平台是最最经典的s3c2440了，说了要做这件事情很久了，就是改几行代码，一直没有做。前几天逼了自己一下，终于给做了，拖延症患者伤不起。
以下是需要读者对napi机制有所熟悉：
step1:在board_info结构体里面增加struct napi_struct napi；（这个还用说……）
step2：在dm9000_probe函数中增加netif_napi_add(ndev, &db->napi, dm9000_napi_poll, 64);
dm9000_napi_poll函数实现如下：
static int dm9000_napi_poll(struct napi_struct *napi, int budget)
{
board_info_t *db = container_of(napi, board_info_t, napi);
unsigned long flags;
u8 reg_save;
spin_lock_irqsave(&db->lock, flags);
reg_save = readb(db->io_addr);
dm9000_rx(db->ndev, budget);
napi_complete(napi);
iow(db, DM9000_IMR, db->imr_all);
writeb(reg_save, db->io_addr);
spin_unlock_irqrestore(&db->lock, flags);
return 0;
}
step3：在dm9000_open函数中增加napi_enable(&db->napi);//使能 NAPI
在dm9000_stop函数中增加napi_disable(&db->napi);//禁止 NAPI
step4:修改dm9000_interrupt中断函数，如下
static irqreturn_t dm9000_interrupt(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
board_info_t *db = netdev_priv(dev);
int int_status;
unsigned long flags;
u8 reg_save;
dm9000_dbg(db, 3, "entering %s\n", __func__);
/* A real interrupt coming */
/* holders of db->lock must always block IRQs */
spin_lock_irqsave(&db->lock, flags);
/* Save previous register address */
reg_save = readb(db->io_addr);
/* Disable all interrupts */
iow(db, DM9000_IMR, IMR_PAR);
/* Got DM9000 interrupt status */
int_status = ior(db, DM9000_ISR); /* Got ISR */
iow(db, DM9000_ISR, int_status); /* Clear ISR status */
if (netif_msg_intr(db))
dev_dbg(db->dev, "interrupt status %02x\n", int_status);
/* Received the coming packet */
if (int_status & ISR_PRS)//接受中断的话执行napi_schedule
{
napi_schedule(&db->napi);
}
/* Trnasmit Interrupt check */
if (int_status & ISR_PTS)
dm9000_tx_done(dev, db);
if (db->type != TYPE_DM9000E) {
if (int_status & ISR_LNKCHNG) {
/* fire a link-change request */
schedule_delayed_work(&db->phy_poll, 1);
}
}
/* Re-enable interrupt mask */
if ((int_status & ISR_PRS) == 0)//如果不是接收函数，可以重新使能中断
iow(db, DM9000_IMR, db->imr_all);
/* Restore previous register address */
writeb(reg_save, db->io_addr);
spin_unlock_irqrestore(&db->lock, flags);
return IRQ_HANDLED;
}
step5：修改接受函数，如下：
static void
dm9000_rx(struct net_device *dev, int budget)
{
board_info_t *db = netdev_priv(dev);
struct dm9000_rxhdr rxhdr;
struct sk_buff *skb;
u8 rxbyte, *rdptr;
bool GoodPacket;
int RxLen, rxTime = 0;
/* Check packet ready or not */
do {
ior(db, DM9000_MRCMDX); /* Dummy read */
/* Get most updated data */
rxbyte = readb(db->io_data);
/* Status check: this byte must be 0 or 1 */
if (rxbyte & DM9000_PKT_ERR) {
dev_warn(db->dev, "status check fail: %d\n", rxbyte);
iow(db, DM9000_RCR, 0x00); /* Stop Device */
iow(db, DM9000_ISR, IMR_PAR); /* Stop INT request */
break;
}
if (!(rxbyte & DM9000_PKT_RDY))
break;
/* A packet ready now & Get status/length */
GoodPacket = true;
writeb(DM9000_MRCMD, db->io_addr);
(db->inblk)(db->io_data, &rxhdr, sizeof(rxhdr));
RxLen = le16_to_cpu(rxhdr.RxLen);
if (netif_msg_rx_status(db))
dev_dbg(db->dev, "RX: status %02x, length %04x\n",
rxhdr.RxStatus, RxLen);
/* Packet Status check */
if (RxLen < 0x40) {
GoodPacket = false;
if (netif_msg_rx_err(db))
dev_dbg(db->dev, "RX: Bad Packet (runt)\n");
}
if (RxLen > DM9000_PKT_MAX) {
dev_dbg(db->dev, "RST: RX Len:%x\n", RxLen);
}
/* rxhdr.RxStatus is identical to RSR register. */
if (rxhdr.RxStatus & (RSR_FOE | RSR_CE | RSR_AE |
RSR_PLE | RSR_RWTO |
RSR_LCS | RSR_RF)) {
GoodPacket = false;
if (rxhdr.RxStatus & RSR_FOE) {
if (netif_msg_rx_err(db))
dev_dbg(db->dev, "fifo error\n");
dev->stats.rx_fifo_errors++;
}
if (rxhdr.RxStatus & RSR_CE) {
if (netif_msg_rx_err(db))
dev_dbg(db->dev, "crc error\n");
dev->stats.rx_crc_errors++;
}
if (rxhdr.RxStatus & RSR_RF) {
if (netif_msg_rx_err(db))
dev_dbg(db->dev, "length error\n");
dev->stats.rx_length_errors++;
}
}
/* Move data from DM9000 */
if (GoodPacket &&
((skb = dev_alloc_skb(RxLen + 4)) != NULL)) {
skb_reserve(skb, 2);
rdptr = (u8 *) skb_put(skb, RxLen - 4);
/* Read received packet from RX SRAM */
(db->inblk)(db->io_data, rdptr, RxLen);
dev->stats.rx_bytes += RxLen;
/* Pass to upper layer */
skb->protocol = eth_type_trans(skb, dev);
if (db->rx_csum) {
if ((((rxbyte & 0x1c) << 3) & rxbyte) == 0)
skb->ip_summed = CHECKSUM_UNNECESSARY;
else
skb_checksum_none_assert(skb);
}
netif_rx(skb);
dev->stats.rx_packets++;
} else {
/* need to dump the packet's data */
(db->dumpblk)(db->io_data, RxLen);
}
rxTime++;
} while ((rxbyte & DM9000_PKT_RDY)&&(rxTime < budget));
// printk("rxTime:%d\n", rxTime);
}
改完了就可以开始测试了。
不过保险起见，最好在timeout、suspend、resume三个函数中增加响应的enable和disable函数。
性能上面的提升？呵呵~~~~~
移植中犯的一个错误，在中断函数里判断到是接收中断就直接调用完napi_schedule退出了，忽略了进中断的时候可能发送中断也被置位了的情况，结果老是timeout出错，这个是一个要注意的地方。进中断之后，可能是发送和接收中断同时置位了。
接下来就是要把dma机制移植上去，估计要花点时间了这个。