[PATCH net-next 1/3] dsa: mv88e6xxx: Timeout based on iterations, not time
From: Andrew Lunn <andrew@lunn.ch>
Date: 2016-08-19 01:55:13
Subsystem:
marvell 88e6xxx ethernet switch fabric driver, networking drivers, networking [dsa], the rest · Maintainers:
Andrew Lunn, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vladimir Oltean, Linus Torvalds
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 <andrew@lunn.ch> --- 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