From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH v2 4/7] iommu/of: Handle iommu-map property for PCI Date: Wed, 15 Jun 2016 12:21:27 +0100 Message-ID: <57613A37.6080600@arm.com> References: <69952eda726c370ed6e5739bdd2e32cdc4466bfb.1464966939.git.robin.murphy@arm.com> <20160614144559.GK19407@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160614144559.GK19407-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Will Deacon Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On 14/06/16 15:45, Will Deacon wrote: > On Fri, Jun 03, 2016 at 06:15:39PM +0100, Robin Murphy wrote: >> Now that we have a way to pick up the RID translation and target IOMMU, >> hook up of_iommu_configure() to bring PCI devices into the of_xlate >> mechanism and allow them IOMMU-backed DMA ops without the need for >> driver-specific handling. >> >> CC: Rob Herring >> CC: Frank Rowand >> Signed-off-by: Robin Murphy >> --- >> >> v2: Skip disabled IOMMUs. >> >> drivers/iommu/of_iommu.c | 44 +++++++++++++++++++++++++++++++++++++------- >> 1 file changed, 37 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c >> index 662f9a600f4f..5716131199b3 100644 >> --- a/drivers/iommu/of_iommu.c >> +++ b/drivers/iommu/of_iommu.c >> @@ -22,6 +22,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> static const struct of_device_id __iommu_of_table_sentinel >> @@ -134,20 +135,49 @@ const struct iommu_ops *of_iommu_get_ops(struct device_node *np) >> return ops; >> } >> >> +static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data) >> +{ >> + struct of_phandle_args *iommu_spec = data; >> + >> + iommu_spec->args[0] = alias; >> + return iommu_spec->np == pdev->bus->dev.of_node; >> +} >> + >> const struct iommu_ops *of_iommu_configure(struct device *dev, >> struct device_node *master_np) >> { >> struct of_phandle_args iommu_spec; >> - struct device_node *np; >> + struct device_node *np = NULL; >> const struct iommu_ops *ops = NULL; >> int idx; >> >> - /* >> - * We can't do much for PCI devices without knowing how >> - * device IDs are wired up from the PCI bus to the IOMMU. >> - */ >> - if (dev_is_pci(dev)) >> - return NULL; >> + if (dev_is_pci(dev)) { >> + /* >> + * Start by tracing the RID alias down the PCI topology as >> + * far as the host bridge whose OF node we have... >> + */ >> + iommu_spec.np = master_np; >> + pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid, >> + &iommu_spec); >> + /* >> + * ...then find out what that becomes once it escapes the PCI >> + * bus into the system beyond, and which IOMMU it ends up at. >> + */ >> + if (of_pci_map_rid(master_np, "iommu-map", iommu_spec.args[0], >> + &np, iommu_spec.args) || >> + !of_device_is_available(np)) >> + return NULL; > > Hmm, do we need to of_node_put(np) in the case that it's not available? Ah yes, now I see; I moved the put into the loop iteration for the non-PCI case so that a "continue" does the job, but I've not handled the equivalent here. Robin. > > Will >