From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH 2/3] dmaengine: sun6i: Add support for Allwinner A23 (sun8i) variant Date: Wed, 17 Sep 2014 17:55:40 +0200 Message-ID: <20140917155540.GJ2166@lukather> References: <1410616381-30226-1-git-send-email-wens@csie.org> <1410616381-30226-3-git-send-email-wens@csie.org> <20140916103540.GF9948@lukather> Reply-To: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Tu8ztk+XgTAiG9Id" Return-path: Content-Disposition: inline In-Reply-To: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Chen-Yu Tsai Cc: Vinod Koul , Dan Williams , Grant Likely , Rob Herring , linux-arm-kernel , linux-sunxi , dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree List-Id: devicetree@vger.kernel.org --Tu8ztk+XgTAiG9Id Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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 =3D 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 :) >=20 > 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 --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --Tu8ztk+XgTAiG9Id Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUGa78AAoJEBx+YmzsjxAgAYoP/iT+1ghRVNp19AojA8I6dkW9 eiDmStZe056B22M7Vw8wnbQFv5Khz44ZoKt25AakUDhpB0WWkWRhRwJ+8oQTmjSF oq5B7JqP4Z8hBdEy3oxQQtWOEtVEUEUbdcmiBV5ENve2/6RkH3WCQYaGEFVgJY63 GMnHRrEwNM6tt/Ju4xqDN7SPra0fBOiCfMcF46Q9MwuVhM2tCF2sKYxwHCPC+Mur s3MM9evDnVRUDR2HT9FIUkB1Ee14b0AgXBmsU+7A16AHQ6xkl3ZELlQDvBl85S+p FG3kTGVA6dsCUITlcBMKbqFEgvgO+Nr7YJwlsz8GxkiSpzpg/fQkHJ6QGjJUZrzt e1OMg2cwWrUkLmdxI0boR9Uo3vfKtU4Vkr7ed/YMzyoxLTVbmrlGmr/ipHZ+8+rb xlmCbwDbtleWqisjDBf71SDpDUIQaCrNmnsVbEyb0Oz5Jj7k6hLhBhD2E6TzZrET pFABoGdSZ5a6MaH7M7gviO3PKpZ/hqoSfNLZbM/g4S/39hdU7ihIZ8+i7ddXaRUQ +SXZ/OcOW3bCIhl7Aa8XN8/UiumdF1KDvBfc5ZJ2uvo8ufttXB3G38tiGtcQsEam eLFW+XvZyt0J+9OIu+wPLGz+gSrsYaS7ffiydaPIedZZjnjsZ50rLSRmkl9AjB25 lM9svwtMO544di1mGHsn =xCUB -----END PGP SIGNATURE----- --Tu8ztk+XgTAiG9Id--