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[2603:6081:7b01:cbda:2ef0:5dff:fedb:a8ba]) by smtp.gmail.com with ESMTPSA id y66-20020a37af45000000b0067dc0fc539fsm21064038qke.86.2022.04.12.05.01.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Apr 2022 05:01:08 -0700 (PDT) Date: Tue, 12 Apr 2022 08:01:06 -0400 From: Tom Rini To: Abdellatif El Khlifi , rob.herring@arm.com Cc: u-boot@lists.denx.de, vishnu.banavath@arm.com, xueliang.zhong@arm.com, nd@arm.com, rui.silva@linaro.org Subject: Re: [PATCH 0/6] introduce Arm FF-A support Message-ID: <20220412120106.GH14282@bill-the-cat> References: <20220329151659.16894-1-abdellatif.elkhlifi@arm.com> <20220406194711.GN14282@bill-the-cat> <20220407125424.GA32742@e121910.cambridge.arm.com> <20220407125811.GO14282@bill-the-cat> <20220412114315.GA18372@e121910.cambridge.arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="42reXr+7zTeC9EGk" Content-Disposition: inline In-Reply-To: <20220412114315.GA18372@e121910.cambridge.arm.com> X-Clacks-Overhead: GNU Terry Pratchett X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.39 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" X-Virus-Scanned: clamav-milter 0.103.5 at phobos.denx.de X-Virus-Status: Clean --42reXr+7zTeC9EGk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 12, 2022 at 12:43:15PM +0100, Abdellatif El Khlifi wrote: > On Thu, Apr 07, 2022 at 08:58:11AM -0400, Tom Rini wrote: > > On Thu, Apr 07, 2022 at 01:54:24PM +0100, Abdellatif El Khlifi wrote: > > > On Wed, Apr 06, 2022 at 03:47:11PM -0400, Tom Rini wrote: > > > > On Tue, Mar 29, 2022 at 04:16:53PM +0100, abdellatif.elkhlifi@arm.c= om wrote: > > > > > From: Abdellatif El Khlifi > > > > >=20 > > > > > This patchset adds support for Arm FF-A (Arm Firmware Framework f= or Armv8-A v1.0). > > > > >=20 > > > > > FF-A support is generic by design and can be used by any Arm plat= form. > > > > >=20 > > > > > The features added are as follows: > > > > > =20 > > > > > 1/ FF-A device driver > > > > > 2/ armffa command > > > > > 3/ FF-A Sandbox driver > > > > > 4/ FF-A Sandbox test cases > > > > > 5/ FF-A MM communication > > > > >=20 > > > > >=20 > > > > > The suggested design sees FF-A as a data bus allowing data exchan= ge with the firmware > > > > > running under TrustZone HW (such as Optee). The same approach was= followed in the > > > > > FF-A driver in Linux kernel (https://git.kernel.org/pub/scm/linux= /kernel/git/torvalds/linux.git/tree/drivers/firmware/arm_ffa/bus.c?h=3Dv5.1= 5#n211)) > > > > >=20 > > > > > u-boot boards using FF-A can provide a device tree node in a -u-boot.dtsi file. > > > > > Since the node can not be hosted in Linux device tree, we suggest= using u-boot device tree. > > > >=20 > > > > Why can't the node be in the upstream tree? It should be, so that = it > > > > can be shared between all users. Especially since there's in-Linux > > > > users? > > > >=20 > > > > --=20 > > > > Tom > > >=20 > > > Linux already has an FF-A bus driver and doesn't use a device tree no= de for FF-A. > > >=20 > > > The Linux driver registers FF-A as a bus: > > >=20 > > > int arm_ffa_bus_init(void) > > > { > > > return bus_register(&ffa_bus_type); > > > } > > >=20 > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tr= ee/drivers/firmware/arm_ffa/bus.c?h=3Dv5.15#n211 > > >=20 > > > So, there is no user for the node in Linux. That's why we suggest hos= ting the node in the u-boot device tree (a u-boot.dtsi file) > >=20 > > OK, but you can still push it upstream as it's not required to have an > > in tree user. >=20 > During the review of Corstone-1000 patchset, Rui Silva had a discussion w= ith the Linux device tree maintainer > (Rob Herring). Rob is not in favour of an FFA node in the kernel device t= ree. This is why we are including the FFA node > in u-boot device tree (u-boot.dtsi files). I'm a bit confused now, can you please link to the kernel thread? Or Rob, can you chime in here please? --=20 Tom --42reXr+7zTeC9EGk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQGzBAABCgAdFiEEGjx/cOCPqxcHgJu/FHw5/5Y0tywFAmJVagIACgkQFHw5/5Y0 tyyf4gwAkR9mETDfBhQbL2sqXecoB+avMukg70PvC9L+YTB/iqIcoeEsxswojzp1 gWhMt83L2exyvW+icabApDZFTfizpGS7L15y9XGgRm91ybdjaZQmFgS7PHfaIEKX eOFBAvkJHXyH3VmjgMS6pABK1RlXO8NcYPQ8bb1FwjFtoPtMqGTO9ggXGvUhaUCf WQ+5Z673YvE7kKCwqtWjOTV/VtfCwk3WP+G1iCMBU+OZoTnu2hmal+4GHvNekOGm LtXqlXPfye4L2eCo+NViVRRkr1K6W0TatP5C6PWEhI5ZCgC52FHdJe4cvOe3zQu4 f1p1fmgYM8Mg6KCU5rzOh1XlMRnlHZ81jRxpXNOLsfMDcYM/Vj5L6AVbx2PAdEgO 5YffVsucmu39cWXHwwOPk0kdpsbL5b5v+JhoXv8ILcQfBFr/XJex+ElyMwtHS1nG SOPrCuI4TS3b4R/4O930etNGCueWO7kSop36q2fwgrS+RKvhlrzel8BaDgjQbH0/ 4IuEiX6y =oGOz -----END PGP SIGNATURE----- --42reXr+7zTeC9EGk--