From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8CEB41419BC for ; Tue, 30 Apr 2024 10:22:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714472569; cv=none; b=uHxVIh74zdbwht5O8eDvw8adrPlw6/9EnzE0aEcpM63tNb3eucLWiejqb1O5nVNxAzvTza8JaYGAFKGn23aEu9UAlIqjLAnfkzr7QKadEB+kgwFtN4vKlf8qX4JFLq1YXi0607v6bPIh/7/0RCUBtUa9bBOQ5sdBxIMmn0BWkBE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714472569; c=relaxed/simple; bh=krf2c1GkUobPI6NrzHHAPV2pd3geJngPoEGsQX9XiYg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Cal1xZLlaE5Bu1S9T9BCJUt7uMjB6V9j2WpzxoW3OyStDqQkNXbUwe8il4VjrXFVJZcBRr+uloOflqzRAxyo0cf3Es4rs4INNvwvWdy7S69ljVUzdmWwAJYhQ77U/V96uguT2iTFVWkv1uQUQ70SQCasSVQhTFu21nYtUlZz77g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 74FE71480 for ; Tue, 30 Apr 2024 03:23:14 -0700 (PDT) Received: from e110455-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C02603F73F for ; Tue, 30 Apr 2024 03:22:47 -0700 (PDT) Date: Tue, 30 Apr 2024 11:22:29 +0100 From: Liviu Dudau To: Jean-Philippe Brucker Cc: will@kernel.org, lpieralisi@kernel.org, kw@linux.com, robh@kernel.org, bhelgaas@google.com, krzk+dt@kernel.org, conor+dt@kernel.org, sudeep.holla@arm.com, joro@8bytes.org, robin.murphy@arm.com, nicolinc@nvidia.com, ketanp@nvidia.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, devicetree@vger.kernel.org Subject: Re: [PATCH 1/3] dt-bindings: PCI: generic: Add ats-supported property Message-ID: References: <20240429113938.192706-2-jean-philippe@linaro.org> <20240429113938.192706-3-jean-philippe@linaro.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240429113938.192706-3-jean-philippe@linaro.org> On Mon, Apr 29, 2024 at 12:39:37PM +0100, Jean-Philippe Brucker wrote: > Add a way for firmware to tell the OS that ATS is supported by the PCI > root complex. An endpoint with ATS enabled may send Translation Requests > and Translated Memory Requests, which look just like Normal Memory > Requests with a non-zero AT field. So a root controller that ignores the > AT field may simply forward the request to the IOMMU as a Normal Memory > Request, which could end badly. In any case, the endpoint will be > unusable. > > The ats-supported property allows the OS to only enable ATS in endpoints > if the root controller can handle ATS requests. Only add the property to > pcie-host-ecam-generic for the moment. For non-generic root controllers, > availability of ATS can be inferred from the compatible string. > > Signed-off-by: Jean-Philippe Brucker > Reviewed-by: Rob Herring Reviewed-by: Liviu Dudau > --- > From a while ago: https://lore.kernel.org/all/20200219222454.GA16221@bogus/ > --- > Documentation/devicetree/bindings/pci/host-generic-pci.yaml | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pci/host-generic-pci.yaml b/Documentation/devicetree/bindings/pci/host-generic-pci.yaml > index d25423aa71674..94d4a4914a483 100644 > --- a/Documentation/devicetree/bindings/pci/host-generic-pci.yaml > +++ b/Documentation/devicetree/bindings/pci/host-generic-pci.yaml > @@ -110,6 +110,12 @@ properties: > iommu-map-mask: true > msi-parent: true > > + ats-supported: > + description: > + Indicates that a PCIe host controller supports ATS, and can handle Memory > + Requests with Address Type (AT). > + type: boolean > + > required: > - compatible > - reg > -- > 2.44.0 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯