drivers/gpu/drm/virtio/virtgpu_vram.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/virtio/virtgpu_vram.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/virtio/virtgpu_vram.c
Extension
.c
Size
6472 bytes
Lines
252
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!is_virtio_device(dev) || !vgdev->has_resource_assign_uuid) {
			ret = -EIO;
			goto out;
		}
		return sgt;
	}

	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
	if (ret)
		goto out;

	addr = dma_map_resource(dev, vram->vram_node.start,
				vram->vram_node.size, dir,
				DMA_ATTR_SKIP_CPU_SYNC);
	ret = dma_mapping_error(dev, addr);
	if (ret)
		goto out;

	sg_set_page(sgt->sgl, NULL, vram->vram_node.size, 0);
	sg_dma_address(sgt->sgl) = addr;
	sg_dma_len(sgt->sgl) = vram->vram_node.size;

	return sgt;
out:
	sg_free_table(sgt);
	kfree(sgt);
	return ERR_PTR(ret);
}

void virtio_gpu_vram_unmap_dma_buf(struct device *dev,
				   struct sg_table *sgt,
				   enum dma_data_direction dir)
{
	if (sgt->nents) {
		dma_unmap_resource(dev, sg_dma_address(sgt->sgl),
				   sg_dma_len(sgt->sgl), dir,
				   DMA_ATTR_SKIP_CPU_SYNC);
	}
	sg_free_table(sgt);
	kfree(sgt);
}

static const struct drm_gem_object_funcs virtio_gpu_vram_funcs = {
	.open = virtio_gpu_gem_object_open,
	.close = virtio_gpu_gem_object_close,
	.free = virtio_gpu_vram_free,
	.mmap = virtio_gpu_vram_mmap,
	.export = virtgpu_gem_prime_export,
};

bool virtio_gpu_is_vram(struct virtio_gpu_object *bo)
{
	return bo->base.base.funcs == &virtio_gpu_vram_funcs;
}

static int virtio_gpu_vram_map(struct virtio_gpu_object *bo)
{
	int ret;
	uint64_t offset;
	struct virtio_gpu_object_array *objs;
	struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
	struct virtio_gpu_object_vram *vram = to_virtio_gpu_vram(bo);

	if (!vgdev->has_host_visible)
		return -EINVAL;

	spin_lock(&vgdev->host_visible_lock);
	ret = drm_mm_insert_node(&vgdev->host_visible_mm, &vram->vram_node,
				 bo->base.base.size);
	spin_unlock(&vgdev->host_visible_lock);

	if (ret)
		return ret;

	objs = virtio_gpu_array_alloc(1);
	if (!objs) {
		ret = -ENOMEM;
		goto err_remove_node;
	}

	virtio_gpu_array_add_obj(objs, &bo->base.base);
	/*TODO: Add an error checking helper function in drm_mm.h */
	offset = vram->vram_node.start - vgdev->host_visible_region.addr;

	ret = virtio_gpu_cmd_map(vgdev, objs, offset);
	if (ret) {
		virtio_gpu_array_put_free(objs);
		goto err_remove_node;
	}

Annotation

Implementation Notes