[PATCH v2 0/4] firmware: qemu_fw_cfg: implement file system

[Ahmad Fatoum <a.fatoum@barebox.org>]

The character device we currently have is cumbersome to use.
The Linux way to access it at /sys/firmware/qemu_fw_cfg
is much nicer to use, so this series adds support for a similar
FS to barebox.

A very nice result of having file system access to the QEMU variables
in barebox is that we get a trivial way to pass data to barebox.
To make it even more convenient to use, this series enables overriding
individual files in the environment via the new mechanism, e.g.:

  pytest --env nv/boot.default=fit --env boot/fit=@boot.sh

v1 -> v2:
  - drop already upstream patches
  - drop truncate (Sascha)
  - make writing files besides "raw" an error (Sascha)
  - mount file system unconditionally, so environment can be read
    from it

Ahmad Fatoum (4):
  fs: add qemu_fw_cfg file system
  firmware: qemu_fw_cfg: register at device initcall level
  video: ramfb: use new qemu fw_cfg FS
  fs: qemu_fw_cfg: support populating environment via QEMU fw_cfg

 conftest.py                    |  22 ++
 defaultenv/defaultenv.c        |  22 ++
 drivers/firmware/qemu_fw_cfg.c |   2 +-
 drivers/video/Kconfig          |   2 +-
 drivers/video/ramfb.c          |  98 ++------
 fs/Kconfig                     |   7 +
 fs/Makefile                    |   1 +
 fs/qemu_fw_cfg.c               | 446 +++++++++++++++++++++++++++++++++
 include/envfs.h                |   5 +
 include/string.h               |   5 +
 10 files changed, 525 insertions(+), 85 deletions(-)
 create mode 100644 fs/qemu_fw_cfg.c

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2.39.5