From 0fd5d79efa4a35c5b0944f7dc42b440d56af4b04 Mon Sep 17 00:00:00 2001
From: Chris Packham <chris.packham@alliedtelesis.co.nz>
Date: Tue, 24 Nov 2020 17:34:40 +1300
Subject: [PATCH] net: dsa: mv88e6xxx: Handle error in serdes_get_regs
If the underlying read operation failed we would end up writing stale
data to the supplied buffer. This would end up with the last
successfully read value repeating. Fix this by only writing the data
when we know the read was good. This will mean that failed values will
return 0xffff.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
drivers/net/dsa/mv88e6xxx/serdes.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c b/drivers/net/dsa/mv88e6xxx/serdes.c
index e60e8f0d0225a..3195936dc5be7 100644
--- a/drivers/net/dsa/mv88e6xxx/serdes.c
+++ b/drivers/net/dsa/mv88e6xxx/serdes.c
@@ -400,14 +400,16 @@ void mv88e6352_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p)
{
u16 *p = _p;
u16 reg;
+ int err;
int i;
if (!mv88e6352_port_has_serdes(chip, port))
return;
for (i = 0 ; i < 32; i++) {
- mv88e6352_serdes_read(chip, i, ®);
- p[i] = reg;
+ err = mv88e6352_serdes_read(chip, i, ®);
+ if (!err)
+ p[i] = reg;
}
}
@@ -1096,6 +1098,7 @@ void mv88e6390_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p)
u16 *p = _p;
int lane;
u16 reg;
+ int err;
int i;
lane = mv88e6xxx_serdes_get_lane(chip, port);
@@ -1103,8 +1106,9 @@ void mv88e6390_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p)
return;
for (i = 0 ; i < ARRAY_SIZE(mv88e6390_serdes_regs); i++) {
- mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
- mv88e6390_serdes_regs[i], ®);
- p[i] = reg;
+ err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
+ mv88e6390_serdes_regs[i], ®);
+ if (!err)
+ p[i] = reg;
}
}
--
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