[PATCH 02/13] drm/amdgpu: add shadow bo support

[Chunming Zhou]

shadow bo is the shadow of a bo, which is always in GTT,
which can be used to backup the original bo.

Change-Id: Ia27d4225c47ff41d3053eb691276e29fb2d64026
Signed-off-by: Chunming Zhou <David1.Zhou at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 36 +++++++++++++++++++++++++++---
 include/uapi/drm/amdgpu_drm.h              |  2 ++
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 183781d..d415805 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -506,6 +506,7 @@ struct amdgpu_bo {
 	struct amdgpu_device		*adev;
 	struct drm_gem_object		gem_base;
 	struct amdgpu_bo		*parent;
+	struct amdgpu_bo		*shadow;
 
 	struct ttm_bo_kmap_obj		dma_buf_vmap;
 	struct amdgpu_mn		*mn;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index d8e69a7..e6ecf16 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -389,6 +389,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
 {
 	struct ttm_placement placement = {0};
 	struct ttm_place placements[AMDGPU_GEM_DOMAIN_MAX + 1];
+	int r;
 
 	memset(&placements, 0,
 	       (AMDGPU_GEM_DOMAIN_MAX + 1) * sizeof(struct ttm_place));
@@ -396,9 +397,32 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
 	amdgpu_ttm_placement_init(adev, &placement,
 				  placements, domain, flags);
 
-	return amdgpu_bo_create_restricted(adev, size, byte_align, kernel,
-					   domain, flags, sg, &placement,
-					   resv, bo_ptr);
+	r = amdgpu_bo_create_restricted(adev, size, byte_align, kernel,
+					domain, flags, sg, &placement,
+					resv, bo_ptr);
+	if (r)
+		return r;
+
+	if (flags & AMDGPU_GEM_CREATE_SHADOW) {
+		memset(&placements, 0,
+		       (AMDGPU_GEM_DOMAIN_MAX + 1) * sizeof(struct ttm_place));
+
+		amdgpu_ttm_placement_init(adev, &placement,
+					  placements, AMDGPU_GEM_DOMAIN_GTT,
+					  AMDGPU_GEM_CREATE_CPU_GTT_USWC);
+
+		r = amdgpu_bo_create_restricted(adev, size, byte_align, kernel,
+						AMDGPU_GEM_DOMAIN_GTT,
+						AMDGPU_GEM_CREATE_CPU_GTT_USWC,
+						NULL, &placement,
+						(*bo_ptr)->tbo.resv,
+						&(*bo_ptr)->shadow);
+		if (r)
+			amdgpu_bo_unref(bo_ptr);
+	} else
+		(*bo_ptr)->shadow = NULL;
+
+	return r;
 }
 
 int amdgpu_bo_kmap(struct amdgpu_bo *bo, void **ptr)
@@ -455,6 +479,12 @@ void amdgpu_bo_unref(struct amdgpu_bo **bo)
 
 	if ((*bo) == NULL)
 		return;
+	if ((*bo)->shadow) {
+		tbo = &((*bo)->shadow->tbo);
+		ttm_bo_unref(&tbo);
+		if (tbo == NULL)
+			(*bo)->shadow = NULL;
+	}
 
 	tbo = &((*bo)->tbo);
 	ttm_bo_unref(&tbo);
diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index 8df3816..da2d3e1 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -77,6 +77,8 @@
 #define AMDGPU_GEM_CREATE_CPU_GTT_USWC		(1 << 2)
 /* Flag that the memory should be in VRAM and cleared */
 #define AMDGPU_GEM_CREATE_VRAM_CLEARED		(1 << 3)
+/* Flag that create shadow bo(GTT) while allocating vram bo */
+#define AMDGPU_GEM_CREATE_SHADOW		(1 << 4)
 
 struct drm_amdgpu_gem_create_in  {
 	/** the requested memory size */
-- 
1.9.1