[net-next v2 06/10] dpaa_eth: enable Rx checksum offload

From: Madalin Bucur
Date: Thu Mar 09 2017 - 10:17:09 EST


Use the FMan HW parser L4CV flag to offload Rx checksumming.

Signed-off-by: Madalin Bucur <madalin.bucur@xxxxxxx>
---
drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 29 ++++++++++++++++++++++++--
1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index e19181f..a7a595c 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -137,6 +137,13 @@ MODULE_PARM_DESC(tx_timeout, "The Tx timeout in ms");
/* L4 Type field: TCP */
#define FM_L4_PARSE_RESULT_TCP 0x20

+/* FD status field indicating whether the FM Parser has attempted to validate
+ * the L4 csum of the frame.
+ * Note that having this bit set doesn't necessarily imply that the checksum
+ * is valid. One would have to check the parse results to find that out.
+ */
+#define FM_FD_STAT_L4CV 0x00000004
+
#define DPAA_SGT_MAX_ENTRIES 16 /* maximum number of entries in SG Table */
#define DPAA_BUFF_RELEASE_MAX 8 /* maximum number of buffers released at once */

@@ -235,6 +242,7 @@ static int dpaa_netdev_init(struct net_device *net_dev,
* For conformity, we'll still declare GSO explicitly.
*/
net_dev->features |= NETIF_F_GSO;
+ net_dev->features |= NETIF_F_RXCSUM;

net_dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
/* we do not want shared skbs on TX */
@@ -1526,6 +1534,23 @@ static struct sk_buff *dpaa_cleanup_tx_fd(const struct dpaa_priv *priv,
return skb;
}

+static u8 rx_csum_offload(const struct dpaa_priv *priv, const struct qm_fd *fd)
+{
+ /* The parser has run and performed L4 checksum validation.
+ * We know there were no parser errors (and implicitly no
+ * L4 csum error), otherwise we wouldn't be here.
+ */
+ if ((priv->net_dev->features & NETIF_F_RXCSUM) &&
+ (be32_to_cpu(fd->status) & FM_FD_STAT_L4CV))
+ return CHECKSUM_UNNECESSARY;
+
+ /* We're here because either the parser didn't run or the L4 checksum
+ * was not verified. This may include the case of a UDP frame with
+ * checksum zero or an L4 proto other than TCP/UDP
+ */
+ return CHECKSUM_NONE;
+}
+
/* Build a linear skb around the received buffer.
* We are guaranteed there is enough room at the end of the data buffer to
* accommodate the shared info area of the skb.
@@ -1556,7 +1581,7 @@ static struct sk_buff *contig_fd_to_skb(const struct dpaa_priv *priv,
skb_reserve(skb, fd_off);
skb_put(skb, qm_fd_get_length(fd));

- skb->ip_summed = CHECKSUM_NONE;
+ skb->ip_summed = rx_csum_offload(priv, fd);

return skb;

@@ -1616,7 +1641,7 @@ static struct sk_buff *sg_fd_to_skb(const struct dpaa_priv *priv,
if (WARN_ON(unlikely(!skb)))
goto free_buffers;

- skb->ip_summed = CHECKSUM_NONE;
+ skb->ip_summed = rx_csum_offload(priv, fd);

/* Make sure forwarded skbs will have enough space
* on Tx, if extra headers are added.
--
2.1.0