ARM-Linux驅動--DM9000網卡驅動分析（三）

內核版本：2.6.35

主機平臺：Ubuntu11.04

內核版本：2.6.39

交叉編譯器：arm-linuc-gcc4.3.2

原創作品，轉載請標明出處http://blog.csdn.net/yming0221/article/details/6615027

本文接上文

ARM-Linux驅動--DM9000網卡驅動分析（一）

ARM-Linux驅動--DM9000網卡驅動分析（二）

下面開始看網卡設備的打開、關閉函數和操作函數

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static const struct net_device_ops dm9000_netdev_ops = {

.ndo_open = dm9000_open,

.ndo_stop = dm9000_stop,

.ndo_start_xmit = dm9000_start_xmit,

.ndo_tx_timeout = dm9000_timeout,

.ndo_set_multicast_list = dm9000_hash_table,

.ndo_do_ioctl = dm9000_ioctl,

.ndo_change_mtu = eth_change_mtu,

.ndo_validate_addr = eth_validate_addr,

.ndo_set_mac_address = eth_mac_addr,

#ifdef CONFIG_NET_POLL_CONTROLLER

.ndo_poll_controller = dm9000_poll_controller,

#endif

};

1、DM9000的打開函數

由于在函數alloc_netdev_mq()中分配net_device和網卡的私有數據是一起分配的，詳見函數的實現

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struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,

void (*setup)(struct net_device *), unsigned int queue_count)

{

...................

alloc_size = sizeof(struct net_device);

if (sizeof_priv) {

alloc_size = ALIGN(alloc_size, NETDEV_ALIGN);

alloc_size += sizeof_priv;

}

alloc_size += NETDEV_ALIGN - 1;

p = kzalloc(alloc_size, GFP_KERNEL);

if (!p) {

printk(KERN_ERR "alloc_netdev: Unable to allocate device.n");

return NULL;

}

tx = kcalloc(queue_count, sizeof(struct netdev_queue), GFP_KERNEL);

if (!tx) {

printk(KERN_ERR "alloc_netdev: Unable to allocate "

"tx qdiscs.n");

goto free_p;

}

#ifdef CONFIG_RPS

rx = kcalloc(queue_count, sizeof(struct netdev_rx_queue), GFP_KERNEL);

if (!rx) {

printk(KERN_ERR "alloc_netdev: Unable to allocate "

"rx queues.n");

goto free_tx;

}

..............

}

所以使用函數netdev_priv()函數返回的是網卡的私有數據的地址，函數的實現如下：

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static inline void *netdev_priv(const struct net_device *dev)

{

return (char *)dev + ALIGN(sizeof(struct net_device), NETDEV_ALIGN);

}

這樣兩者會同時生存和消失。

dm9000_open()函數

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static int

dm9000_open(struct net_device *dev)

{

board_info_t *db = netdev_priv(dev);

unsigned long irqflags = db->irq_res->flags & IRQF_TRIGGER_MASK;

if (netif_msg_ifup(db))

dev_dbg(db->dev, "enabling %sn", dev->name);

if (irqflags == IRQF_TRIGGER_NONE)

dev_warn(db->dev, "WARNING: no IRQ resource flags set.n");

irqflags |= IRQF_SHARED;

if (request_irq(dev->irq, dm9000_interrupt, irqflags, dev->name, dev))

return -EAGAIN;

dm9000_reset(db);

dm9000_init_dm9000(dev);

db->dbug_cnt = 0;

mii_check_media(&db->mii, netif_msg_link(db), 1);

netif_start_queue(dev);

dm9000_schedule_poll(db);

return 0;

}

2、網卡關閉函數

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static int

dm9000_stop(struct net_device *ndev)

{

board_info_t *db = netdev_priv(ndev);

if (netif_msg_ifdown(db))

dev_dbg(db->dev, "shutting down %sn", ndev->name);

cancel_delayed_work_sync(&db->phy_poll);

netif_stop_queue(ndev);

netif_carrier_off(ndev);

free_irq(ndev->irq, ndev);

dm9000_shutdown(ndev);

return 0;

}

下面是調用的dm9000_shutdown(ndev)函數，該函數的功能是復位phy，配置寄存器GPR位0為1，關閉dm9000電源，配置寄存器IMR位7為1，disable中斷，配置寄存器RCR，disable接收

函數如下:

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static void

dm9000_shutdown(struct net_device *dev)

{

board_info_t *db = netdev_priv(dev);

dm9000_phy_write(dev, 0, MII_BMCR, BMCR_RESET);

iow(db, DM9000_GPR, 0x01);

iow(db, DM9000_IMR, IMR_PAR);

iow(db, DM9000_RCR, 0x00);

}

3、接下來了解一下數據的發送函數dm9000_start_xmit

上圖可以看出DM9000的SRAM中地址0x0000到0x0BFF是TXBuffer，從0x0C00到0x3FFF是RXBuffer，包的有效數據必須提前放到TXBuffer緩沖區，使用端口命令來選擇MWCMD寄存器。最后設置TXCR寄存器的bit[0]TXREQ來自動發送包。

發送包的步驟如下:

（1）檢查存儲器寬度，通過讀取ISR的bit[7:6]來確定位數

（2）寫數據到TXSRAM

（3）寫傳輸長度到TXPLL和TXPLH寄存器

（4）設置TXCR的bit[0]TXREQ來發送包

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static int

dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev)

{

unsigned long flags;

board_info_t *db = netdev_priv(dev);

dm9000_dbg(db, 3, "%s:n", __func__);

if (db->tx_pkt_cnt > 1)

return NETDEV_TX_BUSY;

spin_lock_irqsave(&db->lock, flags);

writeb(DM9000_MWCMD, db->io_addr);

(db->outblk)(db->io_data, skb->data, skb->len);

dev->stats.tx_bytes += skb->len;

db->tx_pkt_cnt++;

if (db->tx_pkt_cnt == 1) {

dm9000_send_packet(dev, skb->ip_summed, skb->len);

} else {

db->queue_pkt_len = skb->len;

db->queue_ip_summed = skb->ip_summed;

netif_stop_queue(dev);

}

spin_unlock_irqrestore(&db->lock, flags);

dev_kfree_skb(skb);

return NETDEV_TX_OK;

}

上面函數調用下面的函數 dm9000_send_packet來發送數據

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static void dm9000_send_packet(struct net_device *dev,

int ip_summed,

u16 pkt_len)

{

board_info_t *dm = to_dm9000_board(dev);

if (dm->ip_summed != ip_summed) {

if (ip_summed == CHECKSUM_NONE)

iow(dm, DM9000_TCCR, 0);

else

iow(dm, DM9000_TCCR, TCCR_IP | TCCR_UDP | TCCR_TCP);

dm->ip_summed = ip_summed;

}

iow(dm, DM9000_TXPLL, pkt_len);

iow(dm, DM9000_TXPLH, pkt_len >> 8);

iow(dm, DM9000_TCR, TCR_TXREQ);

}

5、下面看一下當一個數據包發送完成后的中斷處理函數dm9000_tx_done

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static void dm9000_tx_done(struct net_device *dev, board_info_t *db)

{

int tx_status = ior(db, DM9000_NSR);

if (tx_status & (NSR_TX2END | NSR_TX1END)) {

db->tx_pkt_cnt--;

dev->stats.tx_packets++;

if (netif_msg_tx_done(db))

dev_dbg(db->dev, "tx done, NSR xn", tx_status);

if (db->tx_pkt_cnt > 0)

dm9000_send_packet(dev, db->queue_ip_summed,

db->queue_pkt_len);

netif_wake_queue(dev);

}

}