[ECOS] who can tell me the relations between net device and net driver?

[=?gb2312?B?1cUgwcE=?= <johnsonest at hotmail dot com>]

Hello,everyone!
    I am confused by ecos net driver,following is a sample:
this is device i82559:

typedef struct i82559 {
   cyg_uint8                           // (split up for atomic byte 
access)
       found:1,                        // was hardware discovered?
       mac_addr_ok:1,                  // can we bring up?
       active:1,                       // has this if been brung up?
       hardwired_esa:1,                // set if ESA is hardwired via CDL
       promisc:1,                      // set if in promisc mode
       multicast_all:1,                // set if MultiCastALL mode
       oversized:1,                    // set if oversized packets are 
received (VLAN mode)
       spare1:1; 
   cyg_uint8                           // Count nested sends to reject
       within_send:8;                  //     nested requests to send
   cyg_uint8
       tx_in_progress:1,               // transmit in progress flag
       tx_queue_full:1,                // all Tx descriptors used flag
       spare3:6; 
   cyg_uint8  index;                   // 0 or 1 or whatever
   cyg_uint32 devid;                   // PCI device id
   cyg_uint32 memory_address;          // PCI memory address
   cyg_uint32 io_address;              // memory mapped I/O address
   cyg_uint8  mac_address[6];          // mac (hardware) address
   void *ndp;                          // Network Device Pointer

   int next_rx_descriptor;             // descriptor index for RFDs
   RFD* rx_ring[MAX_RX_DESCRIPTORS];   // location of Rx descriptors

   int tx_descriptor_add;              // descriptor index for additions
   int tx_descriptor_active;           // descriptor index for active tx
   int tx_descriptor_remove;           // descriptor index for remove

   TxCB* tx_ring[MAX_TX_DESCRIPTORS];  // location of Tx descriptors
   unsigned long tx_keys[MAX_TX_DESCRIPTORS];
                                       // keys for tx q management

   // Interrupt handling stuff
   cyg_vector_t    vector;             // interrupt vector
   cyg_handle_t    interrupt_handle;   // handle for int.handler
   cyg_interrupt   interrupt_object;

#ifdef KEEP_STATISTICS
   void *p_statistics;                 // pointer to statistical counters
#endif

   cyg_uint32 platform_timeout;        // Some platforms use a timeout
   int tx_descriptor_timeout;          // Is it fixated on this tx?

} I82559;

I do not know "void *ndp; // Network Device Pointer" pointer what? it 
should be a hardware independent device,but no this device structure was 
defined.
and i do not find where to init __NETDEVTAB__[] !

in following code:

typedef struct cyg_netdevtab_entry {
   const char        *name;
   bool             (*init)(struct cyg_netdevtab_entry *tab);
   void              *device_instance;  // Local data, instance specific
   unsigned long     status;
} CYG_HAL_TABLE_TYPE cyg_netdevtab_entry_t;
device_instance is what? i guess it is a device

and struct eth_drv_sc {
   struct eth_hwr_funs *funs;
   void                *driver_private;
   const char          *dev_name;
   int                  state;
   struct arpcom        sc_arpcom; /* ethernet common */
};

who can explain in details to me ? thank you very much!!!!!!!!!!!!!!
please email to me

BRS/johnsonest

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