target/linux/generic/patches-3.18/077-07-bgmac-simplify-rx-DMA-error-handling.patch

   1 From: Felix Fietkau <nbd@openwrt.org>
   2 Date: Sun, 12 Apr 2015 22:23:07 +0200
   3 Subject: [PATCH] bgmac: simplify rx DMA error handling
   4
   5 Unmap the DMA buffer before checking it. If it is poisoned, map it again
   6 and pass it back to the hardware.
   7
   8 Signed-off-by: Felix Fietkau <nbd@openwrt.org>
   9 ---
  10
  11 --- a/drivers/net/ethernet/broadcom/bgmac.c
  12 +++ b/drivers/net/ethernet/broadcom/bgmac.c
  13 @@ -405,25 +405,20 @@ static int bgmac_dma_rx_read(struct bgma
  14                 u16 len, flags;
  15
  16                 /* Unmap buffer to make it accessible to the CPU */
  17 -               dma_sync_single_for_cpu(dma_dev, slot->dma_addr,
  18 -                                       BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
  19 +               dma_unmap_single(dma_dev, slot->dma_addr,
  20 +                                BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
  21
  22                 /* Get info from the header */
  23                 len = le16_to_cpu(rx->len);
  24                 flags = le16_to_cpu(rx->flags);
  25
  26                 do {
  27 -                       dma_addr_t old_dma_addr = slot->dma_addr;
  28                         int err;
  29
  30                         /* Check for poison and drop or pass the packet */
  31                         if (len == 0xdead && flags == 0xbeef) {
  32                                 bgmac_err(bgmac, "Found poisoned packet at slot %d, DMA issue!\n",
  33                                           ring->start);
  34 -                               dma_sync_single_for_device(dma_dev,
  35 -                                                          slot->dma_addr,
  36 -                                                          BGMAC_RX_BUF_SIZE,
  37 -                                                          DMA_FROM_DEVICE);
  38                                 break;
  39                         }
  40
  41 @@ -436,18 +431,8 @@ static int bgmac_dma_rx_read(struct bgma
  42                                 /* Poison the old skb */
  43                                 rx->len = cpu_to_le16(0xdead);
  44                                 rx->flags = cpu_to_le16(0xbeef);
  45 -
  46 -                               dma_sync_single_for_device(dma_dev,
  47 -                                                          slot->dma_addr,
  48 -                                                          BGMAC_RX_BUF_SIZE,
  49 -                                                          DMA_FROM_DEVICE);
  50                                 break;
  51                         }
  52 -                       bgmac_dma_rx_setup_desc(bgmac, ring, ring->start);
  53 -
  54 -                       /* Unmap old skb, we'll pass it to the netfif */
  55 -                       dma_unmap_single(dma_dev, old_dma_addr,
  56 -                                        BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
  57
  58                         skb = build_skb(buf, BGMAC_RX_ALLOC_SIZE);
  59                         skb_put(skb, BGMAC_RX_FRAME_OFFSET +
  60 @@ -461,6 +446,8 @@ static int bgmac_dma_rx_read(struct bgma
  61                         handled++;
  62                 } while (0);
  63
  64 +               bgmac_dma_rx_setup_desc(bgmac, ring, ring->start);
  65 +
  66                 if (++ring->start >= BGMAC_RX_RING_SLOTS)
  67                         ring->start = 0;
  68