[0/8] drm/sun4i: Support the Display Engine frontend

Hi,

This is a first serie to enable the display engine frontend.

This hardware block is found in the first generation Display Engine from
Allwinner. Its role is to implement more advanced features that the
associated backend, even though the backend alone can be used (and was used
so far) for basic composition.

Among those features, we will find hardware scaling, that is supported in
this serie, colorspace conversions, or more exotic formats support such as
the one output by the VPU.

Let me know what you think,
Maxime

Maxime Ripard (8):
  drm/sun4i: backend: Move line stride setup to buffer setup function
  drm/sun4i: backend: Allow a NULL plane pointer to retrieve the format
  drm/sun4i: sun4i_layer: Add a custom plane state
  drm/sun4i: crtc: Add a custom crtc atomic_check
  drm/sun4i: Add a driver for the display frontend
  drm/sun4i: sun4i_layer: Wire in the frontend
  drm/sun4i: sun4i_layer: Add a custom atomic_check for the frontend
  ARM: dts: sun8i: a33 Enable our display frontend

 arch/arm/boot/dts/sun8i-a33.dtsi       |   1 +-
 drivers/gpu/drm/sun4i/Makefile         |   3 +-
 drivers/gpu/drm/sun4i/sun4i_backend.c  | 139 +++++++++-
 drivers/gpu/drm/sun4i/sun4i_backend.h  |   6 +-
 drivers/gpu/drm/sun4i/sun4i_crtc.c     |  14 +-
 drivers/gpu/drm/sun4i/sun4i_drv.c      |  16 +-
 drivers/gpu/drm/sun4i/sun4i_drv.h      |   1 +-
 drivers/gpu/drm/sun4i/sun4i_frontend.c | 377 ++++++++++++++++++++++++++-
 drivers/gpu/drm/sun4i/sun4i_frontend.h | 102 +++++++-
 drivers/gpu/drm/sun4i/sun4i_layer.c    |  75 ++++-
 drivers/gpu/drm/sun4i/sun4i_layer.h    |  11 +-
 drivers/gpu/drm/sun4i/sunxi_engine.h   |   2 +-
 12 files changed, 727 insertions(+), 20 deletions(-)
 create mode 100644 drivers/gpu/drm/sun4i/sun4i_frontend.c
 create mode 100644 drivers/gpu/drm/sun4i/sun4i_frontend.h

base-commit: 4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323

On 13/12/2017 16:33, Maxime Ripard wrote:
> Now that we have everything in place, we can start enabling the frontend.
> This is more difficult than one would assume since there can only be one
> plane using the frontend per-backend.
> 
> We therefore need to make sure that the userspace will not try to setup
> multiple planes using it, since that would be impossible. In order to
> prevent that, we can create an atomic_check callback that will check that
> only one plane will effectively make use of the frontend in a given
> configuration, and will toggle the switch in that plane state so that the
> proper setup function can do their role.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  drivers/gpu/drm/sun4i/sun4i_backend.c | 65 ++++++++++++++++++++++++++++-
>  drivers/gpu/drm/sun4i/sun4i_backend.h |  2 +-
>  2 files changed, 67 insertions(+)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
> index f1d19767c55d..a7b87a12990e 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> @@ -11,6 +11,7 @@
>   */
>  
>  #include <drm/drmP.h>
> +#include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_crtc_helper.h>
> @@ -271,6 +272,69 @@ int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
>  	return 0;
>  }
>  
> +static bool sun4i_backend_plane_uses_scaler(struct drm_plane_state *state)
> +{
> +	u16 src_h = state->src_h >> 16;
> +	u16 src_w = state->src_w >> 16;
> +
> +	DRM_DEBUG_DRIVER("Input size %dx%d, output size %dx%d\n",
> +			 src_w, src_h, state->crtc_w, state->crtc_h);
> +
> +	if ((state->crtc_h != src_h) || (state->crtc_w != src_w))
> +		return true;
> +
> +	return false;
> +}
> +
> +static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
> +{
> +	struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
> +	struct sun4i_backend *backend = layer->backend;
> +
> +	if (IS_ERR(backend->frontend))
> +		return false;
> +
> +	return sun4i_backend_plane_uses_scaler(state);
> +}
> +
> +static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
> +				      struct drm_crtc_state *crtc_state)
> +{
> +	struct drm_atomic_state *state = crtc_state->state;
> +	struct drm_device *drm = state->dev;
> +	struct drm_plane *plane;
> +	unsigned int num_frontend_planes = 0;
> +
> +	DRM_DEBUG_DRIVER("Starting checking our planes\n");
> +
> +	if (!crtc_state->planes_changed)
> +		return 0;
> +
> +	drm_for_each_plane_mask(plane, drm, crtc_state->plane_mask) {
> +		struct drm_plane_state *plane_state =
> +			drm_atomic_get_plane_state(state, plane);
> +		struct sun4i_layer_state *layer_state =
> +			state_to_sun4i_layer_state(plane_state);
> +
> +		if (sun4i_backend_plane_uses_frontend(plane_state)) {
> +			DRM_DEBUG_DRIVER("Using the frontend for plane %d\n",
> +					 plane->index);
> +
> +			layer_state->uses_frontend = true;
> +			num_frontend_planes++;
> +		} else {
> +			layer_state->uses_frontend = false;
> +		}
> +	}
> +
> +	if (num_frontend_planes > SUN4I_BACKEND_NUM_FRONTEND_LAYERS) {
> +		DRM_DEBUG_DRIVER("Too many planes going through the frontend, rejecting\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int sun4i_backend_init_sat(struct device *dev) {
>  	struct sun4i_backend *backend = dev_get_drvdata(dev);
>  	int ret;
> @@ -384,6 +448,7 @@ static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv,
>  }
>  
>  static const struct sunxi_engine_ops sun4i_backend_engine_ops = {
> +	.atomic_check			= sun4i_backend_atomic_check,
>  	.commit				= sun4i_backend_commit,
>  	.layers_init			= sun4i_layers_init,
>  	.apply_color_correction		= sun4i_backend_apply_color_correction,
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.h b/drivers/gpu/drm/sun4i/sun4i_backend.h
> index 636a51521e77..3b5531440fa3 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.h
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.h
> @@ -144,6 +144,8 @@
>  #define SUN4I_BACKEND_HWCCOLORTAB_OFF		0x4c00
>  #define SUN4I_BACKEND_PIPE_OFF(p)		(0x5000 + (0x400 * (p)))
>  
> +#define SUN4I_BACKEND_NUM_FRONTEND_LAYERS	1
> +
>  struct sun4i_backend {
>  	struct sunxi_engine	engine;
>  	struct sun4i_frontend	*frontend;
> 

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>