From mboxrd@z Thu Jan 1 00:00:00 1970 From: johnstul@us.ibm.com (John Stultz) Date: Mon, 12 Nov 2012 13:36:19 -0800 Subject: [PATCH V2 2/11] time: convert arch_gettimeoffset to a pointer In-Reply-To: <1352753462-2915-1-git-send-email-swarren@wwwdotorg.org> References: <1352753462-2915-1-git-send-email-swarren@wwwdotorg.org> Message-ID: <50A16BD3.5010707@us.ibm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 11/12/2012 12:51 PM, Stephen Warren wrote: > From: Stephen Warren > > 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 > Cc: Mike Frysinger > Cc: Mikael Starvik > Cc: Hirokazu Takata > Cc: John Stultz > Cc: Thomas Gleixner > Acked-by: Geert Uytterhoeven > Acked-by: Jesper Nilsson > Signed-off-by: Stephen Warren > --- > 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 thanks -john