media: allegro: extract RBSP handler from H.264 NAL generator

The RBSP structure is the same for HEVC and H.264. In order to be able
to reuse the RBSP handler for generating HEVC NAL units, extract the
functions from the H.264 generator.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 60 insertions, 0 deletions

diff --git a/drivers/media/platform/allegro-dvt/nal-rbsp.h b/drivers/media/platform/allegro-dvt/nal-rbsp.h
new file mode 100644
index 000000000000..90cc1a4f716d
--- /dev/null
+++ b/drivers/media/platform/allegro-dvt/nal-rbsp.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2020 Pengutronix, Michael Tretter <kernel@pengutronix.de>
+ */
+
+#ifndef __NAL_RBSP_H__
+#define __NAL_RBSP_H__
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+struct rbsp;
+
+struct nal_rbsp_ops {
+	int (*rbsp_bit)(struct rbsp *rbsp, int *val);
+	int (*rbsp_bits)(struct rbsp *rbsp, int n, unsigned int *val);
+	int (*rbsp_uev)(struct rbsp *rbsp, unsigned int *val);
+	int (*rbsp_sev)(struct rbsp *rbsp, int *val);
+};
+
+/**
+ * struct rbsp - State object for handling a raw byte sequence payload
+ * @data: pointer to the data of the rbsp
+ * @size: maximum size of the data of the rbsp
+ * @pos: current bit position inside the rbsp
+ * @num_consecutive_zeros: number of zeros before @pos
+ * @ops: per datatype functions for interacting with the rbsp
+ * @error: an error occurred while handling the rbsp
+ *
+ * This struct is passed around the various parsing functions and tracks the
+ * current position within the raw byte sequence payload.
+ *
+ * The @ops field allows to separate the operation, i.e., reading/writing a
+ * value from/to that rbsp, from the structure of the NAL unit. This allows to
+ * have a single function for iterating the NAL unit, while @ops has function
+ * pointers for handling each type in the rbsp.
+ */
+struct rbsp {
+	u8 *data;
+	size_t size;
+	unsigned int pos;
+	unsigned int num_consecutive_zeros;
+	struct nal_rbsp_ops *ops;
+	int error;
+};
+
+extern struct nal_rbsp_ops write;
+extern struct nal_rbsp_ops read;
+
+void rbsp_init(struct rbsp *rbsp, void *addr, size_t size,
+	       struct nal_rbsp_ops *ops);
+
+void rbsp_bit(struct rbsp *rbsp, int *value);
+void rbsp_bits(struct rbsp *rbsp, int n, int *value);
+void rbsp_uev(struct rbsp *rbsp, unsigned int *value);
+void rbsp_sev(struct rbsp *rbsp, int *value);
+
+void rbsp_trailing_bits(struct rbsp *rbsp);
+
+#endif /* __NAL_RBSP_H__ */