1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/firewire/phy-packet-definitions.h b/drivers/firewire/phy-packet-definitions.h
new file mode 100644
index 000000000000..479bb3431afb
--- /dev/null
+++ b/drivers/firewire/phy-packet-definitions.h
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// phy-packet-definitions.h - The definitions of phy packet for IEEE 1394.
+//
+// Copyright (c) 2024 Takashi Sakamoto
+
+#ifndef _FIREWIRE_PHY_PACKET_DEFINITIONS_H
+#define _FIREWIRE_PHY_PACKET_DEFINITIONS_H
+
+#define SELF_ID_EXTENDED_MASK				0x00800000
+#define SELF_ID_EXTENDED_SHIFT				23
+#define SELF_ID_MORE_PACKETS_MASK			0x00000001
+#define SELF_ID_MORE_PACKETS_SHIFT			0
+
+#define SELF_ID_EXTENDED_SEQUENCE_MASK			0x00700000
+#define SELF_ID_EXTENDED_SEQUENCE_SHIFT			20
+
+#define SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT		4
+
+static inline bool phy_packet_self_id_get_extended(u32 quadlet)
+{
+	return (quadlet & SELF_ID_EXTENDED_MASK) >> SELF_ID_EXTENDED_SHIFT;
+}
+
+static inline bool phy_packet_self_id_get_more_packets(u32 quadlet)
+{
+	return (quadlet & SELF_ID_MORE_PACKETS_MASK) >> SELF_ID_MORE_PACKETS_SHIFT;
+}
+
+static inline unsigned int phy_packet_self_id_extended_get_sequence(u32 quadlet)
+{
+	return (quadlet & SELF_ID_EXTENDED_SEQUENCE_MASK) >> SELF_ID_EXTENDED_SEQUENCE_SHIFT;
+}
+
+struct self_id_sequence_enumerator {
+	const u32 *cursor;
+	unsigned int quadlet_count;
+};
+
+static inline const u32 *self_id_sequence_enumerator_next(
+		struct self_id_sequence_enumerator *enumerator, unsigned int *quadlet_count)
+{
+	const u32 *self_id_sequence, *cursor;
+	u32 quadlet;
+	unsigned int count;
+	unsigned int sequence;
+
+	if (enumerator->cursor == NULL || enumerator->quadlet_count == 0)
+		return ERR_PTR(-ENODATA);
+	cursor = enumerator->cursor;
+	count = 1;
+
+	quadlet = *cursor;
+	sequence = 0;
+	while (phy_packet_self_id_get_more_packets(quadlet)) {
+		if (count >= enumerator->quadlet_count ||
+		    count >= SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT)
+			return ERR_PTR(-EPROTO);
+		++cursor;
+		++count;
+		quadlet = *cursor;
+
+		if (!phy_packet_self_id_get_extended(quadlet) ||
+		    sequence != phy_packet_self_id_extended_get_sequence(quadlet))
+			return ERR_PTR(-EPROTO);
+		++sequence;
+	}
+
+	*quadlet_count = count;
+	self_id_sequence = enumerator->cursor;
+
+	enumerator->cursor += count;
+	enumerator->quadlet_count -= count;
+
+	return self_id_sequence;
+}
+
+#endif // _FIREWIRE_PHY_PACKET_DEFINITIONS_H