drivers/pci/pci-stub.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Simple stub driver to reserve a PCI device
0004  *
0005  * Copyright (C) 2008 Red Hat, Inc.
0006  * Author:
0007  *  Chris Wright
0008  *
0009  * Usage is simple, allocate a new id to the stub driver and bind the
0010  * device to it.  For example:
0011  *
0012  * # echo "8086 10f5" > /sys/bus/pci/drivers/pci-stub/new_id
0013  * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
0014  * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/pci-stub/bind
0015  * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
0016  * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/pci-stub
0017  */
0018
0019 #include <linux/module.h>
0020 #include <linux/pci.h>
0021
0022 static char ids[1024] __initdata;
0023
0024 module_param_string(ids, ids, sizeof(ids), 0);
0025 MODULE_PARM_DESC(ids, "Initial PCI IDs to add to the stub driver, format is "
0026          "\"vendor:device[:subvendor[:subdevice[:class[:class_mask]]]]\""
0027          " and multiple comma separated entries can be specified");
0028
0029 static int pci_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)
0030 {
0031     pci_info(dev, "claimed by stub\n");
0032     return 0;
0033 }
0034
0035 static struct pci_driver stub_driver = {
0036     .name       = "pci-stub",
0037     .id_table   = NULL, /* only dynamic id's */
0038     .probe      = pci_stub_probe,
0039     .driver_managed_dma = true,
0040 };
0041
0042 static int __init pci_stub_init(void)
0043 {
0044     char *p, *id;
0045     int rc;
0046
0047     rc = pci_register_driver(&stub_driver);
0048     if (rc)
0049         return rc;
0050
0051     /* no ids passed actually */
0052     if (ids[0] == '\0')
0053         return 0;
0054
0055     /* add ids specified in the module parameter */
0056     p = ids;
0057     while ((id = strsep(&p, ","))) {
0058         unsigned int vendor, device, subvendor = PCI_ANY_ID,
0059             subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
0060         int fields;
0061
0062         if (!strlen(id))
0063             continue;
0064
0065         fields = sscanf(id, "%x:%x:%x:%x:%x:%x",
0066                 &vendor, &device, &subvendor, &subdevice,
0067                 &class, &class_mask);
0068
0069         if (fields < 2) {
0070             pr_warn("pci-stub: invalid ID string \"%s\"\n", id);
0071             continue;
0072         }
0073
0074         pr_info("pci-stub: add %04X:%04X sub=%04X:%04X cls=%08X/%08X\n",
0075                vendor, device, subvendor, subdevice, class, class_mask);
0076
0077         rc = pci_add_dynid(&stub_driver, vendor, device,
0078                    subvendor, subdevice, class, class_mask, 0);
0079         if (rc)
0080             pr_warn("pci-stub: failed to add dynamic ID (%d)\n",
0081                 rc);
0082     }
0083
0084     return 0;
0085 }
0086
0087 static void __exit pci_stub_exit(void)
0088 {
0089     pci_unregister_driver(&stub_driver);
0090 }
0091
0092 module_init(pci_stub_init);
0093 module_exit(pci_stub_exit);
0094
0095 MODULE_LICENSE("GPL");
0096 MODULE_AUTHOR("Chris Wright <chrisw@sous-sol.org>");