From 49d4db3953cb9004ff94efc0c176e026c820af5a Mon Sep 17 00:00:00 2001 From: Quan Nguyen Date: Wed, 26 Jul 2023 15:00:00 +0700 Subject: [PATCH] i2c: designware: Correct length byte validation logic Commit 0daede80f870 ("i2c: designware: Convert driver to using regmap API") changes the logic to validate the whole 32-bit return value of DW_IC_DATA_CMD register instead of 8-bit LSB without reason. Later, commit f53f15ba5a85 ("i2c: designware: Get right data length"), introduced partial fix but not enough because the "tmp > 0" still test tmp as 32-bit value and is wrong in case the IC_DATA_CMD[11] is set. Revert the logic to just before commit 0daede80f870 ("i2c: designware: Convert driver to using regmap API"). Fixes: f53f15ba5a85 ("i2c: designware: Get right data length") Fixes: 0daede80f870 ("i2c: designware: Convert driver to using regmap API") Cc: stable@vger.kernel.org Signed-off-by: Tam Nguyen Signed-off-by: Quan Nguyen Acked-by: Jarkko Nikula Link: https://lore.kernel.org/r/20230726080001.337353-2-tamnguyenchi@os.amperecomputing.com Reviewed-by: Andi Shyti Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-designware-master.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c index 3bfd7a2..6fdb66f 100644 --- a/drivers/i2c/busses/i2c-designware-master.c +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -588,9 +588,10 @@ i2c_dw_read(struct dw_i2c_dev *dev) u32 flags = msgs[dev->msg_read_idx].flags; regmap_read(dev->map, DW_IC_DATA_CMD, &tmp); + tmp &= DW_IC_DATA_CMD_DAT; /* Ensure length byte is a valid value */ if (flags & I2C_M_RECV_LEN && - (tmp & DW_IC_DATA_CMD_DAT) <= I2C_SMBUS_BLOCK_MAX && tmp > 0) { + tmp <= I2C_SMBUS_BLOCK_MAX && tmp > 0) { len = i2c_dw_recv_len(dev, tmp); } *buf++ = tmp; -- 2.7.4