[PATCH 5.10 118/406] mlxsw: i2c: Limit single transaction buffer size

Greg Kroah-Hartman
2023-09-17T19:24:42Z

From: Vadim Pasternak <vadimp@nvidia.com>

[ Upstream commit d7248f1cc835bd80e936dc5b2d94b149bdd0077d ]

Maximum size of buffer is obtained from underlying I2C adapter and in
case adapter allows I2C transaction buffer size greater than 100 bytes,
transaction will fail due to firmware limitation.

As a result driver will fail initialization.

Limit the maximum size of transaction buffer by 100 bytes to fit to
firmware.

Remove unnecessary calculation:
max_t(u16, MLXSW_I2C_BLK_DEF, quirk_size).
This condition can not happened.

Fixes: 3029a693beda ("mlxsw: i2c: Allow flexible setting of I2C transactions size")
Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/mellanox/mlxsw/i2c.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/i2c.c b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
index f20dca41424c9..61d2f621d65fc 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/i2c.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
@@ -47,6 +47,7 @@
#define MLXSW_I2C_MBOX_SIZE_BITS 12
#define MLXSW_I2C_ADDR_BUF_SIZE 4
#define MLXSW_I2C_BLK_DEF 32
+#define MLXSW_I2C_BLK_MAX 100
#define MLXSW_I2C_RETRY 5
#define MLXSW_I2C_TIMEOUT_MSECS 5000
#define MLXSW_I2C_MAX_DATA_SIZE 256
@@ -576,7 +577,7 @@ static int mlxsw_i2c_probe(struct i2c_client *client,
return -EOPNOTSUPP;
}

- mlxsw_i2c->block_size = max_t(u16, MLXSW_I2C_BLK_DEF,
+ mlxsw_i2c->block_size = min_t(u16, MLXSW_I2C_BLK_MAX,
min_t(u16, quirks->max_read_len,
quirks->max_write_len));
} else {
--
2.40.1