[PATCH] mv643xx_eth: Cache align skb->data if CONFIG_NOT_COHERENT_CACHE

When I/O is non-cache-coherent, we need to ensure that the I/O buffers
we use don't share cache lines with other data.

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 14 insertions, 4 deletions

diff --git a/drivers/net/mv643xx_eth.h b/drivers/net/mv643xx_eth.h
index 7754d1974b9e..4262c1da6d4a 100644
--- a/drivers/net/mv643xx_eth.h
+++ b/drivers/net/mv643xx_eth.h
@@ -42,13 +42,23 @@
 #define MAX_DESCS_PER_SKB       1
 #endif
 
+/*
+ * The MV643XX HW requires 8-byte alignment.  However, when I/O
+ * is non-cache-coherent, we need to ensure that the I/O buffers
+ * we use don't share cache lines with other data.
+ */
+#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_NOT_COHERENT_CACHE)
+#define ETH_DMA_ALIGN           L1_CACHE_BYTES
+#else
+#define ETH_DMA_ALIGN           8
+#endif
+
 #define ETH_VLAN_HLEN           4
 #define ETH_FCS_LEN             4
-#define ETH_DMA_ALIGN           8       /* hw requires 8-byte alignment */
-#define ETH_HW_IP_ALIGN         2       /* hw aligns IP header */
+#define ETH_HW_IP_ALIGN         2               /* hw aligns IP header */
 #define ETH_WRAPPER_LEN         (ETH_HW_IP_ALIGN + ETH_HLEN + \
-                                ETH_VLAN_HLEN + ETH_FCS_LEN)
-#define ETH_RX_SKB_SIZE         ((dev->mtu + ETH_WRAPPER_LEN + 7) & ~0x7)
+                                        ETH_VLAN_HLEN + ETH_FCS_LEN)
+#define ETH_RX_SKB_SIZE         (dev->mtu + ETH_WRAPPER_LEN + ETH_DMA_ALIGN)
 
 #define ETH_RX_QUEUES_ENABLED   (1 << 0)        /* use only Q0 for receive */
 #define ETH_TX_QUEUES_ENABLED   (1 << 0)        /* use only Q0 for transmit */