drivers/pci/pci-stub.c

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