[PATCH] Backport mt7621 ethernet driver fixes to prevent freezes

Fabian Bläse fabian at blaese.de
So Aug 2 19:54:59 CEST 2020


Currently devices based on mt7621 might freeze due to issues
with the ethernet driver. (see [1])

This patch might fix these freezes and will be included in OpenWrt 19.07.4 [2].
While it is hard to reproduce the issue and this patch is therefore not verified
to fix the issue, it is backported into our firmware anyway.

This patch can be removed when upgrading to OpenWrt 19.07.4.

[1] https://forum.openwrt.org/t/mtk-soc-eth-watchdog-timeout-after-r11573
[2] https://github.com/openwrt/openwrt/commit/c8f8e59816eca49d776562d2d302bf990a87faf0

Signed-off-by: Fabian Bläse <fabian at blaese.de>
---
 .../0010-ramips-gsw_mt7621-disable-PORT.patch | 58 +++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 build_patches/openwrt/0010-ramips-gsw_mt7621-disable-PORT.patch

diff --git a/build_patches/openwrt/0010-ramips-gsw_mt7621-disable-PORT.patch b/build_patches/openwrt/0010-ramips-gsw_mt7621-disable-PORT.patch
new file mode 100644
index 0000000..7e6c540
--- /dev/null
+++ b/build_patches/openwrt/0010-ramips-gsw_mt7621-disable-PORT.patch
@@ -0,0 +1,58 @@
+From 498f1f4f5df2d077ba524f5735906bb52c12d580 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20=C5=A0tetiar?= <ynezz at true.cz>
+Date: Tue, 11 Feb 2020 11:17:41 +0100
+Subject: [PATCH] ramips: gsw_mt7621: disable PORT 5 MAC RX/TX flow control by
+ default
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Looking at the current upstream driver implementation, it seems like the
+TX/RX flow control is enabled only if the flow control pause option is
+resolved from the device/link partner advertisements (or otherwise set).
+
+On the other hand, our current in-tree driver force enables TX/RX
+flow control by default, thus possibly leading to TX timeouts if the
+other end sends pause frames (which are not properly handled?):
+
+ WARNING: CPU: 3 PID: 0 at net/sched/sch_generic.c:320 dev_watchdog+0x1ac/0x324
+ NETDEV WATCHDOG: eth0 (mtk_soc_eth): transmit queue 0 timed out
+
+Disabling the flow control on PORT 5 MAC seems to fix this issues as the
+pause frames are then filtered out. While at it, I'm removing the if
+condition completely as suggested, since this code is run only on mt7621
+SoC, so there is no need to check for the silicon revisions.
+
+Ref: https://lists.openwrt.org/pipermail/openwrt-devel/2017-November/009882.html
+Ref: https://forum.openwrt.org/t/mtk-soc-eth-watchdog-timeout-after-r11573/50000/12
+Suggested-by: Felix Fietkau <nbd at nbd.name>
+Reported-by: Rosen Penev <rosenp at gmail.com>
+Signed-off-by: Petr Štetiar <ynezz at true.cz>
+(cherry picked from commit c8f8e59816eca49d776562d2d302bf990a87faf0)
+---
+ .../drivers/net/ethernet/mediatek/gsw_mt7621.c       | 12 +++---------
+ 1 file changed, 3 insertions(+), 9 deletions(-)
+
+diff --git a/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/gsw_mt7621.c b/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/gsw_mt7621.c
+index 89be23900738..232bcd8cf4ea 100644
+--- a/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/gsw_mt7621.c
++++ b/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/gsw_mt7621.c
+@@ -98,15 +98,9 @@ static void mt7621_hw_init(struct mt7620_gsw *gsw, struct device_node *np)
+ 	mt7530_mdio_w32(gsw, 0x7000, 0x3);
+ 	usleep_range(10, 20);
+ 
+-	if ((rt_sysc_r32(SYSC_REG_CHIP_REV_ID) & 0xFFFF) == 0x0101) {
+-		/* (GE1, Force 1000M/FD, FC ON, MAX_RX_LENGTH 1536) */
+-		mtk_switch_w32(gsw, 0x2305e30b, GSW_REG_MAC_P0_MCR);
+-		mt7530_mdio_w32(gsw, 0x3600, 0x5e30b);
+-	} else {
+-		/* (GE1, Force 1000M/FD, FC ON, MAX_RX_LENGTH 1536) */
+-		mtk_switch_w32(gsw, 0x2305e33b, GSW_REG_MAC_P0_MCR);
+-		mt7530_mdio_w32(gsw, 0x3600, 0x5e33b);
+-	}
++	/* (GE1, Force 1000M/FD, FC OFF, MAX_RX_LENGTH 1536) */
++	mtk_switch_w32(gsw, 0x2305e30b, GSW_REG_MAC_P0_MCR);
++	mt7530_mdio_w32(gsw, 0x3600, 0x5e30b);
+ 
+ 	/* (GE2, Link down) */
+ 	mtk_switch_w32(gsw, 0x8000, GSW_REG_MAC_P1_MCR);
-- 
2.28.0



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