1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * UIO PCI Express sva driver 4 * 5 * Copyright (c) 2025 Beijing Institute of Open Source Chip (BOSC) 6 */ 7 8 #include <linux/device.h> 9 #include <linux/module.h> 10 #include <linux/pci.h> 11 #include <linux/uio_driver.h> 12 #include <linux/iommu.h> 13 14 struct uio_pci_sva_dev { 15 struct pci_dev *pdev; 16 struct uio_info info; 17 struct iommu_sva *sva_handle; 18 int pasid; 19 }; 20 21 static irqreturn_t irq_handler(int irq, struct uio_info *dev_info) 22 { 23 return IRQ_HANDLED; 24 } 25 26 static int uio_pci_sva_open(struct uio_info *info, struct inode *inode) 27 { 28 struct iommu_sva *handle; 29 struct uio_pci_sva_dev *udev = info->priv; 30 struct iommu_domain *domain; 31 32 if (!udev || !udev->pdev) 33 return -ENODEV; 34 35 domain = iommu_get_domain_for_dev(&udev->pdev->dev); 36 if (domain) 37 iommu_detach_device(domain, &udev->pdev->dev); 38 39 handle = iommu_sva_bind_device(&udev->pdev->dev, current->mm); 40 if (IS_ERR(handle)) 41 return -EINVAL; 42 43 udev->pasid = iommu_sva_get_pasid(handle); 44 45 udev->sva_handle = handle; 46 47 return 0; 48 } 49 50 static int uio_pci_sva_release(struct uio_info *info, struct inode *inode) 51 { 52 struct uio_pci_sva_dev *udev = info->priv; 53 54 if (!udev || !udev->pdev) 55 return -ENODEV; 56 57 iommu_sva_unbind_device(udev->sva_handle); 58 59 return 0; 60 } 61 62 static int probe(struct pci_dev *pdev, const struct pci_device_id *id) 63 { 64 struct uio_pci_sva_dev *udev; 65 int ret, i, irq = 0; 66 67 ret = pci_enable_device(pdev); 68 if (ret) { 69 dev_err(&pdev->dev, "pci_enable_device failed: %d\n", ret); 70 return ret; 71 } 72 73 ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)); 74 if (ret) 75 goto out_disable; 76 77 pci_set_master(pdev); 78 79 ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX | PCI_IRQ_MSI); 80 if (ret > 0) { 81 irq = pci_irq_vector(pdev, 0); 82 if (irq < 0) { 83 dev_err(&pdev->dev, "Failed to get MSI vector\n"); 84 ret = irq; 85 goto out_disable; 86 } 87 } else 88 dev_warn(&pdev->dev, 89 "No IRQ vectors available (%d), using polling\n", ret); 90 91 udev = devm_kzalloc(&pdev->dev, sizeof(struct uio_pci_sva_dev), 92 GFP_KERNEL); 93 if (!udev) { 94 ret = -ENOMEM; 95 goto out_disable; 96 } 97 98 udev->pdev = pdev; 99 udev->info.name = "uio_pci_sva"; 100 udev->info.version = "0.0.1"; 101 udev->info.open = uio_pci_sva_open; 102 udev->info.release = uio_pci_sva_release; 103 udev->info.irq = irq; 104 udev->info.handler = irq_handler; 105 udev->info.priv = udev; 106 107 for (i = 0; i < MAX_UIO_MAPS; i++) { 108 struct resource *r = &pdev->resource[i]; 109 struct uio_mem *uiomem = &udev->info.mem[i]; 110 111 if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM)) 112 continue; 113 114 if (uiomem >= &udev->info.mem[MAX_UIO_MAPS]) { 115 dev_warn(&pdev->dev, "Do not support more than %d iomem\n", 116 MAX_UIO_MAPS); 117 break; 118 } 119 120 uiomem->memtype = UIO_MEM_PHYS; 121 uiomem->addr = r->start & PAGE_MASK; 122 uiomem->offs = r->start & ~PAGE_MASK; 123 uiomem->size = 124 (uiomem->offs + resource_size(r) + PAGE_SIZE - 1) & 125 PAGE_MASK; 126 uiomem->name = r->name; 127 } 128 129 ret = devm_uio_register_device(&pdev->dev, &udev->info); 130 if (ret) { 131 dev_err(&pdev->dev, "Failed to register uio device\n"); 132 goto out_free; 133 } 134 135 pci_set_drvdata(pdev, udev); 136 137 return 0; 138 139 out_free: 140 kfree(udev); 141 out_disable: 142 pci_disable_device(pdev); 143 144 return ret; 145 } 146 147 static void remove(struct pci_dev *pdev) 148 { 149 struct uio_pci_sva_dev *udev = pci_get_drvdata(pdev); 150 151 pci_release_regions(pdev); 152 pci_disable_device(pdev); 153 kfree(udev); 154 } 155 156 static ssize_t pasid_show(struct device *dev, 157 struct device_attribute *attr, char *buf) 158 { 159 struct pci_dev *pdev = to_pci_dev(dev); 160 struct uio_pci_sva_dev *udev = pci_get_drvdata(pdev); 161 162 return sysfs_emit(buf, "%d\n", udev->pasid); 163 } 164 static DEVICE_ATTR_RO(pasid); 165 166 static struct attribute *uio_pci_sva_attrs[] = { 167 &dev_attr_pasid.attr, 168 NULL 169 }; 170 171 static const struct attribute_group uio_pci_sva_attr_group = { 172 .attrs = uio_pci_sva_attrs, 173 }; 174 175 static const struct attribute_group *uio_pci_sva_attr_groups[] = { 176 &uio_pci_sva_attr_group, 177 NULL 178 }; 179 180 static struct pci_driver uio_pci_generic_sva_driver = { 181 .name = "uio_pci_sva", 182 .dev_groups = uio_pci_sva_attr_groups, 183 .id_table = NULL, 184 .probe = probe, 185 .remove = remove, 186 }; 187 188 module_pci_driver(uio_pci_generic_sva_driver); 189 MODULE_VERSION("0.0.01"); 190 MODULE_LICENSE("GPL v2"); 191 MODULE_AUTHOR("Yaxing Guo <guoyaxing@bosc.ac.cn>"); 192 MODULE_DESCRIPTION("Generic UIO sva driver for PCI"); 193