From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH v3 2/2] ARM: dts: tegra20: Add video decoder node Date: Thu, 12 Oct 2017 15:25:43 +0200 Message-ID: <20171012132543.GB4453@ulmo> References: <0b6150a7-5b2b-ca4d-eb34-b6614e4833df@mentor.com> <81f39096-dc66-c98b-50f6-fc81ee1804ec@gmail.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4779250832270834947==" Return-path: In-Reply-To: <81f39096-dc66-c98b-50f6-fc81ee1804ec@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: Dmitry Osipenko Cc: devel@driverdev.osuosl.org, devicetree@vger.kernel.org, Stephen Warren , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Jonathan Hunter , Rob Herring , Dan Carpenter , linux-tegra@vger.kernel.org, Mauro Carvalho Chehab , Vladimir Zapolskiy , linux-media@vger.kernel.org List-Id: devicetree@vger.kernel.org --===============4779250832270834947== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="yNb1oOkm5a9FJOVX" Content-Disposition: inline --yNb1oOkm5a9FJOVX Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 12, 2017 at 03:06:17PM +0300, Dmitry Osipenko wrote: > Hello Vladimir, >=20 > On 12.10.2017 10:43, Vladimir Zapolskiy wrote: > > Hello Dmitry, > >=20 > > On 10/11/2017 11:08 PM, Dmitry Osipenko wrote: > >> Add a device node for the video decoder engine found on Tegra20. > >> > >> Signed-off-by: Dmitry Osipenko > >> --- > >> arch/arm/boot/dts/tegra20.dtsi | 17 +++++++++++++++++ > >> 1 file changed, 17 insertions(+) > >> > >> diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra2= 0.dtsi > >> index 7c85f97f72ea..1b5d54b6c0cb 100644 > >> --- a/arch/arm/boot/dts/tegra20.dtsi > >> +++ b/arch/arm/boot/dts/tegra20.dtsi > >> @@ -249,6 +249,23 @@ > >> */ > >> }; > >> =20 > >> + vde@6001a000 { > >> + compatible =3D "nvidia,tegra20-vde"; > >> + reg =3D <0x6001a000 0x3D00 /* VDE registers */ > >> + 0x40000400 0x3FC00>; /* IRAM region */ > >=20 > > this notation of a used region in IRAM is non-standard and potentially = it > > may lead to conflicts for IRAM resource between users. > >=20 > > My proposal is to add a valid device tree node to describe an IRAM regi= on > > firstly, then reserve a subregion in it by using a new "iram" property. > >=20 >=20 > The defined in DT IRAM region used by VDE isn't exactly correct, actually= it > should be much smaller. I don't know exactly what parts of IRAM VDE uses,= for > now it is just safer to assign the rest of the IRAM region to VDE. >=20 > I'm not sure whether it really worthy to use a dynamic allocator for a si= ngle > static allocation, but maybe it would come handy later.. Stephen / Jon / > Thierry, what do you think? This sounds like a good idea. I agree that this currently doesn't seem to be warranted, but consider what would happen if at some point we have more devices requiring access to the IRAM. Spreading individual reg properties all across the DT will make it very difficult to ensure they don't overlap. Presumably the mmio-sram driver will check that pool don't overlap. Or even if it doesn't it will make it a lot easier to verify because it's all in the same DT node and then consumers only reference it. I like Vladimir's proposal. I also suspect that Rob may want us to stick to a standardized way referencing such external memory. Thierry --yNb1oOkm5a9FJOVX Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlnfbVQACgkQ3SOs138+ s6FmFw//eCUI+ej3kBZD7m/m/3cwRQX4TiDocDMffTFJGiZU6zpL0cY2g7aMQmrv 9nRYO8rwx9oJ8iWd+XxO73xS8DR/RPWzhGdyOgi3fN9rFSR7BxMW8lFmBoNfeYH1 BKLeBj4Trp41uaI0x8mtvEnRi2D5ibjuu242eidL41hclHBdPkNyTu0K+tMgQ+C2 nFR9Ekyw7w8xTA78pR/1d3q8FM/xIv1EhgMRBIzxeT9gtcwUdHsWI54p6U1v9gPK fzDDa/g9PrA8lLZrkKzoDMfo4gErUSaJQCgnyMyrBr+CAk5D/AkLh0Gch4qpVbkC 1ihjIXddoxVq1Y+I5Pxt9hvUc1ZgCxzRs8xnN5Sv8TNybi4/ef7sbw65qKclIw86 HBHfV8gZMppaWnoZhdy+JJ5pMjh9JuS6dCiZ34/FNwT9ZST+ZRvqovSlXw75ykmh pA5wv0EMlPAitO90IFujcpVAzWhxwZz/59STtp9AdZxWms1yDJIGcLNbGOH2G3Uo hl7EOtj4Jk9llGQ/MDxJr8RkdLxO6XZUVQBhUUlPhMPb5erh83GdDzNRRbKGcx9o WbM2octIDEI1HD4qGjo+2aqyNxFH5rsYieGEe5LRPfvXBExnI5fFC5+CM/gafg68 Djuk0EOryL9YsMKBXpnEjjelsTGX8Stwb+XikXhaEZEvt4XMzxk= =4ebh -----END PGP SIGNATURE----- --yNb1oOkm5a9FJOVX-- --===============4779250832270834947== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel --===============4779250832270834947==--