Support auxiliary domains for arm-smmu-v2 to initialize and support multiple pagetables for a single SMMU context bank. Since the smmu-v2 hardware doesn't have any built in support for switching the pagetable base it is left as an exercise to the caller to actually use the pagetable; aux domains in the IOMMU driver are only preoccupied with creating and managing the pagetable memory.
Following is a pseudo code example of how a domain can be created /* Check to see if aux domains are supported */ if (iommu_dev_has_feature(dev, IOMMU_DEV_FEAT_AUX)) { iommu = iommu_domain_alloc(...); if (iommu_aux_attach_device(domain, dev)) return FAIL; /* Save the base address of the pagetable for use by the driver iommu_domain_get_attr(domain, DOMAIN_ATTR_PTBASE, &ptbase); } Then 'domain' can be used like any other iommu domain to map and unmap iova addresses in the pagetable. The driver/hardware is used to switch the pagetable according to its own specific implementation. v3: Trivial update to reflect new pgtable ops situation Signed-off-by: Jordan Crouse <jcro...@codeaurora.org> --- drivers/iommu/arm-smmu.c | 125 +++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 110 insertions(+), 15 deletions(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 33e6928..589da47 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -262,6 +262,8 @@ struct arm_smmu_domain { spinlock_t cb_lock; /* Serialises ATS1* ops and TLB syncs */ u32 attributes; struct iommu_domain domain; + bool is_aux; + u64 ttbr0; }; struct arm_smmu_option_prop { @@ -803,6 +805,12 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S2)) smmu_domain->stage = ARM_SMMU_DOMAIN_S1; + /* Aux domains can only be created for stage-1 tables */ + if (smmu_domain->is_aux && smmu_domain->stage != ARM_SMMU_DOMAIN_S1) { + ret = -EINVAL; + goto out_unlock; + } + /* * Choosing a suitable context format is even more fiddly. Until we * grow some way for the caller to express a preference, and/or move @@ -850,6 +858,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, ias = min(ias, 32UL); oas = min(oas, 32UL); } + smmu_domain->tlb_ops = &arm_smmu_s1_tlb_ops; break; case ARM_SMMU_DOMAIN_NESTED: @@ -869,6 +878,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, ias = min(ias, 40UL); oas = min(oas, 40UL); } + if (smmu->version == ARM_SMMU_V2) smmu_domain->tlb_ops = &arm_smmu_s2_tlb_ops_v2; else @@ -878,23 +888,30 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, ret = -EINVAL; goto out_unlock; } - ret = __arm_smmu_alloc_bitmap(smmu->context_map, start, - smmu->num_context_banks); - if (ret < 0) - goto out_unlock; - cfg->cbndx = ret; - if (smmu->version < ARM_SMMU_V2) { - cfg->irptndx = atomic_inc_return(&smmu->irptndx); - cfg->irptndx %= smmu->num_context_irqs; - } else { - cfg->irptndx = cfg->cbndx; - } + /* + * Aux domains will use the same context bank assigned to the master + * domain for the device + */ + if (!smmu_domain->is_aux) { + ret = __arm_smmu_alloc_bitmap(smmu->context_map, start, + smmu->num_context_banks); + if (ret < 0) + goto out_unlock; - if (smmu_domain->stage == ARM_SMMU_DOMAIN_S2) - cfg->vmid = cfg->cbndx + 1 + smmu->cavium_id_base; - else - cfg->asid = cfg->cbndx + smmu->cavium_id_base; + cfg->cbndx = ret; + if (smmu->version < ARM_SMMU_V2) { + cfg->irptndx = atomic_inc_return(&smmu->irptndx); + cfg->irptndx %= smmu->num_context_irqs; + } else { + cfg->irptndx = cfg->cbndx; + } + + if (smmu_domain->stage == ARM_SMMU_DOMAIN_S2) + cfg->vmid = cfg->cbndx + 1 + smmu->cavium_id_base; + else + cfg->asid = cfg->cbndx + smmu->cavium_id_base; + } pgtbl_cfg = (struct io_pgtable_cfg) { .pgsize_bitmap = smmu->pgsize_bitmap, @@ -917,11 +934,21 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, goto out_clear_smmu; } + /* Cache the TTBR0 for the aux domain */ + smmu_domain->ttbr0 = pgtbl_cfg.arm_lpae_s1_cfg.ttbr[0]; + /* Update the domain's page sizes to reflect the page table format */ domain->pgsize_bitmap = pgtbl_cfg.pgsize_bitmap; domain->geometry.aperture_end = (1UL << ias) - 1; domain->geometry.force_aperture = true; + /* + * aux domains don't use split tables or program the hardware so we're + * done setting it up + */ + if (smmu_domain->is_aux) + goto out; + /* Initialise the context bank with our page table cfg */ arm_smmu_init_context_bank(smmu_domain, &pgtbl_cfg); arm_smmu_write_context_bank(smmu, cfg->cbndx); @@ -939,6 +966,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, cfg->irptndx = INVALID_IRPTNDX; } +out: mutex_unlock(&smmu_domain->init_mutex); /* Publish page table ops for map/unmap */ @@ -962,6 +990,12 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) if (!smmu || domain->type == IOMMU_DOMAIN_IDENTITY) return; + /* All we need to do for aux devices is destroy the pagetable */ + if (smmu_domain->is_aux) { + free_io_pgtable_ops(smmu_domain->pgtbl_ops); + return; + } + ret = arm_smmu_rpm_get(smmu); if (ret < 0) return; @@ -1242,14 +1276,17 @@ static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain, struct arm_smmu_client_match_data { bool direct_mapping; + bool allow_aux_domain; }; static const struct arm_smmu_client_match_data qcom_adreno = { .direct_mapping = true, + .allow_aux_domain = true, }; static const struct arm_smmu_client_match_data qcom_mdss = { .direct_mapping = true, + .allow_aux_domain = false, }; static const struct of_device_id arm_smmu_client_of_match[] = { @@ -1269,6 +1306,55 @@ arm_smmu_client_data(struct device *dev) return match ? match->data : NULL; } +static bool arm_smmu_supports_aux(struct device *dev) +{ + const struct arm_smmu_client_match_data *data = + arm_smmu_client_data(dev); + + return (data && data->allow_aux_domain); +} + +static bool arm_smmu_dev_has_feat(struct device *dev, + enum iommu_dev_features feat) +{ + if (feat != IOMMU_DEV_FEAT_AUX) + return false; + + return arm_smmu_supports_aux(dev); +} + +static int arm_smmu_dev_enable_feat(struct device *dev, + enum iommu_dev_features feat) +{ + /* If supported aux domain support is always "on" */ + if (feat == IOMMU_DEV_FEAT_AUX && arm_smmu_supports_aux(dev)) + return 0; + + return -ENODEV; +} + +static int arm_smmu_dev_disable_feat(struct device *dev, + enum iommu_dev_features feat) +{ + return -EBUSY; +} + +/* Set up a new aux domain and create a new pagetable with the same + * characteristics as the master + */ +static int arm_smmu_aux_attach_dev(struct iommu_domain *domain, + struct device *dev) +{ + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); + struct arm_smmu_device *smmu = fwspec_smmu(fwspec); + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); + + smmu_domain->is_aux = true; + + /* No power is needed because aux domain doesn't touch the hardware */ + return arm_smmu_init_domain_context(domain, smmu); +} + static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) { int ret; @@ -1631,6 +1717,11 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain, *(int *)data = !!(smmu_domain->attributes & (1 << DOMAIN_ATTR_SPLIT_TABLES)); return 0; + case DOMAIN_ATTR_PTBASE: + if (!smmu_domain->is_aux) + return -ENODEV; + *((u64 *)data) = smmu_domain->ttbr0; + return 0; default: return -ENODEV; } @@ -1741,7 +1832,11 @@ static struct iommu_ops arm_smmu_ops = { .capable = arm_smmu_capable, .domain_alloc = arm_smmu_domain_alloc, .domain_free = arm_smmu_domain_free, + .dev_has_feat = arm_smmu_dev_has_feat, + .dev_enable_feat = arm_smmu_dev_enable_feat, + .dev_disable_feat = arm_smmu_dev_disable_feat, .attach_dev = arm_smmu_attach_dev, + .aux_attach_dev = arm_smmu_aux_attach_dev, .map = arm_smmu_map, .unmap = arm_smmu_unmap, .flush_iotlb_all = arm_smmu_flush_iotlb_all, -- 2.7.4 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu