ARM: OMAP2: skip unnecessary TLDR write during non-autoreload for gptimer
authorPaul Walmsley <paul@pwsan.com>
Thu, 11 Dec 2008 01:36:34 +0000 (17:36 -0800)
committerTony Lindgren <tony@atomide.com>
Thu, 11 Dec 2008 01:36:34 +0000 (17:36 -0800)
commit64ce2907b1966593d3b4ce5396adb17d7348637d
treeea044c1216d5b15621d69ca4bb566ffe5ff90d65
parenta94b9e5a81d7f69297bb1681c5130a185e047f57
ARM: OMAP2: skip unnecessary TLDR write during non-autoreload for gptimer

The GPTIMER TLDR register does not need to be written if the GPTIMER
is not in autoreload mode.  This is the usual case for dynamic tick-enabled
kernels.

Simulation data indicate that skipping the read that occurs as part of
the write should save at least 300-320 ns for each GPTIMER1 timer
reprogram.  (This assumes L4-Wakeup is at 19MHz and GPTIMER write
posting is enabled.)  Skipping the write itself probably won't have
much impact since it should be posted on the OCP interconnect.

Tested on 2430SDP and 3430SDP.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Richard Woodruff <r-woodruff2@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
arch/arm/plat-omap/dmtimer.c