mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-30 12:13:51 -04:00
Code Issues Packages Projects Releases Wiki Activity

media: Documentation: uapi: Update V4L2 ISP for extensible stats

Browse Source 
Rework the userspace-api documentation of V4L2 ISP to support
statistics.

Update all occurences of 'v4l2_isp_param' types to match the uAPI
changes and add a section to document the statistics serialization
format.

Signed-off-by: Antoine Bouyer <antoine.bouyer@nxp.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
[Update on uAPI changes]
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
This commit is contained in:
Antoine Bouyer
2026-06-27 15:41:59 +02:00
committed by Sakari Ailus
parent 01498beb8d
commit 46479e5475
1 changed files with 33 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
Documentation/userspace-api/media/v4l/v4l2-isp.rst
View File

@@ -18,22 +18,22 @@ single C structure that contains a header, followed by a binary buffer where
userspace programs a variable number of ISP configuration data block, one for
each supported ISP feature.
The :c:type:`v4l2_isp_params_buffer` structure defines the buffer header which
is followed by a binary buffer of ISP configuration data. Userspace shall
correctly populate the buffer header with the generic parameters format version
and with the size (in bytes) of the binary data buffer where it will store the
ISP blocks configuration.
The :c:type:`v4l2_isp_buffer` structure defines the buffer header which is
followed by a binary buffer of ISP configuration data. Userspace shall correctly
populate the buffer header with the serialization format version and with the
size (in bytes) of the binary data buffer where it will store the ISP blocks
configuration.
Each *ISP configuration block* is preceded by an header implemented by the
:c:type:`v4l2_isp_params_block_header` structure, followed by the configuration
Each *ISP configuration block* is preceded by a header implemented by the
:c:type:`v4l2_isp_block_header` structure, followed by the configuration
parameters for that specific block, defined by the ISP driver specific data
types.
Userspace applications are responsible for correctly populating each block's
header fields (type, flags and size) and the block-specific parameters.
ISP block enabling, disabling and configuration
-----------------------------------------------
ISP parameters block enabling, disabling and configuration
----------------------------------------------------------
When userspace wants to configure and enable an ISP block it shall fully
populate the block configuration and set the V4L2_ISP_PARAMS_FL_BLOCK_ENABLE
@@ -59,7 +59,30 @@ definition without invalidating the existing ones.
ISP statistics
==============
Support for generic statistics format is not yet implemented in Video4Linux2.
The generic ISP statistics format is identical to the generic ISP configuration
parameters format. It is realized by defining a C structure that contains a
header, followed by binary buffer where the ISP driver copies a variable number
of ISP statistics blocks.
Extensible statistics buffers have :c:type:`v4l2_isp_buffer` header followed by
a binary buffer of ISP statistics data. ISP drivers populate the buffer header
with the serialization format version and with the size (in bytes) of the binary
data buffer where ISP statistics data are serialized. Applications shall
validate that the serialization format version matches the expected one and that
the buffer size doesn't exceed the maximum size for a statistics buffer as
declared by the driver's uAPI header.
Each *ISP statistics block* is preceded by a header implemented by the
:c:type:`v4l2_isp_block_header` structure, followed by the statistics data for
that specific block. The driver might optionally report platform-specific flags
associated with each statistics block.
Applications inspect the statistics block type as reported in the header and
validates the reported size matches the block's expected size before accessing
the ISP statistics data.
Extension to the statistics format can be implemented by adding new blocks
definition without invalidating the existing ones.
V4L2 ISP uAPI data types
========================