Messages in this thread | | | Date | Mon, 12 Nov 2012 13:36:19 -0800 | From | John Stultz <> | Subject | Re: [PATCH V2 2/11] time: convert arch_gettimeoffset to a pointer |
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On 11/12/2012 12:51 PM, Stephen Warren wrote: > From: Stephen Warren <swarren@nvidia.com> > > Currently, whenever CONFIG_ARCH_USES_GETTIMEOFFSET is enabled, each > arch core provides a single implementation of arch_gettimeoffset(). In > many cases, different sub-architectures, different machines, or > different timer providers exist, and so the arch ends up implementing > arch_gettimeoffset() as a call-through-pointer anyway. Examples are > ARM, Cris, M68K, and it's arguable that the remaining architectures, > M32R and Blackfin, should be doing this anyway. > > Modify arch_gettimeoffset so that it itself is a function pointer, which > the arch initializes. This will allow later changes to move the > initialization of this function into individual machine support or timer > drivers. This is particularly useful for code in drivers/clocksource > which should rely on an arch-independant mechanism to register their > implementation of arch_gettimeoffset(). > > This patch also converts the Cris architecture to set arch_gettimeoffset > directly to the final implementation in time_init(), because Cris already > had separate time_init() functions per sub-architecture. M68K and ARM > are converted to set arch_gettimeoffset the final implementation in later > patches, because they already have function pointers in place for this > purpose. > > Cc: Russell King <linux@arm.linux.org.uk> > Cc: Mike Frysinger <vapier@gentoo.org> > Cc: Mikael Starvik <starvik@axis.com> > Cc: Hirokazu Takata <takata@linux-m32r.org> > Cc: John Stultz <johnstul@us.ibm.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> > Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> > Signed-off-by: Stephen Warren <swarren@nvidia.com> > --- > v2: > * s/gettimeoffset/get_arch_timeoffset/ to make the name less generic > and more arch-specific. > > (Note: I've only reposted patch 2/11 this time around, and I still hope > to take it through the arm-soc tree due to dependencies, so I'm not > requesting this be applied by the timekeeping maintainers)
One last thing to watch out for: If you're trying to build a kernel that mixes clocksource support with get_arch_timeoffset, you'll need to rework the #ifdef in update_wall_time(), since we currently assume with get_arch_timeoffset() that you're using tick + interpolation, so every call to update_wall_time() only moves time forward by one jiffy.
Otherwise, thanks for the name tweak. Going through the arm-soc tree is fine with me.
Acked-by: John Stultz <johnstul@us.ibm.com>
thanks -john
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