openwrt/target/linux/generic/backport-6.1/790-13-v6.4-net-dsa-mt7530-skip-locking-if-MDIO-bus-isn-t-presen.patch
Daniel Golle 401a6ccfaf generic: 6.1: sync mt7530 DSA driver with upstream
Backport lots upstream changes, many of them fixes, for the mt7530 DSA
driver. Some of them may or may not find they way into Linux 6.1
stable, some certainly won't because they are fixes for backported
commits which aren't even present in Linux 6.1 upstream.

Apart from adding new patches, also remove mutated patch
723-net-mt7531-ensure-all-MACs-are-powered-down-before-r.patch
which should never have been added for Linux 6.1 -- it was applied
already upstream but coincidentally would fuzzy-apply in the wrong
place as well (for MT7530 instead of MT7531). While that didn't really
hurt anyone it is just unneeded.

The other deleted patch
795-mt7530-register-OF-node-for-internal-MDIO-bus.patch
has been replaced by an equivalent commit with a more complete patch
description by upstream maintainer Arınç Ünal.

The remaining differences compared to the upstream driver are:
 * C22/C45 MDIO ops aren't split
   Upstream did that, backporting it would require making changes to
   *all* DSA drivers
 * 'slave' -> 'user', 'master' -> 'conduit' language change in DSA
 * support for selecting preferred CPU port on MT7531
   Also this would require too many DSA framework changes potentially
   affecting other devices. If we ever really use Linux 6.1 in a
   release (I hope not) we can still reconsider to make the effort to
   backport that.

In addition to some minor bug fixes and style improvements the switch
should now behave more conformant when it comes to link-local frames,
and we will again be able to cleanly pick patches from upstream.

MAINTAIERS NOTE:
Three patches are already part of Linux stable and should be removed with
the next minor kernel version bump:
789-STABLE-01-net-dsa-mt7530-prevent-possible-incorrect-XTAL-frequ.patch
789-STABLE-02-net-dsa-mt7530-fix-link-local-frames-that-ingress-vl.patch
789-STABLE-03-net-dsa-mt7530-fix-handling-of-all-link-local-frames.patch

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
2024-04-10 18:50:32 +01:00

48 lines
1.6 KiB
Diff

From 86e1168a214b7ab0883acf1e7a6885a7a949e3e7 Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
Date: Mon, 3 Apr 2023 02:19:28 +0100
Subject: [PATCH 13/48] net: dsa: mt7530: skip locking if MDIO bus isn't
present
As MT7530 and MT7531 internally use 32-bit wide registers, each access
to any register of the switch requires several operations on the MDIO
bus. Hence if there is congruent access, e.g. due to PCS or PHY
polling, this can mess up and interfere with another ongoing register
access sequence.
However, the MDIO bus mutex is only relevant for MDIO-connected
switches. Prepare switches which have there registers directly mapped
into the SoCs register space via MMIO which do not require such
locking. There we can simply use regmap's default locking mechanism.
Hence guard mutex operations to only be performed in case of MDIO
connected switches.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/dsa/mt7530.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -144,13 +144,15 @@ err:
static void
mt7530_mutex_lock(struct mt7530_priv *priv)
{
- mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
+ if (priv->bus)
+ mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
}
static void
mt7530_mutex_unlock(struct mt7530_priv *priv)
{
- mutex_unlock(&priv->bus->mdio_lock);
+ if (priv->bus)
+ mutex_unlock(&priv->bus->mdio_lock);
}
static void