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