Re: [PATCH v3 04/11] drm/sun4i: abstract the layer type

From: Icenowy Zheng <icenowy-h8G6r0blFSE@public.gmane.org>
To: Sean Paul <seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Maxime Ripard
	<maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
	Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
	Jernej Skrabec <jernej.skrabec-gGgVlfcn5nU@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org,
	linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH v3 04/11] drm/sun4i: abstract the layer type
Date: Wed, 5 Apr 2017 03:53:22 +0800	[thread overview]
Message-ID: <dbf0f478-ff53-0ced-24a3-e9de7077efd9@aosc.io> (raw)
In-Reply-To: <20170404192837.pvlhwyeut45vg2wg@art_vandelay>

在 2017年04月05日 03:28, Sean Paul 写道:
> On Thu, Mar 30, 2017 at 03:46:06AM +0800, Icenowy Zheng wrote:
>> As we are going to add support for the Allwinner DE2 Mixer in sun4i-drm
>> driver, we will finally have two types of layer.
>>
>> Abstract the layer type to void * and a ops struct, which contains the
>> only function used by crtc -- get the drm_plane struct of the layer.
>>
>> Signed-off-by: Icenowy Zheng <icenowy-h8G6r0blFSE@public.gmane.org>
>> ---
>> Refactored patch in v3.
>>
>>  drivers/gpu/drm/sun4i/sun4i_crtc.c  | 19 +++++++++++--------
>>  drivers/gpu/drm/sun4i/sun4i_crtc.h  |  3 ++-
>>  drivers/gpu/drm/sun4i/sun4i_layer.c | 19 ++++++++++++++++++-
>>  drivers/gpu/drm/sun4i/sun4i_layer.h |  2 +-
>>  drivers/gpu/drm/sun4i/sunxi_layer.h | 17 +++++++++++++++++
>>  5 files changed, 49 insertions(+), 11 deletions(-)
>>  create mode 100644 drivers/gpu/drm/sun4i/sunxi_layer.h
>>
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_crtc.c b/drivers/gpu/drm/sun4i/sun4i_crtc.c
>> index 3c876c3a356a..33854ee7f636 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_crtc.c
>> +++ b/drivers/gpu/drm/sun4i/sun4i_crtc.c
>> @@ -29,6 +29,7 @@
>>  #include "sun4i_crtc.h"
>>  #include "sun4i_drv.h"
>>  #include "sun4i_layer.h"
>> +#include "sunxi_layer.h"
>>  #include "sun4i_tcon.h"
>>
>>  static void sun4i_crtc_atomic_begin(struct drm_crtc *crtc,
>> @@ -149,7 +150,7 @@ struct sun4i_crtc *sun4i_crtc_init(struct drm_device *drm,
>>  	scrtc->tcon = tcon;
>>
>>  	/* Create our layers */
>> -	scrtc->layers = sun4i_layers_init(drm, scrtc->backend);
>> +	scrtc->layers = (void **)sun4i_layers_init(drm, scrtc);
>>  	if (IS_ERR(scrtc->layers)) {
>>  		dev_err(drm->dev, "Couldn't create the planes\n");
>>  		return NULL;
>> @@ -157,14 +158,15 @@ struct sun4i_crtc *sun4i_crtc_init(struct drm_device *drm,
>>
>>  	/* find primary and cursor planes for drm_crtc_init_with_planes */
>>  	for (i = 0; scrtc->layers[i]; i++) {
>> -		struct sun4i_layer *layer = scrtc->layers[i];
>> +		void *layer = scrtc->layers[i];
>> +		struct drm_plane *plane = scrtc->layer_ops->get_plane(layer);
>>
>> -		switch (layer->plane.type) {
>> +		switch (plane->type) {
>>  		case DRM_PLANE_TYPE_PRIMARY:
>> -			primary = &layer->plane;
>> +			primary = plane;
>>  			break;
>>  		case DRM_PLANE_TYPE_CURSOR:
>> -			cursor = &layer->plane;
>> +			cursor = plane;
>>  			break;
>>  		default:
>>  			break;
>> @@ -190,10 +192,11 @@ struct sun4i_crtc *sun4i_crtc_init(struct drm_device *drm,
>>  	/* Set possible_crtcs to this crtc for overlay planes */
>>  	for (i = 0; scrtc->layers[i]; i++) {
>>  		uint32_t possible_crtcs = BIT(drm_crtc_index(&scrtc->crtc));
>> -		struct sun4i_layer *layer = scrtc->layers[i];
>> +		void *layer = scrtc->layers[i];
>> +		struct drm_plane *plane = scrtc->layer_ops->get_plane(layer);
>>
>> -		if (layer->plane.type == DRM_PLANE_TYPE_OVERLAY)
>> -			layer->plane.possible_crtcs = possible_crtcs;
>> +		if (plane->type == DRM_PLANE_TYPE_OVERLAY)
>> +			plane->possible_crtcs = possible_crtcs;
>>  	}
>>
>>  	return scrtc;
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_crtc.h b/drivers/gpu/drm/sun4i/sun4i_crtc.h
>> index 230cb8f0d601..a4036ee44cf8 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_crtc.h
>> +++ b/drivers/gpu/drm/sun4i/sun4i_crtc.h
>> @@ -19,7 +19,8 @@ struct sun4i_crtc {
>>
>>  	struct sun4i_backend		*backend;
>>  	struct sun4i_tcon		*tcon;
>> -	struct sun4i_layer		**layers;
>> +	void				**layers;
>> +	const struct sunxi_layer_ops	*layer_ops;
>
> I think you should probably take a different approach to abstract the layer
> type. How about creating
>
> struct sunxi_layer {
>         struct drm_plane plane;
> }
>
> base and then subclassing that for sun4i and sun8i? By doing this you can avoid
> the nasty casting and you can also get rid of the get_plane() hook and
> layer_ops.

For the situation that using ** things are easily to get weird.

>
> Sean
>
>
>
>>  };
>>
>>  static inline struct sun4i_crtc *drm_crtc_to_sun4i_crtc(struct drm_crtc *crtc)
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_layer.c b/drivers/gpu/drm/sun4i/sun4i_layer.c
>> index f26bde5b9117..bc4a70d6968b 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_layer.c
>> +++ b/drivers/gpu/drm/sun4i/sun4i_layer.c
>> @@ -16,7 +16,9 @@
>>  #include <drm/drmP.h>
>>
>>  #include "sun4i_backend.h"
>> +#include "sun4i_crtc.h"
>>  #include "sun4i_layer.h"
>> +#include "sunxi_layer.h"
>>
>>  struct sun4i_plane_desc {
>>  	       enum drm_plane_type     type;
>> @@ -100,6 +102,17 @@ static const struct sun4i_plane_desc sun4i_backend_planes[] = {
>>  	},
>>  };
>>
>> +static struct drm_plane *sun4i_layer_get_plane(void *layer)
>> +{
>> +	struct sun4i_layer *sun4i_layer = layer;
>> +
>> +	return &sun4i_layer->plane;
>> +}
>> +
>> +static const struct sunxi_layer_ops layer_ops = {
>> +	.get_plane = sun4i_layer_get_plane,
>> +};
>> +
>>  static struct sun4i_layer *sun4i_layer_init_one(struct drm_device *drm,
>>  						struct sun4i_backend *backend,
>>  						const struct sun4i_plane_desc *plane)
>> @@ -129,9 +142,10 @@ static struct sun4i_layer *sun4i_layer_init_one(struct drm_device *drm,
>>  }
>>
>>  struct sun4i_layer **sun4i_layers_init(struct drm_device *drm,
>> -				       struct sun4i_backend *backend)
>> +				       struct sun4i_crtc *crtc)
>>  {
>>  	struct sun4i_layer **layers;
>> +	struct sun4i_backend *backend = crtc->backend;
>>  	int i;
>>
>>  	layers = devm_kcalloc(drm->dev, ARRAY_SIZE(sun4i_backend_planes) + 1,
>> @@ -181,5 +195,8 @@ struct sun4i_layer **sun4i_layers_init(struct drm_device *drm,
>>  		layers[i] = layer;
>>  	};
>>
>> +	/* Assign layer ops to the CRTC */
>> +	crtc->layer_ops = &layer_ops;
>> +
>>  	return layers;
>>  }
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_layer.h b/drivers/gpu/drm/sun4i/sun4i_layer.h
>> index 4be1f0919df2..425eea7b9e3b 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_layer.h
>> +++ b/drivers/gpu/drm/sun4i/sun4i_layer.h
>> @@ -27,6 +27,6 @@ plane_to_sun4i_layer(struct drm_plane *plane)
>>  }
>>
>>  struct sun4i_layer **sun4i_layers_init(struct drm_device *drm,
>> -				       struct sun4i_backend *backend);
>> +				       struct sun4i_crtc *crtc);
>>
>>  #endif /* _SUN4I_LAYER_H_ */
>> diff --git a/drivers/gpu/drm/sun4i/sunxi_layer.h b/drivers/gpu/drm/sun4i/sunxi_layer.h
>> new file mode 100644
>> index 000000000000..d8838ec39299
>> --- /dev/null
>> +++ b/drivers/gpu/drm/sun4i/sunxi_layer.h
>> @@ -0,0 +1,17 @@
>> +/*
>> + * Copyright (C) 2017 Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org>
>> + *
>> + * 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.
>> + */
>> +
>> +#ifndef _SUNXI_LAYER_H_
>> +#define _SUNXI_LAYER_H_
>> +
>> +struct sunxi_layer_ops {
>> +	struct drm_plane *(*get_plane)(void *layer);
>> +};
>> +
>> +#endif /* _SUNXI_LAYER_H_ */
>> --
>> 2.12.0
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

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