pci-stub.c

Go to the documentation of this file.

/* pci-stub - simple stub driver to reserve a pci device
 *
 * Copyright (C) 2008 Red Hat, Inc.
 * Author:
 *  Chris Wright
 *
 * This work is licensed under the terms of the GNU GPL, version 2.
 *
 * Usage is simple, allocate a new id to the stub driver and bind the
 * device to it.  For example:
 * 
 * # echo "8086 10f5" > /sys/bus/pci/drivers/pci-stub/new_id
 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/pci-stub/bind
 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/pci-stub
 */

#include <linux/module.h>
#include <linux/pci.h>

static char ids[1024] __initdata;

module_param_string(ids, ids, sizeof(ids), 0);
MODULE_PARM_DESC(ids, "Initial PCI IDs to add to the stub driver, format is "
         "\"vendor:device[:subvendor[:subdevice[:class[:class_mask]]]]\""
         " and multiple comma separated entries can be specified");

static int pci_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
    dev_printk(KERN_INFO, &dev->dev, "claimed by stub\n");
    return 0;
}

static struct pci_driver stub_driver = {
    .name       = "pci-stub",
    .id_table   = NULL, /* only dynamic id's */
    .probe      = pci_stub_probe,
};

static int __init pci_stub_init(void)
{
    char *p, *id;
    int rc;

    rc = pci_register_driver(&stub_driver);
    if (rc)
        return rc;

    /* no ids passed actually */
    if (ids[0] == '\0')
        return 0;

    /* add ids specified in the module parameter */
    p = ids;
    while ((id = strsep(&p, ","))) {
        unsigned int vendor, device, subvendor = PCI_ANY_ID,
            subdevice = PCI_ANY_ID, class=0, class_mask=0;
        int fields;

        if (!strlen(id))
            continue;

        fields = sscanf(id, "%x:%x:%x:%x:%x:%x",
                &vendor, &device, &subvendor, &subdevice,
                &class, &class_mask);

        if (fields < 2) {
            printk(KERN_WARNING
                   "pci-stub: invalid id string \"%s\"\n", id);
            continue;
        }

        printk(KERN_INFO
               "pci-stub: add %04X:%04X sub=%04X:%04X cls=%08X/%08X\n",
               vendor, device, subvendor, subdevice, class, class_mask);

        rc = pci_add_dynid(&stub_driver, vendor, device,
                   subvendor, subdevice, class, class_mask, 0);
        if (rc)
            printk(KERN_WARNING
                   "pci-stub: failed to add dynamic id (%d)\n", rc);
    }

    return 0;
}

static void __exit pci_stub_exit(void)
{
    pci_unregister_driver(&stub_driver);
}

module_init(pci_stub_init);
module_exit(pci_stub_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Chris Wright <[email protected]>");