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
42 /* Interrupt handler. Read/modify/write the command register to disable
43 * the interrupt. */
irqhandler(int irq,struct uio_info * info)44 static irqreturn_t irqhandler(int irq, struct uio_info *info)
45 {
46 struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
47
48 if (!pci_check_and_mask_intx(gdev->pdev))
49 return IRQ_NONE;
50
51 /* UIO core will signal the user process. */
52 return IRQ_HANDLED;
53 }
54
probe(struct pci_dev * pdev,const struct pci_device_id * id)55 static int probe(struct pci_dev *pdev,
56 const struct pci_device_id *id)
57 {
58 struct uio_pci_generic_dev *gdev;
59 int err;
60
61 err = pci_enable_device(pdev);
62 if (err) {
63 dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
64 __func__, err);
65 return err;
66 }
67
68 if (pdev->irq && !pci_intx_mask_supported(pdev)) {
69 err = -ENODEV;
70 goto err_verify;
71 }
72
73 gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
74 if (!gdev) {
75 err = -ENOMEM;
76 goto err_alloc;
77 }
78
79 gdev->info.name = "uio_pci_generic";
80 gdev->info.version = DRIVER_VERSION;
81 gdev->pdev = pdev;
82 if (pdev->irq) {
83 gdev->info.irq = pdev->irq;
84 gdev->info.irq_flags = IRQF_SHARED;
85 gdev->info.handler = irqhandler;
86 } else {
87 dev_warn(&pdev->dev, "No IRQ assigned to device: "
88 "no support for interrupts?\n");
89 }
90
91 err = uio_register_device(&pdev->dev, &gdev->info);
92 if (err)
93 goto err_register;
94 pci_set_drvdata(pdev, gdev);
95
96 return 0;
97 err_register:
98 kfree(gdev);
99 err_alloc:
100 err_verify:
101 pci_disable_device(pdev);
102 return err;
103 }
104
remove(struct pci_dev * pdev)105 static void remove(struct pci_dev *pdev)
106 {
107 struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev);
108
109 uio_unregister_device(&gdev->info);
110 pci_disable_device(pdev);
111 kfree(gdev);
112 }
113
114 static struct pci_driver uio_pci_driver = {
115 .name = "uio_pci_generic",
116 .id_table = NULL, /* only dynamic id's */
117 .probe = probe,
118 .remove = remove,
119 };
120
121 module_pci_driver(uio_pci_driver);
122 MODULE_VERSION(DRIVER_VERSION);
123 MODULE_LICENSE("GPL v2");
124 MODULE_AUTHOR(DRIVER_AUTHOR);
125 MODULE_DESCRIPTION(DRIVER_DESC);
126
