uio_pci_generic_sva.c

  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
 14struct 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
 21static irqreturn_t irq_handler(int irq, struct uio_info *dev_info)
 22{
 23	return IRQ_HANDLED;
 24}
 25
 26static 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
 50static 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
 62static 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
139out_free:
140	kfree(udev);
141out_disable:
142	pci_disable_device(pdev);
143
144	return ret;
145}
146
147static 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
156static 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}
164static DEVICE_ATTR_RO(pasid);
165
166static struct attribute *uio_pci_sva_attrs[] = {
167	&dev_attr_pasid.attr,
168	NULL
169};
170
171static const struct attribute_group uio_pci_sva_attr_group = {
172	.attrs = uio_pci_sva_attrs,
173};
174
175static const struct attribute_group *uio_pci_sva_attr_groups[] = {
176	&uio_pci_sva_attr_group,
177	NULL
178};
179
180static 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
188module_pci_driver(uio_pci_generic_sva_driver);
189MODULE_VERSION("0.0.01");
190MODULE_LICENSE("GPL v2");
191MODULE_AUTHOR("Yaxing Guo <guoyaxing@bosc.ac.cn>");
192MODULE_DESCRIPTION("Generic UIO sva driver for PCI");