From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CCDC0D272 for ; Fri, 13 Oct 2023 07:41:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jCfzTnfS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA431C433C7; Fri, 13 Oct 2023 07:41:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697182876; bh=HCwC6BY1bb24e17Bl+yq4xWJAW4Po3ldTzp38IgTEq4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jCfzTnfSPNpr8oHgUrMAWWnGod72/w0SFUhRryo5wbDOeG76rzR9TMuDoQ2Sad0hP /j71x4Nhiuaz6uiC8BwRiTh5/TE6HuK+cT6suCUjlZ3JHWFA0Ma7vnSANFyuFDANaw feIEzFicz9B/+sM24DE+X12K8tAMgUpenuZINmyQkg46K2qmdUAft2WB84uHs/3hfE mLAITV3d5wU9XT33C2qGpePlAaR81pj4iInfmIBp+VHm4UYM1wdGKmpVaYeAqbtwk5 LUPUm9uYj2HD/MlLl9A4Dr8alOYiy8u/HbxvCWmFnn+saMX4Vz4APGkZt1ZnMA+t6f kWz7+6MPDP24A== Date: Fri, 13 Oct 2023 08:41:10 +0100 From: Conor Dooley To: Anup Patel Cc: Palmer Dabbelt , Paul Walmsley , Thomas Gleixner , Marc Zyngier , Rob Herring , Krzysztof Kozlowski , Frank Rowand , Conor Dooley , Atish Patra , Andrew Jones , Sunil V L , Saravana Kannan , Anup Patel , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Conor Dooley , Krzysztof Kozlowski Subject: Re: [PATCH v10 07/15] dt-bindings: interrupt-controller: Add RISC-V incoming MSI controller Message-ID: <20231013-pluck-skies-1b4ee57e770c@spud> References: <20231003044403.1974628-1-apatel@ventanamicro.com> <20231003044403.1974628-8-apatel@ventanamicro.com> <20231012-countable-darkish-7e449edc763d@spud> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="SpvMUTlv7MvkLw0D" Content-Disposition: inline In-Reply-To: --SpvMUTlv7MvkLw0D Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hey Anup, On Fri, Oct 13, 2023 at 12:16:45PM +0530, Anup Patel wrote: > On Thu, Oct 12, 2023 at 10:05=E2=80=AFPM Conor Dooley = wrote: > > On Tue, Oct 03, 2023 at 10:13:55AM +0530, Anup Patel wrote: > > > We add DT bindings document for the RISC-V incoming MSI controller > > > (IMSIC) defined by the RISC-V advanced interrupt architecture (AIA) > > > specification. > > > > > > Signed-off-by: Anup Patel > > > Reviewed-by: Conor Dooley > > > > Just FYI, since they'll reply to this themselves, but some of the > > Microchip folks have run into problems with sparse hart indexes while > > trying to use the imsic binding to describe some configurations they > > have. I think there were also so problems with how to describe to a > > linux guest which file to use, when the first hart available to the > > guest does not use the first file. They'll do a better job of describing > > their problems than I will, so I shall leave it to them! >=20 > Quoting AIA spec: > "For the purpose of locating the memory pages of interrupt files in the > address space, assume each hart (or each hart within a group) has a > unique hart number that may or may not be related to the unique hart > identifiers (=E2=80=9Chart IDs=E2=80=9D) that the RISC-V Privileged Archi= tecture assigns > to harts." >=20 > It is very easy to get confused between the AIA "hart index" and > "hart IDs" defined by the RISC-V Privileged specification but these > are two very different things. The AIA "hart index" over here is the > bits in the address of an IMSIC file. >=20 > This DT binding follows the IMSIC file arrangement in the address > space as defined by the section "3.6 Arrangement of the memory > regions of multiple interrupt files" of the AIA specification. This > arrangement is MANDATORY for platforms having both APLIC > and IMSIC because in MSI-mode the APLIC generates target > MSI address based the IMSIC file arrangement described in the > section "3.6 Arrangement of the memory regions of multiple > interrupt files". In fact, this also applies to virtual platforms > created by hypervisors (KVM, Xen, ...) Thanks for pointing this out - I'll pass it on and hopefully it is helpful to them. If not, I expect that you'll hear :) Cheers, Conor. --SpvMUTlv7MvkLw0D Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZSj0lgAKCRB4tDGHoIJi 0npGAQC6rGsNEsyvptpG1+5wrE9ET1h1yjmigGMA1ot+EgTHewD/eQHPUyx/z1tG Jx0CDrTp0SXbanOo3/If7opBTzOB5Qc= =owzU -----END PGP SIGNATURE----- --SpvMUTlv7MvkLw0D--