gpu: nvgpu: add TSG support for engine context

All channels in a TSG need to share same engine context
i.e. pointer in RAMFC of all channels in a TSG must point
to same NV_RAMIN_GR_WFI_TARGET

To get this, add a pointer to gr_ctx inside TSG struct so
that TSG can maintain its own unique gr_ctx
Also, change the type of gr_ctx in a channel to pointer
variable so that if channel is part of TSG it can point
to TSG's gr_ctx otherwise it will point to its own gr_ctx

In gk20a_alloc_obj_ctx(), allocate gr_ctx as below :

1) If channel is not part of any TSG
- allocate its own gr_ctx buffer if it is already not allocated

2) If channel is part of TSG
- Check if TSG has already allocated gr_ctx (as part of TSG)
- If yes, channel's gr_ctx will point to that of TSG's
- If not, then it means channels is first to be bounded to
  this TSG
- And in this case we will allocate new gr_ctx on TSG first
  and then make channel's gr_ctx to point to this gr_ctx

Also, gr_ctx will be released as below ;

1) If channels is not part of TSG, then it will be released
   when channels is closed
2) Otherwise, it will be released when TSG itself is closed

Bug 1470692

Change-Id: Id347217d5b462e0e972cd3d79d17795b37034a50
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/417065
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
index 4d236a70..21949012 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
@@ -56,7 +56,7 @@ struct fence {
 
 /* contexts associated with a channel */
 struct channel_ctx_gk20a {
-        struct gr_ctx_desc      gr_ctx;
+        struct gr_ctx_desc      *gr_ctx;
         struct pm_ctx_desc      pm_ctx;
         struct patch_desc       patch_ctx;
         struct zcull_ctx_desc   zcull_ctx;