openwrt/target/linux/bcm27xx/patches-4.19/950-0658-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch
Adrian Schmutzler 7d7aa2fd92 brcm2708: rename target to bcm27xx
This change makes the names of Broadcom targets consistent by using
the common notation based on SoC/CPU ID (which is used internally
anyway), bcmXXXX instead of brcmXXXX.
This is even used for target TITLE in make menuconfig already,
only the short target name used brcm so far.

Despite, since subtargets range from bcm2708 to bcm2711, it seems
appropriate to use bcm27xx instead of bcm2708 (again, as already done
for BOARDNAME).

This also renames the packages brcm2708-userland and brcm2708-gpu-fw.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: Álvaro Fernández Rojas <noltari@gmail.com>
2020-02-14 14:10:51 +01:00

53 lines
1.8 KiB
Diff

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);