mirror of https://github.com/thesofproject/sof.git
9ef233de48
About
-----
This is a high level keyword extension on top of the existing ALSA
conf topology format designed to:
1) Simplify the ALSA conf topology definitions by providing high level
"classes" so topology designers need to write less config for common
object definitions.
2) Allow simple reuse of objects. Define once and reuse (like M4) with
the ability to alter objects configuration attributes from defaults.
3) Allow data type and value verification. This is not done today and
frequently crops up in FW bug reports.
Common Topology Classes
-----------------------
Topology today has some common classes that are often reused throughout
with slightly altered configurations. i.e. widgets (components),
pipelines, dais and controls.
This PR introduces the high level concept of reusable "class" like
definition for a AIF_IN/AIF_OUT type object that can be used to create
topology objects.
Common Topology Attributes
--------------------------
Topology defines a lot of attributes per object with different types
and constraints. Today there is no easy way to validate type or
constraints and this can lead to many hard to find problems in FW at
runtime.
A new keyword "DefineAttribute" has been added to define attribute
type, size, min value, max value, enum_values. This then allows
alsatplg to validate each topology object attribute.
Topology Classes define the list of attributes that they use and
whether the attribute is mandatory, can be overridden by parent users
or is immutable. This also helps alsatplg emit the appropriate errors
for attribute misuse.
Common Topology Arguments
-------------------------
Arguments are used to pass essential data needed for instantiating an
object particularly needed for the object name. A new keyword
"DefineArgument" has been added to define the arguments. The order in
which the arguments are defined determines the name for the widget.
For example, in the case of the host widget, the name would be
constructed as "host.1.playback" where "1" is the pipeline_id argument
value and "playback" is the direction argument value.
Attribute Inheritance:
----------------------
One of the key features of Topology2.0 is howthe attribute values are
propagated from a parent object to a child object. This is accomplished
by adding attributes/arguments with the same name for a parent and an
object. By doing so, when creating a child object, the value for the
common attribute is populated from the parent. If the value is provided
in the child object instance, then it overrides the value coming from
the parent.
ALSA Conf Parser
----------------
All the changes being proposed and discussed here must be 100%
compliant with the ALSA conf parser. i.e. no syntax changes or
changes to semantics for any existing keyword.
It's intended that there will be NO changes to the ALSA conf parser
(unless new keywords require this ?) and all topology building
changes will be in the alsatplg compiler.
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
|
||
|---|---|---|
| .github | ||
| doc | ||
| installer | ||
| keys | ||
| rimage@5aeb95b19b | ||
| scripts | ||
| smex | ||
| src | ||
| test | ||
| tools | ||
| zephyr | ||
| .gitignore | ||
| .gitmodules | ||
| .travis.yml | ||
| CMakeLists.txt | ||
| CODEOWNERS | ||
| Kconfig | ||
| Kconfig.xtos-build | ||
| Kconfig.xtos-dbg | ||
| LICENCE | ||
| README.md | ||
README.md
Sound Open Firmware
Status
Documentation
See docs
Running the tests
See unit testing documentation
Deployment
TODO: Add additional notes about how to deploy this on a live system
Contributing
See Contributing to the Project
License
This project is licensed under the BSD Clause 3 - see the LICENCE file for details