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/linux/arch/arm/include/asm/
H A Darch_timer.hdiff 0b46b8a718c6e90910a1b1b0fe797be3c167e186 Mon Nov 24 08:02:44 CET 2014 Sonny Rao <sonnyrao@chromium.org> clocksource: arch_timer: Fix code to use physical timers when requested

This is a bug fix for using physical arch timers when
the arch_timer_use_virtual boolean is false. It restores the
arch_counter_get_cntpct() function after removal in

0d651e4e "clocksource: arch_timer: use virtual counters"

We need this on certain ARMv7 systems which are architected like this:

* The firmware doesn't know and doesn't care about hypervisor mode and
we don't want to add the complexity of hypervisor there.

* The firmware isn't involved in SMP bringup or resume.

* The ARCH timer come up with an uninitialized offset between the
virtual and physical counters. Each core gets a different random
offset.

* The device boots in "Secure SVC" mode.

* Nothing has touched the reset value of CNTHCTL.PL1PCEN or
CNTHCTL.PL1PCTEN (both default to 1 at reset)

One example of such as system is RK3288 where it is much simpler to
use the physical counter since there's nobody managing the offset and
each time a core goes down and comes back up it will get reinitialized
to some other random value.

Fixes: 0d651e4e65e9 ("clocksource: arch_timer: use virtual counters")
Cc: stable@vger.kernel.org
Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
/linux/arch/arm64/include/asm/
H A Darch_timer.hdiff 0b46b8a718c6e90910a1b1b0fe797be3c167e186 Mon Nov 24 08:02:44 CET 2014 Sonny Rao <sonnyrao@chromium.org> clocksource: arch_timer: Fix code to use physical timers when requested

This is a bug fix for using physical arch timers when
the arch_timer_use_virtual boolean is false. It restores the
arch_counter_get_cntpct() function after removal in

0d651e4e "clocksource: arch_timer: use virtual counters"

We need this on certain ARMv7 systems which are architected like this:

* The firmware doesn't know and doesn't care about hypervisor mode and
we don't want to add the complexity of hypervisor there.

* The firmware isn't involved in SMP bringup or resume.

* The ARCH timer come up with an uninitialized offset between the
virtual and physical counters. Each core gets a different random
offset.

* The device boots in "Secure SVC" mode.

* Nothing has touched the reset value of CNTHCTL.PL1PCEN or
CNTHCTL.PL1PCTEN (both default to 1 at reset)

One example of such as system is RK3288 where it is much simpler to
use the physical counter since there's nobody managing the offset and
each time a core goes down and comes back up it will get reinitialized
to some other random value.

Fixes: 0d651e4e65e9 ("clocksource: arch_timer: use virtual counters")
Cc: stable@vger.kernel.org
Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
/linux/drivers/clocksource/
H A Darm_arch_timer.cdiff 0b46b8a718c6e90910a1b1b0fe797be3c167e186 Mon Nov 24 08:02:44 CET 2014 Sonny Rao <sonnyrao@chromium.org> clocksource: arch_timer: Fix code to use physical timers when requested

This is a bug fix for using physical arch timers when
the arch_timer_use_virtual boolean is false. It restores the
arch_counter_get_cntpct() function after removal in

0d651e4e "clocksource: arch_timer: use virtual counters"

We need this on certain ARMv7 systems which are architected like this:

* The firmware doesn't know and doesn't care about hypervisor mode and
we don't want to add the complexity of hypervisor there.

* The firmware isn't involved in SMP bringup or resume.

* The ARCH timer come up with an uninitialized offset between the
virtual and physical counters. Each core gets a different random
offset.

* The device boots in "Secure SVC" mode.

* Nothing has touched the reset value of CNTHCTL.PL1PCEN or
CNTHCTL.PL1PCTEN (both default to 1 at reset)

One example of such as system is RK3288 where it is much simpler to
use the physical counter since there's nobody managing the offset and
each time a core goes down and comes back up it will get reinitialized
to some other random value.

Fixes: 0d651e4e65e9 ("clocksource: arch_timer: use virtual counters")
Cc: stable@vger.kernel.org
Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>