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
irq_handler(int irq,struct uio_info * dev_info)21 static irqreturn_t irq_handler(int irq, struct uio_info *dev_info)
22 {
23 return IRQ_HANDLED;
24 }
25
uio_pci_sva_open(struct uio_info * info,struct inode * inode)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
uio_pci_sva_release(struct uio_info * info,struct inode * inode)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
probe(struct pci_dev * pdev,const struct pci_device_id * id)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
remove(struct pci_dev * pdev)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
pasid_show(struct device * dev,struct device_attribute * attr,char * buf)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