DRM: Add DRM GEM CMA helper

Many embedded drm devices do not have a IOMMU and no dedicated
memory for graphics. These devices use CMA (Contiguous Memory
Allocator) backed graphics memory. This patch provides helper
functions to be able to share the code. The code technically does
not depend on CMA as the backend allocator, the name has been chosen
because CMA makes for a nice, short but still descriptive function
prefix.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
[Make DRM_GEM_CMA_HELPER a boolean Kconfig option]
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
new file mode 100644
index 0000000..f0f6b1a
--- /dev/null
+++ b/include/drm/drm_gem_cma_helper.h
@@ -0,0 +1,44 @@
+#ifndef __DRM_GEM_CMA_HELPER_H__
+#define __DRM_GEM_CMA_HELPER_H__
+
+struct drm_gem_cma_object {
+	struct drm_gem_object base;
+	dma_addr_t paddr;
+	void *vaddr;
+};
+
+static inline struct drm_gem_cma_object *
+to_drm_gem_cma_obj(struct drm_gem_object *gem_obj)
+{
+	return container_of(gem_obj, struct drm_gem_cma_object, base);
+}
+
+/* free gem object. */
+void drm_gem_cma_free_object(struct drm_gem_object *gem_obj);
+
+/* create memory region for drm framebuffer. */
+int drm_gem_cma_dumb_create(struct drm_file *file_priv,
+		struct drm_device *drm, struct drm_mode_create_dumb *args);
+
+/* map memory region for drm framebuffer to user space. */
+int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
+		struct drm_device *drm, uint32_t handle, uint64_t *offset);
+
+/* set vm_flags and we can change the vm attribute to other one at here. */
+int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
+
+/*
+ * destroy memory region allocated.
+ *	- a gem handle and physical memory region pointed by a gem object
+ *	would be released by drm_gem_handle_delete().
+ */
+int drm_gem_cma_dumb_destroy(struct drm_file *file_priv,
+		struct drm_device *drm, unsigned int handle);
+
+/* allocate physical memory. */
+struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
+		unsigned int size);
+
+extern const struct vm_operations_struct drm_gem_cma_vm_ops;
+
+#endif /* __DRM_GEM_CMA_HELPER_H__ */