From: Jean Pihet <j-pihet@xxxxxx> The OMAP3 PRCM registers accesses are known to be slow, with a PRCM register read taking up to 12-14us depending on the OPP. This patch adds a caching mechanism on the power domains state registers. When the cache is cold or has been invalidated a register access is performed, otherwise the register value is retrieved from the registers cache. The API is made of read and write functions for fields in the cache, as well as an invalidate and helper functions to invalidate parts of the cache contents (i.e. previous, current power states and all fields in the cache). The power domain code is converted to use the API to read and write the previous, current and next states for the power domains states, logical and memory states. The PM debug code also uses the caching API instead of the internal pwrdm->state variable. Using the caching mechanism optimizes the performance of the system in the transitions to and from the low power states. Tested on Beagleboard using cpuidle in RET and OFF modes. Based on the linux-omap git tree (3.4.0-rc2) [1] with the changes for the functional power states [2] and the per-device PM QoS support for OMAP [3]. [1] git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git [2] http://marc.info/?l=linux-omap&m=133475291911194&w=2 [3] http://marc.info/?l=linux-omap&m=133475685213067&w=2 Jean Pihet (5): ARM: OMAP2+: PM: implement a caching mechanism on the power domains state registers ARM: OMAP2+: PM: use the power domains registers cache for the power states ARM: OMAP2+: PM: use the power domains registers cache for the logic and mem states ARM: OMAP2+: PM: use the power domains registers cache invalidate API ARM: OMAP2+: PM debug: use the power domains registers caching API arch/arm/mach-omap2/pm-debug.c | 16 ++- arch/arm/mach-omap2/pm34xx.c | 6 + arch/arm/mach-omap2/powerdomain.c | 272 ++++++++++++++++++++++++++++++++----- arch/arm/mach-omap2/powerdomain.h | 45 ++++++- 4 files changed, 297 insertions(+), 42 deletions(-) -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
