drm/vc4: Expose dma-buf fences for V3D rendering.

This is needed for proper synchronization with display on another DRM
device (pl111 or tinydrm) with buffers produced by vc4 V3D.  Fixes the
new igt vc4_dmabuf_poll testcase, and rendering of one of the glmark2
desktop tests on pl111+vc4.

This doesn't yet introduce waits on another device's fences before
vc4's rendering/display, because I don't have testcases for them.

v2: Reuse dma_fence_free(), retitle commit message to clarify that
    it's not a full dma-buf fencing implementation yet.

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/20170412191202.22740-6-eric@anholt.net
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 36 insertions, 1 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
index af29432a6471..80b2f9e55c5c 100644
--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -19,6 +19,8 @@
  * rendering can return quickly.
  */
 
+#include <linux/dma-buf.h>
+
 #include "vc4_drv.h"
 #include "uapi/drm/vc4_drm.h"
 
@@ -88,6 +90,10 @@ static void vc4_bo_destroy(struct vc4_bo *bo)
 
 	vc4->bo_stats.num_allocated--;
 	vc4->bo_stats.size_allocated -= obj->size;
+
+	if (bo->resv == &bo->_resv)
+		reservation_object_fini(bo->resv);
+
 	drm_gem_cma_free_object(obj);
 }
 
@@ -244,8 +250,12 @@ struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
 			return ERR_PTR(-ENOMEM);
 		}
 	}
+	bo = to_vc4_bo(&cma_obj->base);
 
-	return to_vc4_bo(&cma_obj->base);
+	bo->resv = &bo->_resv;
+	reservation_object_init(bo->resv);
+
+	return bo;
 }
 
 int vc4_dumb_create(struct drm_file *file_priv,
@@ -369,6 +379,13 @@ static void vc4_bo_cache_time_timer(unsigned long data)
 	schedule_work(&vc4->bo_cache.time_work);
 }
 
+struct reservation_object *vc4_prime_res_obj(struct drm_gem_object *obj)
+{
+	struct vc4_bo *bo = to_vc4_bo(obj);
+
+	return bo->resv;
+}
+
 struct dma_buf *
 vc4_prime_export(struct drm_device *dev, struct drm_gem_object *obj, int flags)
 {
@@ -440,6 +457,24 @@ void *vc4_prime_vmap(struct drm_gem_object *obj)
 	return drm_gem_cma_prime_vmap(obj);
 }
 
+struct drm_gem_object *
+vc4_prime_import_sg_table(struct drm_device *dev,
+			  struct dma_buf_attachment *attach,
+			  struct sg_table *sgt)
+{
+	struct drm_gem_object *obj;
+	struct vc4_bo *bo;
+
+	obj = drm_gem_cma_prime_import_sg_table(dev, attach, sgt);
+	if (IS_ERR(obj))
+		return obj;
+
+	bo = to_vc4_bo(obj);
+	bo->resv = attach->dmabuf->resv;
+
+	return obj;
+}
+
 int vc4_create_bo_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv)
 {