Re: [PATCH 2/5] ucc_geth: Word align Ethernet RX data

From: Joakim Tjernlund <redacted>
To: netdev@vger.kernel.org,
Cc: Joakim Tjernlund <redacted>
Date: 2012/09/18 18:56
Subject: [PATCH 2/5] ucc_geth: Word align Ethernet RX data

UCC controller can shift received Ethernet frames 2 bytes into the buffer,
making IP data word aligned, this patch enables that feature.

Signed-off-by: Joakim Tjernlund <redacted>
---
 drivers/net/ethernet/freescale/ucc_geth.c |   19 +++++++++++--------
 drivers/net/ethernet/freescale/ucc_geth.h |    1 +
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/freescale/ucc_geth.c b/drivers/net/ethernet/freescale/ucc_geth.c
index e609c93..5f1460a 100644
--- a/drivers/net/ethernet/freescale/ucc_geth.c
+++ b/drivers/net/ethernet/freescale/ucc_geth.c

@@ -160,6 +160,7 @@ static struct ucc_geth_info ugeth_primary_info = {
    .numThreadsRx = UCC_GETH_NUM_OF_THREADS_1,
    .riscTx = QE_RISC_ALLOCATION_RISC1_AND_RISC2,
    .riscRx = QE_RISC_ALLOCATION_RISC1_AND_RISC2,
+   .ipAddressAlignment = 1,
 };

 static struct ucc_geth_info ugeth_info[8];

@@ -211,12 +212,13 @@ static struct sk_buff *get_new_skb(struct ucc_geth_private *ugeth,
       u8 __iomem *bd)
 {
    struct sk_buff *skb = NULL;
+   u16 buf_len = ugeth->ug_info->uf_info.max_rx_buf_length +
+      UCC_GETH_RX_DATA_BUF_ALIGNMENT +
+      UCC_GETH_RX_IP_ALIGNMENT;

    skb = __skb_dequeue(&ugeth->rx_recycle);
    if (!skb)
-      skb = netdev_alloc_skb(ugeth->ndev,
-                  ugeth->ug_info->uf_info.max_rx_buf_length +
-                  UCC_GETH_RX_DATA_BUF_ALIGNMENT);
+      skb = netdev_alloc_skb(ugeth->ndev, buf_len);
    if (skb == NULL)
       return NULL;

@@ -231,10 +233,9 @@ static struct sk_buff *get_new_skb(struct ucc_geth_private *ugeth,
    out_be32(&((struct qe_bd __iomem *)bd)->buf,
             dma_map_single(ugeth->dev,
                  skb->data,
-                 ugeth->ug_info->uf_info.max_rx_buf_length +
-                 UCC_GETH_RX_DATA_BUF_ALIGNMENT,
+                 buf_len,
                  DMA_FROM_DEVICE));
-
+   skb_reserve(skb, UCC_GETH_RX_IP_ALIGNMENT);
    out_be32((u32 __iomem *)bd,
          (R_E | R_I | (in_be32((u32 __iomem*)bd) & R_W)));

@@ -1877,7 +1878,8 @@ static void ucc_geth_free_rx(struct ucc_geth_private *ugeth)
                   in_be32(&((struct qe_bd __iomem *)bd)->buf),
                   ugeth->ug_info->
                   uf_info.max_rx_buf_length +
-                  UCC_GETH_RX_DATA_BUF_ALIGNMENT,
+                  UCC_GETH_RX_DATA_BUF_ALIGNMENT +
+                  UCC_GETH_RX_IP_ALIGNMENT,
                   DMA_FROM_DEVICE);
                dev_kfree_skb_any(
                   ugeth->rx_skbuff[i][j]);

@@ -3352,7 +3354,8 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ)
       if (skb_queue_len(&ugeth->rx_recycle) < RX_BD_RING_LEN &&
               skb_recycle_check(skb,
                 ugeth->ug_info->uf_info.max_rx_buf_length +
-                UCC_GETH_RX_DATA_BUF_ALIGNMENT))
+                UCC_GETH_RX_DATA_BUF_ALIGNMENT +
+                UCC_GETH_RX_IP_ALIGNMENT))
          __skb_queue_head(&ugeth->rx_recycle, skb);
       else
          dev_kfree_skb(skb);

diff --git a/drivers/net/ethernet/freescale/ucc_geth.h b/drivers/net/ethernet/freescale/ucc_geth.h
index f71b3e7..aeb743c 100644
--- a/drivers/net/ethernet/freescale/ucc_geth.h
+++ b/drivers/net/ethernet/freescale/ucc_geth.h

@@ -855,6 +855,7 @@ struct ucc_geth_hardware_statistics {
 #define UCC_GETH_RX_BD_RING_SIZE_ALIGNMENT   4
 #define UCC_GETH_TX_BD_RING_SIZE_MEMORY_ALIGNMENT   32
 #define UCC_GETH_RX_DATA_BUF_ALIGNMENT      64
+#define UCC_GETH_RX_IP_ALIGNMENT      2 /* IP word alignment */

 #define UCC_GETH_TAD_EF                         0x80
 #define UCC_GETH_TAD_V                          0x40
--

1.7.8.6