smmu 学习笔记之初始化

2019-11-07 23:43:49

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在使能了ACPI的情况下，会调用acpi_smmu_v3_init来初始化#ifdef CONFIG_ACPIstatic int __init acpi_smmu_v3_init(struct acpi_table_header *table){ if (iort_node_match(ACPI_IORT_NODE_SMMU_V3)) return arm_smmu_init(); return 0;}IORT_ACPI_DECLARE(arm_smmu_v3, ACPI_SIG_IORT, acpi_smmu_v3_init);#endif在acpi_smmu_v3_init 中首先调用iort_node_match来能否找到匹配的ACPI_IORT_NODE_SMMU_V3bool iort_node_match(u8 type){ struct acpi_iort_node *node; node = iort_scan_node(type, iort_match_type_callback, NULL); return node != NULL;}可见如果node 不是NULL 就返回true，也就是找到了ACPI_IORT_NODE_SMMU_V3static struct acpi_iort_node *iort_scan_node(enum acpi_iort_node_type type, iort_find_node_callback callback, void *context){ struct acpi_iort_node *iort_node, *iort_end; struct acpi_table_iort *iort; int i; if (!iort_table) return NULL; /* Get the first IORT node */ iort = (struct acpi_table_iort *)iort_table; iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort, iort->node_offset); iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort_table, iort_table->length); for (i = 0; i < iort->node_count; i++) { if (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND, "IORT node pointer overflows, bad table!/n")) return NULL; if (iort_node->type == type && ACPI_SUCCESS(callback(iort_node, context))) return iort_node; iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node, iort_node->length); } return NULL;}在iort_scan_node 中首先得到iort的起始和结束 iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort, iort->node_offset); iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort_table, iort_table->length);然后通过for循环遍历这段memory，然后找到iort_node->type 是否等于ACPI_IORT_NODE_SMMU_V3，如果等于的话，就调用callback.这个callbackstatic acpi_statusiort_match_type_callback(struct acpi_iort_node *node, void *context){ return AE_OK;}仅仅是返回ok而已。如果iort_node_match 返回非NULL的话，就调用arm_smmu_initstatic struct platform_driver arm_smmu_driver = { .driver = { .name = "arm-smmu-v3", .of_match_table = of_match_ptr(arm_smmu_of_match), }, .PRobe = arm_smmu_device_probe, .remove = arm_smmu_device_remove,};static int __init arm_smmu_init(void){ static bool registered; int ret = 0; if (!registered) { ret = platform_driver_register(&arm_smmu_driver); registered = !ret; } return ret;}arm_smmu_init 调用platform_driver_register 注册driver，因为ACPI已经注册device了，然后就调用arm_smmu_device_probestatic int arm_smmu_device_probe(struct platform_device *pdev){ int irq, ret; struct resource *res; struct arm_smmu_device *smmu; struct device *dev = &pdev->dev; bool bypass; smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL); if (!smmu) { dev_err(dev, "failed to allocate arm_smmu_device/n"); return -ENOMEM; } smmu->dev = dev; /* Base address */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (resource_size(res) + 1 < SZ_128K) { dev_err(dev, "MMIO region too small (%pr)/n", res); return -EINVAL; } smmu->base = devm_ioremap_resource(dev, res); if (IS_ERR(smmu->base)) return PTR_ERR(smmu->base); /* Interrupt lines */ irq = platform_get_irq_byname(pdev, "eventq"); if (irq > 0) smmu->evtq.q.irq = irq; irq = platform_get_irq_byname(pdev, "priq"); if (irq > 0) smmu->priq.q.irq = irq; irq = platform_get_irq_byname(pdev, "cmdq-sync"); if (irq > 0) smmu->cmdq.q.irq = irq; irq = platform_get_irq_byname(pdev, "gerror"); if (irq > 0) smmu->gerr_irq = irq; if (dev->of_node) ret = arm_smmu_device_dt_probe(pdev, smmu, &bypass); else ret = arm_smmu_device_acpi_probe(pdev, smmu, &bypass); if (ret) return ret; /* Probe the h/w */ ret = arm_smmu_device_hw_probe(smmu); if (ret) return ret; /* Initialise in-memory data structures */ ret = arm_smmu_init_structures(smmu); if (ret) return ret; /* Record our private device structure */ platform_set_drvdata(pdev, smmu); /* Reset the device */ ret = arm_smmu_device_reset(smmu, bypass); if (ret) return ret; /* And we're up. Go go go! */ fwnode_iommu_set_ops(dev->fwnode, &arm_smmu_ops);#ifdef CONFIG_PCI if (pci_bus_type.iommu_ops != &arm_smmu_ops) { pci_request_acs(); ret = bus_set_iommu(&pci_bus_type, &arm_smmu_ops); if (ret) return ret; }#endif#ifdef CONFIG_ARM_AMBA if (amba_bustype.iommu_ops != &arm_smmu_ops) { ret = bus_set_iommu(&amba_bustype, &arm_smmu_ops); if (ret) return ret; }#endif if (platform_bus_type.iommu_ops != &arm_smmu_ops) { ret = bus_set_iommu(&platform_bus_type, &arm_smmu_ops); if (ret) return ret; } return 0;}首先申请arm_smmu_device 的空间 smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL); if (!smmu) { dev_err(dev, "failed to allocate arm_smmu_device/n"); return -ENOMEM; }然后就得到四个中断号 irq = platform_get_irq_byname(pdev, "eventq"); if (irq > 0) smmu->evtq.q.irq = irq; irq = platform_get_irq_byname(pdev, "priq"); if (irq > 0) smmu->priq.q.irq = irq; irq = platform_get_irq_byname(pdev, "cmdq-sync"); if (irq > 0) smmu->cmdq.q.irq = irq; irq = platform_get_irq_byname(pdev, "gerror"); if (irq > 0) smmu->gerr_irq = irq;由于我们是APCI 模式，所以dev->of_node为null，因此调用arm_smmu_device_acpi_probestatic int arm_smmu_device_acpi_probe(struct platform_device *pdev, struct arm_smmu_device *smmu, bool *bypass){ struct acpi_iort_smmu_v3 *iort_smmu; struct device *dev = smmu->dev; struct acpi_iort_node *node; node = *(struct acpi_iort_node **)dev_get_platdata(dev); /* Retrieve SMMUv3 specific data */ iort_smmu = (struct acpi_iort_smmu_v3 *)node->node_data; if (iort_smmu->flags & ACPI_IORT_SMMU_V3_COHACC_OVERRIDE) smmu->features |= ARM_SMMU_FEAT_COHERENCY; *bypass = false; return 0;}arm_smmu_device_acpi_probe 只是判定是否有enable ACPI_IORT_SMMU_V3_COHACC_OVERRIDE 这个feature而已。arm_smmu_device_hw_probe 函数也是判断是否有enable相关hw，有的话，就置位相关flag。arm_smmu_init_structures 中有分两个函数初始化static int arm_smmu_init_structures(struct arm_smmu_device *smmu){ int ret; ret = arm_smmu_init_queues(smmu); if (ret) return ret; return arm_smmu_init_strtab(smmu);}static int arm_smmu_init_queues(struct arm_smmu_device *smmu){ int ret; /* cmdq */ spin_lock_init(&smmu->cmdq.lock); ret = arm_smmu_init_one_queue(smmu, &smmu->cmdq.q, ARM_SMMU_CMDQ_PROD, ARM_SMMU_CMDQ_CONS, CMDQ_ENT_DWordS); if (ret) return ret; /* evtq */ ret = arm_smmu_init_one_queue(smmu, &smmu->evtq.q, ARM_SMMU_EVTQ_PROD, ARM_SMMU_EVTQ_CONS, EVTQ_ENT_DWORDS); if (ret) return ret; /* priq */ if (!(smmu->features & ARM_SMMU_FEAT_PRI)) return 0; return arm_smmu_init_one_queue(smmu, &smmu->priq.q, ARM_SMMU_PRIQ_PROD, ARM_SMMU_PRIQ_CONS, PRIQ_ENT_DWORDS);}arm_smmu_init_queues 中主要是调用arm_smmu_init_one_queue 来填充cmdq/evtq/priq 这三个数据结构.arm_smmu_init_strtab 中也是根据ARM_SMMU_FEAT_2_LVL_STRTAB 来判断是用arm_smmu_init_strtab_2lvl 还是 arm_smmu_init_strtab_linear ，这两个函数都填充相关结构体。fwnode_iommu_set_ops 则是申请iommu_fwentry 结构，其中iommu_fwentry中的一项就代表iommu操作的ops，然后将iommu_fwentry 保存到iommu_fwentry_list中.最后分别初始化三个总线，pci_bus_type/amba_bustype/platform_bus_type

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