# \[PATCH net-next 1/3\] dsa: mv88e6xxx: Timeout based on iterations, not time - From: Andrew Lunn \ - Date: 2016-08-19 01:55:13 - List: netdev - Page: https://ratatoskr.run/netdev/2016/08/11025902 - Thread: https://ratatoskr.run/netdev/2016/08/11025905/t.md ```text The mv88e6xxx driver times out operations on the switch based on looping until an elapsed wall clock time is reached. However, if usleep_range() sleeps much longer than expected, it could timeout with an error without actually checking to see if the devices has completed the operation. So replace the elapsed time with a fixed upper bound on the number of loops. Testing on various switches has shown that switches takes either 0 or 1 iteration, so a maximum of 16 iterations is a safe limit. Signed-off-by: Andrew Lunn --- drivers/net/dsa/mv88e6xxx/chip.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index a230fcba5b64..ac8e9af4879f 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -309,9 +309,9 @@ static int mv88e6xxx_serdes_write(struct mv88e6xxx_chip *chip, int reg, u16 val) static int mv88e6xxx_wait(struct mv88e6xxx_chip *chip, int addr, int reg, u16 mask) { - unsigned long timeout = jiffies + HZ / 10; + int i; - while (time_before(jiffies, timeout)) { + for (i = 0; i < 16; i++) { u16 val; int err; @@ -375,7 +375,7 @@ static int _mv88e6xxx_reg_write(struct mv88e6xxx_chip *chip, int addr, static int mv88e6xxx_ppu_disable(struct mv88e6xxx_chip *chip) { int ret; - unsigned long timeout; + int i; ret = _mv88e6xxx_reg_read(chip, REG_GLOBAL, GLOBAL_CONTROL); if (ret < 0) @@ -386,8 +386,7 @@ static int mv88e6xxx_ppu_disable(struct mv88e6xxx_chip *chip) if (ret) return ret; - timeout = jiffies + 1 * HZ; - while (time_before(jiffies, timeout)) { + for (i = 0; i < 16; i++) { ret = _mv88e6xxx_reg_read(chip, REG_GLOBAL, GLOBAL_STATUS); if (ret < 0) return ret; @@ -403,8 +402,7 @@ static int mv88e6xxx_ppu_disable(struct mv88e6xxx_chip *chip) static int mv88e6xxx_ppu_enable(struct mv88e6xxx_chip *chip) { - int ret, err; - unsigned long timeout; + int ret, err, i; ret = _mv88e6xxx_reg_read(chip, REG_GLOBAL, GLOBAL_CONTROL); if (ret < 0) @@ -415,8 +413,7 @@ static int mv88e6xxx_ppu_enable(struct mv88e6xxx_chip *chip) if (err) return err; - timeout = jiffies + 1 * HZ; - while (time_before(jiffies, timeout)) { + for (i = 0; i < 16; i++) { ret = _mv88e6xxx_reg_read(chip, REG_GLOBAL, GLOBAL_STATUS); if (ret < 0) return ret; -- 2.8.1 ```