drm/msm: Add a helper function for in-kernel buffer allocations

Nearly all of the buffer allocations for kernel allocate an buffer object,
virtual address and GPU iova at the same time. Make a helper function to
handle the details.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
[dropped msm_fbdev conversion to new helper, since it interferes with
display-handover work, where we want to separate allocation and mapping]
Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
index 791bca3..bf065a5 100644
--- a/drivers/gpu/drm/msm/msm_ringbuffer.c
+++ b/drivers/gpu/drm/msm/msm_ringbuffer.c
@@ -33,16 +33,14 @@ struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int size)
 	}
 
 	ring->gpu = gpu;
-	ring->bo = msm_gem_new(gpu->dev, size, MSM_BO_WC);
-	if (IS_ERR(ring->bo)) {
-		ret = PTR_ERR(ring->bo);
-		ring->bo = NULL;
-		goto fail;
-	}
 
-	ring->start = msm_gem_get_vaddr(ring->bo);
+	/* Pass NULL for the iova pointer - we will map it later */
+	ring->start = msm_gem_kernel_new(gpu->dev, size, MSM_BO_WC,
+		gpu->aspace, &ring->bo, NULL);
+
 	if (IS_ERR(ring->start)) {
 		ret = PTR_ERR(ring->start);
+		ring->start = 0;
 		goto fail;
 	}
 	ring->end   = ring->start + (size / 4);