From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suravee Suthikulpanit Subject: Re: [PATCH V2 0/4] PCI: ACPI: Setting up DMA coherency for PCI device from _CCA attribute Date: Wed, 26 Aug 2015 09:36:28 +0700 Message-ID: <55DD262C.3010008@amd.com> References: <1440524009-5359-1-git-send-email-Suravee.Suthikulpanit@amd.com> <240091906.Gl2z931jjW@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <240091906.Gl2z931jjW@wuerfel> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Arnd Bergmann , linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, will.deacon@arm.com, linux-acpi@vger.kernel.org, hanjun.guo@linaro.org, linux-pci@vger.kernel.org, bhelgaas@google.com, lenb@kernel.org List-Id: linux-acpi@vger.kernel.org Hi Arnd, On 8/26/15 01:48, Arnd Bergmann wrote: > On Wednesday 26 August 2015 00:33:25 Suravee Suthikulpanit wrote: >> This patch adds support to setup DMA coherency for PCI device using >> the ACPI _CCA attribute. According to the ACPI spec, the _CCA attribute >> is required for ARM64. Therefore, this patch is a pre-req for ACPI PCI >> support for ARM64 which is currently in development. >> >> Also, this should not affect other architectures that does not define >> CONFIG_ACPI_CCA_REQUIRED, since the default value is coherent. >> > > We only support ACPI on SBSA compliant platforms, and SBSA mandates > cache-coherent PCI, so I don't think this is actually needed, > just use coherent all the time and do WARN_ON(!CCA) to catch people > that try to incorrectly use ACPI on a non-SBSA platform. > > Arnd Thanks for pointing out. The CONFIG_ACPI_CCA_REQUIRED is already existed and selected in arch/arm64/Kconfig, and used for both PCI and non-PCI devices. I am not adding anything specific for the PCI case. Although, I think WARN_ON(!CCA) when it is required is a good idea. I'll find a proper place for it. Thanks, Suravee. > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH V2 0/4] PCI: ACPI: Setting up DMA coherency for PCI device from _CCA attribute To: Arnd Bergmann , References: <1440524009-5359-1-git-send-email-Suravee.Suthikulpanit@amd.com> <240091906.Gl2z931jjW@wuerfel> CC: , , , , , , , , From: Suravee Suthikulpanit Message-ID: <55DD262C.3010008@amd.com> Date: Wed, 26 Aug 2015 09:36:28 +0700 MIME-Version: 1.0 In-Reply-To: <240091906.Gl2z931jjW@wuerfel> Content-Type: text/plain; charset="windows-1252"; format=flowed Sender: linux-acpi-owner@vger.kernel.org List-ID: Hi Arnd, On 8/26/15 01:48, Arnd Bergmann wrote: > On Wednesday 26 August 2015 00:33:25 Suravee Suthikulpanit wrote: >> This patch adds support to setup DMA coherency for PCI device using >> the ACPI _CCA attribute. According to the ACPI spec, the _CCA attribute >> is required for ARM64. Therefore, this patch is a pre-req for ACPI PCI >> support for ARM64 which is currently in development. >> >> Also, this should not affect other architectures that does not define >> CONFIG_ACPI_CCA_REQUIRED, since the default value is coherent. >> > > We only support ACPI on SBSA compliant platforms, and SBSA mandates > cache-coherent PCI, so I don't think this is actually needed, > just use coherent all the time and do WARN_ON(!CCA) to catch people > that try to incorrectly use ACPI on a non-SBSA platform. > > Arnd Thanks for pointing out. The CONFIG_ACPI_CCA_REQUIRED is already existed and selected in arch/arm64/Kconfig, and used for both PCI and non-PCI devices. I am not adding anything specific for the PCI case. Although, I think WARN_ON(!CCA) when it is required is a good idea. I'll find a proper place for it. Thanks, Suravee. > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suravee.Suthikulpanit@amd.com (Suravee Suthikulpanit) Date: Wed, 26 Aug 2015 09:36:28 +0700 Subject: [PATCH V2 0/4] PCI: ACPI: Setting up DMA coherency for PCI device from _CCA attribute In-Reply-To: <240091906.Gl2z931jjW@wuerfel> References: <1440524009-5359-1-git-send-email-Suravee.Suthikulpanit@amd.com> <240091906.Gl2z931jjW@wuerfel> Message-ID: <55DD262C.3010008@amd.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Arnd, On 8/26/15 01:48, Arnd Bergmann wrote: > On Wednesday 26 August 2015 00:33:25 Suravee Suthikulpanit wrote: >> This patch adds support to setup DMA coherency for PCI device using >> the ACPI _CCA attribute. According to the ACPI spec, the _CCA attribute >> is required for ARM64. Therefore, this patch is a pre-req for ACPI PCI >> support for ARM64 which is currently in development. >> >> Also, this should not affect other architectures that does not define >> CONFIG_ACPI_CCA_REQUIRED, since the default value is coherent. >> > > We only support ACPI on SBSA compliant platforms, and SBSA mandates > cache-coherent PCI, so I don't think this is actually needed, > just use coherent all the time and do WARN_ON(!CCA) to catch people > that try to incorrectly use ACPI on a non-SBSA platform. > > Arnd Thanks for pointing out. The CONFIG_ACPI_CCA_REQUIRED is already existed and selected in arch/arm64/Kconfig, and used for both PCI and non-PCI devices. I am not adding anything specific for the PCI case. Although, I think WARN_ON(!CCA) when it is required is a good idea. I'll find a proper place for it. Thanks, Suravee. > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >