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[RFC][NET] Alignment in mv643xx_eth

To: Dale Farnsworth <dale@farnsworth.org>
Subject: [RFC][NET] Alignment in mv643xx_eth
From: Ralf Baechle <ralf@linux-mips.org>
Date: Mon, 26 Feb 2007 19:52:06 +0000
Cc: netdev@vger.kernel.org, linux-mips@linux-mips.org, Jeff Garzik <jeff@garzik.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.4.2.2i
The driver contains this little piece of candy:

#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_NOT_COHERENT_CACHE)
#define ETH_DMA_ALIGN           L1_CACHE_BYTES
#else
#define ETH_DMA_ALIGN           8
#endif

Any reason why we're not using dma_get_cache_alignment() instead?

  Ralf

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index d98e53e..3e045a6 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -147,13 +147,13 @@ static void mv643xx_eth_rx_refill_descs(struct net_device 
*dev)
        int unaligned;
 
        while (mp->rx_desc_count < mp->rx_ring_size) {
-               skb = dev_alloc_skb(ETH_RX_SKB_SIZE + ETH_DMA_ALIGN);
+               skb = dev_alloc_skb(ETH_RX_SKB_SIZE + 
dma_get_cache_alignment());
                if (!skb)
                        break;
                mp->rx_desc_count++;
-               unaligned = (u32)skb->data & (ETH_DMA_ALIGN - 1);
+               unaligned = (u32)skb->data & (dma_get_cache_alignment() - 1);
                if (unaligned)
-                       skb_reserve(skb, ETH_DMA_ALIGN - unaligned);
+                       skb_reserve(skb, dma_get_cache_alignment() - unaligned);
                pkt_info.cmd_sts = ETH_RX_ENABLE_INTERRUPT;
                pkt_info.byte_cnt = ETH_RX_SKB_SIZE;
                pkt_info.buf_ptr = dma_map_single(NULL, skb->data,
diff --git a/drivers/net/mv643xx_eth.h b/drivers/net/mv643xx_eth.h
index 33c5faf..7cb0a41 100644
--- a/drivers/net/mv643xx_eth.h
+++ b/drivers/net/mv643xx_eth.h
@@ -42,17 +42,6 @@
 #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_HW_IP_ALIGN                2               /* hw aligns IP header 
*/

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