Re: sparc generic time / clockevents

Peter Keilty
2007-02-23T22:16:22Z

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) {
>
>
>
>