diff options
| author | Peter Korsgaard <peter@korsgaard.com> | 2013-12-16 11:35:35 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-12-18 17:46:55 -0500 |
| commit | 4263c86dca5198da6bd3ad826d0b2304fbe25776 (patch) | |
| tree | 9b5705a6b9b1ae2f6d93293acc221897d12ef583 /drivers/net/usb | |
| parent | cabd0e3a3861d45569b8f91633c98fc48d820cdb (diff) | |
dm9601: work around tx fifo sync issue on dm962x
Certain dm962x revisions contain an bug, where if a USB bulk transfer retry
(E.G. if bulk crc mismatch) happens right after a transfer with odd or
maxpacket length, the internal tx hardware fifo gets out of sync causing
the interface to stop working.
Work around it by adding up to 3 bytes of padding to ensure this situation
cannot trigger.
This workaround also means we never pass multiple-of-maxpacket size skb's
to usbnet, so the length adjustment to handle usbnet's padding of those can
be removed.
Cc: <stable@vger.kernel.org>
Reported-by: Joseph Chang <joseph_chang@davicom.com.tw>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/usb')
| -rw-r--r-- | drivers/net/usb/dm9601.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c index ca99c35666c5..14aa48fa8d7e 100644 --- a/drivers/net/usb/dm9601.c +++ b/drivers/net/usb/dm9601.c @@ -473,7 +473,7 @@ static int dm9601_rx_fixup(struct usbnet *dev, struct sk_buff *skb) static struct sk_buff *dm9601_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags) { - int len; + int len, pad; /* format: b1: packet length low @@ -481,12 +481,23 @@ static struct sk_buff *dm9601_tx_fixup(struct usbnet *dev, struct sk_buff *skb, b3..n: packet data */ - len = skb->len; + len = skb->len + DM_TX_OVERHEAD; + + /* workaround for dm962x errata with tx fifo getting out of + * sync if a USB bulk transfer retry happens right after a + * packet with odd / maxpacket length by adding up to 3 bytes + * padding. + */ + while ((len & 1) || !(len % dev->maxpacket)) + len++; - if (skb_headroom(skb) < DM_TX_OVERHEAD) { + len -= DM_TX_OVERHEAD; /* hw header doesn't count as part of length */ + pad = len - skb->len; + + if (skb_headroom(skb) < DM_TX_OVERHEAD || skb_tailroom(skb) < pad) { struct sk_buff *skb2; - skb2 = skb_copy_expand(skb, DM_TX_OVERHEAD, 0, flags); + skb2 = skb_copy_expand(skb, DM_TX_OVERHEAD, pad, flags); dev_kfree_skb_any(skb); skb = skb2; if (!skb) @@ -495,10 +506,10 @@ static struct sk_buff *dm9601_tx_fixup(struct usbnet *dev, struct sk_buff *skb, __skb_push(skb, DM_TX_OVERHEAD); - /* usbnet adds padding if length is a multiple of packet size - if so, adjust length value in header */ - if ((skb->len % dev->maxpacket) == 0) - len++; + if (pad) { + memset(skb->data + skb->len, 0, pad); + __skb_put(skb, pad); + } skb->data[0] = len; skb->data[1] = len >> 8; |