net: dsa: mv88e6xxx: Export VTU as devlink region

Export the raw VTU data and related registers in a devlink region so
that it can be inspected from userspace and compared to the current
bridge configuration.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20201109082927.8684-1-tobias@waldekranz.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/mv88e6xxx/chip.h

@@ -245,6 +245,7 @@ enum mv88e6xxx_region_id {
 	MV88E6XXX_REGION_GLOBAL1 = 0,
 	MV88E6XXX_REGION_GLOBAL2,
 	MV88E6XXX_REGION_ATU,
+	MV88E6XXX_REGION_VTU,
 
 	_MV88E6XXX_REGION_MAX,
 };

drivers/net/dsa/mv88e6xxx/devlink.c

@@ -415,6 +415,92 @@ out:
 	return err;
 }
 
+/**
+ * struct mv88e6xxx_devlink_vtu_entry - Devlink VTU entry
+ * @fid:   Global1/2:   FID and VLAN policy.
+ * @sid:   Global1/3:   SID, unknown filters and learning.
+ * @op:    Global1/5:   FID (old chipsets).
+ * @vid:   Global1/6:   VID, valid, and page.
+ * @data:  Global1/7-9: Membership data and priority override.
+ * @resvd: Reserved. Also happens to align the size to 16B.
+ *
+ * The VTU entry format varies between chipset generations, the
+ * descriptions above represent the superset of all possible
+ * information, not all fields are valid on all devices. Since this is
+ * a low-level debug interface, copy all data verbatim and defer
+ * parsing to the consumer.
+ */
+struct mv88e6xxx_devlink_vtu_entry {
+	u16 fid;
+	u16 sid;
+	u16 op;
+	u16 vid;
+	u16 data[3];
+	u16 resvd;
+};
+
+static int mv88e6xxx_region_vtu_snapshot(struct devlink *dl,
+					 const struct devlink_region_ops *ops,
+					 struct netlink_ext_ack *extack,
+					 u8 **data)
+{
+	struct mv88e6xxx_devlink_vtu_entry *table, *entry;
+	struct dsa_switch *ds = dsa_devlink_to_ds(dl);
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_vtu_entry vlan;
+	int err;
+
+	table = kcalloc(chip->info->max_vid + 1,
+			sizeof(struct mv88e6xxx_devlink_vtu_entry),
+			GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	entry = table;
+	vlan.vid = chip->info->max_vid;
+	vlan.valid = false;
+
+	mv88e6xxx_reg_lock(chip);
+
+	do {
+		err = mv88e6xxx_g1_vtu_getnext(chip, &vlan);
+		if (err)
+			break;
+
+		if (!vlan.valid)
+			break;
+
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6352_G1_VTU_FID,
+						&entry->fid);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6352_G1_VTU_SID,
+						&entry->sid);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_OP,
+						&entry->op);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_VID,
+						&entry->vid);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_DATA1,
+						&entry->data[0]);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_DATA2,
+						&entry->data[1]);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_DATA3,
+						&entry->data[2]);
+		if (err)
+			break;
+
+		entry++;
+	} while (vlan.vid < chip->info->max_vid);
+
+	mv88e6xxx_reg_unlock(chip);
+
+	if (err) {
+		kfree(table);
+		return err;
+	}
+
+	*data = (u8 *)table;
+	return 0;
+}
+
 static int mv88e6xxx_region_port_snapshot(struct devlink_port *devlink_port,
 					  const struct devlink_port_region_ops *ops,
 					  struct netlink_ext_ack *extack,
@@ -473,6 +559,12 @@ static struct devlink_region_ops mv88e6xxx_region_atu_ops = {
 	.destructor = kfree,
 };
 
+static struct devlink_region_ops mv88e6xxx_region_vtu_ops = {
+	.name = "vtu",
+	.snapshot = mv88e6xxx_region_vtu_snapshot,
+	.destructor = kfree,
+};
+
 static const struct devlink_port_region_ops mv88e6xxx_region_port_ops = {
 	.name = "port",
 	.snapshot = mv88e6xxx_region_port_snapshot,
@@ -496,6 +588,10 @@ static struct mv88e6xxx_region mv88e6xxx_regions[] = {
 		.ops = &mv88e6xxx_region_atu_ops
 	  /* calculated at runtime */
 	},
+	[MV88E6XXX_REGION_VTU] = {
+		.ops = &mv88e6xxx_region_vtu_ops
+	  /* calculated at runtime */
+	},
 };
 
 static void
@@ -574,9 +670,16 @@ static int mv88e6xxx_setup_devlink_regions_global(struct dsa_switch *ds,
 		ops = mv88e6xxx_regions[i].ops;
 		size = mv88e6xxx_regions[i].size;
 
-		if (i == MV88E6XXX_REGION_ATU)
+		switch (i) {
+		case MV88E6XXX_REGION_ATU:
 			size = mv88e6xxx_num_databases(chip) *
 				sizeof(struct mv88e6xxx_devlink_atu_entry);
+			break;
+		case MV88E6XXX_REGION_VTU:
+			size = chip->info->max_vid *
+				sizeof(struct mv88e6xxx_devlink_vtu_entry);
+			break;
+		}
 
 		region = dsa_devlink_region_create(ds, ops, 1, size);
 		if (IS_ERR(region))

drivers/net/dsa/mv88e6xxx/global1.h

@@ -329,6 +329,8 @@ void mv88e6xxx_g1_atu_prob_irq_free(struct mv88e6xxx_chip *chip);
 int mv88e6165_g1_atu_get_hash(struct mv88e6xxx_chip *chip, u8 *hash);
 int mv88e6165_g1_atu_set_hash(struct mv88e6xxx_chip *chip, u8 hash);
 
+int mv88e6xxx_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_vtu_entry *entry);
 int mv88e6185_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 			     struct mv88e6xxx_vtu_entry *entry);
 int mv88e6185_g1_vtu_loadpurge(struct mv88e6xxx_chip *chip,

drivers/net/dsa/mv88e6xxx/global1_vtu.c

@@ -276,8 +276,8 @@ static int mv88e6xxx_g1_vtu_stu_get(struct mv88e6xxx_chip *chip,
 	return 0;
 }
 
-static int mv88e6xxx_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
+int mv88e6xxx_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
-				    struct mv88e6xxx_vtu_entry *entry)
+			     struct mv88e6xxx_vtu_entry *entry)
 {
 	int err;