thunderbolt: Add support for USB4 DROM

USB4 router DROM differs sligthly from Thunderbolt 1-3 DROM. For
instance it does not include UID and CRC8 in the header section, and it
has product descriptor genereric entry to describe the product IDs and
related information. If the "Version" field in the DROM header section
reads 3 it means the router only has USB4 DROM and if it reads 1 it
means the router supports TBT3 compatible DROM.

For this reason, update the DROM parsing code to support "pure" USB4
DROMs too.

While there drop the extra empty line at the end of tb_drom_read().

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/eeprom.c

@@ -277,6 +277,16 @@ struct tb_drom_entry_port {
 	u8 unknown4:2;
 } __packed;
 
+/* USB4 product descriptor */
+struct tb_drom_entry_desc {
+	struct tb_drom_entry_header header;
+	u16 bcdUSBSpec;
+	u16 idVendor;
+	u16 idProduct;
+	u16 bcdProductFWRevision;
+	u32 TID;
+	u8 productHWRevision;
+};
 
 /**
  * tb_drom_read_uid_only() - Read UID directly from DROM
@@ -329,6 +339,16 @@ static int tb_drom_parse_entry_generic(struct tb_switch *sw,
 		if (!sw->device_name)
 			return -ENOMEM;
 		break;
+	case 9: {
+		const struct tb_drom_entry_desc *desc =
+			(const struct tb_drom_entry_desc *)entry;
+
+		if (!sw->vendor && !sw->device) {
+			sw->vendor = desc->idVendor;
+			sw->device = desc->idProduct;
+		}
+		break;
+	}
 	}
 
 	return 0;
@@ -521,6 +541,51 @@ static int tb_drom_read_n(struct tb_switch *sw, u16 offset, u8 *val,
 	return tb_eeprom_read_n(sw, offset, val, count);
 }
 
+static int tb_drom_parse(struct tb_switch *sw)
+{
+	const struct tb_drom_header *header =
+		(const struct tb_drom_header *)sw->drom;
+	u32 crc;
+
+	crc = tb_crc8((u8 *) &header->uid, 8);
+	if (crc != header->uid_crc8) {
+		tb_sw_warn(sw,
+			"DROM UID CRC8 mismatch (expected: %#x, got: %#x), aborting\n",
+			header->uid_crc8, crc);
+		return -EINVAL;
+	}
+	if (!sw->uid)
+		sw->uid = header->uid;
+	sw->vendor = header->vendor_id;
+	sw->device = header->model_id;
+
+	crc = tb_crc32(sw->drom + TB_DROM_DATA_START, header->data_len);
+	if (crc != header->data_crc32) {
+		tb_sw_warn(sw,
+			"DROM data CRC32 mismatch (expected: %#x, got: %#x), continuing\n",
+			header->data_crc32, crc);
+	}
+
+	return tb_drom_parse_entries(sw);
+}
+
+static int usb4_drom_parse(struct tb_switch *sw)
+{
+	const struct tb_drom_header *header =
+		(const struct tb_drom_header *)sw->drom;
+	u32 crc;
+
+	crc = tb_crc32(sw->drom + TB_DROM_DATA_START, header->data_len);
+	if (crc != header->data_crc32) {
+		tb_sw_warn(sw,
+			   "DROM data CRC32 mismatch (expected: %#x, got: %#x), aborting\n",
+			   header->data_crc32, crc);
+		return -EINVAL;
+	}
+
+	return tb_drom_parse_entries(sw);
+}
+
 /**
  * tb_drom_read() - Copy DROM to sw->drom and parse it
  * @sw: Router whose DROM to read and parse
@@ -534,7 +599,6 @@ static int tb_drom_read_n(struct tb_switch *sw, u16 offset, u8 *val,
 int tb_drom_read(struct tb_switch *sw)
 {
 	u16 size;
-	u32 crc;
 	struct tb_drom_header *header;
 	int res, retries = 1;
 
@@ -599,30 +663,21 @@ parse:
 		goto err;
 	}
 
-	crc = tb_crc8((u8 *) &header->uid, 8);
-	if (crc != header->uid_crc8) {
-		tb_sw_warn(sw,
-			"drom uid crc8 mismatch (expected: %#x, got: %#x), aborting\n",
-			header->uid_crc8, crc);
-		goto err;
-	}
-	if (!sw->uid)
-		sw->uid = header->uid;
-	sw->vendor = header->vendor_id;
-	sw->device = header->model_id;
+	tb_sw_dbg(sw, "DROM version: %d\n", header->device_rom_revision);
 
-	crc = tb_crc32(sw->drom + TB_DROM_DATA_START, header->data_len);
-	if (crc != header->data_crc32) {
-		tb_sw_warn(sw,
-			"drom data crc32 mismatch (expected: %#x, got: %#x), continuing\n",
-			header->data_crc32, crc);
+	switch (header->device_rom_revision) {
+	case 3:
+		res = usb4_drom_parse(sw);
+		break;
+	default:
+		tb_sw_warn(sw, "DROM device_rom_revision %#x unknown\n",
+			   header->device_rom_revision);
+		fallthrough;
+	case 1:
+		res = tb_drom_parse(sw);
+		break;
 	}
 
-	if (header->device_rom_revision > 2)
-		tb_sw_warn(sw, "drom device_rom_revision %#x unknown\n",
-			header->device_rom_revision);
-
-	res = tb_drom_parse_entries(sw);
 	/* If the DROM parsing fails, wait a moment and retry once */
 	if (res == -EILSEQ && retries--) {
 		tb_sw_warn(sw, "parsing DROM failed, retrying\n");
@@ -632,10 +687,11 @@ parse:
 			goto parse;
 	}
 
-	return res;
+	if (!res)
+		return 0;
+
 err:
 	kfree(sw->drom);
 	sw->drom = NULL;
 	return -EIO;
-
 }