襄樊大型网站建设,wordpress取消邮箱,平面设计培训学校推荐,怎么做广告推广网络协议分为很多层#xff0c;而驱动这层对应于实际的物理网卡部分#xff0c;这也是最底层的部分#xff0c;以cs89x0.c这个驱动程序为例来分析下网卡驱动程序框架。
正常开发一个驱动程序时#xff0c;一般都遵循以下几个步骤#xff1a; 1.分配某个结构体 2.设置该结…网络协议分为很多层而驱动这层对应于实际的物理网卡部分这也是最底层的部分以cs89x0.c这个驱动程序为例来分析下网卡驱动程序框架。
正常开发一个驱动程序时一般都遵循以下几个步骤 1.分配某个结构体 2.设置该结构体 3.注册 4.硬件相关操作
首先分析cs89x0.c的入口函数
int __init init_module(void)
{struct net_device *dev alloc_etherdev(sizeof(struct net_local));struct net_local *lp;int ret 0;#if defined(CONFIG_ARCH_S3C2410)unsigned int oldval_bwscon; /* 用来保存BWSCON寄存器的值 */unsigned int oldval_bankcon3; /* 用来保存S3C2410_BANKCON3寄存器的值 */
#endif#if DEBUGGINGnet_debug debug;
#elsedebug 0;
#endifif (!dev)return -ENOMEM;#if defined(CONFIG_ARCH_S3C2410)// 将CS8900A的物理地址转换为虚拟地址0x300是CS8900A内部的IO空间的偏移地址dev-base_addr io (unsigned int)ioremap(S3C24XX_PA_CS8900, SZ_1M) 0x300;dev-irq irq cs8900_irq_map[0]; /* 中断号 *//* 设置默认MAC地址* MAC地址可以由CS8900A外接的EEPROM设定(有些单板没接EEPROM)* 或者启动系统后使用ifconfig修改*/dev-dev_addr[0] 0x08;dev-dev_addr[1] 0x89;dev-dev_addr[2] 0x89;dev-dev_addr[3] 0x89;dev-dev_addr[4] 0x89;dev-dev_addr[5] 0x89;/* 设置Bank3: 总线宽度为16, 使能nWAIT, 使能UB/LB。by www.100ask.net */oldval_bwscon *((volatile unsigned int *)S3C2410_BWSCON);*((volatile unsigned int *)S3C2410_BWSCON) (oldval_bwscon ~(312)) \| S3C2410_BWSCON_DW3_16 | S3C2410_BWSCON_WS3 | S3C2410_BWSCON_ST3;/* 设置BANK3的时间参数, by www.100ask.net */oldval_bankcon3 *((volatile unsigned int *)S3C2410_BANKCON3);*((volatile unsigned int *)S3C2410_BANKCON3) 0x1f7c;
#elsedev-irq irq;dev-base_addr io;
#endiflp netdev_priv(dev);#if ALLOW_DMAif (use_dma) {lp-use_dma use_dma;lp-dma dma;lp-dmasize dmasize;}
#endifspin_lock_init(lp-lock);/* boy, theyd better get these right */if (!strcmp(media, rj45))lp-adapter_cnf A_CNF_MEDIA_10B_T | A_CNF_10B_T;else if (!strcmp(media, aui))lp-adapter_cnf A_CNF_MEDIA_AUI | A_CNF_AUI;else if (!strcmp(media, bnc))lp-adapter_cnf A_CNF_MEDIA_10B_2 | A_CNF_10B_2;elselp-adapter_cnf A_CNF_MEDIA_10B_T | A_CNF_10B_T;if (duplex-1)lp-auto_neg_cnf AUTO_NEG_ENABLE;if (io 0) {printk(KERN_ERR cs89x0.c: Module autoprobing not allowed.\n);printk(KERN_ERR cs89x0.c: Append io0xNNN\n);ret -EPERM;goto out;} else if (io 0x1ff) {ret -ENXIO;goto out;}#if ALLOW_DMAif (use_dma dmasize ! 16 dmasize ! 64) {printk(KERN_ERR cs89x0.c: dma size must be either 16K or 64K, not %dK\n, dmasize);ret -EPERM;goto out;}
#endifret cs89x0_probe1(dev, io, 1);if (ret)goto out;dev_cs89x0 dev;return 0;
out:
#if defined(CONFIG_ARCH_S3C2410)iounmap(dev-base_addr);/* 恢复寄存器原来的值 */*((volatile unsigned int *)S3C2410_BWSCON) oldval_bwscon;*((volatile unsigned int *)S3C2410_BANKCON3) oldval_bankcon3;
#endif free_netdev(dev);return ret;
}入口函数里首先分配了net_device 结构体然后对该结构体进行进行填充最后调用cs89x0_probe1进行下一步处理。
cs89x0_probe1(struct net_device *dev, int ioaddr, int modular)
{
.............dev-open net_open;dev-stop net_close;dev-tx_timeout net_timeout;dev-watchdog_timeo HZ;**dev-hard_start_xmit net_send_packet;**dev-get_stats net_get_stats;dev-set_multicast_list set_multicast_list;dev-set_mac_address set_mac_address;
.....
.....retval register_netdev(dev);}cs89x0_probe1里又进一步对net_device 进行了填充其中hard_start_xmit 就是发送数据函数然后通过register_netdev进行注册。
进一步查看net_send_packet
static int net_send_packet(struct sk_buff *skb, struct net_device *dev)
{struct net_local *lp netdev_priv(dev);if (net_debug 3) {printk(%s: sent %d byte packet of type %x\n,dev-name, skb-len,(skb-data[ETH_ALENETH_ALEN] 8) | skb-data[ETH_ALENETH_ALEN1]);}/* keep the upload from being interrupted, since weask the chip to start transmitting before thewhole packet has been completely uploaded. */spin_lock_irq(lp-lock);netif_stop_queue(dev);/* initiate a transmit sequence */writeword(dev-base_addr, TX_CMD_PORT, lp-send_cmd);writeword(dev-base_addr, TX_LEN_PORT, skb-len);/* Test to see if the chip has allocated memory for the packet */if ((readreg(dev, PP_BusST) READY_FOR_TX_NOW) 0) {/** Gasp! It hasnt. But that shouldnt happen since* were waiting for TxOk, so return 1 and requeue this packet.*/spin_unlock_irq(lp-lock);if (net_debug) printk(cs89x0: Tx buffer not free!\n);return 1;}/* Write the contents of the packet */writewords(dev-base_addr, TX_FRAME_PORT,skb-data,(skb-len1) 1);spin_unlock_irq(lp-lock);lp-stats.tx_bytes skb-len;dev-trans_start jiffies;dev_kfree_skb (skb);/** We DO NOT call netif_wake_queue() here.* We also DO NOT call netif_start_queue().** Either of these would cause another bottom half run through* net_send_packet() before this packet has fully gone out. That causes* us to hit the Gasp! above and the send is rescheduled. it runs like* a dog. We just return and wait for the Tx completion interrupt handler* to restart the netdevice layer*/return 0;
}net_send_packet里用到了sk_buff 这个结构体sk_buff 就是数据的载体net_send_packet里通过sk_buff 发送了数据那数据又是如何接受的呢其实是通过中断接受数据的net_interrupt处理如下
static irqreturn_t net_interrupt(int irq, void *dev_id)
{struct net_device *dev dev_id;struct net_local *lp;int ioaddr, status;int handled 0;ioaddr dev-base_addr;lp netdev_priv(dev);/* we MUST read all the events out of the ISQ, otherwise well neverget interrupted again. As a consequence, we cant have any limiton the number of times we loop in the interrupt handler. Thehardware guarantees that eventually well run out of events. Ofcourse, if youre on a slow machine, and packets are arrivingfaster than you can read them off, youre screwed. Hasta lavista, baby! */while ((status readword(dev-base_addr, ISQ_PORT))) {if (net_debug 4)printk(%s: event%04x\n, dev-name, status);handled 1;switch(status ISQ_EVENT_MASK) {case ISQ_RECEIVER_EVENT:/* Got a packet(s). */net_rx(dev);break;case ISQ_TRANSMITTER_EVENT:lp-stats.tx_packets;netif_wake_queue(dev); /* Inform upper layers. */if ((status ( TX_OK |TX_LOST_CRS |TX_SQE_ERROR |TX_LATE_COL |TX_16_COL)) ! TX_OK) {if ((status TX_OK) 0) lp-stats.tx_errors;if (status TX_LOST_CRS) lp-stats.tx_carrier_errors;if (status TX_SQE_ERROR) lp-stats.tx_heartbeat_errors;if (status TX_LATE_COL) lp-stats.tx_window_errors;if (status TX_16_COL) lp-stats.tx_aborted_errors;}break;case ISQ_BUFFER_EVENT:if (status READY_FOR_TX) {/* we tried to transmit a packet earlier,but inexplicably ran out of buffers.That shouldnt happen since we only everload one packet. Shrug. Do the rightthing anyway. */netif_wake_queue(dev); /* Inform upper layers. */}if (status TX_UNDERRUN) {if (net_debug 0) printk(%s: transmit underrun\n, dev-name);lp-send_underrun;if (lp-send_underrun 3) lp-send_cmd TX_AFTER_381;else if (lp-send_underrun 6) lp-send_cmd TX_AFTER_ALL;/* transmit cycle is done, althoughframe wasnt transmitted - thisavoids having to wait for the upperlayers to timeout on us, in theevent of a tx underrun */netif_wake_queue(dev); /* Inform upper layers. */}
#if ALLOW_DMAif (lp-use_dma (status RX_DMA)) {int count readreg(dev, PP_DmaFrameCnt);while(count) {if (net_debug 5)printk(%s: receiving %d DMA frames\n, dev-name, count);if (net_debug 2 count 1)printk(%s: receiving %d DMA frames\n, dev-name, count);dma_rx(dev);if (--count 0)count readreg(dev, PP_DmaFrameCnt);if (net_debug 2 count 0)printk(%s: continuing with %d DMA frames\n, dev-name, count);}}
#endifbreak;case ISQ_RX_MISS_EVENT:lp-stats.rx_missed_errors (status 6);break;case ISQ_TX_COL_EVENT:lp-stats.collisions (status 6);break;}}return IRQ_RETVAL(handled);
}net_interrupt里又调用net_rx(dev);进行处理
net_rx(struct net_device *dev)
{struct net_local *lp netdev_priv(dev);struct sk_buff *skb;int status, length;int ioaddr dev-base_addr;status readword(ioaddr, RX_FRAME_PORT);length readword(ioaddr, RX_FRAME_PORT);if ((status RX_OK) 0) {count_rx_errors(status, lp);return;}/* Malloc up new buffer. */skb dev_alloc_skb(length 2);if (skb NULL) {
#if 0 /* Again, this seems a cruel thing to do */printk(KERN_WARNING %s: Memory squeeze, dropping packet.\n, dev-name);
#endiflp-stats.rx_dropped;return;}skb_reserve(skb, 2); /* longword align L3 header */readwords(ioaddr, RX_FRAME_PORT, skb_put(skb, length), length 1);if (length 1)skb-data[length-1] readword(ioaddr, RX_FRAME_PORT);if (net_debug 3) {printk( %s: received %d byte packet of type %x\n,dev-name, length,(skb-data[ETH_ALENETH_ALEN] 8) | skb-data[ETH_ALENETH_ALEN1]);}skb-protocoleth_type_trans(skb,dev);netif_rx(skb);dev-last_rx jiffies;lp-stats.rx_packets;lp-stats.rx_bytes length;
}net_rx里也会构造一个sk_buff 结构体然后调用netif_rx(skb);进行发包。
总结发送数据和接受数据是通过hard_start_xmit 和netif_rx完成的而数据的载体都是sk_buff 结构体。
