drm/i915/bdw: implement semaphore signal
Semaphore signalling works similarly to previous GENs with the exception that the per ring mailboxes no longer exist. Instead you must define your own space, somewhere in the GTT. The comments in the code define the layout I've opted for, which should be fairly future proof. Ie. I tried to define offsets in abstract terms (NUM_RINGS, seqno size, etc). NOTE: If one wanted to move this to the HWSP they could. I've decided one 4k object would be easier to deal with, and provide potential wins with cache locality, but that's all speculative. v2: Update the macro to not need the other ring's ring->id (Chris) Update the comment to use the correct formula (Chris) v3: Move the macros the ringbuffer.h to prevent churn in next patch (Ville) v4: Fixed compilation rebase conflict commit 1ec9e26d Author: Daniel Vetter <daniel.vetter@ffwll.ch> Date: Fri Feb 14 14:01:11 2014 +0100 drm/i915: Consolidate binding parameters into flags v5: VCS2 rebase Replace hweight_long with hweight32 v6 (Rodrigo): * Add missed VC2 gen8 ring signal init * fixing conflicst on rebase * minor fixes on address table * remove WARN_ON Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> [danvet: s/BUG_ON/WARN_ON/] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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