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Commit 0104fdbb authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

drm/i915: Introduce i915_gem_object_create_stolen() 



Allow for the creation of GEM objects backed by stolen memory. As these
are not backed by ordinary pages, we create a fake dma mapping and store
the address in the scatterlist rather than obj->pages.

v2: Mark _i915_gem_object_create_stolen() as static, as noticed by Jesse
Barnes.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: default avatarBen Widawsky <ben@bwidawsk.net>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 960e3564

drivers/gpu/drm/i915/i915_drv.h

+3 −0
Original line number Diff line number Diff line
@@ -1576,6 +1576,9 @@ int i915_gem_init_stolen(struct drm_device *dev); 
int i915_gem_stolen_setup_compression(struct drm_device *dev, int size);

void i915_gem_stolen_cleanup_compression(struct drm_device *dev);

void i915_gem_cleanup_stolen(struct drm_device *dev);

struct drm_i915_gem_object *

i915_gem_object_create_stolen(struct drm_device *dev, u32 size);

void i915_gem_object_release_stolen(struct drm_i915_gem_object *obj);



/* i915_gem_tiling.c */

void i915_gem_detect_bit_6_swizzle(struct drm_device *dev);

drivers/gpu/drm/i915/i915_gem.c

+1 −0
Original line number Diff line number Diff line
@@ -3772,6 +3772,7 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj) 
	obj->pages_pin_count = 0;

	i915_gem_object_put_pages(obj);

	i915_gem_object_free_mmap_offset(obj);

	i915_gem_object_release_stolen(obj);



	BUG_ON(obj->pages);

drivers/gpu/drm/i915/i915_gem_stolen.c

+125 −0
Original line number Diff line number Diff line
@@ -192,3 +192,128 @@ int i915_gem_init_stolen(struct drm_device *dev) 


	return 0;

}



static struct sg_table *

i915_pages_create_for_stolen(struct drm_device *dev,

			     u32 offset, u32 size)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct sg_table *st;

	struct scatterlist *sg;



	DRM_DEBUG_DRIVER("offset=0x%x, size=%d\n", offset, size);

	BUG_ON(offset > dev_priv->mm.gtt->stolen_size - size);



	/* We hide that we have no struct page backing our stolen object

	 * by wrapping the contiguous physical allocation with a fake

	 * dma mapping in a single scatterlist.

	 */



	st = kmalloc(sizeof(*st), GFP_KERNEL);

	if (st == NULL)

		return NULL;



	if (sg_alloc_table(st, 1, GFP_KERNEL)) {

		kfree(st);

		return NULL;

	}



	sg = st->sgl;

	sg->offset = offset;

	sg->length = size;



	sg_dma_address(sg) = (dma_addr_t)dev_priv->mm.stolen_base + offset;

	sg_dma_len(sg) = size;



	return st;

}



static int i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)

{

	BUG();

	return -EINVAL;

}



static void i915_gem_object_put_pages_stolen(struct drm_i915_gem_object *obj)

{

	/* Should only be called during free */

	sg_free_table(obj->pages);

	kfree(obj->pages);

}



static const struct drm_i915_gem_object_ops i915_gem_object_stolen_ops = {

	.get_pages = i915_gem_object_get_pages_stolen,

	.put_pages = i915_gem_object_put_pages_stolen,

};



static struct drm_i915_gem_object *

_i915_gem_object_create_stolen(struct drm_device *dev,

			       struct drm_mm_node *stolen)

{

	struct drm_i915_gem_object *obj;



	obj = kzalloc(sizeof(*obj), GFP_KERNEL);

	if (obj == NULL)

		return NULL;



	if (drm_gem_private_object_init(dev, &obj->base, stolen->size))

		goto cleanup;



	i915_gem_object_init(obj, &i915_gem_object_stolen_ops);



	obj->pages = i915_pages_create_for_stolen(dev,

						  stolen->start, stolen->size);

	if (obj->pages == NULL)

		goto cleanup;



	obj->has_dma_mapping = true;

	obj->pages_pin_count = 1;

	obj->stolen = stolen;



	obj->base.write_domain = I915_GEM_DOMAIN_GTT;

	obj->base.read_domains = I915_GEM_DOMAIN_GTT;

	obj->cache_level = I915_CACHE_NONE;



	return obj;



cleanup:

	kfree(obj);

	return NULL;

}



struct drm_i915_gem_object *

i915_gem_object_create_stolen(struct drm_device *dev, u32 size)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct drm_i915_gem_object *obj;

	struct drm_mm_node *stolen;



	if (dev_priv->mm.stolen_base == 0)

		return NULL;



	DRM_DEBUG_KMS("creating stolen object: size=%x\n", size);

	if (size == 0)

		return NULL;



	stolen = drm_mm_search_free(&dev_priv->mm.stolen, size, 4096, 0);

	if (stolen)

		stolen = drm_mm_get_block(stolen, size, 4096);

	if (stolen == NULL)

		return NULL;



	obj = _i915_gem_object_create_stolen(dev, stolen);

	if (obj)

		return obj;



	drm_mm_put_block(stolen);

	return NULL;

}



void

i915_gem_object_release_stolen(struct drm_i915_gem_object *obj)

{

	if (obj->stolen) {

		drm_mm_put_block(obj->stolen);

		obj->stolen = NULL;

	}

}