Hi Maxime, On Thu, Jun 27, 2013 at 07:21:44PM +0200, Maxime Ripard wrote: > On Thu, Jun 27, 2013 at 12:46:49PM +0300, Baruch Siach wrote: > > On Thu, Jun 27, 2013 at 11:35:58AM +0200, Maxime Ripard wrote: > > > On Thu, Jun 27, 2013 at 09:02:34AM +0300, Baruch Siach wrote: > > > > On Wed, Jun 26, 2013 at 11:16:55PM +0200, Maxime Ripard wrote: > > > > > +static u32 sun4i_timer_sched_read(void) > > > > > > > > You commit message mentions "64 bits free running counter", but this > > > > one only > > > > returns 32 bit. > > > > > > Yeah, the callback setup by setup_sched_clock is supposed to be > > > returning a u32, and clocksource_mmio_init only accepts up to 32 bits as > > > well, so I'm only using the lower 32bits of this 64 bits counter. > > > > > > I'll amend the commit log to state this. > > > > But using 64 bit counter for sched_clock is much easier that using 32 bit > > one. > > Easier in what aspect? Both API looks similar.
You can just implement your own simple sched_clock() that just returns the current value of this 64 bit counter, and do away with all the tricky code in kernel/time/sched_clock.c (in tip.git) that is needed to make the 32 -> 64 extension safe. This is not compatible with multi-platform kernel, though. > > You can either wait for the rest of Stephen's patch set > > (http://thread.gmane.org/gmane.linux.ports.arm.msm/4092) before adding 64 > > bit, or you can just make the trivial change to the now generic > > sched_clock code. > > I'll wait for the Stephen's patches to be merged then, and add support > for 64bits counters to clocksource_mmio_init. Sound reasonable. baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - bar...@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il - -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
