On 11/12/2012 12:51 PM, Stephen Warren wrote:
From: Stephen Warren <swarren@xxxxxxxxxx> 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@xxxxxxxxxxxxxxxx> Cc: Mike Frysinger <vapier@xxxxxxxxxx> Cc: Mikael Starvik <starvik@xxxxxxxx> Cc: Hirokazu Takata <takata@xxxxxxxxxxxxxx> Cc: John Stultz <johnstul@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Acked-by: Jesper Nilsson <jesper.nilsson@xxxxxxxx> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> --- 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@xxxxxxxxxx> thanks -john -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
