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
22 static char ids[1024] __initdata;
23
24 module_param_string(ids, ids, sizeof(ids), 0);
25 MODULE_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
pci_stub_probe(struct pci_dev * dev,const struct pci_device_id * id)29 static 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
35 static struct pci_driver stub_driver = {
36 .name = "pci-stub",
37 .id_table = NULL, /* only dynamic id's */
38 .probe = pci_stub_probe,
39 };
40
pci_stub_init(void)41 static int __init pci_stub_init(void)
42 {
43 char *p, *id;
44 int rc;
45
46 rc = pci_register_driver(&stub_driver);
47 if (rc)
48 return rc;
49
50 /* no ids passed actually */
51 if (ids[0] == '\0')
52 return 0;
53
54 /* add ids specified in the module parameter */
55 p = ids;
56 while ((id = strsep(&p, ","))) {
57 unsigned int vendor, device, subvendor = PCI_ANY_ID,
58 subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
59 int fields;
60
61 if (!strlen(id))
62 continue;
63
64 fields = sscanf(id, "%x:%x:%x:%x:%x:%x",
65 &vendor, &device, &subvendor, &subdevice,
66 &class, &class_mask);
67
68 if (fields < 2) {
69 pr_warn("pci-stub: invalid ID string \"%s\"\n", id);
70 continue;
71 }
72
73 pr_info("pci-stub: add %04X:%04X sub=%04X:%04X cls=%08X/%08X\n",
74 vendor, device, subvendor, subdevice, class, class_mask);
75
76 rc = pci_add_dynid(&stub_driver, vendor, device,
77 subvendor, subdevice, class, class_mask, 0);
78 if (rc)
79 pr_warn("pci-stub: failed to add dynamic ID (%d)\n",
80 rc);
81 }
82
83 return 0;
84 }
85
pci_stub_exit(void)86 static void __exit pci_stub_exit(void)
87 {
88 pci_unregister_driver(&stub_driver);
89 }
90
91 module_init(pci_stub_init);
92 module_exit(pci_stub_exit);
93
94 MODULE_LICENSE("GPL");
95 MODULE_AUTHOR("Chris Wright <chrisw@sous-sol.org>");
96