This adds some debugging code to the Axon MSI driver. It creates a
file per MSIC in /sys/kernel/debug/powerpc, which allows the user to
trigger a fake MSI interrupt by writing to the file.
This can be used to test some of the MSI generation path. In
particular, that the MSIC recognises a write to the MSI address,
generates an interrupt and writes the MSI packet into the ring buffer.
All the code is inside #ifdef DEBUG so it causes no harm unless it's
enabled.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
72cac213fd