1/* uio_pci_generic - generic UIO driver for PCI 2.3 devices
2 *
3 * Copyright (C) 2009 Red Hat, Inc.
4 * Author: Michael S. Tsirkin <mst@redhat.com>
5 *
6 * This work is licensed under the terms of the GNU GPL, version 2.
7 *
8 * Since the driver does not declare any device ids, you must allocate
9 * id and bind the device to the driver yourself.  For example:
10 *
11 * # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
12 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
13 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
14 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
15 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
16 *
17 * Driver won't bind to devices which do not support the Interrupt Disable Bit
18 * in the command register. All devices compliant to PCI 2.3 (circa 2002) and
19 * all compliant PCI Express devices should support this bit.
20 */
21
22#include <linux/device.h>
23#include <linux/module.h>
24#include <linux/pci.h>
25#include <linux/slab.h>
26#include <linux/uio_driver.h>
27
28#define DRIVER_VERSION	"0.01.0"
29#define DRIVER_AUTHOR	"Michael S. Tsirkin <mst@redhat.com>"
30#define DRIVER_DESC	"Generic UIO driver for PCI 2.3 devices"
31
32struct uio_pci_generic_dev {
33	struct uio_info info;
34	struct pci_dev *pdev;
35};
36
37static inline struct uio_pci_generic_dev *
38to_uio_pci_generic_dev(struct uio_info *info)
39{
40	return container_of(info, struct uio_pci_generic_dev, info);
41}
42
43/* Interrupt handler. Read/modify/write the command register to disable
44 * the interrupt. */
45static irqreturn_t irqhandler(int irq, struct uio_info *info)
46{
47	struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
48
49	if (!pci_check_and_mask_intx(gdev->pdev))
50		return IRQ_NONE;
51
52	/* UIO core will signal the user process. */
53	return IRQ_HANDLED;
54}
55
56static int __devinit probe(struct pci_dev *pdev,
57			   const struct pci_device_id *id)
58{
59	struct uio_pci_generic_dev *gdev;
60	int err;
61
62	err = pci_enable_device(pdev);
63	if (err) {
64		dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
65			__func__, err);
66		return err;
67	}
68
69	if (!pdev->irq) {
70		dev_warn(&pdev->dev, "No IRQ assigned to device: "
71			 "no support for interrupts?\n");
72		pci_disable_device(pdev);
73		return -ENODEV;
74	}
75
76	if (!pci_intx_mask_supported(pdev)) {
77		err = -ENODEV;
78		goto err_verify;
79	}
80
81	gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
82	if (!gdev) {
83		err = -ENOMEM;
84		goto err_alloc;
85	}
86
87	gdev->info.name = "uio_pci_generic";
88	gdev->info.version = DRIVER_VERSION;
89	gdev->info.irq = pdev->irq;
90	gdev->info.irq_flags = IRQF_SHARED;
91	gdev->info.handler = irqhandler;
92	gdev->pdev = pdev;
93
94	if (uio_register_device(&pdev->dev, &gdev->info))
95		goto err_register;
96	pci_set_drvdata(pdev, gdev);
97
98	return 0;
99err_register:
100	kfree(gdev);
101err_alloc:
102err_verify:
103	pci_disable_device(pdev);
104	return err;
105}
106
107static void remove(struct pci_dev *pdev)
108{
109	struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev);
110
111	uio_unregister_device(&gdev->info);
112	pci_disable_device(pdev);
113	kfree(gdev);
114}
115
116static struct pci_driver driver = {
117	.name = "uio_pci_generic",
118	.id_table = NULL, /* only dynamic id's */
119	.probe = probe,
120	.remove = remove,
121};
122
123static int __init init(void)
124{
125	pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
126	return pci_register_driver(&driver);
127}
128
129static void __exit cleanup(void)
130{
131	pci_unregister_driver(&driver);
132}
133
134module_init(init);
135module_exit(cleanup);
136
137MODULE_VERSION(DRIVER_VERSION);
138MODULE_LICENSE("GPL v2");
139MODULE_AUTHOR(DRIVER_AUTHOR);
140MODULE_DESCRIPTION(DRIVER_DESC);
141