From: Alfred Lee l00g33k@gmail.com
[ Upstream commit 23d775f12dcd23d052a4927195f15e970e27ab26 ]
If the switch is reset during active EEPROM transactions, as in just after an SoC reset after power up, the I2C bus transaction may be cut short leaving the EEPROM internal I2C state machine in the wrong state. When the switch is reset again, the bad state machine state may result in data being read from the wrong memory location causing the switch to enter unexpected mode rendering it inoperational.
Fixes: a3dcb3e7e70c ("net: dsa: mv88e6xxx: Wait for EEPROM done after HW reset") Signed-off-by: Alfred Lee l00g33k@gmail.com Reviewed-by: Andrew Lunn andrew@lunn.ch Link: https://lore.kernel.org/r/20230815001323.24739-1-l00g33k@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/mv88e6xxx/chip.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index 8b2c8546f4c99..177151298d72a 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -2310,6 +2310,14 @@ static void mv88e6xxx_hardware_reset(struct mv88e6xxx_chip *chip)
/* If there is a GPIO connected to the reset pin, toggle it */ if (gpiod) { + /* If the switch has just been reset and not yet completed + * loading EEPROM, the reset may interrupt the I2C transaction + * mid-byte, causing the first EEPROM read after the reset + * from the wrong location resulting in the switch booting + * to wrong mode and inoperable. + */ + mv88e6xxx_g1_wait_eeprom_done(chip); + gpiod_set_value_cansleep(gpiod, 1); usleep_range(10000, 20000); gpiod_set_value_cansleep(gpiod, 0);