From: "Liviu.Dudau@arm.com" <Liviu.Dudau@arm.com> To: Phil Edworthy <phil.edworthy@renesas.com> Cc: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, Bjorn Helgaas <bhelgaas@google.com>, Arnd Bergmann <arnd@arndb.de>, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, Magnus <magnus.damm@gmail.com> Subject: Re: PCIe host controller behind IOMMU on ARM Date: Wed, 4 Nov 2015 14:24:13 +0000 [thread overview] Message-ID: <20151104142412.GS963@e106497-lin.cambridge.arm.com> (raw) In-Reply-To: <PS1PR06MB11807CBE8EB2AC6B0158D2B5F52A0@PS1PR06MB1180.apcprd06.prod.outlook.com> On Wed, Nov 04, 2015 at 01:57:48PM +0000, Phil Edworthy wrote: > Hi, > > I am trying to hook up a PCIe host controller that sits behind an IOMMU, > but having some problems. > > I'm using the pcie-rcar PCIe host controller and it works fine without > the IOMMU, and I can attach the IOMMU to the controller such that any calls > to dma_alloc_coherent made by the controller driver uses the iommu_ops > version of dma_ops. > > However, I can't see how to make the endpoints to utilise the dma_ops that > the controller uses. Shouldn't the endpoints inherit the dma_ops from the > controller? No, not directly. > Any pointers for this? You need to understand the process through which a driver for endpoint get an address to be passed down to the device. Have a look at Documentation/DMA-API-HOWTO.txt, there is a nice explanation there. (Hint: EP driver needs to call dma_map_single). Also, you need to make sure that the bus address that ends up being set into the endpoint gets translated correctly by the host controller into an address that the IOMMU can then translate into physical address. Best regards, Liviu > > Thanks > Phil > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯
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From: Liviu.Dudau@arm.com (Liviu.Dudau at arm.com) To: linux-arm-kernel@lists.infradead.org Subject: PCIe host controller behind IOMMU on ARM Date: Wed, 4 Nov 2015 14:24:13 +0000 [thread overview] Message-ID: <20151104142412.GS963@e106497-lin.cambridge.arm.com> (raw) In-Reply-To: <PS1PR06MB11807CBE8EB2AC6B0158D2B5F52A0@PS1PR06MB1180.apcprd06.prod.outlook.com> On Wed, Nov 04, 2015 at 01:57:48PM +0000, Phil Edworthy wrote: > Hi, > > I am trying to hook up a PCIe host controller that sits behind an IOMMU, > but having some problems. > > I'm using the pcie-rcar PCIe host controller and it works fine without > the IOMMU, and I can attach the IOMMU to the controller such that any calls > to dma_alloc_coherent made by the controller driver uses the iommu_ops > version of dma_ops. > > However, I can't see how to make the endpoints to utilise the dma_ops that > the controller uses. Shouldn't the endpoints inherit the dma_ops from the > controller? No, not directly. > Any pointers for this? You need to understand the process through which a driver for endpoint get an address to be passed down to the device. Have a look at Documentation/DMA-API-HOWTO.txt, there is a nice explanation there. (Hint: EP driver needs to call dma_map_single). Also, you need to make sure that the bus address that ends up being set into the endpoint gets translated correctly by the host controller into an address that the IOMMU can then translate into physical address. Best regards, Liviu > > Thanks > Phil > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ?\_(?)_/?
next prev parent reply other threads:[~2015-11-04 14:24 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-11-04 13:57 PCIe host controller behind IOMMU on ARM Phil Edworthy 2015-11-04 13:57 ` Phil Edworthy 2015-11-04 13:57 ` Phil Edworthy 2015-11-04 14:24 ` Liviu.Dudau [this message] 2015-11-04 14:24 ` Liviu.Dudau at arm.com 2015-11-04 14:24 ` Liviu.Dudau 2015-11-04 14:48 ` Phil Edworthy 2015-11-04 14:48 ` Phil Edworthy 2015-11-04 14:48 ` Phil Edworthy 2015-11-04 15:01 ` Liviu.Dudau 2015-11-04 15:01 ` Liviu.Dudau at arm.com 2015-11-04 15:01 ` Liviu.Dudau 2015-11-04 15:19 ` Phil Edworthy 2015-11-04 15:19 ` Phil Edworthy 2015-11-04 15:19 ` Phil Edworthy 2015-11-04 15:30 ` Will Deacon 2015-11-04 15:30 ` Will Deacon 2015-11-04 15:30 ` Will Deacon 2015-11-04 18:02 ` Phil Edworthy 2015-11-04 18:02 ` Phil Edworthy 2015-11-04 18:02 ` Phil Edworthy 2015-11-09 12:32 ` Phil Edworthy 2015-11-09 12:32 ` Phil Edworthy 2015-11-09 12:32 ` Phil Edworthy 2015-11-11 18:24 ` Liviu.Dudau 2015-11-11 18:24 ` Liviu.Dudau at arm.com 2015-11-11 18:24 ` Liviu.Dudau 2015-11-11 20:22 ` Arnd Bergmann 2015-11-11 20:22 ` Arnd Bergmann 2015-11-11 20:22 ` Arnd Bergmann 2015-11-12 9:26 ` Phil Edworthy 2015-11-12 9:26 ` Phil Edworthy 2015-11-12 9:26 ` Phil Edworthy 2015-11-12 9:49 ` Arnd Bergmann 2015-11-12 9:49 ` Arnd Bergmann 2015-11-12 15:33 ` Phil Edworthy 2015-11-12 15:33 ` Phil Edworthy 2015-11-12 15:33 ` Phil Edworthy 2015-11-12 16:16 ` Arnd Bergmann 2015-11-12 16:16 ` Arnd Bergmann 2015-11-12 16:16 ` Arnd Bergmann 2015-11-13 13:03 ` Phil Edworthy 2015-11-13 13:03 ` Phil Edworthy 2015-11-13 13:03 ` Phil Edworthy 2015-11-13 13:59 ` Arnd Bergmann 2015-11-13 13:59 ` Arnd Bergmann 2015-11-13 14:11 ` Phil Edworthy 2015-11-13 14:11 ` Phil Edworthy 2015-11-13 14:11 ` Phil Edworthy 2015-11-12 10:32 ` Liviu.Dudau 2015-11-12 10:32 ` Liviu.Dudau at arm.com 2015-11-12 10:32 ` Liviu.Dudau
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