[RFC PATCH v3 0/4] dtc: Add a plugin interface

[Andrei Ziureaev <andreiziureaev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

I added a simple live tree API. There's no longer a need to move any
definitions. The live tree struct is hidden from plugins, so it's not an ABI.
The API doesn't allow plugins to modify the live tree yet, but that will
probably change later.

I also removed the EXPORT_FUNCTION macro. Plugins now have to implement
certain prototypes, defined in dtc-plugin.h. This allows plugins to be
generated by tools.
===========

This is one possible implementation of a plugin interface for DTC.

A plugin interface would allow us to add checks in languages other than
C. Specifically, it would allow DTC and DT Schema (which is written in
Python) to be integrated.

It would also allow for better debugging of dts files. For example, DT
Schema would be able to print dts source line information, without us
having to add source line annotations to yaml files.

In the future, plugins will be allowed to modify the live tree and pass
it back for further processing, but the API doesn't support that yet.

There's a question of whether we should relicense some headers to
dual BSD to be able call Python code.

Any thoughts would be much appreciated.

Thanks,
Andrei.

Changes in v3:
- live tree API (dt.h and dt.c)
- additional functionality in dtc.h
- plugins have to implement prototypes
- improved documentation

Changes in v2:
- improved documentation
- plugins must register with the build system
- the "validate_fn_t" hook can return a status
- define "struct reserve_info" in "dtc-plugin.h"
- specify that minor versions are compatible
- check if plugin_dir is NULL, just in case
- better variable names in register_plugin_info

Andrei Ziureaev (4):
  dtc: Add marker type functionality to dtc.h
  dtc: Add a live tree API
  dtc: Add plugin documentation and examples
  dtc: Add a plugin interface

 Documentation/manual.txt         | 146 ++++++++++++++++++++++++++++
 Makefile                         |  29 +++++-
 Makefile.dtc                     |   1 +
 dt.c                             | 158 +++++++++++++++++++++++++++++++
 dt.h                             |  63 ++++++++++++
 dtc-plugin.h                     |  76 +++++++++++++++
 dtc.c                            | 142 ++++++++++++++++++++++++++-
 dtc.h                            |  57 +++++++++++
 plugins/example/Makefile.example |  27 ++++++
 plugins/example/example.c        |  33 +++++++
 treesource.c                     |   8 +-
 11 files changed, 734 insertions(+), 6 deletions(-)
 create mode 100644 dt.c
 create mode 100644 dt.h
 create mode 100644 dtc-plugin.h
 create mode 100644 plugins/example/Makefile.example
 create mode 100644 plugins/example/example.c

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2.17.1