diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec-bitwriter.h b/drivers/media/platform/rockchip/rkvdec/rkvdec-bitwriter.h
new file mode 100644
index 000000000000..288467941abf
--- /dev/null
+++ b/drivers/media/platform/rockchip/rkvdec/rkvdec-bitwriter.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Rockchip Video Decoder bit writer
+ *
+ * Copyright (C) 2026 Collabora, Ltd.
+ *	Detlev Casanova <detlev.casanova@collabora.com>
+ * Copyright (C) 2019 Collabora, Ltd.
+ *	Boris Brezillon <boris.brezillon@collabora.com>
+ */
+
+#ifndef RKVDEC_BIT_WRITER_H_
+#define RKVDEC_BIT_WRITER_H_
+
+#include <linux/types.h>
+#include <linux/bits.h>
+
+struct rkvdec_bw_field {
+	u16 offset;
+	u8 len;
+};
+
+#define BW_FIELD(_offset, _len) ((struct rkvdec_bw_field){ _offset, _len })
+
+static inline void rkvdec_set_bw_field(u32 *buf, struct rkvdec_bw_field field, u32 value)
+{
+	u8 bit = field.offset % 32;
+	u16 word = field.offset / 32;
+	u64 mask = GENMASK_ULL(bit + field.len - 1, bit);
+	u64 val = ((u64)value << bit) & mask;
+
+	buf[word] &= ~mask;
+	buf[word] |= val;
+	if (bit + field.len > 32) {
+		buf[word + 1] &= ~(mask >> 32);
+		buf[word + 1] |= val >> 32;
+	}
+}
+
+#endif /* RKVDEC_BIT_WRITER_H_ */