thunderbolt: Read vendor and device name from DROM

The device DROM contains name of the vendor and device among other
things. Extract this information and expose it to the userspace via two
new attributes.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/thunderbolt/eeprom.c

@@ -204,6 +204,11 @@ struct tb_drom_entry_header {
 	enum tb_drom_entry_type type:1;
 } __packed;
 
+struct tb_drom_entry_generic {
+	struct tb_drom_entry_header header;
+	u8 data[0];
+} __packed;
+
 struct tb_drom_entry_port {
 	/* BYTES 0-1 */
 	struct tb_drom_entry_header header;
@@ -295,6 +300,32 @@ int tb_drom_read_uid_only(struct tb_switch *sw, u64 *uid)
 	return 0;
 }
 
+static int tb_drom_parse_entry_generic(struct tb_switch *sw,
+		struct tb_drom_entry_header *header)
+{
+	const struct tb_drom_entry_generic *entry =
+		(const struct tb_drom_entry_generic *)header;
+
+	switch (header->index) {
+	case 1:
+		/* Length includes 2 bytes header so remove it before copy */
+		sw->vendor_name = kstrndup(entry->data,
+			header->len - sizeof(*header), GFP_KERNEL);
+		if (!sw->vendor_name)
+			return -ENOMEM;
+		break;
+
+	case 2:
+		sw->device_name = kstrndup(entry->data,
+			header->len - sizeof(*header), GFP_KERNEL);
+		if (!sw->device_name)
+			return -ENOMEM;
+		break;
+	}
+
+	return 0;
+}
+
 static int tb_drom_parse_entry_port(struct tb_switch *sw,
 				    struct tb_drom_entry_header *header)
 {
@@ -350,6 +381,7 @@ static int tb_drom_parse_entries(struct tb_switch *sw)
 
 		switch (entry->type) {
 		case TB_DROM_ENTRY_GENERIC:
+			res = tb_drom_parse_entry_generic(sw, entry);
 			break;
 		case TB_DROM_ENTRY_PORT:
 			res = tb_drom_parse_entry_port(sw, entry);