Re: sparc generic time / clockevents

[Peter Keilty <peter.keilty@hp.com>]

john stultz wrote:

> On Fri, 2007-02-23 at 01:55 -0800, David Miller wrote:
>  
>
> > From: Thomas Gleixner <tglx@linutronix.de>
> > Date: Fri, 23 Feb 2007 10:56:18 +0100
> >
> >    
> >
> > > On Fri, 2007-02-23 at 01:25 -0800, David Miller wrote:
> > >      
> > >
> > > > > Yes, all you need is to omit the CLOCK_EVT_FEAT_PERIODIC flag when you
> > > > > register your device.
> > > > >          
> > > > Thanks a lot Thomas.
> > > >
> > > > I noticed while doing this work that the generic clock code is
> > > > incompatible with the time interpolator, since both provide a
> > > > do_{get,set}timeofday() implementation.  Just FYI...
> > > >        
> > > John, can you have a look at this ?
> > >      
> > Note we may not care :-)  All the interpolator does is provide
> > a generic tick based gettimeofday implementation, and the generic
> > clock code does essentially the same thing.
> >
> > And the generic clock code must in fact provide the implementations
> > in order to deal with dyntick issues.
> >
> > The only other platform using the time interpolator is IA64,
> > and after my dyntick implementation on sparc64 the one and
> > only user will be IA64 :-)
> >    
>
> Yea. I actually have some in-progress patches from Peter Keilty that
> convert ia64 and sparc64 time_interpolators to clocksources, then
> removes the time_interpolator code.
>
> The ia64 conversion is more complicated due to the fsyscall asm, but I
> think the sparc64 conversion (below) is pretty straight forward. I've
> only built tested this, so I have no clue if it actually works. 
>
> Any thoughts?
>  
I have only build tested also, I thought it was pretty straight forward.

> thanks
> -john
>
>
> From: Peter Keilty <peter.keilty@hp.com>
>
> Initial sparc64 conversion to generic clocksource/timekeeping code.
>
> Signed-off-by: Peter Keilty <peter.keilty@hp.com>
> Signed-off-by: John Stultz <johnstul@us.ibm.com>
>
>
> Kconfig       |    2 +-
> defconfig     |    2 +-
> kernel/time.c |   34 +++++++++++++++++++++++-----------
> 3 files changed, 25 insertions(+), 13 deletions(-)
>
> linux-2.6.21-rc1_timeofday-arch-sparc64_C7.patch
> ============================================
> diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
> index f75a686..13a4547 100644
> --- a/arch/sparc64/Kconfig
> +++ b/arch/sparc64/Kconfig
> @@ -34,7 +34,7 @@ config LOCKDEP_SUPPORT
> 	bool
> 	default y
>
> -config TIME_INTERPOLATION
> +config GENERIC_TIME
> 	bool
> 	default y
>
> diff --git a/arch/sparc64/defconfig b/arch/sparc64/defconfig
> index 0f44a6a..33e061a 100644
> --- a/arch/sparc64/defconfig
> +++ b/arch/sparc64/defconfig
> @@ -9,7 +9,7 @@ CONFIG_64BIT=y
> CONFIG_MMU=y
> CONFIG_STACKTRACE_SUPPORT=y
> CONFIG_LOCKDEP_SUPPORT=y
> -CONFIG_TIME_INTERPOLATION=y
> +CONFIG_GENERIC_TIME=y
> CONFIG_ARCH_MAY_HAVE_PC_FDC=y
> # CONFIG_ARCH_HAS_ILOG2_U32 is not set
> # CONFIG_ARCH_HAS_ILOG2_U64 is not set
> diff --git a/arch/sparc64/kernel/time.c b/arch/sparc64/kernel/time.c
> index f84da4f..497b29b 100644
> --- a/arch/sparc64/kernel/time.c
> +++ b/arch/sparc64/kernel/time.c
> @@ -31,6 +31,7 @@ #include <linux/percpu.h>
> #include <linux/profile.h>
> #include <linux/miscdevice.h>
> #include <linux/rtc.h>
> +#include <linux/clocksource.h>
>
> #include <asm/oplib.h>
> #include <asm/mostek.h>
> @@ -620,7 +621,7 @@ #endif
> 	if (!mregs && !dregs) {
> 		prom_printf("Something wrong, clock regs not mapped yet.\n");
> 		prom_halt();
> -	}		
> +	}
>
> 	if (mregs) {
> 		spin_lock_irq(&mostek_lock);
> @@ -820,7 +821,7 @@ #endif
> 	}
>
> 	set_system_time();
> -	
> +
> 	local_irq_restore(flags);
>
> 	return 0;
> @@ -975,22 +976,33 @@ static struct notifier_block sparc64_cpu
>
> #endif /* CONFIG_CPU_FREQ */
>
> -static struct time_interpolator sparc64_cpu_interpolator = {
> -	.source		=	TIME_SOURCE_CPU,
> -	.shift		=	16,
> -	.mask		=	0xffffffffffffffffLL
> +static cycle_t read_sparc64_cpuclock(void)
> +{
> +        return (cycle_t)get_cycles();
> +}
> +
> +static struct clocksource clocksource_sparc64_cpuclock = {
> +	.name           = "sparc64_cpuclock",
> +	.rating         = 300,
> +	.read           = read_sparc64_cpuclock,
> +	.mask           = 0xffffffffffffffffLL,
> +	.mult           = 0, /*to be caluclated*/
> +	.shift          = 16,
> +	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
> };
>
> +
> /* The quotient formula is taken from the IA64 port. */
> #define SPARC64_NSEC_PER_CYC_SHIFT	10UL
> void __init time_init(void)
> {
> 	unsigned long clock = sparc64_init_timers();
>
> -	sparc64_cpu_interpolator.frequency = clock;
> -	register_time_interpolator(&sparc64_cpu_interpolator);
> +	clocksource_sparc64_cpuclock.mult = clocksource_hz2mult(clock,
> +					clocksource_sparc64_cpuclock.shift);
> +	clocksource_register(&clocksource_sparc64_cpuclock);
>
> -	/* Now that the interpolator is registered, it is
> +	/* Now that the clocksource is registered, it is
> 	 * safe to start the timer ticking.
> 	 */
> 	sparc64_start_timers();
> @@ -1025,11 +1037,11 @@ #endif
> 	unsigned long flags;
> 	u8 tmp;
>
> -	/* 
> +	/*
> 	 * Not having a register set can lead to trouble.
> 	 * Also starfire doesn't have a tod clock.
> 	 */
> -	if (!mregs && !dregs) 
> +	if (!mregs && !dregs)
> 		return -1;
>
> 	if (mregs) {
>
>
>  
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/