电子产品世界

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

view plainprint?

static struct resource s3c_dm9000_resource[] = {

[0] = {

.start = S3C24XX_PA_DM9000,

.end = S3C24XX_PA_DM9000+ 0x3,

.flags = IORESOURCE_MEM

},

[1]={

.start = S3C24XX_PA_DM9000 + 0x4, //CMD pin is A2 0x20000304

.end = S3C24XX_PA_DM9000 + 0x4 + 0x7c, // 0x20000380

.flags = IORESOURCE_MEM

},

[2] = {

.start = IRQ_EINT7,

.end = IRQ_EINT7,

.flags = IORESOURCE_IRQ

},

};

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：

view plainprint?

static struct dm9000_plat_data s3c_device_dm9000_platdata = {

.flags= DM9000_PLATF_16BITONLY,

};

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

view plainprint?

EXPORT_SYMBOL(s3c_device_dm9000);

3、设备启动的初始化过程

view plainprint?

MACHINE_START(S3C2440, "SMDK2440")

.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,

.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

view plainprint?

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);

platform_add_devices(smdk2440_devices, ARRAY_SIZE(smdk2440_devices));

smdk_machine_init();

}

下面是具体的设备列表

view plainprint?

static struct platform_device *smdk2440_devices[] __initdata = {

&s3c_device_ohci,

&s3c_device_lcd,

&s3c_device_wdt,

&s3c_device_i2c0,

&s3c_device_iis,

&s3c_device_rtc,

&s3c24xx_uda134x,

&s3c_device_dm9000,

&s3c_device_adc,

&s3c_device_ts,

};

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

view plainprint?

struct sk_buff {

struct sk_buff *next;

struct sk_buff *prev;

ktime_t tstamp;

struct sock *sk;

struct net_device *dev;

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;

#ifdef CONFIG_NET_CLS_ACT

__u16 tc_verd;

#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);

#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;

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, dont 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：

view plainprint?

struct net_device {

char name[IFNAMSIZ];

struct pm_qos_request_list *pm_qos_req;

struct hlist_node name_hlist;

char *ifalias;

unsigned long mem_end;

unsigned long mem_start;

unsigned long base_addr;

unsigned int irq;

unsigned char if_port;

unsigned char dma;

unsigned long state;

struct list_head dev_list;

struct list_head napi_list;

struct list_head unreg_list;

unsigned long features;

#define NETIF_F_SG 1

#define NETIF_F_IP_CSUM 2

#define NETIF_F_NO_CSUM 4

#define NETIF_F_HW_CSUM 8

#define NETIF_F_IPV6_CSUM 16

#define NETIF_F_HIGHDMA 32

#define NETIF_F_FRAGLIST 64

#define NETIF_F_HW_VLAN_TX 128

#define NETIF_F_HW_VLAN_RX 256

#define NETIF_F_HW_VLAN_FILTER 512

#define NETIF_F_VLAN_CHALLENGED 1024

#define NETIF_F_GSO 2048

#define NETIF_F_LLTX 4096

#define NETIF_F_NETNS_LOCAL 8192

#define NETIF_F_GRO 16384

#define NETIF_F_LRO 32768

#define NETIF_F_FCOE_CRC (1 << 24)

#define NETIF_F_SCTP_CSUM (1 << 25)

#define NETIF_F_FCOE_MTU (1 << 26)

#define NETIF_F_NTUPLE (1 << 27)

#define NETIF_F_RXHASH (1 << 28)

#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)

#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)

#define NETIF_F_ONE_FOR_ALL (NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ROBUST |

NETIF_F_SG | NETIF_F_HIGHDMA |

NETIF_F_FRAGLIST)

int ifindex;

int iflink;

struct net_device_stats stats;

#ifdef CONFIG_WIRELESS_EXT

const struct iw_handler_def * wireless_handlers;

struct iw_public_data * wireless_data;

#endif

const struct net_device_ops *netdev_ops;

const struct ethtool_ops *ethtool_ops;

const struct header_ops *header_ops;

unsigned int flags;

unsigned short gflags;

unsigned short priv_flags;

unsigned short padded;

unsigned char operstate;

unsigned char link_mode;

unsigned int mtu;

unsigned short type;

unsigned short hard_header_len;

unsigned short needed_headroom;

unsigned short needed_tailroom;

struct net_device *master;

unsigned char perm_addr[MAX_ADDR_LEN];

unsigned char addr_len;

unsigned short dev_id;

spinlock_t addr_list_lock;

struct netdev_hw_addr_list uc;

struct netdev_hw_addr_list mc;

int uc_promisc;

unsigned int promiscuity;

unsigned int allmulti;

#ifdef CONFIG_NET_DSA

void *dsa_ptr;

#endif

void *atalk_ptr;

void *ip_ptr;

void *dn_ptr;

void *ip6_ptr;

void *ec_ptr;

void *ax25_ptr;

struct wireless_dev *ieee80211_ptr;

unsigned long last_rx;

unsigned char *dev_addr;

struct netdev_hw_addr_list dev_addrs;

unsigned char broadcast[MAX_ADDR_LEN];

#ifdef CONFIG_RPS

struct kset *queues_kset;

struct netdev_rx_queue *_rx;

unsigned int num_rx_queues;

#endif

struct netdev_queue rx_queue;

struct netdev_queue *_tx ____cacheline_aligned_in_smp;

unsigned int num_tx_queues;

unsigned int real_num_tx_queues;

struct Qdisc *qdisc;

unsigned long tx_queue_len;

spinlock_t tx_global_lock;

unsigned long trans_start;

int watchdog_timeo;

struct timer_list watchdog_timer;

atomic_t refcnt ____cacheline_aligned_in_smp;

struct list_head todo_list;

struct hlist_node index_hlist;

struct list_head link_watch_list;

enum { NETREG_UNINITIALIZED=0,

NETREG_REGISTERED,

NETREG_UNREGISTERING,

NETREG_UNREGISTERED,

NETREG_RELEASED,

NETREG_DUMMY,

} reg_state:16;

enum {

RTNL_LINK_INITIALIZED,

RTNL_LINK_INITIALIZING,

} rtnl_link_state:16;

void (*destructor)(struct net_device *dev);

#ifdef CONFIG_NETPOLL

struct netpoll_info *npinfo;

#endif

#ifdef CONFIG_NET_NS

struct net *nd_net;

#endif

void *ml_priv;

struct net_bridge_port *br_port;

struct macvlan_port *macvlan_port;

struct garp_port *garp_port;

struct device dev;

const struct attribute_group *sysfs_groups[4];

const struct rtnl_link_ops *rtnl_link_ops;

unsigned long vlan_features;

#define GSO_MAX_SIZE 65536

unsigned int gso_max_size;

#ifdef CONFIG_DCB

const struct dcbnl_rtnl_ops *dcbnl_ops;

#endif

#if defined(CONFIG_FCOE) || defined(CONFIG_FCOE_MODULE)

unsigned int fcoe_ddp_xid;

#endif

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。