target/linux/layerscape/patches-5.4/701-net-0108-sdk_dpaa-ls1043a-errata-impose-S-G-frame-realignment.patch

   1 From bfc02cc199dc6259c2f4e2af8f77c88fe8ba4cc5 Mon Sep 17 00:00:00 2001
   2 From: Camelia Groza <camelia.groza@nxp.com>
   3 Date: Tue, 5 Mar 2019 11:55:54 +0200
   4 Subject: [PATCH] sdk_dpaa: ls1043a errata: impose S/G frame realignment
   5
   6 Scatter/Gather frames are not support on LS1043A beacuse they trigger
   7 the A010022 errata.
   8
   9 Even though we do not advertise S/G support to the stack, we need to
  10 make sure that if S/G frames do reach the driver somehow, they trigger
  11 the errata workaround.
  12
  13 Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
  14 ---
  15  drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth.h |  7 ++++---
  16  .../net/ethernet/freescale/sdk_dpaa/dpaa_eth_sg.c  | 23 +++++-----------------
  17  2 files changed, 9 insertions(+), 21 deletions(-)
  18
  19 --- a/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth.h
  20 +++ b/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth.h
  21 @@ -653,9 +653,10 @@ static inline void _dpa_bp_free_pf(void
  22
  23  /* LS1043A SoC has a HW issue regarding FMan DMA transactions; The issue
  24   * manifests itself at high traffic rates when frames cross 4K memory
  25 - * boundaries or when they are not aligned to 16 bytes; For the moment, we
  26 - * use a SW workaround that realigns frames to 256 bytes. Scatter/Gather
  27 - * frames aren't supported on egress.
  28 + * boundaries, when they are not aligned to 16 bytes or when they have
  29 + * Scatter/Gather fragments; For the moment, we use a SW workaround that
  30 + * realigns frames to 256 bytes. Scatter/Gather frames aren't supported
  31 + * on egress.
  32   */
  33
  34  #ifndef CONFIG_PPC
  35 --- a/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_sg.c
  36 +++ b/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_sg.c
  37 @@ -772,18 +772,19 @@ EXPORT_SYMBOL(skb_to_contig_fd);
  38
  39  #ifndef CONFIG_PPC
  40  /* Verify the conditions that trigger the A010022 errata: data unaligned to
  41 - * 16 bytes and 4K memory address crossings.
  42 + * 16 bytes, 4K memory address crossings and S/G fragments.
  43   */
  44  static bool a010022_check_skb(struct sk_buff *skb, struct dpa_priv_s *priv)
  45  {
  46 -       int nr_frags, i = 0;
  47 -       skb_frag_t *frag;
  48 -
  49         /* Check if the headroom is aligned */
  50         if (((uintptr_t)skb->data - priv->tx_headroom) %
  51             priv->buf_layout[TX].data_align != 0)
  52                 return true;
  53
  54 +       /* Check for paged data in the skb. We do not support S/G fragments */
  55 +       if (skb_is_nonlinear(skb))
  56 +               return true;
  57 +
  58         /* Check if the headroom crosses a boundary */
  59         if (HAS_DMA_ISSUE(skb->head, skb_headroom(skb)))
  60                 return true;
  61 @@ -796,20 +797,6 @@ static bool a010022_check_skb(struct sk_
  62         if (HAS_DMA_ISSUE(skb->head, skb_end_offset(skb)))
  63                 return true;
  64
  65 -       nr_frags = skb_shinfo(skb)->nr_frags;
  66 -
  67 -       while (i < nr_frags) {
  68 -               frag = &skb_shinfo(skb)->frags[i];
  69 -
  70 -               /* Check if a paged fragment crosses a boundary from its
  71 -                * offset to its end.
  72 -                */
  73 -               if (HAS_DMA_ISSUE(frag->page_offset, frag->size))
  74 -                       return true;
  75 -
  76 -               i++;
  77 -       }
  78 -
  79         return false;
  80  }
  81