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 .driver_managed_dma = true,
40 };
41
pci_stub_init(void)42 static 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
pci_stub_exit(void)87 static void __exit pci_stub_exit(void)
88 {
89 pci_unregister_driver(&stub_driver);
90 }
91
92 module_init(pci_stub_init);
93 module_exit(pci_stub_exit);
94
95 MODULE_LICENSE("GPL");
96 MODULE_AUTHOR("Chris Wright <chrisw@sous-sol.org>");
97