target/linux/brcm2708/patches-4.19/950-0748-net-bcmgenet-Workaround-for-Pi-4B-network-issue.patch

   1 From 3695a97f62ba999293cb5f92e29179e8beaa44a8 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Fri, 2 Aug 2019 22:25:27 +0100
   4 Subject: [PATCH 748/782] net: bcmgenet: Workaround for Pi 4B network issue
   5
   6 Some combinations of Pi 4Bs and Ethernet switches don't reliably get a
   7 DCHP-assigned IP address, leaving the unit with a self=assigned 169.254
   8 address.
   9
  10 Forcing renegotiation has been found to be an effective workaround, so
  11 add an automatic renegotiation after the link comes up for the first
  12 time; enable it with genet.force_reneg=y - by default it is disabled.
  13
  14 See: https://github.com/raspberrypi/linux/issues/3108
  15
  16 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  17 ---
  18  .../net/ethernet/broadcom/genet/bcmgenet.c    | 22 +++++++++++++++++++
  19  1 file changed, 22 insertions(+)
  20
  21 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
  22 +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
  23 @@ -72,6 +72,10 @@
  24  #define GENET_RDMA_REG_OFF     (priv->hw_params->rdma_offset + \
  25                                 TOTAL_DESC * DMA_DESC_SIZE)
  26
  27 +static bool force_reneg = false;
  28 +module_param(force_reneg, bool, 0444);
  29 +MODULE_PARM_DESC(force_reneg, "Force a renegotiation after the initial link-up");
  30 +
  31  static inline void bcmgenet_writel(u32 value, void __iomem *offset)
  32  {
  33         /* MIPS chips strapped for BE will automagically configure the
  34 @@ -2610,6 +2614,7 @@ static void bcmgenet_irq_task(struct wor
  35         unsigned int status;
  36         struct bcmgenet_priv *priv = container_of(
  37                         work, struct bcmgenet_priv, bcmgenet_irq_work);
  38 +       static int first_link = 1;
  39
  40         netif_dbg(priv, intr, priv->dev, "%s\n", __func__);
  41
  42 @@ -2622,6 +2627,23 @@ static void bcmgenet_irq_task(struct wor
  43         if (status & UMAC_IRQ_LINK_EVENT) {
  44                 priv->dev->phydev->link = !!(status & UMAC_IRQ_LINK_UP);
  45                 phy_mac_interrupt(priv->dev->phydev);
  46 +
  47 +               if (priv->dev->phydev->link && first_link) {
  48 +                       first_link = 0;
  49 +                       /*
  50 +                        * HACK: Some Pi4Bs, when paired with some switches,
  51 +                        * come up in a strange state where they are unable to
  52 +                        * transmit, causing them to fail to get an IP address.
  53 +                        * Although the failure mechanism is not yet understood,
  54 +                        * forcing renegotiation at this point has been shown
  55 +                        * to be effective in avoiding the problem.
  56 +                        */
  57 +                       if (force_reneg) {
  58 +                               dev_info(&priv->pdev->dev,
  59 +                                        "Forcing renegotiation\n");
  60 +                               genphy_restart_aneg(priv->dev->phydev);
  61 +                       }
  62 +               }
  63         }
  64  }
  65