iopoll: Introduce memory-mapped IO polling macros
iopoll: Introduce memory-mapped IO polling macros

It is sometimes necessary to poll a memory-mapped register until its value
satisfies some condition. Introduce a family of convenience macros that do
this. Tight-looping, sleeping, and timing out can all be accomplished using
these macros.

Cc: Thierry Reding <b75a4d02013b0e68ae2c6bb0dcfd4b7bec282dc9@gmail.com>
Cc: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Cc: Robert Elliott <fcf6aac10c16bf4310224494560ff8cb9772fa2e@hp.com>
Acked-by: Arnd Bergmann <f2c659f01951776204a6c5b902787d9019fbeebd@arndb.de>
Acked-by: Will Deacon <b913f13ef92ac157955c954ccaaff7be065faba4@arm.com>
Signed-off-by: Matt Wagantall <f353a1326f7aad71d23381a3beb9470c3b31d81b@codeaurora.org>
Signed-off-by: Mitchel Humpherys <5070267e141ca308fc855217ddbeaf20e729a7bf@codeaurora.org>
Signed-off-by: Will Deacon <b913f13ef92ac157955c954ccaaff7be065faba4@arm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs