drivers/generic/cbfs-uuid: Add driver to include UUID from CBFS

When system_uuid CBFS file is present and contains the UUID
in a string format, the driver will parse it and convert to binary
format to populate the SMBIOS type 1 UUID field.

TEST=Add UUID file and boot MSI PRO Z690-A DDR4 WIFI and check with
dmidecode if the UUID is populated correctly.

Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Change-Id: I22f22f4e8742716283d2fcaba4894c06cef3a4bf
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64639
Reviewed-by: Krystian Hebel <krystian.hebel@3mdeb.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 66 insertions, 0 deletions

diff --git a/Documentation/drivers/cbfs_smbios.md b/Documentation/drivers/cbfs_smbios.md
new file mode 100644
index 0000000000..54b7ca4179
--- /dev/null
+++ b/Documentation/drivers/cbfs_smbios.md
@@ -0,0 +1,65 @@
+# CBFS SMBIOS hooks
+
+The document describes the coreboot options how to make CBFS files populate
+platform-unique SMBIOS data.
+
+## SMBIOS System UUID
+
+The [DMTF SMBIOS specification] defines a field in the type 1 System
+Information Structure called System UUID. It is a 16 bytes value compliant with
+[RFC4122] and assumed to be unique per platform. Certain mainboard ports have
+SMBIOS hooks to generate the UUID from external data, e.g. Lenovo Thinkpads
+(see DRIVER_LENOVO_SERIALS). This driver aims to provide an option to populate
+the UUID from CBFS for boards that can't generate the UUID from any source.
+
+### Usage
+
+In the coreboot configuration menu (`make menuconfig`) go to `Generic Drivers`
+and select an option `System UUID in CBFS`. The Kconfig system will enable
+`DRIVERS_GENERIC_CBFS_UUID` and the relevant code parts will be compiled into
+coreboot image.
+
+After the coreboot build for your board completes, use the cbfstool to include
+the file containing the UUID:
+
+```shell
+./build/cbfstool build/coreboot.rom add -n system_uuid -t raw -f /path/to/uuid_file.txt
+```
+
+Where `uuid_file.txt` is the unterminated string representation of the SMBIOS
+type 1 UUID, e.g. `4c4c4544-0051-3410-8051-b5c04f375931`. If you use vboot with
+1 or 2 RW partitions you will have to specify the RW regions where the file is
+going to be added too. By default the RW CBFS partitions are truncated, so the
+files would probably not fit, one needs to expand them first.
+
+```shell
+./build/cbfstool build/coreboot.rom expand -r FW_MAIN_A
+./build/cbfstool build/coreboot.rom add -n system_uuid -t raw \
+	-f /path/to/uuid_file.txt -r FW_MAIN_A
+./build/cbfstool build/coreboot.rom truncate -r FW_MAIN_A
+
+./build/cbfstool build/coreboot.rom expand -r FW_MAIN_B
+./build/cbfstool build/coreboot.rom add -n system_uuid -t raw \
+	-f /path/to/uuid_file.txt -r FW_MAIN_B
+./build/cbfstool build/coreboot.rom truncate -r FW_MAIN_B
+```
+
+By default cbfstool adds files to COREBOOT region only, so when vboot is
+enabled and the platform is booting from RW partition, the file would not be
+picked up by the driver.
+
+One may retrieve the UUID from running system (if it exists) using the
+following command:
+
+```shell
+echo -n `sudo dmidecode -s system-uuid` > uuid_file.txt
+```
+
+The above command ensures the file does not end with whitespaces like LF and/or
+CR. The above command will not add any whitespaces. But the driver will handle
+situations where up to 2 additional bytes like CR and LF will be included in
+the file. Any more than that will make the driver fail to populate UUID in
+SMBIOS.
+
+[DMTF SMBIOS specification]: https://www.dmtf.org/standards/smbios
+[RFC4122]: https://www.ietf.org/rfc/rfc4122.txt
diff --git a/Documentation/drivers/index.md b/Documentation/drivers/index.md
index ac9b0141cb..95c1e312a0 100644
--- a/Documentation/drivers/index.md
+++ b/Documentation/drivers/index.md
@@ -14,3 +14,4 @@ Some of the drivers currently available include:
 * [SMMSTOREv2](smmstorev2.md)
 * [SoundWire](soundwire.md)
 * [USB4 Retimer](retimer.md)
+* [CBFS SMBIOS hooks](cbfs_smbios.md)