pci驱动,问题..

我在linux下写了一个pci卡的驱动, 代码如下:

  resource_begin = pci_resource_start(dev, 0);
  resource_end = pci_resource_end(dev, 0);
  printk(\"resource_begin = 0x%x\\n\", resource_begin);
  printk(\"resource_end = 0x%x\\n\", resource_end);  

  resource_flag =  pci_resource_flags(dev, 0);
  if(resource_flag == IORESOURCE_IO)
  {
    printk(\"resource is io\\n\");
  }
  else if(resource_flag == IORESOURCE_MEM)
  {
    printk(\"resource is mem\\n\");
  }
    if(pci_enable_device(dev))
  {
    printk(\"enable_device fail\");
    return -EBUSY;
  }
  else
    printk(\"enable_device success\");
    
  /*if(check_mem_region(resource_begin, 0x3ff))
  {
    printk(\"drivername: memory already in use\\n\");
    return -EBUSY;
  }*/
  request_mem_region(resource_begin, 0x3ff, \"scull\");  
  printk(\"result = 0x%x\\n\", result);
  printk(\"result = 0x%x\\n\", result);
  resource_virtual_address =(long)ioremap_nocache(resource_begin, sz);
  printk(\"resource_virtual_address = 0x%x\\n\", resource_virtual_address);
  
  printk(\"result = 0x%x\\n\", result);
  long test = resource_virtual_address + 0x120;
  writel(0x028f , test);
  printk(\"resource_virtual_address = 0x%x\\n\", resource_virtual_address+0x120);  
  iounmap((void *)resource_virtual_address);

  release_mem_region(resource_begin, 0x3ff);
  return 0; /* 模块初始化 *

主要是,执行writel(0x028f, test)后,应该led灯亮,但是,我这里没有成功,而且,我用
check_mem_region函数时返回也是失败的,我在windows下写了个驱动试了一下,硬件没有问题,
而且我得到的基地址也正确,我的设备资源是mem的,我想问一下,为什么,我会写不进去,
怎么写,多谢了.....

ioremap_nocache(resource_begin, sz)
这个函数调用sz为多少，应该为pci_resource_len()或者为resource_begin-resource_end

[编辑 -  2/24/05 by  baaniaw]