1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Simple stub driver to reserve a PCI device
4 *
5 * Copyright (C) 2008 Red Hat, Inc.
6 * Author:
7 *	Chris Wright
8 *
9 * Usage is simple, allocate a new id to the stub driver and bind the
10 * device to it.  For example:
11 *
12 * # echo "8086 10f5" > /sys/bus/pci/drivers/pci-stub/new_id
13 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
14 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/pci-stub/bind
15 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
16 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/pci-stub
17 */
18
19#include <linux/module.h>
20#include <linux/pci.h>
21
22static char ids[1024] __initdata;
23
24module_param_string(ids, ids, sizeof(ids), 0);
25MODULE_PARM_DESC(ids, "Initial PCI IDs to add to the stub driver, format is "
26		 "\"vendor:device[:subvendor[:subdevice[:class[:class_mask]]]]\""
27		 " and multiple comma separated entries can be specified");
28
29static int pci_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)
30{
31	pci_info(dev, "claimed by stub\n");
32	return 0;
33}
34
35static struct pci_driver stub_driver = {
36	.name		= "pci-stub",
37	.id_table	= NULL,	/* only dynamic id's */
38	.probe		= pci_stub_probe,
39	.driver_managed_dma = true,
40};
41
42static int __init pci_stub_init(void)
43{
44	char *p, *id;
45	int rc;
46
47	rc = pci_register_driver(&stub_driver);
48	if (rc)
49		return rc;
50
51	/* no ids passed actually */
52	if (ids[0] == '\0')
53		return 0;
54
55	/* add ids specified in the module parameter */
56	p = ids;
57	while ((id = strsep(&p, ","))) {
58		unsigned int vendor, device, subvendor = PCI_ANY_ID,
59			subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
60		int fields;
61
62		if (!strlen(id))
63			continue;
64
65		fields = sscanf(id, "%x:%x:%x:%x:%x:%x",
66				&vendor, &device, &subvendor, &subdevice,
67				&class, &class_mask);
68
69		if (fields < 2) {
70			pr_warn("pci-stub: invalid ID string \"%s\"\n", id);
71			continue;
72		}
73
74		pr_info("pci-stub: add %04X:%04X sub=%04X:%04X cls=%08X/%08X\n",
75		       vendor, device, subvendor, subdevice, class, class_mask);
76
77		rc = pci_add_dynid(&stub_driver, vendor, device,
78				   subvendor, subdevice, class, class_mask, 0);
79		if (rc)
80			pr_warn("pci-stub: failed to add dynamic ID (%d)\n",
81				rc);
82	}
83
84	return 0;
85}
86
87static void __exit pci_stub_exit(void)
88{
89	pci_unregister_driver(&stub_driver);
90}
91
92module_init(pci_stub_init);
93module_exit(pci_stub_exit);
94
95MODULE_LICENSE("GPL");
96MODULE_AUTHOR("Chris Wright <chrisw@sous-sol.org>");
97