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) {
>
>
>  
>