硬件平台：FL2440（s3c2440）

内核版本：2.6.35

主机平台：Ubuntu11.04

内核版本：2.6.39

原创作品，转载请标明出处http://blog.csdn.net/yming0221/article/details/6609742

1、下图是DM9000的引脚图

2、这里我们结合具体的开发板FL2440

下面是FL2440和DM9000的引脚链接图

本人移植DM9000的时候将设备的资源定义放在了arch/arm/plat-s3c24xx/devs.c中，详情点击上一篇博文linux内核移植-移植2.6.35.4内核到s3c2440

下面是设备的资源定义

/*DM9000*/ /* 定义该设备使用的资源 */ static struct resource s3c_dm9000_resource[] = { [0] = { /* 寄存器定义在mach-s3c2410/include/mach/map.h */ .start = S3C24XX_PA_DM9000, /* 实际地址 0x20000300 */ .end = S3C24XX_PA_DM9000+ 0x3, /* 0x20000303 */ .flags = IORESOURCE_MEM /* 资源标志为地址资源 */ }, [1]={ .start = S3C24XX_PA_DM9000 + 0x4, //CMD pin is A2 0x20000304 .end = S3C24XX_PA_DM9000 + 0x4 + 0x7c, // 0x20000380 .flags = IORESOURCE_MEM /* 资源标志为地址资源 */ }, [2] = { .start = IRQ_EINT7, /* 中断为外部7号中断 */ .end = IRQ_EINT7, /* 中断为外部7号中断 */ .flags = IORESOURCE_IRQ /* 资源标志为中断资源 */ }, };

这里可以看到，DM9000网卡使用的地址空间资源在nGCS4地址区域，所以上图的DM9000地址使能引脚连接nGCS4引脚。中断使用的是EINT7外部中断。

接着定义平台数据和平台设备，代码如下：

/* 定义平台数据 */ static struct dm9000_plat_data s3c_device_dm9000_platdata = { .flags= DM9000_PLATF_16BITONLY, }; /* 定义平台设备 */ struct platform_device s3c_device_dm9000 = { .name= "dm9000", //设备名，该名称与平台设备驱动中的名称一致 .id= 0, .num_resources= ARRAY_SIZE(s3c_dm9000_resource), .resource= s3c_dm9000_resource, //定义设备的资源 .dev= { .platform_data = &s3c_device_dm9000_platdata, //定义平台数据 } };

最后导出函数符号，保存函数地址和名称

EXPORT_SYMBOL(s3c_device_dm9000);

3、设备启动的初始化过程

MACHINE_START(S3C2440, "SMDK2440") /* Maintainer: Ben Dooks ben-linux@fluff.org */ .phys_io = S3C2410_PA_UART, .io_pg_offst = (((u32)S3C24XX_VA_UART) >> 18) & 0xfffc, .boot_params = S3C2410_SDRAM_PA + 0x100, .init_irq = s3c24xx_init_irq,/* 初始化中断 */ .map_io = smdk2440_map_io, .init_machine = smdk2440_machine_init,//定义设备的初始化函数 .timer = &s3c24xx_timer, MACHINE_END

而后会执行下面函数

static void __init smdk2440_machine_init(void) { s3c24xx_fb_set_platdata(&smdk2440_fb_info); s3c_i2c0_set_platdata(NULL); s3c24xx_ts_set_platdata(&smdk2410_ts_cfg);/* Added by yan */ platform_add_devices(smdk2440_devices, ARRAY_SIZE(smdk2440_devices));/* 向平台中添加设备 */ smdk_machine_init(); }

下面是具体的设备列表

static struct platform_device *smdk2440_devices[] __initdata = { &s3c_device_ohci, &s3c_device_lcd,/* ok */ &s3c_device_wdt,/* ok */ &s3c_device_i2c0, &s3c_device_iis, &s3c_device_rtc,/* ok */ &s3c24xx_uda134x, &s3c_device_dm9000, &s3c_device_adc,/* ok */ &s3c_device_ts,/* ok */ };

这样系统启动时，会给设备列表中的设备分配资源（地址资源和中断资源等）。

4、信息传输中的信息封装结构

4.1、sk_buff结构，定义在include/linux/skbuff.h中

struct sk_buff { /* These two members must be first. */ struct sk_buff *next; struct sk_buff *prev; ktime_t tstamp; struct sock *sk; struct net_device *dev; /* * This is the control buffer. It is free to use for every * layer. Please put your private variables there. If you * want to keep them across layers you have to do a skb_clone() * first. This is owned by whoever has the skb queued ATM. */ char cb[48] __aligned(8); unsigned long _skb_refdst; #ifdef CONFIG_XFRM struct sec_path *sp; #endif unsigned int len, data_len; __u16 mac_len, hdr_len; union { __wsum csum; struct { __u16 csum_start; __u16 csum_offset; }; }; __u32 priority; kmemcheck_bitfield_begin(flags1); __u8 local_df:1, cloned:1, ip_summed:2, nohdr:1, nfctinfo:3; __u8 pkt_type:3, fclone:2, ipvs_property:1, peeked:1, nf_trace:1; kmemcheck_bitfield_end(flags1); __be16 protocol; void (*destructor)(struct sk_buff *skb); #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) struct nf_conntrack *nfct; struct sk_buff *nfct_reasm; #endif #ifdef CONFIG_BRIDGE_NETFILTER struct nf_bridge_info *nf_bridge; #endif int skb_iif; #ifdef CONFIG_NET_SCHED __u16 tc_index; /* traffic control index */ #ifdef CONFIG_NET_CLS_ACT __u16 tc_verd; /* traffic control verdict */ #endif #endif __u32 rxhash; kmemcheck_bitfield_begin(flags2); __u16 queue_mapping:16; #ifdef CONFIG_IPV6_NDISC_NODETYPE __u8 ndisc_nodetype:2, deliver_no_wcard:1; #else __u8 deliver_no_wcard:1; #endif kmemcheck_bitfield_end(flags2); /* 0/14 bit hole */ #ifdef CONFIG_NET_DMA dma_cookie_t dma_cookie; #endif #ifdef CONFIG_NETWORK_SECMARK __u32 secmark; #endif union { __u32 mark; __u32 dropcount; }; __u16 vlan_tci; sk_buff_data_t transport_header; sk_buff_data_t network_header; sk_buff_data_t mac_header; /* These elements must be at the end, see alloc_skb() for details. */ sk_buff_data_t tail; sk_buff_data_t end; unsigned char *head, *data; unsigned int truesize; atomic_t users; };

元素的含义如下（摘自内核,源码,版本2.6.35.4）
*struct sk_buff - socket buffer
* @next: Next buffer inlist
* @prev: Previous buffer in list
* @sk: Socketwe are owned by
* @tstamp: Time we arrived
* @dev:Device we arrived on/are leaving by
* @transport_header:Transport layer header
* @network_header: Network layerheader
* @mac_header: Link layer header
*@_skb_refdst: destination entry (with norefcount bit)
* @sp:the security path, used for xfrm
* @cb: Control buffer. Freefor use by every layer. Put private vars here
* @len: Lengthof actual data
* @data_len: Data length
* @mac_len:Length of link layer header
* @hdr_len: writable headerlength of cloned skb
* @csum: Checksum (must includestart/offset pair)
* @csum_start: Offset from skb->headwhere checksumming should start
* @csum_offset: Offset fromcsum_start where checksum should be stored
* @local_df:allow local fragmentation
* @cloned: Head may be cloned(check refcnt to be sure)
* @nohdr: Payload reference only,must not modify header
* @pkt_type: Packet class
*@fclone: skbuff clone status
* @ip_summed: Driver fed us anIP checksum
* @priority: Packet queueing priority
*@users: User count - see {datagram,tcp}.c
* @protocol:Packet protocol from driver
* @truesize: Buffer size
*@head: Head of buffer
* @data: Data head pointer
*@tail: Tail pointer
* @end: End pointer
*@destructor: Destruct function
* @mark: Generic packetmark
* @nfct: Associated connection, if any
*@ipvs_property: skbuff is owned by ipvs
* @peeked: thispacket has been seen already, so stats have been
* done forit, don't do them again
* @nf_trace: netfilter packet traceflag
* @nfctinfo: Relationship of this skb to theconnection
* @nfct_reasm: netfilter conntrack re-assemblypointer
* @nf_bridge: Saved data about a bridged frame - seebr_netfilter.c
* @skb_iif: ifindex of device we arrivedon
* @rxhash: the packet hash computed on receive
*@queue_mapping: Queue mapping for multiqueue devices
*@tc_index: Traffic control index
* @tc_verd: traffic controlverdict
* @ndisc_nodetype: router type (from link layer)
*@dma_cookie: a cookie to one of several possible DMA operations
*done by skb DMA functions
* @secmark: security marking
*@vlan_tci: vlan tag control information

关于sk_buff的更多分析见另一篇转载的博文http://blog.csdn.net/yming0221/article/details/6609734

4.2、net_device

关于net_device一个非常庞大的结构体，定义在/inlcude/linux/netdevice.h中

如下：

struct net_device { /* * This is the first field of the "visible" part of this structure * (i.e. as seen by users in the "Space.c" file). It is the name * the interface. */ char name[IFNAMSIZ]; struct pm_qos_request_list *pm_qos_req; /* device name hash chain */ struct hlist_node name_hlist; /* snmp alias */ char *ifalias; /* * I/O specific fields * FIXME: Merge these and struct ifmap into one */ unsigned long mem_end; /* shared mem end */ unsigned long mem_start; /* shared mem start */ unsigned long base_addr; /* device I/O address */ unsigned int irq; /* device IRQ number */ /* * Some hardware also needs these fields, but they are not * part of the usual set specified in Space.c. */ unsigned char if_port; /* Selectable AUI, TP,..*/ unsigned char dma; /* DMA channel */ unsigned long state; struct list_head dev_list; struct list_head napi_list; struct list_head unreg_list; /* Net device features */ unsigned long features; #define NETIF_F_SG 1 /* Scatter/gather IO. */ #define NETIF_F_IP_CSUM 2 /* Can checksum TCP/UDP over IPv4. */ #define NETIF_F_NO_CSUM 4 /* Does not require checksum. F.e. loopack. */ #define NETIF_F_HW_CSUM 8 /* Can checksum all the packets. */ #define NETIF_F_IPV6_CSUM 16 /* Can checksum TCP/UDP over IPV6 */ #define NETIF_F_HIGHDMA 32 /* Can DMA to high memory. */ #define NETIF_F_FRAGLIST 64 /* Scatter/gather IO. */ #define NETIF_F_HW_VLAN_TX 128 /* Transmit VLAN hw acceleration */ #define NETIF_F_HW_VLAN_RX 256 /* Receive VLAN hw acceleration */ #define NETIF_F_HW_VLAN_FILTER 512 /* Receive filtering on VLAN */ #define NETIF_F_VLAN_CHALLENGED 1024 /* Device cannot handle VLAN packets */ #define NETIF_F_GSO 2048 /* Enable software GSO. */ #define NETIF_F_LLTX 4096 /* LockLess TX - deprecated. Please */ /* do not use LLTX in new drivers */ #define NETIF_F_NETNS_LOCAL 8192 /* Does not change network namespaces */ #define NETIF_F_GRO 16384 /* Generic receive offload */ #define NETIF_F_LRO 32768 /* large receive offload */ /* the GSO_MASK reserves bits 16 through 23 */ #define NETIF_F_FCOE_CRC (1 << 24) /* FCoE CRC32 */ #define NETIF_F_SCTP_CSUM (1 << 25) /* SCTP checksum offload */ #define NETIF_F_FCOE_MTU (1 << 26) /* Supports max FCoE MTU, 2158 bytes*/ #define NETIF_F_NTUPLE (1 << 27) /* N-tuple filters supported */ #define NETIF_F_RXHASH (1 << 28) /* Receive hashing offload */ /* Segmentation offload features */ #define NETIF_F_GSO_SHIFT 16 #define NETIF_F_GSO_MASK 0x00ff0000 #define NETIF_F_TSO (SKB_GSO_TCPV4 << NETIF_F_GSO_SHIFT) #define NETIF_F_UFO (SKB_GSO_UDP << NETIF_F_GSO_SHIFT) #define NETIF_F_GSO_ROBUST (SKB_GSO_DODGY << NETIF_F_GSO_SHIFT) #define NETIF_F_TSO_ECN (SKB_GSO_TCP_ECN << NETIF_F_GSO_SHIFT) #define NETIF_F_TSO6 (SKB_GSO_TCPV6 << NETIF_F_GSO_SHIFT) #define NETIF_F_FSO (SKB_GSO_FCOE << NETIF_F_GSO_SHIFT) /* List of features with software fallbacks. */ #define NETIF_F_GSO_SOFTWARE (NETIF_F_TSO | NETIF_F_TSO_ECN | NETIF_F_TSO6) #define NETIF_F_GEN_CSUM (NETIF_F_NO_CSUM | NETIF_F_HW_CSUM) #define NETIF_F_V4_CSUM (NETIF_F_GEN_CSUM | NETIF_F_IP_CSUM) #define NETIF_F_V6_CSUM (NETIF_F_GEN_CSUM | NETIF_F_IPV6_CSUM) #define NETIF_F_ALL_CSUM (NETIF_F_V4_CSUM | NETIF_F_V6_CSUM) /* * If one device supports one of these features, then enable them * for all in netdev_increment_features. */ #define NETIF_F_ONE_FOR_ALL (NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ROBUST | \ NETIF_F_SG | NETIF_F_HIGHDMA | \ NETIF_F_FRAGLIST) /* Interface index. Unique device identifier */ int ifindex; int iflink; struct net_device_stats stats; #ifdef CONFIG_WIRELESS_EXT /* List of functions to handle Wireless Extensions (instead of ioctl). * See for details. Jean II */ const struct iw_handler_def * wireless_handlers; /* Instance data managed by the core of Wireless Extensions. */ struct iw_public_data * wireless_data; #endif /* Management operations */ const struct net_device_ops *netdev_ops; const struct ethtool_ops *ethtool_ops; /* Hardware header description */ const struct header_ops *header_ops; unsigned int flags; /* interface flags (a la BSD) */ unsigned short gflags; unsigned short priv_flags; /* Like 'flags' but invisible to userspace. */ unsigned short padded; /* How much padding added by alloc_netdev() */ unsigned char operstate; /* RFC2863 operstate */ unsigned char link_mode; /* mapping policy to operstate */ unsigned int mtu; /* interface MTU value */ unsigned short type; /* interface hardware type */ unsigned short hard_header_len; /* hardware hdr length */ /* extra head- and tailroom the hardware may need, but not in all cases * can this be guaranteed, especially tailroom. Some cases also use * LL_MAX_HEADER instead to allocate the skb. */ unsigned short needed_headroom; unsigned short needed_tailroom; struct net_device *master; /* Pointer to master device of a group, * which this device is member of. */ /* Interface address info. */ unsigned char perm_addr[MAX_ADDR_LEN]; /* permanent hw address */ unsigned char addr_len; /* hardware address length */ unsigned short dev_id; /* for shared network cards */ spinlock_t addr_list_lock; struct netdev_hw_addr_list uc; /* Unicast mac addresses */ struct netdev_hw_addr_list mc; /* Multicast mac addresses */ int uc_promisc; unsigned int promiscuity; unsigned int allmulti; /* Protocol specific pointers */ #ifdef CONFIG_NET_DSA void *dsa_ptr; /* dsa specific data */ #endif void *atalk_ptr; /* AppleTalk link */ void *ip_ptr; /* IPv4 specific data */ void *dn_ptr; /* DECnet specific data */ void *ip6_ptr; /* IPv6 specific data */ void *ec_ptr; /* Econet specific data */ void *ax25_ptr; /* AX.25 specific data */ struct wireless_dev *ieee80211_ptr; /* IEEE 802.11 specific data, assign before registering */ /* * Cache line mostly used on receive path (including eth_type_trans()) */ unsigned long last_rx; /* Time of last Rx */ /* Interface address info used in eth_type_trans() */ unsigned char *dev_addr; /* hw address, (before bcast because most packets are unicast) */ struct netdev_hw_addr_list dev_addrs; /* list of device hw addresses */ unsigned char broadcast[MAX_ADDR_LEN]; /* hw bcast add */ #ifdef CONFIG_RPS struct kset *queues_kset; struct netdev_rx_queue *_rx; /* Number of RX queues allocated at alloc_netdev_mq() time */ unsigned int num_rx_queues; #endif struct netdev_queue rx_queue; struct netdev_queue *_tx ____cacheline_aligned_in_smp; /* Number of TX queues allocated at alloc_netdev_mq() time */ unsigned int num_tx_queues; /* Number of TX queues currently active in device */ unsigned int real_num_tx_queues; /* root qdisc from userspace point of view */ struct Qdisc *qdisc; unsigned long tx_queue_len; /* Max frames per queue allowed */ spinlock_t tx_global_lock; /* * One part is mostly used on xmit path (device) */ /* These may be needed for future network-power-down code. */ /* * trans_start here is expensive for high speed devices on SMP, * please use netdev_queue->trans_start instead. */ unsigned long trans_start; /* Time (in jiffies) of last Tx */ int watchdog_timeo; /* used by dev_watchdog() */ struct timer_list watchdog_timer; /* Number of references to this device */ atomic_t refcnt ____cacheline_aligned_in_smp; /* delayed register/unregister */ struct list_head todo_list; /* device index hash chain */ struct hlist_node index_hlist; struct list_head link_watch_list; /* register/unregister state machine */ enum { NETREG_UNINITIALIZED=0, NETREG_REGISTERED, /* completed register_netdevice */ NETREG_UNREGISTERING, /* called unregister_netdevice */ NETREG_UNREGISTERED, /* completed unregister todo */ NETREG_RELEASED, /* called free_netdev */ NETREG_DUMMY, /* dummy device for NAPI poll */ } reg_state:16; enum { RTNL_LINK_INITIALIZED, RTNL_LINK_INITIALIZING, } rtnl_link_state:16; /* Called from unregister, can be used to call free_netdev */ void (*destructor)(struct net_device *dev); #ifdef CONFIG_NETPOLL struct netpoll_info *npinfo; #endif #ifdef CONFIG_NET_NS /* Network namespace this network device is inside */ struct net *nd_net; #endif /* mid-layer private */ void *ml_priv; /* bridge stuff */ struct net_bridge_port *br_port; /* macvlan */ struct macvlan_port *macvlan_port; /* GARP */ struct garp_port *garp_port; /* class/net/name entry */ struct device dev; /* space for optional device, statistics, and wireless sysfs groups */ const struct attribute_group *sysfs_groups[4]; /* rtnetlink link ops */ const struct rtnl_link_ops *rtnl_link_ops; /* VLAN feature mask */ unsigned long vlan_features; /* for setting kernel sock attribute on TCP connection setup */ #define GSO_MAX_SIZE 65536 unsigned int gso_max_size; #ifdef CONFIG_DCB /* Data Center Bridging netlink ops */ const struct dcbnl_rtnl_ops *dcbnl_ops; #endif #if defined(CONFIG_FCOE) || defined(CONFIG_FCOE_MODULE) /* max exchange id for FCoE LRO by ddp */ unsigned int fcoe_ddp_xid; #endif /* n-tuple filter list attached to this device */ struct ethtool_rx_ntuple_list ethtool_ntuple_list; };

我还没有细细的分析这个结构体，驱动程序在probe函数中使用register_netdev()注册该结构体指明的设备，将内核操作硬件的函数个内核联系起来。

更多见下一节分析ARM-Linux驱动--DM9000网卡驱动分析（二）