linux/arch/tile/include
Chris Metcalf 1337173148 arch/tile: fix __ndelay etc to work better
The current implementations of __ndelay and __udelay call a hypervisor
service to delay, but the hypervisor service isn't actually implemented
very well, and the consensus is that Linux should handle figuring this
out natively and not use a hypervisor service.

By converting nanoseconds to cycles, and then spinning until the
cycle counter reaches the desired cycle, we get several benefits:
first, we are sensitive to the actual clock speed; second, we use
less power by issuing a slow SPR read once every six cycles while
we delay; and third, we properly handle the case of an interrupt by
exiting at the target time rather than after some number of cycles.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01 16:20:04 -05:00
..
arch arch/tile: parameterize system PLs to support KVM port 2010-10-15 15:38:09 -04:00
asm arch/tile: fix __ndelay etc to work better 2011-03-01 16:20:04 -05:00
hv arch/tile: fix __ndelay etc to work better 2011-03-01 16:20:04 -05:00