util/supermicro: Add and use new tool smcbiosinfo

The BMC and tools interacting with it depend on metadata placed inside
the ROM in order the flash the BIOS.

Add a new tool smcbiosinfo, integrate it into the build system, and
generate a 128byte metadata file called smcbiosinfo.bin on build.

You need to provide the BoardID for every SMC mainboard through a new
Kconfig symbol: SUPERMICRO_BOARDID

Some fields are unknown, but it's sufficient to flash it using SMC
vendor tools.

Tested on Supermicro X11SSH:
* Flashing using the WebUI works
* Flashing using SMCIPMITool works

No further validation is done on the firmware.

Change-Id: Id608c2ce78614b45a2fd0b26d97d666f02223998
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35484
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>

Documentation/mainboard/index.md

@@ -126,6 +126,7 @@ The boards in this section are not real mainboards, but emulators.
 
 - [X10SLM+-F](supermicro/x10slm-f.md)
 - [X11 LGA1151 series](supermicro/x11-lga1151-series/x11-lga1151-series.md)
+- [Flashing using the BMC](supermicro/flashing_on_vendorbmc.md)
 
 ## UP
 

Documentation/mainboard/supermicro/flashing_on_vendorbmc.md

@@ -0,0 +1,32 @@
+# Flashing coreboot using SMC IPMI (BMC) firmware
+
+## Metadata
+In order to flash anything to the "BIOS" IC, it needs to contain a valid
+BIOSINFO struct.
+
+The BIOSINFO struct contains a `$FID` marker at the beginning and is
+128 bytes in total. Besides the *BoardID* it contains the *firmware version*
+and *build date*. The BMC verifies that the BoardID is correct and refuses to
+flash if it's not.
+
+The struct has no checksum or cryptographic protection.
+
+## The smcinfobios tool
+
+The smcbiosinfo tool can be found in `util/supermicro/smcbiosinfo`.
+
+It parses the `build/build.h` header to get the current coreboot version and
+build timestamp.
+The *board ID* is passed as command line argument.
+
+It will place a file in CBFS called `smcbiosinfo.bin`, which is then found
+by the vendor tools. The file contains the struct described above.
+
+## Flashing using SMCIPMItool
+
+You can use the *SMCIPMITool* to remotely flash the BIOS:
+
+`SMCIPMITool <remote BMC IP> <user> <password> bios update build/coreboot.rom`
+
+Make sure that the ME isn't in recovery mode, otherwise you get an error
+message on updating the BIOS.