From: Linus Walleij linus.walleij@linaro.org
[ Upstream commit 95ce158b6c93b28842b54b42ad1cb221b9844062 ]
I get sporadic timeouts from the driver when using the MV88E6352. Reading the status again after the loop fixes the problem: the operation is successful but goes undetected.
Some added prints show things like this:
[ 58.356209] mv88e6085 mdio_mux-0.1:00: Timeout while waiting for switch, addr 1b reg 0b, mask 8000, val 0000, data c000 [ 58.367487] mv88e6085 mdio_mux-0.1:00: Timeout waiting for ATU op 4000, fid 0001 (...) [ 61.826293] mv88e6085 mdio_mux-0.1:00: Timeout while waiting for switch, addr 1c reg 18, mask 8000, val 0000, data 9860 [ 61.837560] mv88e6085 mdio_mux-0.1:00: Timeout waiting for PHY command 1860 to complete
The reason is probably not the commands: I think those are mostly fine with the 50+50ms timeout, but the problem appears when OpenWrt brings up several interfaces in parallel on a system with 7 populated ports: if one of them take more than 50 ms and waits one or more of the others can get stuck on the mutex for the switch and then this can easily multiply.
As we sleep and wait, the function loop needs a final check after exiting the loop if we were successful.
Suggested-by: Andrew Lunn andrew@lunn.ch Cc: Tobias Waldekranz tobias@waldekranz.com Fixes: 35da1dfd9484 ("net: dsa: mv88e6xxx: Improve performance of busy bit polling") Signed-off-by: Linus Walleij linus.walleij@linaro.org Reviewed-by: Andrew Lunn andrew@lunn.ch Link: https://lore.kernel.org/r/20230712223405.861899-1-linus.walleij@linaro.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/mv88e6xxx/chip.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index 4db1652015d1d..b69bd44ada1f2 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -109,6 +109,13 @@ int mv88e6xxx_wait_mask(struct mv88e6xxx_chip *chip, int addr, int reg, usleep_range(1000, 2000); }
+ err = mv88e6xxx_read(chip, addr, reg, &data); + if (err) + return err; + + if ((data & mask) == val) + return 0; + dev_err(chip->dev, "Timeout while waiting for switch\n"); return -ETIMEDOUT; }