mb/hp: Add Z220 SFF workstation

* Add initial board commit based on HP8200 SFF.
* Add documentation.
* Serial and PCIe slot are working.

Tested on HP Z220.

Change-Id: I75987a7ea9a008a64281f0d5ab27e5148d36a4ec
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33207
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

Documentation/mainboard/hp/z220_sff.md

@@ -0,0 +1,70 @@
+# HP Z220 SFF Workstation
+
+This page describes how to run coreboot on the [HP Z220 SFF Workstation] desktop
+from [HP].
+
+## TODO
+
+The following things are still missing from this coreboot port:
+
+- Extended HWM reporting
+- Advanced LED control
+- Advanced power configuration in S3
+
+## Flashing coreboot
+
+```eval_rst
++---------------------+-------------+
+| Type                | Value       |
++=====================+=============+
+| Socketed flash      | no          |
++---------------------+-------------+
+| Model               | N25Q128..3E |
++---------------------+-------------+
+| Size                | 16 MiB      |
++---------------------+-------------+
+| In circuit flashing | yes         |
++---------------------+-------------+
+| Package             | SOIC-16     |
++---------------------+-------------+
+| Write protection    | No          |
++---------------------+-------------+
+| Dual BIOS feature   | No          |
++---------------------+-------------+
+| Internal flashing   | yes         |
++---------------------+-------------+
+```
+
+### Internal programming
+
+The SPI flash can be accessed using [flashrom].
+
+### External programming
+
+External programming with an SPI adapter and [flashrom] does work, but it powers the
+whole southbridge complex. You need to supply enough current through the programming adapter.
+
+If you want to use a SOIC pomona test clip, you have to cut the 2nd DRAM DIMM holder,
+as otherwise there's not enough space near the flash.
+
+## Technology
+
+```eval_rst
++------------------+--------------------------------------------------+
+| Northbridge      | :doc:`../../northbridge/intel/sandybridge/index` |
++------------------+--------------------------------------------------+
+| Southbridge      | bd82x6x                                          |
++------------------+--------------------------------------------------+
+| CPU              | model_206ax                                      |
++------------------+--------------------------------------------------+
+| SuperIO          | :doc:`../../superio/nuvoton/npcd378`             |
++------------------+--------------------------------------------------+
+| EC               |                                                  |
++------------------+--------------------------------------------------+
+| Coprocessor      | Intel ME                                         |
++------------------+--------------------------------------------------+
+```
+
+[HP Z220 SFF Workstation]: https://support.hp.com/za-en/document/c03386950
+[HP]: https://www.hp.com/
+[flashrom]: https://flashrom.org/Flashrom

Documentation/mainboard/index.md

@@ -54,6 +54,7 @@ The boards in this section are not real mainboards, but emulators.
 ## HP
 
 - [Compaq 8200 Elite SFF](hp/compaq_8200_sff.md)
+- [Z220 Workstation SFF](hp/z220_sff.md)
 
 ### EliteBook series