学步园

dm9000驱动中一共包含两个中断

//这个中断函数主要做的事情是读dm9000寄存器NSR,WCR,根据读到的内容
//作出相应提示
static irqreturn_t dm9000_wol_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	board_info_t *db = netdev_priv(dev);
	unsigned long flags;
	unsigned nsr, wcr;

	//关中断，获得自旋锁
	spin_lock_irqsave(&db->lock, flags);

	nsr = ior(db, DM9000_NSR);
	wcr = ior(db, DM9000_WCR);

	dev_dbg(db->dev, "%s: NSR=0x%02x, WCR=0x%02x\n", __func__, nsr, wcr);

	if (nsr & NSR_WAKEST) {
		/* clear, so we can avoid */
		iow(db, DM9000_NSR, NSR_WAKEST);

		if (wcr & WCR_LINKST)
			dev_info(db->dev, "wake by link status change\n");
		if (wcr & WCR_SAMPLEST)
			dev_info(db->dev, "wake by sample packet\n");
		if (wcr & WCR_MAGICST )
			dev_info(db->dev, "wake by magic packet\n");
		if (!(wcr & (WCR_LINKST | WCR_SAMPLEST | WCR_MAGICST)))
			dev_err(db->dev, "wake signalled with no reason? "
				"NSR=0x%02x, WSR=0x%02x\n", nsr, wcr);

	}

	//释放自旋锁，恢复本地中断
	spin_unlock_irqrestore(&db->lock, flags);

	return (nsr & NSR_WAKEST) ? IRQ_HANDLED : IRQ_NONE;
}


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 */
	//获取自旋锁，关中断
	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);

	//通过读DM9000中断寄存器，判断是哪种类型中断，并作出相应处理
	/* 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 */
	//如果是接收中断，读取接收的数据并存入skbuff，并提交协议上一层
	if (int_status & ISR_PRS)
		dm9000_rx(dev);

	/* Trnasmit Interrupt check */
	//发送中断，如果还有包未发完，继续发送。
	if (int_status & ISR_PTS)
		dm9000_tx_done(dev, db);

	//如果是DM9000E系列的芯片，作特别处理。
	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 */
	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;
}