[PATCH 1/2 v2] mv643xx_eth: use sw csum for big packets

From: Saeed Bishara
Date: Wed Jun 09 2010 - 04:51:29 EST


Some controllers (KW, Dove) limits the TX IP/layer4 checksum offloading to a max size.

Signed-off-by: Saeed Bishara <saeed@xxxxxxxxxxx>
---
drivers/net/mv643xx_eth.c | 7 ++++++-
include/linux/mv643xx_eth.h | 5 +++++
2 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index e345ec8..2d0e06b 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -289,6 +289,7 @@ struct mv643xx_eth_shared_private {
unsigned int t_clk;
int extended_rx_coal_limit;
int tx_bw_control;
+ int tx_csum_limit;
};

#define TX_BW_CONTROL_ABSENT 0
@@ -782,7 +783,8 @@ static int txq_submit_skb(struct tx_queue *txq, struct sk_buff *skb)
skb->protocol != htons(ETH_P_8021Q));

tag_bytes = (void *)ip_hdr(skb) - (void *)skb->data - ETH_HLEN;
- if (unlikely(tag_bytes & ~12)) {
+ if (unlikely(tag_bytes & ~12) ||
+ skb->len > mp->shared->tx_csum_limit) {
if (skb_checksum_help(skb) == 0)
goto no_csum;
kfree_skb(skb);
@@ -2666,6 +2668,9 @@ static int mv643xx_eth_shared_probe(struct platform_device *pdev)
* Detect hardware parameters.
*/
msp->t_clk = (pd != NULL && pd->t_clk != 0) ? pd->t_clk : 133000000;
+ msp->tx_csum_limit = pd->tx_csum_limit ? pd->tx_csum_limit : 9 * 1024;
+ /* add header count so we can compare against skb->len */
+ msp->tx_csum_limit += ETH_HLEN;
infer_hw_params(msp);

platform_set_drvdata(pdev, msp);
diff --git a/include/linux/mv643xx_eth.h b/include/linux/mv643xx_eth.h
index cbbbe9b..30b0c4e 100644
--- a/include/linux/mv643xx_eth.h
+++ b/include/linux/mv643xx_eth.h
@@ -19,6 +19,11 @@ struct mv643xx_eth_shared_platform_data {
struct mbus_dram_target_info *dram;
struct platform_device *shared_smi;
unsigned int t_clk;
+ /*
+ * Max packet size for Tx IP/Layer 4 checksum, when set to 0, default
+ * limit of 9KiB will be used.
+ */
+ int tx_csum_limit;
};

#define MV643XX_ETH_PHY_ADDR_DEFAULT 0
--
1.6.0.4

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