-From 82a6bacc6df57c05093bea3f628d4d0b5f7a49a2 Mon Sep 17 00:00:00 2001
-From: Phil Elwell <phil@raspberrypi.org>
-Date: Fri, 2 Aug 2019 22:25:27 +0100
-Subject: [PATCH 748/806] net: bcmgenet: Workaround for Pi 4B network issue
-
-Some combinations of Pi 4Bs and Ethernet switches don't reliably get a
-DCHP-assigned IP address, leaving the unit with a self=assigned 169.254
-address.
-
-Forcing renegotiation has been found to be an effective workaround, so
-add an automatic renegotiation after the link comes up for the first
-time; enable it with genet.force_reneg=y - by default it is disabled.
-
-See: https://github.com/raspberrypi/linux/issues/3108
-
-Signed-off-by: Phil Elwell <phil@raspberrypi.org>
----
- .../net/ethernet/broadcom/genet/bcmgenet.c | 22 +++++++++++++++++++
- 1 file changed, 22 insertions(+)
-
---- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
-+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
-@@ -72,6 +72,10 @@
- #define GENET_RDMA_REG_OFF (priv->hw_params->rdma_offset + \
- TOTAL_DESC * DMA_DESC_SIZE)
-
-+static bool force_reneg = false;
-+module_param(force_reneg, bool, 0444);
-+MODULE_PARM_DESC(force_reneg, "Force a renegotiation after the initial link-up");
-+
- static inline void bcmgenet_writel(u32 value, void __iomem *offset)
- {
- /* MIPS chips strapped for BE will automagically configure the
-@@ -2612,6 +2616,7 @@ static void bcmgenet_irq_task(struct wor
- unsigned int status;
- struct bcmgenet_priv *priv = container_of(
- work, struct bcmgenet_priv, bcmgenet_irq_work);
-+ static int first_link = 1;
-
- netif_dbg(priv, intr, priv->dev, "%s\n", __func__);
-
-@@ -2625,9 +2630,26 @@ static void bcmgenet_irq_task(struct wor
- phy_init_hw(priv->dev->phydev);
-
- /* Link UP/DOWN event */
-- if (status & UMAC_IRQ_LINK_EVENT)
-+ if (status & UMAC_IRQ_LINK_EVENT) {
- phy_mac_interrupt(priv->dev->phydev);
-
-+ if (priv->dev->phydev->link && first_link) {
-+ first_link = 0;
-+ /*
-+ * HACK: Some Pi4Bs, when paired with some switches,
-+ * come up in a strange state where they are unable to
-+ * transmit, causing them to fail to get an IP address.
-+ * Although the failure mechanism is not yet understood,
-+ * forcing renegotiation at this point has been shown
-+ * to be effective in avoiding the problem.
-+ */
-+ if (force_reneg) {
-+ dev_info(&priv->pdev->dev,
-+ "Forcing renegotiation\n");
-+ genphy_restart_aneg(priv->dev->phydev);
-+ }
-+ }
-+ }
- }
-
- /* bcmgenet_isr1: handle Rx and Tx priority queues */