From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [linux-sunxi] Re: [PATCH 2/7] dt-bindings: add binding for the Allwinner A64 DE2 bus Date: Tue, 27 Mar 2018 10:11:31 +0200 Message-ID: <20180327081131.hd652vkhohez2hcc@flea> References: <20180316175354.21437-1-icenowy@aosc.io> <20180320184646.dynqv6qubzabroe4@flea> <2866474.lRHIcLtROC@jernej-laptop> <9520BDDE-BFE3-4220-B48D-01A00CFA94DE@aosc.io> <20180326222258.uxpgj4bk4pg56b7o@rob-hp-laptop> <9A6A8961-D45C-4033-962E-83CCE8F01651@aosc.io> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="l7cgdzalfbw6gs6o" Return-path: Content-Disposition: inline In-Reply-To: <9A6A8961-D45C-4033-962E-83CCE8F01651@aosc.io> Sender: linux-kernel-owner@vger.kernel.org To: Icenowy Zheng Cc: linux-arm-kernel@lists.infradead.org, Rob Herring , devicetree@vger.kernel.org, jernej.skrabec@siol.net, linux-sunxi@googlegroups.com, linux-kernel@vger.kernel.org, Chen-Yu Tsai , linux-clk@vger.kernel.org List-Id: devicetree@vger.kernel.org --l7cgdzalfbw6gs6o Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 27, 2018 at 07:31:18AM +0800, Icenowy Zheng wrote: >=20 >=20 > =E4=BA=8E 2018=E5=B9=B43=E6=9C=8827=E6=97=A5 GMT+08:00 =E4=B8=8A=E5=8D=88= 6:22:58, Rob Herring =E5=86=99=E5=88=B0: > >On Thu, Mar 22, 2018 at 02:08:43PM +0800, Icenowy Zheng wrote: > >>=20 > >>=20 > >> =E4=BA=8E 2018=E5=B9=B43=E6=9C=8822=E6=97=A5 GMT+08:00 =E4=B8=8A=E5=8D= =881:13:42, "Jernej =C5=A0krabec" > > =E5=86=99=E5=88=B0: > >> >Hi all, > >> > > >> >Dne sreda, 21. marec 2018 ob 03:18:13 CET je Icenowy Zheng > >napisal(a): > >> >> =E4=BA=8E 2018=E5=B9=B43=E6=9C=8821=E6=97=A5 GMT+08:00 =E4=B8=8A=E5= =8D=882:46:46, Maxime Ripard > >> >=20 > >> >=E5=86=99=E5=88=B0: > >> >> >On Sat, Mar 17, 2018 at 01:53:49AM +0800, Icenowy Zheng wrote: > >> >> >> All the sub-blocks of Allwinner A64 DE2 needs the SRAM C on A64 > >> >SoC > >> >> > > >> >> >to > >> >> > > >> >> >> be claimed, otherwise the whole DE2 space is inaccessible. > >> >> >>=20 > >> >> >> Add a device tree binding of the DE2 part as a sub-bus. > >> >> > > >> >> >Where did you get the info that it was a bus? > >> >>=20 > >> >> There's no direct evidence, just some guess. > >> >>=20 > >> >> The DE2 is a whole part that is just allocated a memory > >> >> space at the user manual, and the SRAM controls the > >> >> access to all modules in the DE2. > >> >>=20 > >> >> So it might be a bus. > >> >>=20 > >> >> Implement it as a bus is a clear representation on A64. > >> > > >> >Since there is already syscon for same mmio region, we migh as well > >use > >> >it=20 > >> >when loading ccu-sun8i-de2 driver on A64. > >> > > >> >Other options, like SRAM driver or bus driver, might better > >represent > >> >HW, but=20 > >>=20 > >> I think the device tree should properly represent the HW, > >> it's a basic requirment. > >>=20 > >> >then we would have two DT nodes covering same mmio region, which I > >> >think is=20 > >> >not really acceptable. > >>=20 > >> It's acceptable, and DE2 is not the only user of SRAM controller so > >far. > > > >No, it's not acceptable. Don't create overlapping mmio regions in DT. >=20 > Then should the SRAM controller driver be configured to take the syscon? We could have a single DT node that would export a syscon yes, just like you did for the R40 ethernet case. I'm not sure the SRAM controller itself needs to take the syscon, it just can export its own. Maxime --=20 Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com --l7cgdzalfbw6gs6o Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAlq5/LIACgkQ0rTAlCFN r3Rqsg//bcROXUQWqCJ3N0cm6teljACF1FqkqeO/94ZIlcYMMP30HYKZ+jFU8j8n /mp/Mm6pE1X5YT0Jkf0WXeFP0ns9xlF0aNTITEVZ45w682EFqUgOIrxB0vsJTndv dYmPpIO9Rb9I5sA04umttMTh1undUL8g90Gy3uDBktcI12C81Bge7ebgbdfOM/Zt S08zg/Z5JD5OrF7ojggNKnJUg+hSDTAB/zB7URAIj8fuNlP5TMdEkZRV1LdHrZtd 2Bz2uwprH8CdoeG/5Jm33cwtYximXvGtFPRkz2f2EAWICYPVTJuQA7QpZ8T8j0hB Kwkc+MruItlgPk/3CIGLOjYqR1181OU4N1FpwOhfGvXtNv+UhmReUwbhqJGCopBy leO8XTUq3G1w/X3xgLSTPCUe47akV2EAkAGMWBoOf4bopVkHE8Th4OV0mpo3ntjl KZJvWjGpPv3O61m3Rqw5ZEFxtO7t9xPiR/Ix4iif8lrZaWRMqVbuBQknwS7+oJbf ilm2+MJkZfN8rZ6RsjNYgpQVkJ5cScdf7n3iJ1ziGQX592OZfjzQORMMusvrJBhX Rusk68z8Ge8ZKrgZ92pB5k/PYFniUlSjBjzHMXUjKnJKDY5BR94c7k7n3G8qJS4p Zgl+H4c42Q2TIX4esUklJNcBCkzb1gXsVv5YGGVePlksP6FoiEg= =yP6i -----END PGP SIGNATURE----- --l7cgdzalfbw6gs6o--