[PATCH v6 3/7] drm/mediatek: Add secure buffer control flow to mtk_drm_gem

[Jason-JH . Lin]

Add secure buffer control flow to mtk_drm_gem.

When user space takes DRM_MTK_GEM_CREATE_RESTRICTED flag and size
to create a mtk_drm_gem object, mtk_drm_gem will find a matched size
dma buffer from secure dma-heap and bind it to mtk_drm_gem object.

TODO:
1. Drop the mtk_gem_create_from_heap() after we change the ioctl to
   DMA_HEAP_IOCTL_ALLOC.
2. Checking the private data of dmabuf instead of strncmp the exp_name.

Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
Signed-off-by: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c |  2 +-
 drivers/gpu/drm/mediatek/mtk_gem.c     | 85 +++++++++++++++++++++++++-
 drivers/gpu/drm/mediatek/mtk_gem.h     |  4 ++
 3 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 11e1555e9aa4..ff40ca5dd2a0 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -573,7 +573,7 @@ static void mtk_drm_kms_deinit(struct drm_device *drm)
 
 static const struct drm_ioctl_desc mtk_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(MTK_GEM_CREATE, mtk_gem_create_ioctl,
-			  DRM_UNLOCKED | DRM_AUTH | DRM_RENDER_ALLOW),
+			  DRM_AUTH | DRM_RENDER_ALLOW),
 };
 
 DEFINE_DRM_GEM_FOPS(mtk_drm_fops);
diff --git a/drivers/gpu/drm/mediatek/mtk_gem.c b/drivers/gpu/drm/mediatek/mtk_gem.c
index 91f6cfa3f1b7..118ea7f0a71c 100644
--- a/drivers/gpu/drm/mediatek/mtk_gem.c
+++ b/drivers/gpu/drm/mediatek/mtk_gem.c
@@ -5,6 +5,8 @@
 
 #include <linux/dma-buf.h>
 #include <linux/vmalloc.h>
+#include <linux/dma-heap.h>
+#include <uapi/linux/dma-heap.h>
 #include <drm/mediatek_drm.h>
 
 #include <drm/drm.h>
@@ -103,6 +105,81 @@ struct mtk_gem_obj *mtk_gem_create(struct drm_device *dev,
 	return ERR_PTR(ret);
 }
 
+struct mtk_gem_obj *mtk_gem_create_from_heap(struct drm_device *dev,
+					     const char *heap, size_t size)
+{
+	struct mtk_drm_private *priv = dev->dev_private;
+	struct mtk_gem_obj *mtk_gem;
+	struct drm_gem_object *obj;
+	struct dma_heap *dma_heap;
+	struct dma_buf *dma_buf;
+	struct dma_buf_attachment *attach;
+	struct sg_table *sgt;
+	struct iosys_map map = {};
+	int ret;
+
+	mtk_gem = mtk_gem_init(dev, size);
+	if (IS_ERR(mtk_gem))
+		return ERR_CAST(mtk_gem);
+
+	obj = &mtk_gem->base;
+
+	dma_heap = dma_heap_find(heap);
+	if (!dma_heap) {
+		DRM_ERROR("heap find fail\n");
+		goto err_gem_free;
+	}
+	dma_buf = dma_heap_buffer_alloc(dma_heap, size,
+					O_RDWR | O_CLOEXEC, DMA_HEAP_VALID_HEAP_FLAGS);
+	if (IS_ERR(dma_buf)) {
+		DRM_ERROR("buffer alloc fail\n");
+		dma_heap_put(dma_heap);
+		goto err_gem_free;
+	}
+	dma_heap_put(dma_heap);
+
+	attach = dma_buf_attach(dma_buf, priv->dma_dev);
+	if (IS_ERR(attach)) {
+		DRM_ERROR("attach fail, return\n");
+		dma_buf_put(dma_buf);
+		goto err_gem_free;
+	}
+
+	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+	if (IS_ERR(sgt)) {
+		DRM_ERROR("map failed, detach and return\n");
+		dma_buf_detach(dma_buf, attach);
+		dma_buf_put(dma_buf);
+		goto err_gem_free;
+	}
+	obj->import_attach = attach;
+	mtk_gem->dma_addr = sg_dma_address(sgt->sgl);
+	mtk_gem->sg = sgt;
+	mtk_gem->size = dma_buf->size;
+
+	if (!strcmp(heap, "restricted_mtk_cm") || !strcmp(heap, "restricted_mtk_cma")) {
+		/* secure buffer can not be mapped */
+		mtk_gem->secure = true;
+	} else {
+		ret = dma_buf_vmap(dma_buf, &map);
+		mtk_gem->kvaddr = map.vaddr;
+		if (ret) {
+			DRM_ERROR("map failed, ret=%d\n", ret);
+			dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
+			dma_buf_detach(dma_buf, attach);
+			dma_buf_put(dma_buf);
+			mtk_gem->kvaddr = NULL;
+		}
+	}
+
+	return mtk_gem;
+
+err_gem_free:
+	drm_gem_object_release(obj);
+	kfree(mtk_gem);
+	return ERR_PTR(-ENOMEM);
+}
+
 void mtk_gem_free_object(struct drm_gem_object *obj)
 {
 	struct mtk_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
@@ -230,7 +307,9 @@ struct drm_gem_object *mtk_gem_prime_import_sg_table(struct drm_device *dev,
 	if (IS_ERR(mtk_gem))
 		return ERR_CAST(mtk_gem);
 
+	mtk_gem->secure = (!strncmp(attach->dmabuf->exp_name, "restricted", 10));
 	mtk_gem->dma_addr = sg_dma_address(sg->sgl);
+	mtk_gem->size = attach->dmabuf->size;
 	mtk_gem->sg = sg;
 
 	return &mtk_gem->base;
@@ -296,7 +375,11 @@ int mtk_gem_create_ioctl(struct drm_device *dev, void *data,
 	struct drm_mtk_gem_create *args = data;
 	int ret;
 
-	mtk_gem = mtk_gem_create(dev, args->size, false);
+	if (args->flags & DRM_MTK_GEM_CREATE_RESTRICTED)
+		mtk_gem = mtk_gem_create_from_heap(dev, "restricted_mtk_cma", args->size);
+	else
+		mtk_gem = mtk_gem_create(dev, args->size, false);
+
 	if (IS_ERR(mtk_gem))
 		return PTR_ERR(mtk_gem);
 
diff --git a/drivers/gpu/drm/mediatek/mtk_gem.h b/drivers/gpu/drm/mediatek/mtk_gem.h
index b71a7e7b405a..7f6b23b9875a 100644
--- a/drivers/gpu/drm/mediatek/mtk_gem.h
+++ b/drivers/gpu/drm/mediatek/mtk_gem.h
@@ -27,9 +27,11 @@ struct mtk_gem_obj {
 	void			*cookie;
 	void			*kvaddr;
 	dma_addr_t		dma_addr;
+	size_t			size;
 	unsigned long		dma_attrs;
 	struct sg_table		*sg;
 	struct page		**pages;
+	bool			secure;
 };
 
 #define to_mtk_gem_obj(x) container_of(x, struct mtk_gem_obj, base)
@@ -37,6 +39,8 @@ struct mtk_gem_obj {
 void mtk_gem_free_object(struct drm_gem_object *gem);
 struct mtk_gem_obj *mtk_gem_create(struct drm_device *dev, size_t size,
 				   bool alloc_kmap);
+struct mtk_gem_obj *mtk_gem_create_from_heap(struct drm_device *dev,
+					     const char *heap, size_t size);
 int mtk_gem_dumb_create(struct drm_file *file_priv, struct drm_device *dev,
 			struct drm_mode_create_dumb *args);
 struct sg_table *mtk_gem_prime_get_sg_table(struct drm_gem_object *obj);
-- 
2.18.0