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[66.90.144.107]) by smtp.gmail.com with ESMTPSA id 3-20020a4a1b03000000b00441c26f8fadsm723780oop.12.2022.09.08.15.32.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Sep 2022 15:32:48 -0700 (PDT) Received: (nullmailer pid 3461521 invoked by uid 1000); Thu, 08 Sep 2022 22:32:47 -0000 Date: Thu, 8 Sep 2022 17:32:47 -0500 From: Rob Herring To: Thierry Reding Cc: Joerg Roedel , Will Deacon , Robin Murphy , Nicolin Chen , Krishna Reddy , Dmitry Osipenko , Alyssa Rosenzweig , Janne Grunau , Sameer Pujar , devicetree@vger.kernel.org, iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org, asahi@lists.linux.dev Subject: Re: [PATCH v8 1/5] dt-bindings: reserved-memory: Document iommu-addresses Message-ID: <20220908223247.GA3448766-robh@kernel.org> References: <20220905170833.396892-1-thierry.reding@gmail.com> <20220905170833.396892-2-thierry.reding@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220905170833.396892-2-thierry.reding@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On Mon, Sep 05, 2022 at 07:08:29PM +0200, Thierry Reding wrote: > From: Thierry Reding > > This adds the "iommu-addresses" property to reserved-memory nodes, which > allow describing the interaction of memory regions with IOMMUs. Two use- > cases are supported: > > 1. Static mappings can be described by pairing the "iommu-addresses" > property with a "reg" property. This is mostly useful for adopting > firmware-allocated buffers via identity mappings. One common use- > case where this is required is if early firmware or bootloaders > have set up a bootsplash framebuffer that a display controller is > actively scanning out from during the operating system boot > process. > > 2. If an "iommu-addresses" property exists without a "reg" property, > the reserved-memory node describes an IOVA reservation. Such memory > regions are excluded from the IOVA space available to operating > system drivers and can be used for regions that must not be used to > map arbitrary buffers. > > Each mapping or reservation is tied to a specific device via a phandle > to the device's device tree node. This allows a reserved-memory region > to be reused across multiple devices. > > Signed-off-by: Thierry Reding > --- > Changes in v8: > - include validation warning fixes that had crept into an unrelated patch > > Changes in v7: > - keep reserved-memory.txt to avoid broken references > > Changes in v6: > - add device phandle to iommu-addresses property in examples > - remove now unused dt-bindings/reserved-memory.h header > > .../reserved-memory/reserved-memory.yaml | 70 +++++++++++++++++++ > 1 file changed, 70 insertions(+) Thanks for being persistent with this. It looks good to me. Reviewed-by: Rob Herring I really don't like new common bindings with only 1 user, so I hope the Asahi folks chime in here. Or really anyone else look at it. Rob