nios ii网络驱动程序分析

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1、NIOSII网络驱动程序分析  网络是嵌入式应用的常备功能，在NIOSII中集成了UCOSII和LWIP，分析网络设备在NIOSII中的来龙去脉对学习NIOSII设备驱动程序有典型的意义。设备的定义和系统设备联表管理。1.  驱动程序提供的freedev_rtl8019.h中定义一个freedev_rtl8019_if结构的全局变量dev#defineFREEDEV_RTL8019_INSTANCE(name,dev)freedev_rtl8019_ifdev={ {   ALT_LLIST_ENTRY,   {     0,     name##_NAME,

2、     freedev_rtl8019_init,     freedev_rtl8019_rx,   }, }, name##_BASE, name##_IRQ, 8, 0, 0}结构freedev_rtl8019_if定义如下：typedefstruct{ alt_lwip_dev_list   lwip_dev_list; int                base_addr; int                irq; int                bus_width; sys_sem_t          semaphore;

3、 sys_sem_t          arp_semaphore; alt_u8             tx_packet_no;/*NumberofpacketallocatedforTx*/}freedev_rtl8019_if;相关结构定义如下：typedefstruct{ alt_llist    llist;    /*forinternaluse*/ alt_lwip_dev dev;}alt_lwip_dev_list;structalt_lwip_dev{ /*ThenetifpointerMUSTbethefirstelementinthestruct

4、ure*/ structnetif      `      *netif; constchar*      name; err_t(*init_routine)(structnetif*); void(*rx_routine)();};structnetif{ /**pointertonextinlinkedlist*/ structnetif*next;  /**IPaddressconfigurationinnetworkbyteorder*/ structip_addrip_addr; structip_addrnetmask; structip_addrgw; /*

5、*Thisfunctioniscalledbythenetworkdevicedriver  * topassapacketuptheTCP/IPstack.*/ err_t(*input)(structpbuf*p,structnetif*inp); /**ThisfunctioniscalledbytheIPmodulewhenitwants  * tosendapacketontheinterface.Thisfunctiontypically  * firstresolvesthehardwareaddress,thensendsthepacket.*/ err_t

6、(*output)(structnetif*netif,structpbuf*p,structip_addr*ipaddr); /**ThisfunctioniscalledbytheARPmodulewhenitwants  * tosendapacketontheinterface.Thisfunctionoutputs  * thepbufas-isonthelinkmedium.*/ err_t(*linkoutput)(structnetif*netif,structpbuf*p); /**Thisfieldcanbesetbythedevicedriverand

7、couldpoint  * tostateinformationforthedevice.*/ void*state;#ifLWIP_DHCP /**theDHCPclientstateinformationforthisnetif*/ structdhcp*dhcp;#endif /**numberofbytesusedinhwaddr*/ unsignedcharhwaddr_len; /**linklevelhardwareaddressofthisinterface*/ unsignedcharhwaddr