Documentation: media: move Memory Consistency Flags

Commit Message

Hans Verkuil July 20, 2024, 10:46 a.m. UTC

The documentation of the Memory Consistency Flags was part of the struct
v4l2_buffer documentation, but that struct doesn't use those flags. Instead
it is used by VIDIOC_CREATE_BUFS and VIDIOC_REQBUFS. Move the documentation
from buffer.rst to vidioc-reqbufs.rst which is where it belongs.

Signed-off-by: Hans Verkuil <[e-mail]>
---

Patch

diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
index 52bbee81c080..856874341882 100644
--- a/Documentation/userspace-api/media/v4l/buffer.rst
+++ b/Documentation/userspace-api/media/v4l/buffer.rst
@@ -694,41 +694,6 @@  enum v4l2_memory
       - 4
       - The buffer is used for :ref:`DMA shared buffer <dmabuf>` I/O.

-.. _memory-flags:
-
-Memory Consistency Flags
-------------------------
-
-.. raw:: latex
-
-    \small
-
-.. tabularcolumns:: |p{7.0cm}|p{2.1cm}|p{8.4cm}|
-
-.. cssclass:: longtable
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-    :widths:       3 1 4
-
-    * .. _`V4L2-MEMORY-FLAG-NON-COHERENT`:
-
-      - ``V4L2_MEMORY_FLAG_NON_COHERENT``
-      - 0x00000001
-      - A buffer is allocated either in coherent (it will be automatically
-	coherent between the CPU and the bus) or non-coherent memory. The
-	latter can provide performance gains, for instance the CPU cache
-	sync/flush operations can be avoided if the buffer is accessed by the
-	corresponding device only and the CPU does not read/write to/from that
-	buffer. However, this requires extra care from the driver -- it must
-	guarantee memory consistency by issuing a cache flush/sync when
-	consistency is needed. If this flag is set V4L2 will attempt to
-	allocate the buffer in non-coherent memory. The flag takes effect
-	only if the buffer is used for :ref:`memory mapping <mmap>` I/O and the
-	queue reports the :ref:`V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS
-	<V4L2-BUF-CAP-SUPPORTS-MMAP-CACHE-HINTS>` capability.
-
 .. raw:: latex

     \normalsize
diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
index bbc22dd76032..634c2517221a 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
@@ -73,6 +73,8 @@  aborting or finishing any DMA in progress, an implicit

 .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|

+.. cssclass:: longtable
+
 .. flat-table:: struct v4l2_requestbuffers
     :header-rows:  0
     :stub-columns: 0
@@ -123,14 +125,6 @@  aborting or finishing any DMA in progress, an implicit
 .. _V4L2-BUF-CAP-SUPPORTS-MAX-NUM-BUFFERS:
 .. _V4L2-BUF-CAP-SUPPORTS-REMOVE-BUFS:

-.. raw:: latex
-
-   \footnotesize
-
-.. tabularcolumns:: |p{8.1cm}|p{2.2cm}|p{7.0cm}|
-
-.. cssclass:: longtable
-
 .. flat-table:: V4L2 Buffer Capabilities Flags
     :header-rows:  0
     :stub-columns: 0
@@ -167,6 +161,29 @@  aborting or finishing any DMA in progress, an implicit
         :ref:`V4L2_BUF_FLAG_NO_CACHE_CLEAN <V4L2-BUF-FLAG-NO-CACHE-CLEAN>` and
         :ref:`V4L2_MEMORY_FLAG_NON_COHERENT <V4L2-MEMORY-FLAG-NON-COHERENT>`.

+.. _memory-flags:
+.. _V4L2-MEMORY-FLAG-NON-COHERENT:
+
+.. flat-table:: Memory Consistency Flags
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+    * - ``V4L2_MEMORY_FLAG_NON_COHERENT``
+      - 0x00000001
+      - A buffer is allocated either in coherent (it will be automatically
+	coherent between the CPU and the bus) or non-coherent memory. The
+	latter can provide performance gains, for instance the CPU cache
+	sync/flush operations can be avoided if the buffer is accessed by the
+	corresponding device only and the CPU does not read/write to/from that
+	buffer. However, this requires extra care from the driver -- it must
+	guarantee memory consistency by issuing a cache flush/sync when
+	consistency is needed. If this flag is set V4L2 will attempt to
+	allocate the buffer in non-coherent memory. The flag takes effect
+	only if the buffer is used for :ref:`memory mapping <mmap>` I/O and the
+	queue reports the :ref:`V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS
+	<V4L2-BUF-CAP-SUPPORTS-MMAP-CACHE-HINTS>` capability.
+
 .. raw:: latex

    \normalsize