Commit graph

2 commits

Author SHA1 Message Date
Thomas Veerman 2b793e4945 libsys: refactor frclock api
Make the frclock functions similar to the tsc utility functions. This
way, we can call frclock functions from the framebuffer driver which
will use frclock on ARM and tsc on X86.

Also, frclock_64_to_micros computed seconds, not microseconds

Change-Id: I6718ae0fb7db050794f6f032205923e1a32dc1ac
2013-02-22 13:08:21 +00:00
Thomas Veerman db8c1ee9d0 ARM: provide free running clock to replace ccnt
The Cycle CouNTer on ARM cannot be used reliably as it wraps around
rather quickly and can be altered by user space (on Minix). Furthermore,
it's buggy when wrapping and is not implemented at all on the Linaro
Beagleboard emulator.

This patch programs GPTIMER10 as a free running clock at 1.625 MHz (it
doesn't generate interrupts). It's memory mapped into every process,
which enables libsys to provide micro_delay().

Change-Id: Iba004c6c62976762fe154ea390d69e518eec1531
2013-01-31 15:19:11 +00:00