Commit 5620a0d1aac ("firmware: delete in-kernel firmware") removed the
entire firmware directory.  Unfortunately it thereby also removed the
support for built-in firmware.

This restores the ability to build firmware directly into the kernel by
pruning the original Makefile to the necessary minimum.  The default for
EXTRA_FIRMWARE_DIR is now the standard directory /lib/firmware/.

Fixes: 5620a0d1aac ("firmware: delete in-kernel firmware")
Signed-off-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Acked-by: Greg K-H <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull firmware removal from Greg KH:
 "Many many years ago (at the kernel summit in Boston), we all came to
  the agreement that the firmware/ tree should be dropped from the
  kernel, and everyone use the linux-firmware package instead. For some
  minor reason, David Woodhouse didn't send the pull request at that
  point in time, and everyone forgot about this.

  The topic came up in the hallway track at the Plumbers conference this
  week, so here's a single patch that drops the whole firmware tree. The
  last firmware update was back in 2013, and all distros have been using
  linux-firmware instead since at least that year, if not before. The
  only commits to that directory since 2013 was some kbuild fixups for
  various build tool issues.

  So lets finally drop this, we don't need to lug them around in the
  kernel source tree anymore, especially as no one wants or uses them.

  This has passed build testing with 0-day, I don't think it made it
  into linux-next this week, but I figured it was good to get in before
  4.14-rc1 was out"

* tag 'firmware_removal-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  firmware: delete in-kernel firmware

The last firmware change for the in-kernel firmware source code was back
in 2013.  Everyone has been relying on the out-of-tree linux-firmware
package for a long long time.

So let's drop it, it's baggage we don't need to keep dragging around
(and having to fix random kbuild issues over time...)

Cc: Kyle McMartin <kyle@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull Kbuild updates from Masahiro Yamada:

 - Use Make-builtin $(abspath ...) helper to get absolute path

 - Add W=2 extra warning option to detect unused macros

 - Use more KCONFIG_CONFIG instead hard-coded .config

 - Fix bugs of tar*-pkg targets

* tag 'kbuild-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: buildtar: do not print successful message if tar returns error
  kbuild: buildtar: fix tar error when CONFIG_MODULES is disabled
  kbuild: Use KCONFIG_CONFIG in buildtar
  Kbuild: enable -Wunused-macros warning for "make W=2"
  kbuild: use $(abspath ...) instead of $(shell cd ... && /bin/pwd)

Pull documentation updates from Jonathan Corbet:
 "After a fair amount of churn in the last couple of cycles, docs are
  taking it easier this time around. Lots of fixes and some new
  documentation, but nothing all that radical. Perhaps the most
  interesting change for many is the scripts/sphinx-pre-install tool
  from Mauro; it will tell you exactly which packages you need to
  install to get a working docs toolchain on your system.

  There are two little patches reaching outside of Documentation/; both
  just tweak kerneldoc comments to eliminate warnings and fix some
  dangling doc pointers"

* 'docs-next' of git://git.lwn.net/linux: (52 commits)
  Documentation/sphinx: fix kernel-doc decode for non-utf-8 locale
  genalloc: Fix an incorrect kerneldoc comment
  doc: Add documentation for the genalloc subsystem
  assoc_array: fix path to assoc_array documentation
  kernel-doc parser mishandles declarations split into lines
  docs: ReSTify table of contents in core.rst
  docs: process: drop git snapshots from applying-patches.rst
  Documentation:input: fix typo
  swap: Remove obsolete sentence
  sphinx.rst: Allow Sphinx version 1.6 at the docs
  docs-rst: fix verbatim font size on tables
  Documentation: stable-kernel-rules: fix broken git urls
  rtmutex: update rt-mutex
  rtmutex: update rt-mutex-design
  docs: fix minimal sphinx version in conf.py
  docs: fix nested numbering in the TOC
  NVMEM documentation fix: A minor typo
  docs-rst: pdf: use same vertical margin on all Sphinx versions
  doc: Makefile: if sphinx is not found, run a check script
  docs: Fix paths in security/keys
  ...

Kbuild conventionally uses $(shell cd ... && /bin/pwd) idiom to get
the absolute path of the directory because GNU Make 3.80, the minimal
supported version at that time, did not support $(abspath ...) or
$(realpath ...).

Commit 37d69ee30808 ("docs: bump minimal GNU Make version to 3.81")
dropped the GNU Make 3.80 support, so we are now allowed to use those
make-builtin helpers.

This conversion will provide better portability without relying on
the pwd command or its location /bin/pwd.

I am intentionally using $(realpath ...) instead $(abspath ...) in
some places.  The difference between the two is $(realpath ...)
returns an empty string if the given path does not exist.  It is
convenient in places where we need to error-out if the makefile fails
to create an output directory.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Thierry Reding <treding@nvidia.com>