media: visl: add virtual stateless decoder driver

A virtual stateless device for stateless uAPI development purposes.

This tool's objective is to help the development and testing of
userspace applications that use the V4L2 stateless API to decode media.

A userspace implementation can use visl to run a decoding loop even when
no hardware is available or when the kernel uAPI for the codec has not
been upstreamed yet. This can reveal bugs at an early stage.

This driver can also trace the contents of the V4L2 controls submitted
to it.  It can also dump the contents of the vb2 buffers through a
debugfs interface. This is in many ways similar to the tracing
infrastructure available for other popular encode/decode APIs out there
and can help develop a userspace application by using another (working)
one as a reference.

Note that no actual decoding of video frames is performed by visl. The
V4L2 test pattern generator is used to write various debug information
to the capture buffers instead.

Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

1 files changed, 176 insertions, 0 deletions

diff --git a/drivers/media/test-drivers/visl/visl.h b/drivers/media/test-drivers/visl/visl.h
new file mode 100644
index 000000000000..31639f2e593d
--- /dev/null
+++ b/drivers/media/test-drivers/visl/visl.h
@@ -0,0 +1,176 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A virtual stateless device for stateless uAPI development purposes.
+ *
+ * This tool's objective is to help the development and testing of userspace
+ * applications that use the V4L2 stateless API to decode media.
+ *
+ * A userspace implementation can use visl to run a decoding loop even when no
+ * hardware is available or when the kernel uAPI for the codec has not been
+ * upstreamed yet. This can reveal bugs at an early stage.
+ *
+ * This driver can also trace the contents of the V4L2 controls submitted to it.
+ * It can also dump the contents of the vb2 buffers through a debugfs
+ * interface. This is in many ways similar to the tracing infrastructure
+ * available for other popular encode/decode APIs out there and can help develop
+ * a userspace application by using another (working) one as a reference.
+ *
+ * Note that no actual decoding of video frames is performed by visl. The V4L2
+ * test pattern generator is used to write various debug information to the
+ * capture buffers instead.
+ *
+ * Copyright (C) 2022 Collabora, Ltd.
+ *
+ * Based on the vim2m driver, that is:
+ *
+ * Copyright (c) 2009-2010 Samsung Electronics Co., Ltd.
+ * Pawel Osciak, <pawel@osciak.com>
+ * Marek Szyprowski, <m.szyprowski@samsung.com>
+ *
+ * Based on the vicodec driver, that is:
+ *
+ * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * Based on the Cedrus VPU driver, that is:
+ *
+ * Copyright (C) 2016 Florent Revest <florent.revest@free-electrons.com>
+ * Copyright (C) 2018 Paul Kocialkowski <paul.kocialkowski@bootlin.com>
+ * Copyright (C) 2018 Bootlin
+ */
+
+#ifndef _VISL_H_
+#define _VISL_H_
+
+#include <linux/debugfs.h>
+#include <linux/list.h>
+
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/tpg/v4l2-tpg.h>
+
+#define VISL_NAME		"visl"
+#define VISL_M2M_NQUEUES	2
+
+#define TPG_STR_BUF_SZ		2048
+
+extern unsigned int visl_transtime_ms;
+
+struct visl_ctrls {
+	const struct visl_ctrl_desc *ctrls;
+	unsigned int num_ctrls;
+};
+
+struct visl_coded_format_desc {
+	u32 pixelformat;
+	struct v4l2_frmsize_stepwise frmsize;
+	const struct visl_ctrls *ctrls;
+	unsigned int num_decoded_fmts;
+	const u32 *decoded_fmts;
+};
+
+extern const struct visl_coded_format_desc visl_coded_fmts[];
+extern const size_t num_coded_fmts;
+
+enum {
+	V4L2_M2M_SRC = 0,
+	V4L2_M2M_DST = 1,
+};
+
+extern unsigned int visl_debug;
+#define dprintk(dev, fmt, arg...) \
+	v4l2_dbg(1, visl_debug, &(dev)->v4l2_dev, "%s: " fmt, __func__, ## arg)
+
+extern int visl_dprintk_frame_start;
+extern unsigned int visl_dprintk_nframes;
+extern bool keep_bitstream_buffers;
+extern int bitstream_trace_frame_start;
+extern unsigned int bitstream_trace_nframes;
+
+#define frame_dprintk(dev, current, fmt, arg...) \
+	do { \
+		if (visl_dprintk_frame_start > -1 && \
+		    (current) >= visl_dprintk_frame_start && \
+		    (current) < visl_dprintk_frame_start + visl_dprintk_nframes) \
+			dprintk(dev, fmt, ## arg); \
+	} while (0) \
+
+struct visl_q_data {
+	unsigned int		sequence;
+};
+
+struct visl_dev {
+	struct v4l2_device	v4l2_dev;
+	struct video_device	vfd;
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_device	mdev;
+#endif
+
+	struct mutex		dev_mutex;
+
+	struct v4l2_m2m_dev	*m2m_dev;
+
+#ifdef CONFIG_VISL_DEBUGFS
+	struct dentry		*debugfs_root;
+	struct dentry		*bitstream_debugfs;
+	struct list_head	bitstream_blobs;
+
+	/* Protects the "blob" list */
+	struct mutex		bitstream_lock;
+#endif
+};
+
+enum visl_codec {
+	VISL_CODEC_NONE,
+	VISL_CODEC_FWHT,
+	VISL_CODEC_MPEG2,
+	VISL_CODEC_VP8,
+	VISL_CODEC_VP9,
+	VISL_CODEC_H264,
+	VISL_CODEC_HEVC,
+};
+
+struct visl_blob {
+	struct list_head list;
+	struct dentry *dentry;
+	struct debugfs_blob_wrapper blob;
+};
+
+struct visl_ctx {
+	struct v4l2_fh		fh;
+	struct visl_dev	*dev;
+	struct v4l2_ctrl_handler hdl;
+
+	struct mutex		vb_mutex;
+
+	struct visl_q_data	q_data[VISL_M2M_NQUEUES];
+	enum   visl_codec	current_codec;
+
+	const struct visl_coded_format_desc *coded_format_desc;
+
+	struct v4l2_format	coded_fmt;
+	struct v4l2_format	decoded_fmt;
+
+	struct tpg_data		tpg;
+	u64			capture_streamon_jiffies;
+	char			*tpg_str_buf;
+};
+
+struct visl_ctrl_desc {
+	struct v4l2_ctrl_config cfg;
+};
+
+static inline struct visl_ctx *visl_file_to_ctx(struct file *file)
+{
+	return container_of(file->private_data, struct visl_ctx, fh);
+}
+
+static inline struct visl_ctx *visl_v4l2fh_to_ctx(struct v4l2_fh *v4l2_fh)
+{
+	return container_of(v4l2_fh, struct visl_ctx, fh);
+}
+
+void *visl_find_control_data(struct visl_ctx *ctx, u32 id);
+struct v4l2_ctrl *visl_find_control(struct visl_ctx *ctx, u32 id);
+u32 visl_control_num_elems(struct visl_ctx *ctx, u32 id);
+
+#endif /* _VISL_H_ */