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Subject[PATCH v9 09/13] media: uapi: Add a control for HANTRO driver
Date
The HEVC HANTRO driver needs to know the number of bits to skip at
the beginning of the slice header.
That is a hardware specific requirement so create a dedicated control
for this purpose.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
version 9:
- Corrections in commit message.
- Move control definition in hevc-ctrls.h
- Add note in documentation to explain that this control
may change in the futur

version 5:
- Be even more verbose in control documentation.
- Do not create class for the control.
version 4:
- The control is now an integer which is enough to provide the numbers
of bits to skip.
version 3:
- Fix typo in field name

.../userspace-api/media/drivers/hantro.rst | 19 +++++++++++++++++++
.../userspace-api/media/drivers/index.rst | 1 +
include/media/hevc-ctrls.h | 13 +++++++++++++
3 files changed, 33 insertions(+)
create mode 100644 Documentation/userspace-api/media/drivers/hantro.rst

diff --git a/Documentation/userspace-api/media/drivers/hantro.rst b/Documentation/userspace-api/media/drivers/hantro.rst
new file mode 100644
index 000000000000..cd9754b4e005
--- /dev/null
+++ b/Documentation/userspace-api/media/drivers/hantro.rst
@@ -0,0 +1,19 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Hantro video decoder driver
+===========================
+
+The Hantro video decoder driver implements the following driver-specific controls:
+
+``V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (integer)``
+ Specifies to Hantro HEVC video decoder driver the number of data (in bits) to
+ skip in the slice segment header.
+ If non-IDR, the bits to be skipped go from syntax element "pic_output_flag"
+ to before syntax element "slice_temporal_mvp_enabled_flag".
+ If IDR, the skipped bits are just "pic_output_flag"
+ (separate_colour_plane_flag is not supported).
+
+.. note::
+
+ This control is not yet part of the public kernel API and
+ it is expected to change.
diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst
index 1a9038f5f9fa..12e3c512d718 100644
--- a/Documentation/userspace-api/media/drivers/index.rst
+++ b/Documentation/userspace-api/media/drivers/index.rst
@@ -33,6 +33,7 @@ For more details see the file COPYING in the source distribution of Linux.

ccs
cx2341x-uapi
+ hantro
imx-uapi
max2175
meye-uapi
diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
index 8e0109eea454..b713eeed1915 100644
--- a/include/media/hevc-ctrls.h
+++ b/include/media/hevc-ctrls.h
@@ -224,4 +224,17 @@ struct v4l2_ctrl_hevc_decode_params {
__u64 flags;
};

+/* MPEG-class control IDs specific to the Hantro driver as defined by V4L2 */
+#define V4L2_CID_CODEC_HANTRO_BASE (V4L2_CTRL_CLASS_CODEC | 0x1200)
+/*
+ * V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP -
+ * the number of data (in bits) to skip in the
+ * slice segment header.
+ * If non-IDR, the bits to be skipped go from syntax element "pic_output_flag"
+ * to before syntax element "slice_temporal_mvp_enabled_flag".
+ * If IDR, the skipped bits are just "pic_output_flag"
+ * (separate_colour_plane_flag is not supported).
+ */
+#define V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (V4L2_CID_CODEC_HANTRO_BASE + 0)
+
#endif
--
2.25.1
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