diff mbox series

[3/4] net: dsa: mv88e6xxx: Handle error in serdes_get_regs

Message ID 20201022012516.18720-4-chris.packham@alliedtelesis.co.nz (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series net: dsa: mv88e6xxx: serdes link without phy | expand

Commit Message

Chris Packham Oct. 22, 2020, 1:25 a.m. UTC 
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>
---
Changes in v4:
- new

 drivers/net/dsa/mv88e6xxx/serdes.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

Comments

Andrew Lunn Oct. 23, 2020, 10:39 p.m. UTC | #1 
On Thu, Oct 22, 2020 at 02:25:14PM +1300, Chris Packham wrote:
> 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>

    Andrew
diff mbox series

Patch

diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c b/drivers/net/dsa/mv88e6xxx/serdes.c
index d4f40a739b17..ec9ca7210bb0 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, &reg);
-		p[i] = reg;
+		err = mv88e6352_serdes_read(chip, i, &reg);
+		if (!err)
+			p[i] = reg;
 	}
 }
 
@@ -1049,6 +1051,7 @@  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);
@@ -1056,8 +1059,9 @@  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], &reg);
-		p[i] = reg;
+		err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
+					    mv88e6390_serdes_regs[i], &reg);
+		if (!err)
+			p[i] = reg;
 	}
 }