doc: Add doc for supported flash chips

Change-Id: I05fb60a4caf2cfb30586fa482687b10638996395
Signed-off-by: Anastasia Klimchuk <aklm@flashrom.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/82197
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Alexander Goncharov <chat@joursoir.net>
Reviewed-by: Peter Marheine <pmarheine@chromium.org>

doc/supported_hw/index.rst

@@ -5,4 +5,5 @@ Supported hardware
 .. toctree::
     :maxdepth: 1
 
+    supported_flashchips
     supported_prog/index

doc/supported_hw/supported_flashchips.rst

@@ -0,0 +1,26 @@
+=====================
+Supported flash chips
+=====================
+
+The list of all supported flash chips is in ``flashchips.c`` file in the source tree.
+If you have a flashrom repo cloned locally, you can look at the file in your repo.
+
+Alternatively inspect the file on the `web UI of our GitHub mirror <https://github.com/flashrom/flashrom/blob/main/flashchips.c>`_.
+
+If you can run flashrom locally, the command ``flashrom -L`` prints the list of all supported flash chips
+(see :doc:`/classic_cli_manpage` for more details on command line options). The output of this command is long, so you might
+want to save it to file or grep.
+
+If you want to check whether a flash chip is supported in the given release, you can rebase your local
+repo at the release tag, alternatively select a tag/branch in GitHub web UI (dropdown on the top-left).
+
+Each chip definition is described by a ``struct flashchip`` in ``include/flash.h``, which you can inspect in the same way,
+either in local source tree or on GitHub web UI.
+
+Note the ``.tested`` status of the chip. If the status is ``TEST_UNTESTED`` this means chip definition has been added purely based on
+datasheet, but without testing on real hardware.
+
+Related documents:
+
+   * :doc:`/contrib_howtos/how_to_mark_chip_tested`.
+   * :doc:`/contrib_howtos/how_to_add_new_chip`.