[PATCH 44/48] staging: etnaviv: implement cache maintenance on cpu_(prep|fini)

[Lucas Stach]

This makes sure that we are satifying the cache handling rules outlined
in the previous commit. Cached buffers are pulled into the CPU domain
before access and pushed to the GPU again when the CPU is done.

Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
---
 drivers/staging/etnaviv/etnaviv_gem.c | 41 +++++++++++++++++++++++++++++++++--
 drivers/staging/etnaviv/etnaviv_gem.h |  3 +++
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/etnaviv/etnaviv_gem.c b/drivers/staging/etnaviv/etnaviv_gem.c
index 5ee43861095d..c9300f1e03d5 100644
--- a/drivers/staging/etnaviv/etnaviv_gem.c
+++ b/drivers/staging/etnaviv/etnaviv_gem.c
@@ -424,10 +424,21 @@ void etnaviv_gem_move_to_inactive(struct drm_gem_object *obj)
 	list_add_tail(&etnaviv_obj->mm_list, &priv->inactive_list);
 }
 
+static inline enum dma_data_direction etnaviv_op_to_dma_dir(u32 op)
+{
+	if (op & ETNA_PREP_READ)
+		return DMA_FROM_DEVICE;
+	else if (op & ETNA_PREP_WRITE)
+		return DMA_TO_DEVICE;
+	else
+		return DMA_BIDIRECTIONAL;
+}
+
 int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op,
 		struct timespec *timeout)
 {
 	struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
+	struct drm_device *dev = obj->dev;
 	int ret = 0;
 
 	if (is_active(etnaviv_obj)) {
@@ -444,14 +455,40 @@ int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op,
 		ret = etnaviv_gpu_wait_fence_interruptible(gpu, fence, timeout);
 	}
 
-	/* TODO cache maintenance */
+	if (etnaviv_obj->flags & ETNA_BO_CACHED) {
+		if (!etnaviv_obj->sgt) {
+			void * ret;
+
+			mutex_lock(&dev->struct_mutex);
+			ret = etnaviv_gem_get_pages(etnaviv_obj);
+			mutex_unlock(&dev->struct_mutex);
+			if (IS_ERR(ret))
+				return PTR_ERR(ret);
+		}
+
+		dma_sync_sg_for_cpu(dev->dev, etnaviv_obj->sgt->sgl,
+				    etnaviv_obj->sgt->nents,
+				    etnaviv_op_to_dma_dir(op));
+		etnaviv_obj->last_cpu_prep_op = op;
+	}
 
 	return ret;
 }
 
 int etnaviv_gem_cpu_fini(struct drm_gem_object *obj)
 {
-	/* TODO cache maintenance */
+	struct drm_device *dev = obj->dev;
+	struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
+
+	if (etnaviv_obj->flags & ETNA_BO_CACHED) {
+		/* fini without a prep is almost certainly a userspace error */
+		WARN_ON(etnaviv_obj->last_cpu_prep_op == 0);
+		dma_sync_sg_for_device(dev->dev, etnaviv_obj->sgt->sgl,
+			etnaviv_obj->sgt->nents,
+			etnaviv_op_to_dma_dir(etnaviv_obj->last_cpu_prep_op));
+		etnaviv_obj->last_cpu_prep_op = 0;
+	}
+
 	return 0;
 }
 
diff --git a/drivers/staging/etnaviv/etnaviv_gem.h b/drivers/staging/etnaviv/etnaviv_gem.h
index 4d5455a3fe39..25f7afbc779a 100644
--- a/drivers/staging/etnaviv/etnaviv_gem.h
+++ b/drivers/staging/etnaviv/etnaviv_gem.h
@@ -82,6 +82,9 @@ struct etnaviv_gem_object {
 	bool is_ring_buffer;
 	u32 offset;
 
+	/* cache maintenance */
+	uint32_t last_cpu_prep_op;
+
 	struct etnaviv_gem_userptr userptr;
 };
 
-- 
2.5.1