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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