treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drm/sun4i: backend: Assign the pipes automatically

Since we now have a way to enforce the zpos, check for the number of alpha
planes, the only missing part is to assign our pipe automatically instead
of hardcoding it.

The algorithm is quite simple, but requires two iterations over the list of
planes.

In the first one (which is the same one that we've had to check for alpha,
the frontend usage, and so on), we order the planes by their zpos.

We can then do a second iteration over that array by ascending zpos
starting with the pipe 0. When and if we encounter our alpha plane, we put
it and all the other subsequent planes in the second pipe.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e9caf21d831438d36a3ccc7cef229c9a7ea7f69f.1518802627.git-series.maxime.ripard@bootlin.com

drm/sun4i: backend: Wire in the frontend

Now that we have a driver, we can make use of it. This is done by
adding a flag to our custom plane state that will trigger whether we should
use the frontend on that particular plane or not.

The rest is just plumbing to set up the backend to not perform the DMA but
receive its data from the frontend.

Note that we're still not making any use of the frontend itself, as no one
is setting the flag yet.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/cdffc25eab2d817820cc78cbd24f1f4b99902014.1516613040.git-series.maxime.ripard@free-electrons.com

drm/sun4i: backend: Add a custom plane state

We will need to store some additional data in the future to the state.
Create a custom plane state that will embed those data, in order to store
the pipe or whether or not that plane should use the frontend.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/88dd9c2b0caa550595e7b2ff37dc9d0af2c78609.1516613040.git-series.maxime.ripard@free-electrons.com

drm/sun4i: abstract a engine type

As we are going to add support for the Allwinner DE2 engine in sun4i-drm
driver, we will finally have two types of display engines -- the DE1
backend and the DE2 mixer. They both do some display blending and feed
graphics data to TCON, and is part of the "Display Engine" called by
Allwinner, so I choose to call them both "engine" here.

Abstract the engine type to a new struct with an ops struct, which contains
functions that should be called outside the engine-specified code (in
TCON, CRTC or TV Encoder code).

In order to preserve bisectability, we also switch the backend and layer
code in its own module.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drm/sun4i: return only planes for layers created

As we are going to add support for the Allwinner DE2 Mixer in sun4i-drm
driver, we will finally have two types of layers.

Each layer is bound to a drm_plane that is CRTC-specific, so we create
them when initializing CRTC (calling sun4i_layers_init, which will be
generalized in next patch). The drm_plane's will be used when creating
CRTC, but the CRTC initialization code do not care other properties of
the layer, so we let the sun4i_layers_init function return drm_plane's
only.

As we have no need to trace the layers after the CRTC is properly
created, we drop the layers pointer in sun4i_crtc struct.

Doing this uncouples the CRTC code from the type of layer (the
sun4i_layers_init function name is still hardcoded and will be changed
in the next patch), so that we can finally gain support for the
mixer in DE2, which has different layers.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drm/sun4i: Pass pointer for underlying backend into layer init

sun4i_layer only controls the backend hardware block of the display
pipeline.

Pass pointers to the underlying backend in the layer init function,
instead of trying to fetch it from the drm_device structure. This
avoids the headache of trying to figure out which device the layers
actually belong to.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drm/sun4i: Add backend pointer to sun4i_layer

sun4i_layer only controls the backend hardware block of the display
pipeline. Instead of getting a pointer to the underlying backend
through the drm_device structure, leave one in itself.

Also drop the drm_device pointer, since it is no longer needed.

The next step forward would be to pass the pointer in through
sun4i_layers_init as a parameter. This would make it easier to support
multiple display pipelines layer on.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drm: Add Allwinner A10 Display Engine support

The Allwinner A10 and subsequent SoCs share the same display pipeline, with
variations in the number of controllers (1 or 2), or the presence or not of
some output (HDMI, TV, VGA) or not.

Add a driver with a limited set of features for now, and we will hopefully
support all of them eventually

Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>