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: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1646d03..d1d68f0 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -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);

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5c8df57..3de62b0 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -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);
 

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 10ca473..7299d63 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -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;
+       }
+}