From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v3 1/7] dt-bindings: interconnect: Add a dma interconnect name Date: Thu, 7 Mar 2019 16:47:55 +0100 Message-ID: <20190307154755.5kgc7oh4b5bhg2fj@flea> References: <43eeca13733faefe62f9facc25b8e88f7e593f61.1549897336.git-series.maxime.ripard@bootlin.com> <553c987c-da9a-1f85-fb16-4b9fe17dd14b@linaro.org> <20190305155337.glfvgyddvnkv774m@flea> <0e72fbf7-b100-ddc5-3c19-32f71c37f76f@arm.com> <477995b0-9ac3-b6ca-f5f2-856e4af926f1@linaro.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1786291021==" Return-path: Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 673B16E2F3 for ; Thu, 7 Mar 2019 15:47:59 +0000 (UTC) In-Reply-To: <477995b0-9ac3-b6ca-f5f2-856e4af926f1@linaro.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Georgi Djakov Cc: Mark Rutland , devicetree@vger.kernel.org, Thomas Petazzoni , Arnd Bergmann , Robin Murphy , dri-devel@lists.freedesktop.org, Paul Kocialkowski , Chen-Yu Tsai , Rob Herring , Yong Deng , Frank Rowand , Dave Martin , linux-arm-kernel@lists.infradead.org List-Id: dri-devel@lists.freedesktop.org --===============1786291021== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="5pwrr5aoove3hn6w" Content-Disposition: inline --5pwrr5aoove3hn6w Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 07, 2019 at 05:15:20PM +0200, Georgi Djakov wrote: > Hi, >=20 > On 3/5/19 18:14, Robin Murphy wrote: > > On 05/03/2019 15:53, Maxime Ripard wrote: > >> Hi, > >> > >> On Fri, Mar 01, 2019 at 07:48:15PM +0200, Georgi Djakov wrote: > >>> On 2/11/19 17:02, Maxime Ripard wrote: > >>>> The current DT bindings assume that the DMA will be performed by the > >>>> devices through their parent DT node, and rely on that assumption > >>>> for the > >>>> address translation using dma-ranges. > >>>> > >>>> However, some SoCs have devices that will perform DMA through > >>>> another bus, > >>>> with separate address translation rules. We therefore need to > >>>> express that > >>>> relationship, through the special interconnect name "dma". > >>>> > >>>> Signed-off-by: Maxime Ripard > >>>> --- > >>>> =A0 Documentation/devicetree/bindings/interconnect/interconnect.txt | > >>>> 3 +++ > >>>> =A0 1 file changed, 3 insertions(+) > >>>> > >>>> diff --git > >>>> a/Documentation/devicetree/bindings/interconnect/interconnect.txt > >>>> b/Documentation/devicetree/bindings/interconnect/interconnect.txt > >>>> index 5a3c575b387a..e69fc2d992c3 100644 > >>>> --- a/Documentation/devicetree/bindings/interconnect/interconnect.txt > >>>> +++ b/Documentation/devicetree/bindings/interconnect/interconnect.txt > >>>> @@ -51,6 +51,9 @@ interconnect-names : List of interconnect path > >>>> name strings sorted in the same > >>>> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 interconnect-names to mat= ch interconnect paths with > >>>> interconnect > >>>> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 specifier pairs. > >>>> =A0 +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 Re= served interconnect names: > >>>> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0 * dma: Path from the device to the main > >>>> memory of the system > >>> > >>> Bikeshed: As it's from the device to the main memory, maybe here we c= an > >>> also denote this my calling the path dma-mem or dma-memory. For other > >>> paths, we are trying to mention both the source and the destination a= nd > >>> maybe it would be good to be consistent although this is special one. > >> > >> I'm not sure I understand what you mean. You'd like two interconnect > >> names, one called dma-memory, and one memory-dma? > >=20 > > Hmm, yes, it's not like "dma" describes an actual source or destination > > either :/ >=20 > IIUC, it's a path (bus) that a dma device use to access some memory > (read or/and write). So i have used source-destination above more in the > sense of initiator-target or master-slave. My suggestion was just to > change the reserved interconnect name from "dma" to "dma-mem" or > "dma-memory". If dma is an issue in itself, maybe we can call it "device-memory" ? Maxime --=20 Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --5pwrr5aoove3hn6w Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXIE9KwAKCRDj7w1vZxhR xaLPAP97G3Gb2gq5LO0FvcRpl2j4snXLX7412+cYlkBa71I/oAD/YKCBpiqzTVGQ C7R1CnHQKyFoNDJhh+gnvnOCUSH9cgI= =/Ya7 -----END PGP SIGNATURE----- --5pwrr5aoove3hn6w-- --===============1786291021== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVs --===============1786291021==--