Messages in this thread | | | Date | Thu, 20 Nov 2014 10:23:01 +0100 | From | Daniel Lezcano <> | Subject | Re: [PATCH v4] clocksource: arch_timer: Fix code to use physical timers when requested |
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On 10/08/2014 09:38 AM, Sonny Rao wrote: > 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: Olof Johansson <olof@lixom.net> > ---
Hi Sonny,
the patch does not apply. Could you refresh it please ?
Thanks -- Daniel
> v2: Add fixes tag to commit message, cc stable, copy Doug's > description of the systems which need this in commit message. > v3: Don't change the memory-mapped physical timer/counter code > v4: remove the memory-mapped physical counter code since it's not used > --- > arch/arm/include/asm/arch_timer.h | 9 +++++++++ > arch/arm64/include/asm/arch_timer.h | 10 ++++++++++ > drivers/clocksource/arm_arch_timer.c | 10 +++++++--- > 3 files changed, 26 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h > index 0704e0c..e72aa4d 100644 > --- a/arch/arm/include/asm/arch_timer.h > +++ b/arch/arm/include/asm/arch_timer.h > @@ -78,6 +78,15 @@ static inline u32 arch_timer_get_cntfrq(void) > return val; > } > > +static inline u64 arch_counter_get_cntpct(void) > +{ > + u64 cval; > + > + isb(); > + asm volatile("mrrc p15, 0, %Q0, %R0, c14" : "=r" (cval)); > + return cval; > +} > + > static inline u64 arch_counter_get_cntvct(void) > { > u64 cval; > diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h > index 9400596..58657c4 100644 > --- a/arch/arm64/include/asm/arch_timer.h > +++ b/arch/arm64/include/asm/arch_timer.h > @@ -135,6 +135,16 @@ static inline void arch_timer_evtstrm_enable(int divider) > #endif > } > > +static inline u64 arch_counter_get_cntpct(void) > +{ > + u64 cval; > + > + isb(); > + asm volatile("mrs %0, cntpct_el0" : "=r" (cval)); > + > + return cval; > +} > + > static inline u64 arch_counter_get_cntvct(void) > { > u64 cval; > diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c > index 6b50311..799139f 100644 > --- a/drivers/clocksource/arm_arch_timer.c > +++ b/drivers/clocksource/arm_arch_timer.c > @@ -429,10 +429,14 @@ static void __init arch_counter_register(unsigned type) > u64 start_count; > > /* Register the CP15 based counter if we have one */ > - if (type & ARCH_CP15_TIMER) > - arch_timer_read_counter = arch_counter_get_cntvct; > - else > + if (type & ARCH_CP15_TIMER) { > + if (arch_timer_use_virtual) > + arch_timer_read_counter = arch_counter_get_cntvct; > + else > + arch_timer_read_counter = arch_counter_get_cntpct; > + } else { > arch_timer_read_counter = arch_counter_get_cntvct_mem; > + } > > start_count = arch_timer_read_counter(); > clocksource_register_hz(&clocksource_counter, arch_timer_rate); >
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