drivers/staging/usbip/usbip_event.c

   1 /*
   2  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   3  *
   4  * This is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  17  * USA.
  18  */
  19
  20 #include "usbip_common.h"
  21
  22 static int event_handler(struct usbip_device *ud)
  23 {
  24         dbg_eh("enter\n");
  25
  26         /*
  27          * Events are handled by only this thread.
  28          */
  29         while (usbip_event_happend(ud)) {
  30                 dbg_eh("pending event %lx\n", ud->event);
  31
  32                 /*
  33                  * NOTE: shutdown must come first.
  34                  * Shutdown the device.
  35                  */
  36                 if (ud->event & USBIP_EH_SHUTDOWN) {
  37                         ud->eh_ops.shutdown(ud);
  38
  39                         ud->event &= ~USBIP_EH_SHUTDOWN;
  40
  41                         break;
  42                 }
  43
  44                 /* Stop the error handler. */
  45                 if (ud->event & USBIP_EH_BYE)
  46                         return -1;
  47
  48                 /* Reset the device. */
  49                 if (ud->event & USBIP_EH_RESET) {
  50                         ud->eh_ops.reset(ud);
  51
  52                         ud->event &= ~USBIP_EH_RESET;
  53
  54                         break;
  55                 }
  56
  57                 /* Mark the device as unusable. */
  58                 if (ud->event & USBIP_EH_UNUSABLE) {
  59                         ud->eh_ops.unusable(ud);
  60
  61                         ud->event &= ~USBIP_EH_UNUSABLE;
  62
  63                         break;
  64                 }
  65
  66                 /* NOTREACHED */
  67                 printk(KERN_ERR "%s: unknown event\n", __func__);
  68                 return -1;
  69         }
  70
  71         return 0;
  72 }
  73
  74 static void event_handler_loop(struct usbip_task *ut)
  75 {
  76         struct usbip_device *ud = container_of(ut, struct usbip_device, eh);
  77
  78         while (1) {
  79                 if (signal_pending(current)) {
  80                         dbg_eh("signal catched!\n");
  81                         break;
  82                 }
  83
  84                 if (event_handler(ud) < 0)
  85                         break;
  86
  87                 wait_event_interruptible(ud->eh_waitq, usbip_event_happend(ud));
  88                 dbg_eh("wakeup\n");
  89         }
  90 }
  91
  92 void usbip_start_eh(struct usbip_device *ud)
  93 {
  94         struct usbip_task *eh = &ud->eh;
  95
  96         init_waitqueue_head(&ud->eh_waitq);
  97         ud->event = 0;
  98
  99         usbip_task_init(eh, "usbip_eh", event_handler_loop);
 100
 101         kernel_thread(usbip_thread, (void *)eh, 0);
 102
 103         wait_for_completion(&eh->thread_done);
 104 }
 105 EXPORT_SYMBOL_GPL(usbip_start_eh);
 106
 107 void usbip_stop_eh(struct usbip_device *ud)
 108 {
 109         struct usbip_task *eh = &ud->eh;
 110
 111         wait_for_completion(&eh->thread_done);
 112         dbg_eh("usbip_eh has finished\n");
 113 }
 114 EXPORT_SYMBOL_GPL(usbip_stop_eh);
 115
 116 void usbip_event_add(struct usbip_device *ud, unsigned long event)
 117 {
 118         spin_lock(&ud->lock);
 119
 120         ud->event |= event;
 121
 122         wake_up(&ud->eh_waitq);
 123
 124         spin_unlock(&ud->lock);
 125 }
 126 EXPORT_SYMBOL_GPL(usbip_event_add);
 127
 128 int usbip_event_happend(struct usbip_device *ud)
 129 {
 130         int happend = 0;
 131
 132         spin_lock(&ud->lock);
 133
 134         if (ud->event != 0)
 135                 happend = 1;
 136
 137         spin_unlock(&ud->lock);
 138
 139         return happend;
 140 }
 141 EXPORT_SYMBOL_GPL(usbip_event_happend);