ENGR00170784 - FEC : dma skb buffer map is not used rightly.

Enable "CONFIG_DMA_API_DEBUG" in kernel, and system print:

DMA-API: device driver tries to free DMA memory it has not
allocated [device address=0x0000000046688020]...[<80222494>]
(debug_dma_unmap_page+0x8c/0x98) from [<802a36a0>]
(fec_enet_interrupt+0x430/0x5ac)

Correct the usage of "dma_map_single" function.

Signed-off-by: Fugang Duan  <B38611@freescale.com>

diff --git a/drivers/net/fec.c b/drivers/net/fec.c
index b56a623875d26775b79f77f28e112ac169b47387..c3cb63799c73b4f7296ed98542dcbea28d6af179 100755 (executable)
--- a/drivers/net/fec.c
+++ b/drivers/net/fec.c
@@ -401,7 +401,8 @@ fec_enet_tx(struct net_device *ndev)
                if (bdp == fep->cur_tx && fep->tx_full == 0)
                        break;
 
-               dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
+               if (bdp->cbd_bufaddr)
+                       dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
                                FEC_ENET_TX_FRSIZE, DMA_TO_DEVICE);
                bdp->cbd_bufaddr = 0;
 
@@ -542,7 +543,8 @@ fec_enet_rx(struct net_device *ndev)
                ndev->stats.rx_bytes += pkt_len;
                data = (__u8*)__va(bdp->cbd_bufaddr);
 
-               dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
+               if (bdp->cbd_bufaddr)
+                       dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
                                FEC_ENET_TX_FRSIZE, DMA_FROM_DEVICE);
 
                if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
@@ -1089,7 +1091,6 @@ fec_enet_open(struct net_device *ndev)
        /* I should reset the ring buffers here, but I don't yet know
         * a simple way to do that.
         */
-
        if (!clk_get_usecount(fep->clk))
                clk_enable(fep->clk);
        ret = fec_enet_alloc_buffers(ndev);
@@ -1290,6 +1291,7 @@ static int fec_enet_init(struct net_device *ndev)
 
                /* Initialize the BD for every fragment in the page. */
                bdp->cbd_sc = 0;
+               bdp->cbd_bufaddr = 0;
                bdp++;
        }