Re: [PATCH v3 1/6] ARM/ARM64: arch_timer: add m acros for bits in control register

[Marc Zyngier]

Hi Daniel,

On 2013-08-14 09:50, Daniel Lezcano wrote:
> On 08/13/2013 07:29 PM, Sudeep KarkadaNagesha wrote:
> > From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@xxxxxxx>
> >
> > Add macros to describe the bitfields in the ARM architected timer
> > control register to make code easy to understand.
> >
> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> > Reviewed-by: Will Deacon <will.deacon@xxxxxxx>
> > Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@xxxxxxx>
> > ---
> >  arch/arm/include/asm/arch_timer.h    |  9 +++++++--
> >  arch/arm64/include/asm/arch_timer.h  | 12 ++++++++----
> >  include/clocksource/arm_arch_timer.h |  8 ++++++++
> >  3 files changed, 23 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/arm/include/asm/arch_timer.h 
> > b/arch/arm/include/asm/arch_timer.h
> > index e406d57..9ef74da 100644
> > --- a/arch/arm/include/asm/arch_timer.h
> > +++ b/arch/arm/include/asm/arch_timer.h
> > @@ -95,8 +95,13 @@ static inline void 
> > arch_counter_set_user_access(void)
> >
> >  	asm volatile("mrc p15, 0, %0, c14, c1, 0" : "=r" (cntkctl));
> >
> > -	/* disable user access to everything */
> > -	cntkctl &= ~((3 << 8) | (7 << 0));
> > +	/* Disable user access to both physical/virtual counters/timers. 
> > */
> > +	/* Also disable virtual event stream */
> > +	cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
> > +			| ARCH_TIMER_USR_VT_ACCESS_EN
> > +			| ARCH_TIMER_VIRT_EVT_EN
> > +			| ARCH_TIMER_USR_VCT_ACCESS_EN
> > +			| ARCH_TIMER_USR_PCT_ACCESS_EN);
> >
> >  	asm volatile("mcr p15, 0, %0, c14, c1, 0" : : "r" (cntkctl));
> >  }
> > diff --git a/arch/arm64/include/asm/arch_timer.h 
> > b/arch/arm64/include/asm/arch_timer.h
> > index 98abd47..00b09d0 100644
> > --- a/arch/arm64/include/asm/arch_timer.h
> > +++ b/arch/arm64/include/asm/arch_timer.h
> > @@ -101,12 +101,16 @@ static inline void 
> > arch_counter_set_user_access(void)
> >  {
> >  	u32 cntkctl;
> >
> > -	/* Disable user access to the timers and the physical counter. */
> >  	asm volatile("mrs	%0, cntkctl_el1" : "=r" (cntkctl));
> > -	cntkctl &= ~((3 << 8) | (1 << 0));
> >
> > -	/* Enable user access to the virtual counter and frequency. */
> > -	cntkctl |= (1 << 1);
> > +	/* Disable user access to the timers and the physical counter. */
> > +	cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
> > +			| ARCH_TIMER_USR_VT_ACCESS_EN
> > +			| ARCH_TIMER_USR_PCT_ACCESS_EN);
> > +
> > +	/* Enable user access to the virtual counter. */
> > +	cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
> > +
> >  	asm volatile("msr	cntkctl_el1, %0" : : "r" (cntkctl));
> >  }
>
> Before doing those changes, I suggest you kill 
> include/asm/arch_timer.h
> header file and move the functions directly in the arm_arch_timer.c 
> as
> they are only used by it.

How do you suggest to proceed? Having #ifdefs in arm_arch_timer.c to 
cope with the inline assembly functions present in both arm and arm64 
include files? Doesn't seem much of a progress to me...

> > diff --git a/include/clocksource/arm_arch_timer.h 
> > b/include/clocksource/arm_arch_timer.h
> > index c463ce9..551f7e9 100644
> > --- a/include/clocksource/arm_arch_timer.h
> > +++ b/include/clocksource/arm_arch_timer.h
> > @@ -29,6 +29,14 @@
> >  #define ARCH_TIMER_PHYS_ACCESS		0
> >  #define ARCH_TIMER_VIRT_ACCESS		1
> >
> > +#define ARCH_TIMER_USR_PCT_ACCESS_EN	(1 << 0) /* physical counter 
> > */
> > +#define ARCH_TIMER_USR_VCT_ACCESS_EN	(1 << 1) /* virtual counter */
> > +#define ARCH_TIMER_VIRT_EVT_EN		(1 << 2)
> > +#define ARCH_TIMER_EVT_TRIGGER_SHIFT	(4)
> > +#define ARCH_TIMER_EVT_TRIGGER_MASK	(0xF << 
> > ARCH_TIMER_EVT_TRIGGER_SHIFT)
> > +#define ARCH_TIMER_USR_VT_ACCESS_EN	(1 << 8) /* virtual timer 
> > registers */
> > +#define ARCH_TIMER_USR_PT_ACCESS_EN	(1 << 9) /* physical timer 
> > registers */
> > +
> >  #ifdef CONFIG_ARM_ARCH_TIMER
> >
> >  extern u32 arch_timer_get_rate(void);

        M.
--
Fast, cheap, reliable. Pick two.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/