device.c

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/*-
 * Copyright (c) 2002-2018 The UbixOS Project.
 * All rights reserved.
 *
 * This was developed by Christopher W. Olsen for the UbixOS Project.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1) Redistributions of source code must retain the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors.
 * 2) Redistributions in binary form must reproduce the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors in the documentation and/or
 *    other materials provided with the distribution.
 * 3) Neither the name of the UbixOS Project nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <sys/device.h>
#include <ubixos/spinlock.h>
#include <lib/kmalloc.h>
#include <lib/kprintf.h>
#include <assert.h>
 
/* Linked list of drivers loaded in the system accessable by the subsystem only */
static struct device_node *devices = 0x0;
static struct spinLock deviceSpinLock = SPIN_LOCK_INITIALIZER;
 
/*****************************************************************************************
 
 Function: int deviceAdd(int minor,char type,struct device_interface *devInfo);
 
 Description: This will add a device to the system
 
 Notes:
 
 05/19/2004 - Improving Upon the spec
 
 *****************************************************************************************/
int device_add(int minor, char type, struct device_interface *devInfo) {
  struct device_node *tmpDev = 0x0;
 
  tmpDev = (struct device_node *) kmalloc(sizeof(struct device_node));
  if (tmpDev == NULL)
    kprintf("Error Adding Device: memory failure\n");
 
  tmpDev->prev = 0x0;
  tmpDev->minor = minor;
  tmpDev->type = type;
  tmpDev->devInfo = devInfo;
 
  spinLock(&deviceSpinLock);
  tmpDev->next = devices;
  devices = tmpDev;
  spinUnlock(&deviceSpinLock);
 
  if (tmpDev->devInfo->initialized == 0x0)
    return (tmpDev->devInfo->init(tmpDev));
  else
    return (0x0);
}
 
/*****************************************************************************************
 
 Function: struct device_node *deviceFind(int major,int minor);
 
 Description: This will find a device based on major minor
 
 Notes:
 
 05/19/2004 - Improving Upon the spec
 
 *****************************************************************************************/
struct device_node *device_find(int major, int minor) {
  struct device_node *tmpDev = 0x0;
 
  spinLock(&deviceSpinLock);
 
  for (tmpDev = devices; tmpDev; tmpDev = tmpDev->next) {
    if ((tmpDev->devInfo->major == major) && (tmpDev->minor == minor)) {
      spinUnlock(&deviceSpinLock);
      return (tmpDev);
    }
  }
 
  spinUnlock(&deviceSpinLock);
  return (0x0);
}
 
/********************************************************************************************
 
 Function: int deviceRemove(struct *device_node);
 
 Description: This will remove a device based on it's pointer
 
 *********************************************************************************************/
int device_remove(struct device_node *deviceToDelete) {
  struct device_node *current, *previous;
 
  current = devices;
  previous = NULL;
  spinLock(&deviceSpinLock);
  while (current != NULL) {
    if (current == deviceToDelete)
      break;
    else {
      previous = current;
      current = current->next;
    }
  }
  if (current == NULL) {
    spinUnlock(&deviceSpinLock);
    return 1;
  }
  else {
    if (current == devices)
      devices = devices->next;
    else
      previous->next = current->next;
    kfree(current);
    spinUnlock(&deviceSpinLock);
    return 1;
  }
 
  spinUnlock(&deviceSpinLock);
  return 0x0;
}