網卡中斷主要是在接收新數據和數據發送完成時被調用,提醒網絡驅動設備接收新數據和喚醒發送隊列。
static irqreturn_t smsc911x_irqhandler(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
struct smsc911x_data *pdata = netdev_priv(dev);
u32 intsts = smsc911x_reg_read(pdata, INT_STS);
u32 inten = smsc911x_reg_read(pdata, INT_EN);
int serviced = IRQ_NONE;
u32 temp;
if (unlikely(intsts & inten & INT_STS_SW_INT_)) {/*判斷軟中斷有沒有觸發,如果有則關掉軟中斷並將其清零*/
temp = smsc911x_reg_read(pdata, INT_EN);
temp &= (~INT_EN_SW_INT_EN_);
smsc911x_reg_write(pdata, INT_EN, temp);/*關中斷*/
smsc911x_reg_write(pdata, INT_STS, INT_STS_SW_INT_);/*清零中斷*/
pdata->software_irq_signal = 1;
smp_wmb();
serviced = IRQ_HANDLED;
}
if (unlikely(intsts & inten & INT_STS_RXSTOP_INT_)) {
/* Called when there is a multicast update scheduled and
* it is now safe to complete the update */
SMSC_TRACE(INTR, "RX Stop interrupt");
smsc911x_reg_write(pdata, INT_STS, INT_STS_RXSTOP_INT_);
if (pdata->multicast_update_pending)
smsc911x_rx_multicast_update_workaround(pdata);
serviced = IRQ_HANDLED;
}
if (intsts & inten & INT_STS_TDFA_) {/*發數據完成,喚醒發送隊列*/
temp = smsc911x_reg_read(pdata, FIFO_INT);
temp |= FIFO_INT_TX_AVAIL_LEVEL_;
smsc911x_reg_write(pdata, FIFO_INT, temp);
smsc911x_reg_write(pdata, INT_STS, INT_STS_TDFA_);
netif_wake_queue(dev);
serviced = IRQ_HANDLED;
}
if (unlikely(intsts & inten & INT_STS_RXE_)) {
SMSC_TRACE(INTR, "RX Error interrupt");
smsc911x_reg_write(pdata, INT_STS, INT_STS_RXE_);
serviced = IRQ_HANDLED;
}
if (likely(intsts & inten & INT_STS_RSFL_)) {/*收到新的網卡數據觸發中斷*/
if (likely(napi_schedule_prep(&pdata->napi))) {
/* Disable Rx interrupts */
temp = smsc911x_reg_read(pdata, INT_EN);
temp &= (~INT_EN_RSFL_EN_);
smsc911x_reg_write(pdata, INT_EN, temp);
/* Schedule a NAPI poll */
__napi_schedule(&pdata->napi);
} else {
SMSC_WARNING(RX_ERR,
"napi_schedule_prep failed");
}
serviced = IRQ_HANDLED;
}
return serviced;
}