Greg Kroah-Hartman | 3099e75 | 2005-06-20 21:15:16 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * All the USB notify logic |
| 3 | * |
| 4 | * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de> |
| 5 | * |
| 6 | * notifier functions originally based on those in kernel/sys.c |
| 7 | * but fixed up to not be so broken. |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | |
| 12 | #include <linux/config.h> |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/notifier.h> |
| 15 | #ifdef CONFIG_USB_DEBUG |
| 16 | #define DEBUG |
| 17 | #else |
| 18 | #undef DEBUG |
| 19 | #endif |
| 20 | #include <linux/usb.h> |
| 21 | |
| 22 | #include "usb.h" |
| 23 | |
| 24 | |
| 25 | static struct notifier_block *usb_notifier_list; |
| 26 | static DECLARE_MUTEX(usb_notifier_lock); |
| 27 | |
| 28 | static void usb_notifier_chain_register(struct notifier_block **list, |
| 29 | struct notifier_block *n) |
| 30 | { |
| 31 | down(&usb_notifier_lock); |
| 32 | while (*list) { |
| 33 | if (n->priority > (*list)->priority) |
| 34 | break; |
| 35 | list = &((*list)->next); |
| 36 | } |
| 37 | n->next = *list; |
| 38 | *list = n; |
| 39 | up(&usb_notifier_lock); |
| 40 | } |
| 41 | |
| 42 | static void usb_notifier_chain_unregister(struct notifier_block **nl, |
| 43 | struct notifier_block *n) |
| 44 | { |
| 45 | down(&usb_notifier_lock); |
| 46 | while ((*nl)!=NULL) { |
| 47 | if ((*nl)==n) { |
| 48 | *nl = n->next; |
| 49 | goto exit; |
| 50 | } |
| 51 | nl=&((*nl)->next); |
| 52 | } |
| 53 | exit: |
| 54 | up(&usb_notifier_lock); |
| 55 | } |
| 56 | |
| 57 | static int usb_notifier_call_chain(struct notifier_block **n, |
| 58 | unsigned long val, void *v) |
| 59 | { |
| 60 | int ret=NOTIFY_DONE; |
| 61 | struct notifier_block *nb = *n; |
| 62 | |
| 63 | down(&usb_notifier_lock); |
| 64 | while (nb) { |
| 65 | ret = nb->notifier_call(nb,val,v); |
| 66 | if (ret&NOTIFY_STOP_MASK) { |
| 67 | goto exit; |
| 68 | } |
| 69 | nb = nb->next; |
| 70 | } |
| 71 | exit: |
| 72 | up(&usb_notifier_lock); |
| 73 | return ret; |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * usb_register_notify - register a notifier callback whenever a usb change happens |
| 78 | * @nb: pointer to the notifier block for the callback events. |
| 79 | * |
| 80 | * These changes are either USB devices or busses being added or removed. |
| 81 | */ |
| 82 | void usb_register_notify(struct notifier_block *nb) |
| 83 | { |
| 84 | usb_notifier_chain_register(&usb_notifier_list, nb); |
| 85 | } |
| 86 | EXPORT_SYMBOL_GPL(usb_register_notify); |
| 87 | |
| 88 | /** |
| 89 | * usb_unregister_notify - unregister a notifier callback |
| 90 | * @nb: pointer to the notifier block for the callback events. |
| 91 | * |
| 92 | * usb_register_notifier() must have been previously called for this function |
| 93 | * to work properly. |
| 94 | */ |
| 95 | void usb_unregister_notify(struct notifier_block *nb) |
| 96 | { |
| 97 | usb_notifier_chain_unregister(&usb_notifier_list, nb); |
| 98 | } |
| 99 | EXPORT_SYMBOL_GPL(usb_unregister_notify); |
| 100 | |
| 101 | |
| 102 | void usb_notify_add_device(struct usb_device *udev) |
| 103 | { |
| 104 | usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev); |
| 105 | } |
| 106 | |
| 107 | void usb_notify_remove_device(struct usb_device *udev) |
| 108 | { |
| 109 | usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_REMOVE, udev); |
| 110 | } |
| 111 | |
| 112 | void usb_notify_add_bus(struct usb_bus *ubus) |
| 113 | { |
| 114 | usb_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus); |
| 115 | } |
| 116 | |
| 117 | void usb_notify_remove_bus(struct usb_bus *ubus) |
| 118 | { |
| 119 | usb_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus); |
| 120 | } |