From 8f68f8e28298abdf518648e794c71e534eb8841c Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 15 Jul 2014 11:27:08 +0100 Subject: [PATCH] iommu/arm-smmu: add support for multi-master iommu groups Whilst the driver currently creates one IOMMU group per device, this will soon change when we start supporting non-transparent PCI bridges which require all upstream masters to be assigned to the same address space. This patch reworks our IOMMU group code so that we can easily support multi-master groups. The master configuration (streamids and smrs) is stored as private iommudata on the group, whilst the low-level attach/detach code is updated to avoid double alloc/free when dealing with multiple masters sharing the same SMMU configuration. This unifies device handling, regardless of whether the device sits on the platform or pci bus. Signed-off-by: Will Deacon --- drivers/iommu/arm-smmu.c | 65 ++++++++++++++++++++++++---------------- 1 file changed, 39 insertions(+), 26 deletions(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 958ae8194afe..38f8d670afb3 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -431,17 +431,17 @@ static void parse_driver_options(struct arm_smmu_device *smmu) } while (arm_smmu_options[++i].opt); } -static struct device *dev_get_master_dev(struct device *dev) +static struct device_node *dev_get_dev_node(struct device *dev) { if (dev_is_pci(dev)) { struct pci_bus *bus = to_pci_dev(dev)->bus; while (!pci_is_root_bus(bus)) bus = bus->parent; - return bus->bridge->parent; + return bus->bridge->parent->of_node; } - return dev; + return dev->of_node; } static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu, @@ -466,15 +466,17 @@ static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu, } static struct arm_smmu_master_cfg * -find_smmu_master_cfg(struct arm_smmu_device *smmu, struct device *dev) +find_smmu_master_cfg(struct device *dev) { - struct arm_smmu_master *master; + struct arm_smmu_master_cfg *cfg = NULL; + struct iommu_group *group = iommu_group_get(dev); - if (dev_is_pci(dev)) - return dev->archdata.iommu; + if (group) { + cfg = iommu_group_get_iommudata(group); + iommu_group_put(group); + } - master = find_smmu_master(smmu, dev->of_node); - return master ? &master->cfg : NULL; + return cfg; } static int insert_smmu_master(struct arm_smmu_device *smmu, @@ -550,7 +552,7 @@ static struct arm_smmu_device *find_smmu_for_device(struct device *dev) { struct arm_smmu_device *smmu; struct arm_smmu_master *master = NULL; - struct device_node *dev_node = dev_get_master_dev(dev)->of_node; + struct device_node *dev_node = dev_get_dev_node(dev); spin_lock(&arm_smmu_devices_lock); list_for_each_entry(smmu, &arm_smmu_devices, list) { @@ -1156,9 +1158,10 @@ static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain, struct arm_smmu_device *smmu = smmu_domain->smmu; void __iomem *gr0_base = ARM_SMMU_GR0(smmu); + /* Devices in an IOMMU group may already be configured */ ret = arm_smmu_master_configure_smrs(smmu, cfg); if (ret) - return ret; + return ret == -EEXIST ? 0 : ret; for (i = 0; i < cfg->num_streamids; ++i) { u32 idx, s2cr; @@ -1179,6 +1182,10 @@ static void arm_smmu_domain_remove_master(struct arm_smmu_domain *smmu_domain, struct arm_smmu_device *smmu = smmu_domain->smmu; void __iomem *gr0_base = ARM_SMMU_GR0(smmu); + /* An IOMMU group is torn down by the first device to be removed */ + if ((smmu->features & ARM_SMMU_FEAT_STREAM_MATCH) && !cfg->smrs) + return; + /* * We *must* clear the S2CR first, because freeing the SMR means * that it can be re-allocated immediately. @@ -1200,7 +1207,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) struct arm_smmu_device *smmu, *dom_smmu; struct arm_smmu_master_cfg *cfg; - smmu = dev_get_master_dev(dev)->archdata.iommu; + smmu = find_smmu_for_device(dev); if (!smmu) { dev_err(dev, "cannot attach to SMMU, is it on the same bus?\n"); return -ENXIO; @@ -1228,7 +1235,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) } /* Looks ok, so add the device to the domain */ - cfg = find_smmu_master_cfg(smmu_domain->smmu, dev); + cfg = find_smmu_master_cfg(dev); if (!cfg) return -ENODEV; @@ -1240,7 +1247,7 @@ static void arm_smmu_detach_dev(struct iommu_domain *domain, struct device *dev) struct arm_smmu_domain *smmu_domain = domain->priv; struct arm_smmu_master_cfg *cfg; - cfg = find_smmu_master_cfg(smmu_domain->smmu, dev); + cfg = find_smmu_master_cfg(dev); if (cfg) arm_smmu_domain_remove_master(smmu_domain, cfg); } @@ -1554,17 +1561,19 @@ static int __arm_smmu_get_pci_sid(struct pci_dev *pdev, u16 alias, void *data) return 0; /* Continue walking */ } +static void __arm_smmu_release_pci_iommudata(void *data) +{ + kfree(data); +} + static int arm_smmu_add_device(struct device *dev) { struct arm_smmu_device *smmu; + struct arm_smmu_master_cfg *cfg; struct iommu_group *group; + void (*releasefn)(void *) = NULL; int ret; - if (dev->archdata.iommu) { - dev_warn(dev, "IOMMU driver already assigned to device\n"); - return -EINVAL; - } - smmu = find_smmu_for_device(dev); if (!smmu) return -ENODEV; @@ -1576,7 +1585,6 @@ static int arm_smmu_add_device(struct device *dev) } 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); @@ -1592,11 +1600,20 @@ static int arm_smmu_add_device(struct device *dev) */ pci_for_each_dma_alias(pdev, __arm_smmu_get_pci_sid, &cfg->streamids[0]); - dev->archdata.iommu = cfg; + releasefn = __arm_smmu_release_pci_iommudata; } else { - dev->archdata.iommu = smmu; + struct arm_smmu_master *master; + + master = find_smmu_master(smmu, dev->of_node); + if (!master) { + ret = -ENODEV; + goto out_put_group; + } + + cfg = &master->cfg; } + iommu_group_set_iommudata(group, cfg, releasefn); ret = iommu_group_add_device(group, dev); out_put_group: @@ -1606,10 +1623,6 @@ out_put_group: static void arm_smmu_remove_device(struct device *dev) { - if (dev_is_pci(dev)) - kfree(dev->archdata.iommu); - - dev->archdata.iommu = NULL; iommu_group_remove_device(dev); }