On Mon, Jul 11, 2016 at 02:08:07PM +0100, Chris Wilson wrote:
> Enable the standard GEM dma-buf interface provided by the DRM core, but
> only for exporting the VGEM object. This allows passing around the VGEM
> objects created from the dumb interface and using them as sources
> elsewhere. Creating a VGEM object for a foriegn handle is not supported.
>
> v2: With additional completeness.
> v3: Need to clear the CPU cache upon exporting the dma-addresses.
> v4: Use drm_gem_put_pages() as well.
> v5: Use drm_prime_pages_to_sg()
>
> Testcase: igt/vgem_basic/dmabuf-*
> Testcase: igt/prime_vgem
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
> Cc: Zach Reizner <zachr@xxxxxxxxxx>
> Acked-by: Zach Reizner <zachr@xxxxxxxxxx>
> Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Merged the first 2 patches from this series.
-Daniel
> ---
> drivers/gpu/drm/vgem/vgem_drv.c | 89 ++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 88 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
> index c161b6d7e427..b5fb968d2d5c 100644
> --- a/drivers/gpu/drm/vgem/vgem_drv.c
> +++ b/drivers/gpu/drm/vgem/vgem_drv.c
> @@ -192,14 +192,101 @@ static const struct file_operations vgem_driver_fops = {
> .release = drm_release,
> };
>
> +static int vgem_prime_pin(struct drm_gem_object *obj)
> +{
> + long n_pages = obj->size >> PAGE_SHIFT;
> + struct page **pages;
> +
> + /* Flush the object from the CPU cache so that importers can rely
> + * on coherent indirect access via the exported dma-address.
> + */
> + pages = drm_gem_get_pages(obj);
> + if (IS_ERR(pages))
> + return PTR_ERR(pages);
> +
> + drm_clflush_pages(pages, n_pages);
> + drm_gem_put_pages(obj, pages, true, false);
> +
> + return 0;
> +}
> +
> +static struct sg_table *vgem_prime_get_sg_table(struct drm_gem_object *obj)
> +{
> + struct sg_table *st;
> + struct page **pages;
> +
> + pages = drm_gem_get_pages(obj);
> + if (IS_ERR(pages))
> + return ERR_CAST(pages);
> +
> + st = drm_prime_pages_to_sg(pages, obj->size >> PAGE_SHIFT);
> + drm_gem_put_pages(obj, pages, false, false);
> +
> + return st;
> +}
> +
> +static void *vgem_prime_vmap(struct drm_gem_object *obj)
> +{
> + long n_pages = obj->size >> PAGE_SHIFT;
> + struct page **pages;
> + void *addr;
> +
> + pages = drm_gem_get_pages(obj);
> + if (IS_ERR(pages))
> + return NULL;
> +
> + addr = vmap(pages, n_pages, 0, pgprot_writecombine(PAGE_KERNEL_IO));
> + drm_gem_put_pages(obj, pages, false, false);
> +
> + return addr;
> +}
> +
> +static void vgem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +{
> + vunmap(vaddr);
> +}
> +
> +static int vgem_prime_mmap(struct drm_gem_object *obj,
> + struct vm_area_struct *vma)
> +{
> + int ret;
> +
> + if (obj->size < vma->vm_end - vma->vm_start)
> + return -EINVAL;
> +
> + if (!obj->filp)
> + return -ENODEV;
> +
> + ret = obj->filp->f_op->mmap(obj->filp, vma);
> + if (ret)
> + return ret;
> +
> + fput(vma->vm_file);
> + vma->vm_file = get_file(obj->filp);
> + vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
> + vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> +
> + return 0;
> +}
> +
> static struct drm_driver vgem_driver = {
> - .driver_features = DRIVER_GEM,
> + .driver_features = DRIVER_GEM | DRIVER_PRIME,
> .gem_free_object_unlocked = vgem_gem_free_object,
> .gem_vm_ops = &vgem_gem_vm_ops,
> .ioctls = vgem_ioctls,
> .fops = &vgem_driver_fops,
> +
> .dumb_create = vgem_gem_dumb_create,
> .dumb_map_offset = vgem_gem_dumb_map,
> +
> + .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> + .gem_prime_pin = vgem_prime_pin,
> + .gem_prime_export = drm_gem_prime_export,
> + .gem_prime_get_sg_table = vgem_prime_get_sg_table,
> + .gem_prime_vmap = vgem_prime_vmap,
> + .gem_prime_vunmap = vgem_prime_vunmap,
> + .gem_prime_mmap = vgem_prime_mmap,
> +
> .name = DRIVER_NAME,
> .desc = DRIVER_DESC,
> .date = DRIVER_DATE,
> --
> 2.8.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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