Subject: Re: [PATCH] drivers/net/usb/asix: resync from vendor's copy

From: Mark Lord <[email-masked]>
Date: Wed, 09 Nov 2011 11:57:14 -0500

On 11-11-09 11:47 AM, Mark Lord wrote:
..
> Note:  I'm looking at smsc95xx.c and smsc75xx.c for examples,
> and they both have the same problem I'll have here:
> 
> How to update the csum settings atomically.
> A spinlock is no good, because config register access is over USB.

Nevermind.. a slight change in the logic and all is well again.

static int ax88772b_set_features(struct net_device *netdev, u32 features)
{
        struct usbnet *dev = netdev_priv(netdev);
        struct ax88772b_data *priv = (struct ax88772b_data *)dev->driver_priv;
        unsigned long flags;
        u16 tx_csum = 0, rx_csum = 0;

        spin_lock_irqsave(&priv->features_lock, flags);
        if (features & NETIF_F_HW_CSUM) {
                priv->checksum |= AX_TX_CHECKSUM;
                tx_csum = AX_TXCOE_DEF_CSUM;
        } else
                priv->checksum &= ~AX_TX_CHECKSUM;
        if (features & NETIF_F_RXCSUM) {
                priv->checksum |= AX_RX_CHECKSUM;
                rx_csum = AX_RXCOE_DEF_CSUM;
        } else
                priv->checksum &= ~AX_RX_CHECKSUM;
        spin_unlock_irqrestore(&priv->features_lock, flags);

        ax8817x_write_cmd(dev, AX_CMD_WRITE_RXCOE_CTL,
                                 rx_csum, 0, 0, NULL);
        ax8817x_write_cmd(dev, AX_CMD_WRITE_TXCOE_CTL,
                                 tx_csum, 0, 0, NULL);
        return 0;
}