ARM-Linux驱动--DM9000网卡驱动分析(二)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
交叉编译器：arm-linuc-gcc4.3.2
原创作品，转载请标明出处/yming0221/article/details/6615027
本文接上文
ARM-Linux驱动--DM9000网卡驱动分析(一)
ARM-Linux驱动--DM9000网卡驱动分析(二)
下面开始看网卡设备的打开、关闭函数和操作函数
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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的打开函数
由于在函数alloc_netdev_mq()中分配net_device和网卡的私有数据是一起分配的，详见函数的实现
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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;
}
..............
}
所以使用函数netdev_priv()函数返回的是网卡的私有数据的地址，函数的实现如下：
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static inline void *netdev_priv(const struct net_device *dev)
{
return (char *)dev + ALIGN(sizeof(struct net_device), NETDEV_ALIGN);
}
这样两者会同时生存和消失。
dm9000_open()函数
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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 %s\n", 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、网卡关闭函数
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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 %s\n", 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;
}
下面是调用的dm9000_shutdown(ndev)函数，该函数的功能是复位phy，配置寄存器GPR位0为1，关闭dm9000电源，配置寄存器IMR位7为1，disable中断，配置寄存器RCR，disable接收
函数如下:
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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、接下来了解一下数据的发送函数dm9000_start_xmit
上图可以看出DM9000的SRAM中地址0x0000到0x0BFF是TXBuffer，从0x0C00到0x3FFF是RXBuffer，包的有效数据必须提前放到TXBuffer缓冲区，使用端口命令来选择MWCMD寄存器。最后设置TXCR寄存器的bit[0]TXREQ来自动发送包。
发送包的步骤如下:
(1)检查存储器宽度，通过读取ISR的bit[7:6]来确定位数
(2)写数据到TXSRAM
(3)写传输长度到TXPLL和TXPLH寄存器
(4)设置TXCR的bit[0]TXREQ来发送包
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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;
}
上面函数调用下面的函数 dm9000_send_packet来发送数据
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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、下面看一下当一个数据包发送完成后的中断处理函数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 x\n", tx_status);
if (db->tx_pkt_cnt > 0)
dm9000_send_packet(dev, db->queue_ip_summed,
db->queue_pkt_len);
netif_wake_queue(dev);
}
}
