tree dfdb40d6b02d6a613a5d20ae8a343ac0d024dfcc
parent f93bdefe6269067afc85688d45c646cde350e0d8
author Alex Deucher <alexander.deucher@amd.com> 1362419266 -0500
committer Alex Deucher <alexander.deucher@amd.com> 1372344547 -0400

drm/radeon: implement simple doorbell page allocator

The doorbell aperture is a PCI BAR whose pages can be
mapped to compute resources for things like wptrs
for userspace queues.

This patch maps the BAR and sets up a simple allocator
to allocate pages from the BAR.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>