Messages in this thread | | | Subject | Re: [PATCH v5 1/2] net: moxa: clear TX descriptor length bits | From | Eric Dumazet <> | Date | Wed, 20 Aug 2014 10:10:10 -0700 |
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On Wed, 2014-08-20 at 16:18 +0200, Jonas Jensen wrote: > TX buffer length is not cleared on ndo_start_xmit(). > Failing to do so can bug/hang the controller and > cause TX interrupts to stop altogether.
> > diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c > index 5020fd4..aa45607 100644 > --- a/drivers/net/ethernet/moxa/moxart_ether.c > +++ b/drivers/net/ethernet/moxa/moxart_ether.c > @@ -348,7 +348,8 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev) > > txdes1 = readl(desc + TX_REG_OFFSET_DESC1); > txdes1 |= TX_DESC1_LTS | TX_DESC1_FTS; > - txdes1 &= ~(TX_DESC1_FIFO_COMPLETE | TX_DESC1_INTR_COMPLETE); > + txdes1 &= ~(TX_DESC1_FIFO_COMPLETE | TX_DESC1_INTR_COMPLETE | > + TX_DESC1_BUF_SIZE_MASK); > txdes1 |= (len & TX_DESC1_BUF_SIZE_MASK); > writel(txdes1, desc + TX_REG_OFFSET_DESC1); > writel(TX_DESC0_DMA_OWN, desc + TX_REG_OFFSET_DESC0);
Wouldnt it be faster to not use readl() at all here ?
readl() is only used to get TX_DESC1_END bit.
It seems you could replace the thing by :
txdes1 = TX_DESC1_LTS | TX_DESC1_FTS | (len & TX_DESC1_BUF_SIZE_MASK); if (tx_head == TX_DESC_NUM_MASK) txdes1 |= TX_DESC1_END;
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