[PATCH V4 1/2] drm/fb_cma_helper: Add drm_fb_cma_prepare_fb() helper

[Lucas Stach]

Am Montag, den 14.11.2016, 11:07 +0100 schrieb Marek Vasut:
> Add new drm_fb_cma_prepare_fb() helper function extracted from the
> imx-drm driver. This function checks if the plane has DMABUF attached
> to it, extracts the exclusive fence from it and attaches it to the
> plane state for the atomic helper to wait on it.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Lucas Stach <l.stach at pengutronix.de>

Reviewed-by: Lucas Stach <l.stach at pengutronix.de>

> ---
> V2: Rename the function to drm_fb_cma_prepare_fb()
>     and clarify the documentation (thanks to Lucas Stach)
> V3: - Rename the function to drm_fb_cma_prepare_fb()
>     - Update documentation
> V4: Update to latest next/master (b60de3e)
> ---
>  drivers/gpu/drm/drm_fb_cma_helper.c | 35 +++++++++++++++++++++++++++++++++++
>  include/drm/drm_fb_cma_helper.h     |  3 +++
>  2 files changed, 38 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
> index 4c66644..7198373 100644
> --- a/drivers/gpu/drm/drm_fb_cma_helper.c
> +++ b/drivers/gpu/drm/drm_fb_cma_helper.c
> @@ -18,13 +18,16 @@
>   */
>  
>  #include <drm/drmP.h>
> +#include <drm/drm_atomic.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_crtc_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_fb_cma_helper.h>
> +#include <linux/dma-buf.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/module.h>
> +#include <linux/reservation.h>
>  
>  #define DEFAULT_FBDEFIO_DELAY_MS 50
>  
> @@ -265,6 +268,38 @@ struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
>  }
>  EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
>  
> +/**
> + * drm_fb_cma_prepare_fb() - Prepare CMA framebuffer
> + * @plane: Which plane
> + * @state: Plane state attach fence to
> + *
> + * This should be put into prepare_fb hook of struct &drm_plane_helper_funcs .
> + *
> + * This function checks if the plane FB has an dma-buf attached, extracts
> + * the exclusive fence and attaches it to plane state for the atomic helper
> + * to wait on.
> + *
> + * There is no need for cleanup_fb for CMA based framebuffer drivers.
> + */
> +int drm_fb_cma_prepare_fb(struct drm_plane *plane,
> +			  struct drm_plane_state *state)
> +{
> +	struct dma_buf *dma_buf;
> +	struct dma_fence *fence;
> +
> +	if ((plane->state->fb == state->fb) || !state->fb)
> +		return 0;
> +
> +	dma_buf = drm_fb_cma_get_gem_obj(state->fb, 0)->base.dma_buf;
> +	if (dma_buf) {
> +		fence = reservation_object_get_excl_rcu(dma_buf->resv);
> +		drm_atomic_set_fence_for_plane(state, fence);
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(drm_fb_cma_prepare_fb);
> +
>  #ifdef CONFIG_DEBUG_FS
>  static void drm_fb_cma_describe(struct drm_framebuffer *fb, struct seq_file *m)
>  {
> diff --git a/include/drm/drm_fb_cma_helper.h b/include/drm/drm_fb_cma_helper.h
> index f313211..cc82c73 100644
> --- a/include/drm/drm_fb_cma_helper.h
> +++ b/include/drm/drm_fb_cma_helper.h
> @@ -41,6 +41,9 @@ struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
>  struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
>  	unsigned int plane);
>  
> +int drm_fb_cma_prepare_fb(struct drm_plane *plane,
> +			  struct drm_plane_state *state);
> +
>  #ifdef CONFIG_DEBUG_FS
>  struct seq_file;
>