PCI驱动程序（3）

接着上文给出的源代码，我们可以在rtl8139_init_one中插入一些不同的调试代码，观察设备驱动模块在内核中的一些动作。
8139too 网卡设备的设备内存的头6个字节存放的是该网卡的48位的MAC地址，我们可以通过访问设备内存得到这个MAC地址。下面通过在 rtl8139_init_one在插入代码，以四种不同方式访问设备内存。第一种是通过访问I/O内存实现，后三种则是通过访问I/O端口的形式实现。
第一种：
unsigned long mmio_start, addr1, addr2;
void __iomem *ioaddr;
mmio_start = pci_resource_start( pdev, 1);
ioaddr = pci_iomap(pdev, 1, 0);
addr1 = ioread32( ioaddr );
addr2 = ioread32( ioaddr + 4 );
printk(KERN_INFO "mmio start: %lX\n", mmio_start);
printk(KERN_INFO "ioaddr: %p\n", ioaddr);
printk(KERN_INFO "%02lX.%02lX.%02lX.%02lX.%02lX.%02lX\n",
(addr1) & 0xFF,
(addr1 >> 8) & 0xFF,
(addr1 >> 16 ) & 0xFF,
(addr1 >> 24 ) & 0xFF,
(addr2) & 0xFF,
(addr2 >> 8) & 0xFF );
运行结果：
Mar 10 22:34:56 localhost kernel: mmio start: E0000800
Mar 10 22:34:56 localhost kernel: ioaddr: f8aa6800
Mar 10 22:34:56 localhost kernel: 00.02.3F.AC.41.9D

第二种：
unsigned long pio_start, pio_len, addr1, addr2;
void __iomem *ioaddr;
pio_start = pci_resource_start( pdev, 0);
pio_len = pci_resource_len (pdev, 0);
ioaddr = ioport_map(pio_start, pio_len);
addr1 = ioread32( ioaddr );
addr2 = ioread32( ioaddr + 4 );
printk(KERN_INFO "pio start: %lX\n", pio_start);
printk(KERN_INFO "ioaddr: %p\n", ioaddr);
printk(KERN_INFO "%02lX.%02lX.%02lX.%02lX.%02lX.%02lX\n",
(addr1) & 0xFF,
(addr1 >> 8) & 0xFF,
(addr1 >> 16 ) & 0xFF,
(addr1 >> 24 ) & 0xFF,
(addr2) & 0xFF,
(addr2 >> 8) & 0xFF );
运行结果：
Mar 10 22:30:52 localhost kernel: pio start: 3400
Mar 10 22:30:52 localhost kernel: ioaddr: 00013400
Mar 10 22:30:52 localhost kernel: 00.02.3F.AC.41.9D

第三种：
unsigned long pio_start, addr1, addr2;
pio_start = pci_resource_start( pdev, 0 );
addr1 = inl( pio_start );
addr2 = inl( pio_start + 4 );
printk(KERN_INFO "port io start: %lX\n", pio_start);
printk(KERN_INFO "%02lX.%02lX.%02lX.%02lX.%02lX.%02lX\n",
(addr1) & 0xFF,
(addr1 >> 8) & 0xFF,
(addr1 >> 16) & 0xFF,
(addr1 >> 24) & 0xFF,
(addr2) & 0xFF,
(addr2 >> 8) & 0xFF );
运行结果：
Mar 10 22:36:18 localhost kernel: port io start: 3400
Mar 10 22:36:18 localhost kernel: 00.02.3F.AC.41.9D

第四种：
unsigned long pio_start;
u8 addr1, addr2, addr3, addr4, addr5, addr6;
pio_start = pci_resource_start( pdev, 0 );
addr1 = inb( pio_start );
addr2 = inb( pio_start + 1 );
addr3 = inb( pio_start + 2 );
addr4 = inb( pio_start + 3 );
addr5 = inb( pio_start + 4 );
addr6 = inb( pio_start + 5 );
printk(KERN_INFO "port io start: %lX\n", pio_start);
printk(KERN_INFO "%02X.%02X.%02X.%02X.%02X.%02X\n",
addr1, addr2, addr3, addr4, addr5, addr6 );
运行结果：
Mar 10 22:37:19 localhost kernel: port io start: 3400
Mar 10 22:37:19 localhost kernel: 00.02.3F.AC.41.9D