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From: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>
Cc: Vinod Koul <vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Dan Williams
	<dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Grant Likely
	<grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	linux-arm-kernel
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	linux-sunxi <linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>,
	dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH 2/3] dmaengine: sun6i: Add support for Allwinner A23 (sun8i) variant
Date: Wed, 17 Sep 2014 17:55:40 +0200	[thread overview]
Message-ID: <20140917155540.GJ2166@lukather> (raw)
In-Reply-To: <CAGb2v67jokpXHxR26YoCEB2Y_v07oQZXZfPuGJC_wO=r-SRZhg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

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On Tue, Sep 16, 2014 at 10:13:27PM +0800, Chen-Yu Tsai wrote:
> >> +     /*
> >> +      * sun8i variant requires us to toggle an undocumented register,
> >> +      * as seen in Allwinner's SDK.
> >
> > The BSP I have has this:
> >
> > static void sunxi_dma_hw_init(struct sunxi_dmadev *dev)
> > {
> >         struct sunxi_dmadev *sunxi_dev = dev;
> >
> >         clk_prepare_enable(sunxi_dev->ahb_clk);
> > #ifdef CONFIG_ARCH_SUN8IW3
> >         writel(0x04, sunxi_dev->base + DMA_GATE);
> > #endif
> > }
> >
> > /* All is ok, and open the clock */
> > sunxi_dma_hw_init(sunxi_dev);
> >
> > So I guess we can say that it's not that undocumented :)
> 
> That's right. I meant undocumented in the user manual.
> I did reference the SDK in the comment, didn't I? :)

So something like

writel(DMA_GATE_ENABLE, base->DMA_GATE_REG) wouldn't be too far off :)

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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WARNING: multiple messages have this Message-ID (diff)
From: maxime.ripard@free-electrons.com (Maxime Ripard)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/3] dmaengine: sun6i: Add support for Allwinner A23 (sun8i) variant
Date: Wed, 17 Sep 2014 17:55:40 +0200	[thread overview]
Message-ID: <20140917155540.GJ2166@lukather> (raw)
In-Reply-To: <CAGb2v67jokpXHxR26YoCEB2Y_v07oQZXZfPuGJC_wO=r-SRZhg@mail.gmail.com>

On Tue, Sep 16, 2014 at 10:13:27PM +0800, Chen-Yu Tsai wrote:
> >> +     /*
> >> +      * sun8i variant requires us to toggle an undocumented register,
> >> +      * as seen in Allwinner's SDK.
> >
> > The BSP I have has this:
> >
> > static void sunxi_dma_hw_init(struct sunxi_dmadev *dev)
> > {
> >         struct sunxi_dmadev *sunxi_dev = dev;
> >
> >         clk_prepare_enable(sunxi_dev->ahb_clk);
> > #ifdef CONFIG_ARCH_SUN8IW3
> >         writel(0x04, sunxi_dev->base + DMA_GATE);
> > #endif
> > }
> >
> > /* All is ok, and open the clock */
> > sunxi_dma_hw_init(sunxi_dev);
> >
> > So I guess we can say that it's not that undocumented :)
> 
> That's right. I meant undocumented in the user manual.
> I did reference the SDK in the comment, didn't I? :)

So something like

writel(DMA_GATE_ENABLE, base->DMA_GATE_REG) wouldn't be too far off :)

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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  parent reply	other threads:[~2014-09-17 15:55 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-13 13:52 [PATCH 0/3] ARM: sun8i: Add DMA controller support Chen-Yu Tsai
2014-09-13 13:52 ` Chen-Yu Tsai
     [not found] ` <1410616381-30226-1-git-send-email-wens-jdAy2FN1RRM@public.gmane.org>
2014-09-13 13:52   ` [PATCH 1/3] dmaengine: sun6i: support parameterized compatible strings Chen-Yu Tsai
2014-09-13 13:52     ` Chen-Yu Tsai
     [not found]     ` <1410616381-30226-2-git-send-email-wens-jdAy2FN1RRM@public.gmane.org>
2014-09-16 10:33       ` Maxime Ripard
2014-09-16 10:33         ` Maxime Ripard
2014-09-13 13:53   ` [PATCH 2/3] dmaengine: sun6i: Add support for Allwinner A23 (sun8i) variant Chen-Yu Tsai
2014-09-13 13:53     ` Chen-Yu Tsai
     [not found]     ` <1410616381-30226-3-git-send-email-wens-jdAy2FN1RRM@public.gmane.org>
2014-09-16 10:35       ` Maxime Ripard
2014-09-16 10:35         ` Maxime Ripard
2014-09-16 14:13         ` Chen-Yu Tsai
2014-09-16 14:13           ` Chen-Yu Tsai
     [not found]           ` <CAGb2v67jokpXHxR26YoCEB2Y_v07oQZXZfPuGJC_wO=r-SRZhg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-09-17 15:55             ` Maxime Ripard [this message]
2014-09-17 15:55               ` Maxime Ripard
2014-09-18  1:57               ` Chen-Yu Tsai
2014-09-18  1:57                 ` Chen-Yu Tsai
2014-09-13 13:53   ` [PATCH 3/3] ARM: dts: sun8i: Add DMA controller node Chen-Yu Tsai
2014-09-13 13:53     ` Chen-Yu Tsai

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