counter) and the
sh_cmt clocksource is not enabled.

As sh_cmt is a syscore device when its timer is enabled, this
may lead to a genpd.prepared_count imbalance in the presence of
PM Domains, which may cause a lock-up during reboot after s2ram.

During suspend:
  - pm_genpd_prepare() is called for all non-syscore devices (incl.
    sh_cmt), increasing genpd.prepared_count for each device,
  - clocksource.suspend() is called for all clocksource devices,
  - sh_cmt_clocksource_suspend() calls sh_cmt_stop(), which is a no-op
    as the clocksource was not enabled.

During resume:
  - clocksource.resume() is called for all clocksource devices,
  - sh_cmt_clocksource_resume() calls sh_cmt_start(), which enables the
    clocksource timer, and turns sh_cmt into a syscore device,
  - pm_genpd_complete() is called for all non-syscore devices (excl.
    sh_cmt now!), decreasing genpd.prepared_count for each device but
    sh_cmt.

Now genpd.prepared_count of the PM Domain containing sh_cmt is
still 1 instead of zero.  On subsequent suspend/resume cycles,
sh_cmt is still a syscore device, hence it's skipped for
pm_genpd_{prepare,complete}(), keeping the imbalance of
genpd.prepared_count at 1.

During reboot:

  - platform_drv_shutdown() is called for any platform device that has
    a driver with a .shutdown() method (only rcar-dmac on R-Car Gen2),

  - platform_drv_shutdown() calls dev_pm_domain_detach(), which
    calls genpd_dev_pm_detach(),

  - genpd_dev_pm_detach() keeps calling pm_genpd_remove_device() until
    it doesn't return -EAGAIN[*],

  - If the device is part of the same PM Domain as sh_cmt,
    pm_genpd_remove_device() always fails with -EAGAIN due to
    genpd.prepared_count > 0.

  - Infinite loop in genpd_dev_pm_detach()[*].

[*] Commit 93af5e93 ("PM / Domains: Avoid infinite loops in
    attach/detach code") already limited the number of loop iterations,
    avoiding the lock-up.

To fix this, only disable or enable the clocksource timer on
clocksource suspend resp. resume if the clocksource was enabled.

This was tested on r8a7791/koelsch with the CPG Clock Domain:

  - using arch_sys_counter as the clocksource, which is the default, and
    which showed the problem,

  - using sh_cmt as a clocksource ("echo ffca0000.timer > \
    /sys/devices/system/clocksource/clocksource0/current_clocksource"),
    which behaves the same as before.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438875126-12596-2-git-send-email-daniel.lezcano@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      54d46b7f
  15. 13 3月, 2015 1 次提交
  17. 04 7月, 2014 1 次提交
  19. 02 7月, 2014 2 次提交
  21. 23 5月, 2014 1 次提交
  23. 16 4月, 2014 20 次提交
  25. 18 12月, 2013 1 次提交
  27. 11 12月, 2013 1 次提交
  29. 22 8月, 2013 1 次提交