On 06/23/2017 10:34 PM, Sergei Shtylyov wrote:
Index: media_tree/Documentation/media/v4l-drivers/rcar_imr.rst
===================================================================
--- /dev/null
+++ media_tree/Documentation/media/v4l-drivers/rcar_imr.rst
@@ -0,0 +1,86 @@
+Renesas R-Car Image Rendeder (IMR) Driver
Rendeder -> Renderer
+=========================================
+
+This file documents some driver-specific aspects of the IMR driver, such as
+driver-specific ioctls.
+
+The ioctl reference
+~~~~~~~~~~~~~~~~~~~
+
+VIDIOC_IMR_MESH - Set mapping data
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Argument: struct imr_map_desc
+
+**Description**:
+
+ This ioctl sets up the mesh using which the input frames will be
s/using/through/
+ transformed into the output frames. The mesh can be strictly rectangular
+ (when IMR_MAP_MESH bit is set in imr_map_desc::type) or arbitrary (when
+ that bit is not set).
+
+ A rectangular mesh consists of the imr_mesh structure followed by M*N
+ vertex objects (where M is imr_mesh::rows and N is imr_mesh::columns).
+ In case either IMR_MAP_AUTOSG or IMR_MAP_AUTODG bits were set in
+ imr_map_desc::type, imr_mesh::{x|y}0 specify the coordinates of the top
+ left corner of the auto-generated mesh and imr_mesh::d{x|y} specify the
+ mesh's X/Y steps.
What if any of the other types are used like IMR_MAP_LUCE?
Is this documented in a Renesas datasheet? If so, add a reference to that in this
documentation.
+
+ An arbitrary mesh consists of the imr_vbo structure followed by N
+ triangle objects (where N is imr_vbo::num), consisting of 3 vertex
+ objects each.
+
+ A vertex object has a complex structure:
+
+.. code-block:: none
+
+ __u16 v vertical \ source coordinates (only present
+ __u16 u horizontal / if IMR_MAP_AUTOSG isn't set)
+ __u16 Y vertical \ destination coordinates (only here
+ __u16 X horizontal / if IMR_MAP_AUTODG isn't set)
+ __s8 lofst offset \ luminance correction parameters
+ __u8 lscal scale > (only present if IMR_MAP_LUCE
+ __u16 reserved / is set)
+ __s8 vrofs V value offset \ hue correction parameters
+ __u8 vrscl V value scale \ (only present if IMR_MAP_CLCE
+ __s8 ubofs U value offset / is set)
+ __u8 ubscl U value scale /
Is this the internal structure? Or something that userspace has to fill in?
It's not clear at all.
I recommend giving a few code examples of how this should be used.
+
+**Return value**:
+
+ On success 0 is returned. On error -1 is returned and errno is set
+ appropriately.
+
+**Data types**:
+
+.. code-block:: none
+
+ * struct imr_map_desc
+
+ __u32 type mapping types
This is a bitmask? If so, what combination of bits are allowed?
+ __u32 size total size of the mesh structure
+ __u64 data map-specific user-pointer
+
+ IMR_MAP_MESH regular mesh specification
+ IMR_MAP_AUTOSG auto-generated source coordinates
+ IMR_MAP_AUTODG auto-generated destination coordinates
+ IMR_MAP_LUCE luminance correction flag
+ IMR_MAP_CLCE chromacity correction flag
You probably mean 'chroma'. 'chromacity' isn't a word.
+ IMR_MAP_TCM vertex clockwise-mode order
+ IMR_MAP_UVDPOR(n) source coordinate decimal point position
+ IMR_MAP_DDP destination coordinate sub-pixel mode
+ IMR_MAP_YLDPO(n) luminance correction offset decimal point
+ position
+ IMR_MAP_UBDPO(n) chromacity (U) correction offset decimal point
+ position
+ IMR_MAP_VRDPO(n) chromacity (V) correction offset decimal point
+ position
There is no documentation what how these types relate to IMR_MAP_MESH and
IMR_MAP_AUTOS/DG.
+
+ * struct imr_mesh regular mesh specification
+
+ __u16 rows, columns rectangular mesh sizes
+ __u16 x0, y0, dx, dy auto-generated mesh parameters
+
+ * struct imr_vbo vertex-buffer-object (VBO) descriptor
+
+ __u16 num number of triangles
Sorry, this needs more work.
Regards,
Hans
