diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-4.19/950-0658-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-4.19/950-0658-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-4.19/950-0658-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch b/target/linux/bcm27xx/patches-4.19/950-0658-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch new file mode 100644 index 0000000000..beeeb2f9f1 --- /dev/null +++ b/target/linux/bcm27xx/patches-4.19/950-0658-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch @@ -0,0 +1,52 @@ +From 103afc4641ab8d6587e981a5e3fda27427a8bf4b Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Fri, 9 Aug 2019 08:51:43 +0100 +Subject: [PATCH] net: bcmgenet: Workaround #2 for Pi4 Ethernet fail + +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. In the failure case, the Pi is left able to receive packets +but not send them, suggesting that the MAC<->PHY link is getting into +a bad state. + +It has been found empirically that skipping a reset step by the genet +driver prevents the failures. No downsides have been discovered yet, +and unlike the forced renegotiation it doesn't increase the time to +get an IP address, so the workaround is enabled by default; add + + genet.skip_umac_reset=n + +to the command line to disable it. + +See: https://github.com/raspberrypi/linux/issues/3108 + +Signed-off-by: Phil Elwell <phil@raspberrypi.org> +--- + drivers/net/ethernet/broadcom/genet/bcmgenet.c | 9 +++++++++ + 1 file changed, 9 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 skip_umac_reset = true; ++module_param(skip_umac_reset, bool, 0444); ++MODULE_PARM_DESC(skip_umac_reset, "Skip UMAC reset step"); ++ + static inline void bcmgenet_writel(u32 value, void __iomem *offset) + { + /* MIPS chips strapped for BE will automagically configure the +@@ -1993,6 +1997,11 @@ static void reset_umac(struct bcmgenet_p + bcmgenet_rbuf_ctrl_set(priv, 0); + udelay(10); + ++ if (skip_umac_reset) { ++ pr_warn("Skipping UMAC reset\n"); ++ return; ++ } ++ + /* disable MAC while updating its registers */ + bcmgenet_umac_writel(priv, 0, UMAC_CMD); + |