sonic-linux-kernel/patch/0037-mlxsw-i2c-Limit-single-transaction-buffer-size.patch at db34fdaa56e3ec7c5bb3dfa296064d884c98d794 · sonic-net/sonic-linux-kernel · GitHub

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From 1a589f97c28418f9d50b8efa25e6e437dfc700e3 Mon Sep 17 00:00:00 2001
From: Vadim Pasternak <vadimp@nvidia.com>
Date: Mon, 14 Aug 2023 10:44:41 +0000
Subject: [PATH backport v6.1 37/41] mlxsw: i2c: Limit single transaction
 buffer size

Link: https://github.com/jpirko/linux_mlxsw/commit/162fc0c49b08baf613b1fba211f4d9852845b5b8

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>
---
 drivers/net/ethernet/mellanox/mlxsw/i2c.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/i2c.c b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
index 26e05f129e35..d9a71ad9adae 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/i2c.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
@@ -48,6 +48,7 @@
 #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
@@ -653,9 +654,10 @@ static int mlxsw_i2c_probe(struct i2c_client *client,
 			return -EOPNOTSUPP;
 		}

-		mlxsw_i2c->block_size = max_t(u16, MLXSW_I2C_BLK_DEF,
-					      min_t(u16, quirks->max_read_len,
-						    quirks->max_write_len));
+		mlxsw_i2c->block_size = min_t(u16, min_t(u16, quirks->max_read_len,
+							 quirks->max_write_len),
+					      MLXSW_I2C_BLK_MAX);
+
 	} else {
 		mlxsw_i2c->block_size = MLXSW_I2C_BLK_DEF;
 	}
--
2.20.1