From: Freddy Xin <fre...@asix.com.tw>

The AX88179_178A has a hardware feature that it can insert a 2-bytes pseudo
header in front of each received frame by setting the AX_RX_CTL_IPE bit.
This feature is used to let the IP header be aligned on a doubleword-aligned 
address,
but the NET_IP_ALIGN may equals to 2 and the __netdev_alloc_skb_ip_align in 
USBNET will
reserve 2 bytes also, so in this case the driver shouldn't enable this bit.

This patch modifies the driver to set AX_RX_CTL_IPE just in case of the 
NET_IP_ALIGN equals 0.

Signed-off-by: Freddy Xin <fre...@asix.com.tw>
---
 drivers/net/usb/ax88179_178a.c | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
index 8e8d0fc..d84f0e0 100644
--- a/drivers/net/usb/ax88179_178a.c
+++ b/drivers/net/usb/ax88179_178a.c
@@ -473,8 +473,10 @@ static int ax88179_resume(struct usb_interface *intf)
        msleep(100);
 
        /* Configure RX control register => start operation */
-       tmp16 = AX_RX_CTL_DROPCRCERR | AX_RX_CTL_IPE | AX_RX_CTL_START |
-               AX_RX_CTL_AP | AX_RX_CTL_AMALL | AX_RX_CTL_AB;
+       tmp16 = AX_RX_CTL_DROPCRCERR | AX_RX_CTL_START | AX_RX_CTL_AP |
+               AX_RX_CTL_AMALL | AX_RX_CTL_AB;
+       if (NET_IP_ALIGN == 0)
+               tmp16 |= AX_RX_CTL_IPE;
        ax88179_write_cmd_nopm(dev, AX_ACCESS_MAC, AX_RX_CTL, 2, 2, &tmp16);
 
        return usbnet_resume(intf);
@@ -599,7 +601,9 @@ static void ax88179_set_multicast(struct net_device *net)
        struct ax88179_data *data = (struct ax88179_data *)dev->data;
        u8 *m_filter = ((u8 *)dev->data) + 12;
 
-       data->rxctl = (AX_RX_CTL_START | AX_RX_CTL_AB | AX_RX_CTL_IPE);
+       data->rxctl = (AX_RX_CTL_START | AX_RX_CTL_AB);
+       if (NET_IP_ALIGN == 0)
+               data->rxctl |= AX_RX_CTL_IPE;
 
        if (net->flags & IFF_PROMISC) {
                data->rxctl |= AX_RX_CTL_PRO;
@@ -1054,8 +1058,10 @@ static int ax88179_bind(struct usbnet *dev, struct 
usb_interface *intf)
        ax88179_write_cmd(dev, AX_ACCESS_MAC, AX_TXCOE_CTL, 1, 1, tmp);
 
        /* Configure RX control register => start operation */
-       *tmp16 = AX_RX_CTL_DROPCRCERR | AX_RX_CTL_IPE | AX_RX_CTL_START |
-                AX_RX_CTL_AP | AX_RX_CTL_AMALL | AX_RX_CTL_AB;
+       *tmp16 = AX_RX_CTL_DROPCRCERR | AX_RX_CTL_START | AX_RX_CTL_AP |
+                AX_RX_CTL_AMALL | AX_RX_CTL_AB;
+       if (NET_IP_ALIGN == 0)
+               *tmp16 |= AX_RX_CTL_IPE;
        ax88179_write_cmd(dev, AX_ACCESS_MAC, AX_RX_CTL, 2, 2, tmp16);
 
        *tmp = AX_MONITOR_MODE_PMETYPE | AX_MONITOR_MODE_PMEPOL |
@@ -1143,7 +1149,8 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct 
sk_buff *skb)
 
                if (pkt_cnt == 0) {
                        /* Skip IP alignment psudo header */
-                       skb_pull(skb, 2);
+                       if (NET_IP_ALIGN == 0)
+                               skb_pull(skb, 2);
                        skb->len = pkt_len;
                        skb_set_tail_pointer(skb, pkt_len);
                        skb->truesize = pkt_len + sizeof(struct sk_buff);
@@ -1154,7 +1161,8 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct 
sk_buff *skb)
                ax_skb = skb_clone(skb, GFP_ATOMIC);
                if (ax_skb) {
                        ax_skb->len = pkt_len;
-                       ax_skb->data = skb->data + 2;
+                       if (NET_IP_ALIGN == 0)
+                               ax_skb->data = skb->data + 2;
                        skb_set_tail_pointer(ax_skb, pkt_len);
                        ax_skb->truesize = pkt_len + sizeof(struct sk_buff);
                        ax88179_rx_checksum(ax_skb, pkt_hdr);
@@ -1328,8 +1336,10 @@ static int ax88179_reset(struct usbnet *dev)
        ax88179_write_cmd(dev, AX_ACCESS_MAC, AX_TXCOE_CTL, 1, 1, tmp);
 
        /* Configure RX control register => start operation */
-       *tmp16 = AX_RX_CTL_DROPCRCERR | AX_RX_CTL_IPE | AX_RX_CTL_START |
-                AX_RX_CTL_AP | AX_RX_CTL_AMALL | AX_RX_CTL_AB;
+       *tmp16 = AX_RX_CTL_DROPCRCERR | AX_RX_CTL_START | AX_RX_CTL_AP |
+                AX_RX_CTL_AMALL | AX_RX_CTL_AB;
+       if (NET_IP_ALIGN == 0)
+               *tmp16 |= AX_RX_CTL_IPE;
        ax88179_write_cmd(dev, AX_ACCESS_MAC, AX_RX_CTL, 2, 2, tmp16);
 
        *tmp = AX_MONITOR_MODE_PMETYPE | AX_MONITOR_MODE_PMEPOL |
-- 
1.8.3.2

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