mlxsw: core: Add EMAD string TLV

Add EMAD string TLV, an ASCII string the driver can receive from the
firmware in case of an error.
Signed-off-by: Shalom Toledo <shalomt@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core.c

@@ -249,6 +249,25 @@ MLXSW_ITEM32(emad, op_tlv, class, 0x04, 0, 8);
  */
 MLXSW_ITEM64(emad, op_tlv, tid, 0x08, 0, 64);
 
+/* emad_string_tlv_type
+ * Type of the TLV.
+ * Must be set to 0x2 (string TLV).
+ */
+MLXSW_ITEM32(emad, string_tlv, type, 0x00, 27, 5);
+
+/* emad_string_tlv_len
+ * Length of the string TLV in u32.
+ */
+MLXSW_ITEM32(emad, string_tlv, len, 0x00, 16, 11);
+
+#define MLXSW_EMAD_STRING_TLV_STRING_LEN 128
+
+/* emad_string_tlv_string
+ * String provided by the device's firmware in case of erroneous register access
+ */
+MLXSW_ITEM_BUF(emad, string_tlv, string, 0x04,
+	       MLXSW_EMAD_STRING_TLV_STRING_LEN);
+
 /* emad_reg_tlv_type
  * Type of the TLV.
  * Must be set to 0x3 (register TLV).

drivers/net/ethernet/mellanox/mlxsw/emad.h

@@ -19,7 +19,8 @@
 enum {
 	MLXSW_EMAD_TLV_TYPE_END,
 	MLXSW_EMAD_TLV_TYPE_OP,
-	MLXSW_EMAD_TLV_TYPE_REG = 0x3,
+	MLXSW_EMAD_TLV_TYPE_STRING,
+	MLXSW_EMAD_TLV_TYPE_REG,
 };
 
 /* OP TLV */
@@ -86,6 +87,9 @@ enum {
 	MLXSW_EMAD_OP_TLV_METHOD_EVENT = 5,
 };
 
+/* STRING TLV */
+#define MLXSW_EMAD_STRING_TLV_LEN 33	/* Length in u32 */
+
 /* END TLV */
 #define MLXSW_EMAD_END_TLV_LEN 1	/* Length in u32 */