cs8900网卡驱动解析（五）

几个主要的模块的都写完了，下面开始介绍一下其他的函数。

和net_open对应的函数：

/* The inverse routine to net_open(). *//*①停止队列②关闭网卡③释放中断*/static int net_close(struct net_device *dev){netif_stop_queue(dev);writereg(dev, PP_RxCFG, 0);writereg(dev, PP_TxCFG, 0);writereg(dev, PP_BufCFG, 0);writereg(dev, PP_BusCTL, 0);free_irq(dev->irq, dev);/* Update the statistics here. */return 0;}

再看一下cs8900是如何获取统计信息的：

/*向用户反馈设备状态和统计信息net_device_stats，这是一个net_local的结构体成员。*/static struct net_device_stats *net_get_stats(struct net_device *dev){struct net_local *lp = (struct net_local *)dev->priv;unsigned long flags;//不追了，这个就知道它是在读取各个寄存器状态的信息//然后都存放在net_device_stats这个结构体中，结构体的具体定义在内核中实现。spin_lock_irqsave(&lp->lock, flags);/* Update the statistics from the device registers. */lp->stats.rx_missed_errors += (readreg(dev, PP_RxMiss) >> 6);lp->stats.collisions += (readreg(dev, PP_TxCol) >> 6);spin_unlock_irqrestore(&lp->lock, flags);return &lp->stats;}

 

stats是一个net_device_stats结构，其实说简单点，你只要返回stats结构就可以了，它里面记录了你需要的信息。net_device_stats结构在netdevice.h文件中。

struct net_device_stats{       unsigned long rx_packets;     /* total packets received */       unsigned long tx_packets;     /* total packets transmitted    */       unsigned long rx_bytes;        /* total bytes received  */       unsigned long tx_bytes;        /* total bytes transmitted       */       unsigned long rx_errors;              /* bad packets received         */       unsigned long tx_errors;              /* packet transmit problems   */       unsigned long rx_dropped;    /* no space in linux buffers   */       unsigned long tx_dropped;    /* no space available in linux */       unsigned long multicast;              /* multicast packets received */       unsigned long collisions;        /* detailed rx_errors: */       unsigned long rx_length_errors;       unsigned long rx_over_errors;      /* receiver ring buff overflow       */       unsigned long rx_crc_errors;        /* recved pkt with crc error   */       unsigned long rx_frame_errors;    /* recv'd frame alignment error */       unsigned long rx_fifo_errors;              /* recv'r fifo overrun            */       unsigned long rx_missed_errors;   /* receiver missed packet       */        /* detailed tx_errors */       unsigned long tx_aborted_errors;       unsigned long tx_carrier_errors;       unsigned long tx_fifo_errors;       unsigned long tx_heartbeat_errors;       unsigned long tx_window_errors;              /* for cslip etc */       unsigned long rx_compressed;       unsigned long tx_compressed;};

cs8900_get_stats这个函数虽然简单，但是很实用。

cs8900_set_receive_mode函数设置网卡模式，需要配合手册来阅读。出现的新函数（cs8900_set和cs8900_clear）实际上就是cs8900_write，就是通过与(&)或(|)运算，实用set和clear字样，会使函数非常易读。

大神一句话：对网卡的控制需要熟读硬件手册。

其实还有很多的函数没有写，同时我自己也有很多地方没有弄懂，不过三天都在看着不到七百行的代码了。我觉得我写的注释还可以，如果谁想要这套代码可以给我留言的。