mlxsw: core_linecards: Probe active line cards for devices and expose FW version

In case the line card is active, go over all possible existing
devices (gearboxes) on it and expose FW version of the flashable one.

Example:

$ devlink dev info auxiliary/mlxsw_core.lc.0
auxiliary/mlxsw_core.lc.0:
  versions:
      fixed:
        hw.revision 0
      running:
        ini.version 4
        fw 19.2010.1312
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/networking/devlink/mlxsw.rst

@@ -75,6 +75,9 @@ The ``mlxsw`` driver reports the following versions for line card auxiliary devi
    * - ``ini.version``
      - running
      - Version of line card INI loaded
+   * - ``fw.version``
+     - running
+     - Three digit firmware version of line card device
 
 Driver-specific Traps
 =====================

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

@@ -566,6 +566,12 @@ enum mlxsw_linecard_status_event_type {
 
 struct mlxsw_linecard_bdev;
 
+struct mlxsw_linecard_device_info {
+	u16 fw_major;
+	u16 fw_minor;
+	u16 fw_sub_minor;
+};
+
 struct mlxsw_linecard {
 	u8 slot_index;
 	struct mlxsw_linecards *linecards;
@@ -581,6 +587,9 @@ struct mlxsw_linecard {
 	u16 hw_revision;
 	u16 ini_version;
 	struct mlxsw_linecard_bdev *bdev;
+	struct {
+		struct mlxsw_linecard_device_info info;
+	} device;
 };
 
 struct mlxsw_linecard_types_info;

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

@@ -87,6 +87,47 @@ static const char *mlxsw_linecard_type_name(struct mlxsw_linecard *linecard)
 	return linecard->name;
 }
 
+static int mlxsw_linecard_device_info_update(struct mlxsw_linecard *linecard)
+{
+	struct mlxsw_core *mlxsw_core = linecard->linecards->mlxsw_core;
+	bool flashable_found = false;
+	u8 msg_seq = 0;
+
+	do {
+		struct mlxsw_linecard_device_info info;
+		char mddq_pl[MLXSW_REG_MDDQ_LEN];
+		bool flash_owner;
+		bool data_valid;
+		u8 device_index;
+		int err;
+
+		mlxsw_reg_mddq_device_info_pack(mddq_pl, linecard->slot_index,
+						msg_seq);
+		err = mlxsw_reg_query(mlxsw_core, MLXSW_REG(mddq), mddq_pl);
+		if (err)
+			return err;
+		mlxsw_reg_mddq_device_info_unpack(mddq_pl, &msg_seq,
+						  &data_valid, &flash_owner,
+						  &device_index,
+						  &info.fw_major,
+						  &info.fw_minor,
+						  &info.fw_sub_minor);
+		if (!data_valid)
+			break;
+		if (!flash_owner) /* We care only about flashable ones. */
+			continue;
+		if (flashable_found) {
+			dev_warn_once(linecard->linecards->bus_info->dev, "linecard %u: More flashable devices present, exposing only the first one\n",
+				      linecard->slot_index);
+			return 0;
+		}
+		linecard->device.info = info;
+		flashable_found = true;
+	} while (msg_seq);
+
+	return 0;
+}
+
 static void mlxsw_linecard_provision_fail(struct mlxsw_linecard *linecard)
 {
 	linecard->provisioned = false;
@@ -249,6 +290,18 @@ int mlxsw_linecard_devlink_info_get(struct mlxsw_linecard *linecard,
 	if (err)
 		goto unlock;
 
+	if (linecard->active) {
+		struct mlxsw_linecard_device_info *info = &linecard->device.info;
+
+		sprintf(buf, "%u.%u.%u", info->fw_major, info->fw_minor,
+			info->fw_sub_minor);
+		err = devlink_info_version_running_put(req,
+						       DEVLINK_INFO_VERSION_GENERIC_FW,
+						       buf);
+		if (err)
+			goto unlock;
+	}
+
 unlock:
 	mutex_unlock(&linecard->lock);
 	return err;
@@ -308,6 +361,10 @@ static int mlxsw_linecard_ready_set(struct mlxsw_linecard *linecard)
 	char mddc_pl[MLXSW_REG_MDDC_LEN];
 	int err;
 
+	err = mlxsw_linecard_device_info_update(linecard);
+	if (err)
+		return err;
+
 	mlxsw_reg_mddc_pack(mddc_pl, linecard->slot_index, false, true);
 	err = mlxsw_reg_write(mlxsw_core, MLXSW_REG(mddc), mddc_pl);
 	if (err)