i2c: designware: Handle invalid SMBus block data response length value
authorTam Nguyen <tamnguyenchi@os.amperecomputing.com>
Wed, 26 Jul 2023 08:00:01 +0000 (15:00 +0700)
committerWolfram Sang <wsa@kernel.org>
Mon, 14 Aug 2023 13:28:39 +0000 (15:28 +0200)
commit69f035c480d76f12bf061148ccfd578e1099e5fc
treed58c23a3d59d9ef49815a9ab1cc5bec0c824b9de
parent49d4db3953cb9004ff94efc0c176e026c820af5a
i2c: designware: Handle invalid SMBus block data response length value

In the I2C_FUNC_SMBUS_BLOCK_DATA case, the invalid length byte value
(outside of 1-32) of the SMBus block data response from the Slave device
is not correctly handled by the I2C Designware driver.

In case IC_EMPTYFIFO_HOLD_MASTER_EN==1, which cannot be detected
from the registers, the Master can be disabled only if the STOP bit
is set. Without STOP bit set, the Master remains active, holding the bus
until receiving a block data response length. This hangs the bus and
is unrecoverable.

Avoid this by issuing another dump read to reach the stop condition when
an invalid length byte is received.

Cc: stable@vger.kernel.org
Signed-off-by: Tam Nguyen <tamnguyenchi@os.amperecomputing.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20230726080001.337353-3-tamnguyenchi@os.amperecomputing.com
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
drivers/i2c/busses/i2c-designware-master.c