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Commit 6441e669 authored by Andrew Lunn's avatar Andrew Lunn Committed by David S. Miller
Browse files

dsa: mv88e6xxx: Timeout based on iterations, not time 



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: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7a7e780c

drivers/net/dsa/mv88e6xxx/chip.c

+6 −9
Original line number Diff line number Diff line
@@ -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;