gpu: nvgpu: implement poll() for semaphores

Add poll interface and control ioctls for waiting for GPU job completion
via semaphores.

Poll on a gk20a channel file waits for events from pending semaphore
interrupts (stalling) of that channel. New ioctls enable and disable the
events, and clear a single interrupt event so that next poll doesn't
wake up for it again.

Bug 1528781

Change-Id: I5c6238966b5d0900c8ab263c6a7f8f2611901f33
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/497750
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
index f5c3bd62..db655c32 100644
--- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
@@ -5075,6 +5075,7 @@ static int gk20a_gr_handle_semaphore_pending(struct gk20a *g,
         struct fifo_gk20a *f = &g->fifo;
         struct channel_gk20a *ch = &f->channel[isr_data->chid];
 
+        gk20a_channel_event(ch);
         wake_up(&ch->semaphore_wq);
 
         return 0;