Hi Will, > -----Original Message----- > From: Will Deacon [mailto:will.dea...@arm.com] > Sent: Wednesday, July 09, 2014 6:57 PM > To: Sethi Varun-B16395; alex.william...@redhat.com > Cc: linux-arm-ker...@lists.infradead.org; iommu@lists.linux- > foundation.org; thierry.red...@gmail.com; a...@arndb.de; > ohau...@codeaurora.org; j...@8bytes.org; > a.mota...@virtualopensystems.com; Marc Zyngier > Subject: Re: [PATCH 2/5] iommu/arm-smmu: add support for PCI master > devices > > [Adding Alex; question below] > > On Thu, Jul 03, 2014 at 03:22:37PM +0100, Varun Sethi wrote: > > > +static int __arm_smmu_get_pci_sid(struct pci_dev *pdev, u16 alias, > > > +void > > > +*data) { > > > + *((u16 *)data) = alias; > > > + return 0; /* Continue walking */ } > > [...] > > > > @@ -1598,15 +1642,36 @@ static int arm_smmu_add_device(struct device > > > *dev) > > > return PTR_ERR(group); > > > } > > > > > > + if (dev_is_pci(dev)) { > > > + struct arm_smmu_master_cfg *cfg; > > > + struct pci_dev *pdev = to_pci_dev(dev); > > > + > > > + cfg = kzalloc(sizeof(*cfg), GFP_KERNEL); > > > + if (!cfg) { > > > + ret = -ENOMEM; > > > + goto out_put_group; > > > + } > > > + > > > + cfg->num_streamids = 1; > > > + pci_for_each_dma_alias(pdev, __arm_smmu_get_pci_sid, > > > + &cfg->streamids[0]); > > [Sethi Varun-B16395] We need to look for upstream DMA device. We > > should be using pci_find_dma_isolation_root here. Also, this would > > also imply that there could be multiple devices sharing the same > > stream ID. So, we should check if a particular stream ID value has > > already been configured in the SMR registers. > > pci_find_dma_isolation_root doesn't exist in any of the trees I have. > Alex, is this queued anywhere and do I actually need it? > > The purpose of this code is to find the requester ID of a device as it > appears at the host controller. At this point, we can map it (via > firmware tables that are TBD) to a Stream ID for the SMMU. It looks to me > like pci_for_each_dma_alias walks over non-transparent PCI bridges > correctly, so the callback I provide just updates the alias until the > walk has completed. I think pci_for_each_dma_alias should work fine here. Isolation would be specifically required while setting up the iommu groups.
-Varun _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
