diff options
| author | Dale Farnsworth <dale@farnsworth.org> | 2006-01-16 16:51:22 -0700 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@pobox.com> | 2006-01-17 07:23:37 -0500 |
| commit | b44cd572623cb6a931a947d9108595517fd945f8 (patch) | |
| tree | fc4a28e35531ad9bc3596b262ad834aff82d4662 /drivers | |
| parent | 16e0301831767ee1b8e5e022cc08e76f9f8a8938 (diff) | |
[PATCH] mv643xx_eth: Receive buffers require 8 byte alignment
The Marvell mv643xx ethernet hardware requires that DMA buffers be
aligned to 8-byte boundaries. This patch satisfies this requirement.
Buffers allocated by dev_alloc_skb() only have 4-byte alignment when
slab debugging is enabled.
Also, document that the 2-byte offset to align the IP packets on
receive is a hardware feature and is not tied to NET_IP_ALIGN.
Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
mv643xx_eth.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/mv643xx_eth.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c index f100ca7d3ee..4afb954092a 100644 --- a/drivers/net/mv643xx_eth.c +++ b/drivers/net/mv643xx_eth.c @@ -57,7 +57,9 @@ /* Constants */ #define VLAN_HLEN 4 #define FCS_LEN 4 -#define WRAP NET_IP_ALIGN + ETH_HLEN + VLAN_HLEN + FCS_LEN +#define DMA_ALIGN 8 /* hw requires 8-byte alignment */ +#define HW_IP_ALIGN 2 /* hw aligns IP header */ +#define WRAP HW_IP_ALIGN + ETH_HLEN + VLAN_HLEN + FCS_LEN #define RX_SKB_SIZE ((dev->mtu + WRAP + 7) & ~0x7) #define INT_CAUSE_UNMASK_ALL 0x0007ffff @@ -173,15 +175,19 @@ static void mv643xx_eth_rx_task(void *data) struct mv643xx_private *mp = netdev_priv(dev); struct pkt_info pkt_info; struct sk_buff *skb; + int unaligned; if (test_and_set_bit(0, &mp->rx_task_busy)) panic("%s: Error in test_set_bit / clear_bit", dev->name); while (mp->rx_ring_skbs < (mp->rx_ring_size - 5)) { - skb = dev_alloc_skb(RX_SKB_SIZE); + skb = dev_alloc_skb(RX_SKB_SIZE + DMA_ALIGN); if (!skb) break; mp->rx_ring_skbs++; + unaligned = (u32)skb->data & (DMA_ALIGN - 1); + if (unaligned) + skb_reserve(skb, DMA_ALIGN - unaligned); pkt_info.cmd_sts = ETH_RX_ENABLE_INTERRUPT; pkt_info.byte_cnt = RX_SKB_SIZE; pkt_info.buf_ptr = dma_map_single(NULL, skb->data, RX_SKB_SIZE, @@ -192,7 +198,7 @@ static void mv643xx_eth_rx_task(void *data) "%s: Error allocating RX Ring\n", dev->name); break; } - skb_reserve(skb, 2); + skb_reserve(skb, HW_IP_ALIGN); } clear_bit(0, &mp->rx_task_busy); /* |