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usbip_event.c

/*
 * Copyright (C) 2003-2008 Takahiro Hirofuchi
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
 * USA.
 */

#include "usbip_common.h"

static int event_handler(struct usbip_device *ud)
{
      dbg_eh("enter\n");

      /*
       * Events are handled by only this thread.
       */
      while (usbip_event_happend(ud)) {
            dbg_eh("pending event %lx\n", ud->event);

            /*
             * NOTE: shutdown must come first.
             * Shutdown the device.
             */
            if (ud->event & USBIP_EH_SHUTDOWN) {
                  ud->eh_ops.shutdown(ud);

                  ud->event &= ~USBIP_EH_SHUTDOWN;

                  break;
            }

            /* Stop the error handler. */
            if (ud->event & USBIP_EH_BYE)
                  return -1;

            /* Reset the device. */
            if (ud->event & USBIP_EH_RESET) {
                  ud->eh_ops.reset(ud);

                  ud->event &= ~USBIP_EH_RESET;

                  break;
            }

            /* Mark the device as unusable. */
            if (ud->event & USBIP_EH_UNUSABLE) {
                  ud->eh_ops.unusable(ud);

                  ud->event &= ~USBIP_EH_UNUSABLE;

                  break;
            }

            /* NOTREACHED */
            printk(KERN_ERR "%s: unknown event\n", __func__);
            return -1;
      }

      return 0;
}

static void event_handler_loop(struct usbip_task *ut)
{
      struct usbip_device *ud = container_of(ut, struct usbip_device, eh);

      while (1) {
            if (signal_pending(current)) {
                  dbg_eh("signal catched!\n");
                  break;
            }

            if (event_handler(ud) < 0)
                  break;

            wait_event_interruptible(ud->eh_waitq, usbip_event_happend(ud));
            dbg_eh("wakeup\n");
      }
}

void usbip_start_eh(struct usbip_device *ud)
{
      struct usbip_task *eh = &ud->eh;

      init_waitqueue_head(&ud->eh_waitq);
      ud->event = 0;

      usbip_task_init(eh, "usbip_eh", event_handler_loop);

      kernel_thread(usbip_thread, (void *)eh, 0);

      wait_for_completion(&eh->thread_done);
}
EXPORT_SYMBOL_GPL(usbip_start_eh);

void usbip_stop_eh(struct usbip_device *ud)
{
      struct usbip_task *eh = &ud->eh;

      wait_for_completion(&eh->thread_done);
      dbg_eh("usbip_eh has finished\n");
}
EXPORT_SYMBOL_GPL(usbip_stop_eh);

void usbip_event_add(struct usbip_device *ud, unsigned long event)
{
      spin_lock(&ud->lock);

      ud->event |= event;

      wake_up(&ud->eh_waitq);

      spin_unlock(&ud->lock);
}
EXPORT_SYMBOL_GPL(usbip_event_add);

int usbip_event_happend(struct usbip_device *ud)
{
      int happend = 0;

      spin_lock(&ud->lock);

      if (ud->event != 0)
            happend = 1;

      spin_unlock(&ud->lock);

      return happend;
}
EXPORT_SYMBOL_GPL(usbip_event_happend);

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