On Wed, Nov 14, 2007 at 10:39:24PM +1100, Paul Mackerras wrote:
Exactly. This is not a brute force read()! On input you pass the list
of registers you want to read. Upon return, you get the list of values.
Now, I think the current call could be optimized even more by making
the structure smaller. Today, the structure passed read/write
PMD registers is the same. On write, we pass other information such as
the reset values (sampling periods), randomization parameters and some
flags. They are not needed on read.
Yes, we want to be able to read one or many registers in one call.
The number of PMU counters is not going to shrink, so having a file
descriptor per register looks overkill to me.