1 // SPDX-License-Identifier: GPL-2.0
2 /* uio_pci_generic - generic UIO driver for PCI 2.3 devices
3 *
4 * Copyright (C) 2009 Red Hat, Inc.
5 * Author: Michael S. Tsirkin <mst@redhat.com>
6 *
7 * Since the driver does not declare any device ids, you must allocate
8 * id and bind the device to the driver yourself. For example:
9 *
10 * # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
11 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
12 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
13 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
14 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
15 *
16 * Driver won't bind to devices which do not support the Interrupt Disable Bit
17 * in the command register. All devices compliant to PCI 2.3 (circa 2002) and
18 * all compliant PCI Express devices should support this bit.
19 */
20
21 #include <linux/device.h>
22 #include <linux/module.h>
23 #include <linux/pci.h>
24 #include <linux/slab.h>
25 #include <linux/uio_driver.h>
26
27 #define DRIVER_VERSION "0.01.0"
28 #define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>"
29 #define DRIVER_DESC "Generic UIO driver for PCI 2.3 devices"
30
31 struct uio_pci_generic_dev {
32 struct uio_info info;
33 struct pci_dev *pdev;
34 };
35
36 static inline struct uio_pci_generic_dev *
to_uio_pci_generic_dev(struct uio_info * info)37 to_uio_pci_generic_dev(struct uio_info *info)
38 {
39 return container_of(info, struct uio_pci_generic_dev, info);
40 }
41
release(struct uio_info * info,struct inode * inode)42 static int release(struct uio_info *info, struct inode *inode)
43 {
44 struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
45
46 /*
47 * This driver is insecure when used with devices doing DMA, but some
48 * people (mis)use it with such devices.
49 * Let's at least make sure DMA isn't left enabled after the userspace
50 * driver closes the fd.
51 * Note that there's a non-zero chance doing this will wedge the device
52 * at least until reset.
53 */
54 pci_clear_master(gdev->pdev);
55 return 0;
56 }
57
58 /* Interrupt handler. Read/modify/write the command register to disable
59 * the interrupt. */
irqhandler(int irq,struct uio_info * info)60 static irqreturn_t irqhandler(int irq, struct uio_info *info)
61 {
62 struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
63
64 if (!pci_check_and_mask_intx(gdev->pdev))
65 return IRQ_NONE;
66
67 /* UIO core will signal the user process. */
68 return IRQ_HANDLED;
69 }
70
probe(struct pci_dev * pdev,const struct pci_device_id * id)71 static int probe(struct pci_dev *pdev,
72 const struct pci_device_id *id)
73 {
74 struct uio_pci_generic_dev *gdev;
75 struct uio_mem *uiomem;
76 int err;
77 int i;
78
79 err = pcim_enable_device(pdev);
80 if (err) {
81 dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
82 __func__, err);
83 return err;
84 }
85
86 if (pdev->irq && !pci_intx_mask_supported(pdev))
87 return -ENODEV;
88
89 gdev = devm_kzalloc(&pdev->dev, sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
90 if (!gdev)
91 return -ENOMEM;
92
93 gdev->info.name = "uio_pci_generic";
94 gdev->info.version = DRIVER_VERSION;
95 gdev->info.release = release;
96 gdev->pdev = pdev;
97 if (pdev->irq && (pdev->irq != IRQ_NOTCONNECTED)) {
98 gdev->info.irq = pdev->irq;
99 gdev->info.irq_flags = IRQF_SHARED;
100 gdev->info.handler = irqhandler;
101 } else {
102 dev_warn(&pdev->dev, "No IRQ assigned to device: "
103 "no support for interrupts?\n");
104 }
105
106 uiomem = &gdev->info.mem[0];
107 for (i = 0; i < MAX_UIO_MAPS; ++i) {
108 struct resource *r = &pdev->resource[i];
109
110 if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM))
111 continue;
112
113 if (uiomem >= &gdev->info.mem[MAX_UIO_MAPS]) {
114 dev_warn(
115 &pdev->dev,
116 "device has more than " __stringify(
117 MAX_UIO_MAPS) " I/O memory resources.\n");
118 break;
119 }
120
121 uiomem->memtype = UIO_MEM_PHYS;
122 uiomem->addr = r->start & PAGE_MASK;
123 uiomem->offs = r->start & ~PAGE_MASK;
124 uiomem->size =
125 (uiomem->offs + resource_size(r) + PAGE_SIZE - 1) &
126 PAGE_MASK;
127 uiomem->name = r->name;
128 ++uiomem;
129 }
130
131 while (uiomem < &gdev->info.mem[MAX_UIO_MAPS]) {
132 uiomem->size = 0;
133 ++uiomem;
134 }
135
136 return devm_uio_register_device(&pdev->dev, &gdev->info);
137 }
138
139 static struct pci_driver uio_pci_driver = {
140 .name = "uio_pci_generic",
141 .id_table = NULL, /* only dynamic id's */
142 .probe = probe,
143 };
144
145 module_pci_driver(uio_pci_driver);
146 MODULE_VERSION(DRIVER_VERSION);
147 MODULE_LICENSE("GPL v2");
148 MODULE_AUTHOR(DRIVER_AUTHOR);
149 MODULE_DESCRIPTION(DRIVER_DESC);
150