linux-kernel - Re: [PATCH 4/8] drm/sun4i: add support for sun8i DE2 mixers and display engines

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Message-ID: <1634001.dRmL8h9ofd@jernej-laptop>
Date:   Fri, 24 Feb 2017 16:30:17 +0100
From:   Jernej Škrabec <jernej.skrabec@...l.net>
To:     Rob Herring <robh+dt@...nel.org>
Cc:     Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Icenowy Zheng <icenowy@...c.xyz>, Chen-Yu Tsai <wens@...e.org>,
        David Airlie <airlied@...ux.ie>,
        Jean-Francois Moine <moinejf@...e.fr>,
        linux-clk <linux-clk@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH 4/8] drm/sun4i: add support for sun8i DE2 mixers and display engines

Hi,

Dne petek, 24. februar 2017 ob 14:30:36 CET je Rob Herring napisal(a):
> On Wed, Feb 22, 2017 at 2:09 PM, Maxime Ripard
> 
> <maxime.ripard@...e-electrons.com> wrote:
> > Hi,
> > 
> > On Wed, Feb 22, 2017 at 11:23:06PM +0800, Icenowy Zheng wrote:
> >> Allwinner have a new "Display Engine 2.0" in there new SoCs, which comes
> >> in a new "Display Engine" (mixers instead of old backends and
> >> frontends).
> >> 
> >> Add support for the mixer on Allwinner V3s SoC; it's the simplest one.
> >> 
> >> Signed-off-by: Icenowy Zheng <icenowy@...c.xyz>
> >> ---
> 
> [...]
> 
> >> diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c
> >> b/drivers/gpu/drm/sun4i/sun8i_mixer.c new file mode 100644
> >> index 000000000000..9427b57240d3
> >> --- /dev/null
> >> +++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c
> >> @@ -0,0 +1,417 @@
> >> +/*
> >> + * Copyright (C) 2017 Icenowy Zheng <icenowy@...c.xyz>
> >> + *
> >> + * Based on sun4i_backend.c, which is:
> >> + *   Copyright (C) 2015 Free Electrons
> >> + *   Copyright (C) 2015 NextThing Co
> >> + *
> >> + * 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.
> >> + */
> >> +
> >> +#include <drm/drmP.h>
> >> +#include <drm/drm_atomic_helper.h>
> >> +#include <drm/drm_crtc.h>
> >> +#include <drm/drm_crtc_helper.h>
> >> +#include <drm/drm_fb_cma_helper.h>
> >> +#include <drm/drm_gem_cma_helper.h>
> >> +#include <drm/drm_plane_helper.h>
> >> +
> >> +#include <linux/component.h>
> >> +#include <linux/reset.h>
> >> +#include <linux/of_device.h>
> >> +
> >> +#include "sun8i_mixer.h"
> >> +#include "sun4i_drv.h"
> >> +
> >> +#define SUN8I_DRAM_OFFSET 0x40000000
> > 
> > PHYS_OFFSET?
> 
> PHYS_OFFSET is not portable. __pa(PAGE_OFFSET) instead.
> 
> If your DMA addresses are different from CPU addresses (i.e. have some
> offset), then use "dma-ranges" in DT.
> 
> Rob

That adjustment is not needed and should be removed. Such adjusment breaks DE 
on boards with 2 GiB of RAM.

Regards,
Jernej