Contact chromeos-scale-taskforce@google.com for questions.
ChromeOS device development typically begins with a Google-developed reference design. Partners then create unique implementations from that reference, which we refer to as “variants”.
new_variant.py uses the shell scripts in its same directory, plus some additional programs in private repositories, to automate the process of creating the firmware source code for a new variant of an existing reference board.
The new variant is created as an exact copy of the reference board. After committing the code for the new variant, partners can customize the variant to their requirements by removing features which they do not want to offer (such as LTE), change parts (such as LPDDR3 memory instead of DDR4), or add other differentiating features.
For any commands that you are instructed to run, the shell prompt is shown as (cr) $ for commands that run inside the chroot, and $ for commands that must run outside the chroot.
Output text in some cases may be summarized with [... and ...] containing a brief explanation of what is happening and what messages will be displayed on the screen, rather than copying all of the output.
For any board that uses an Intel SoC, you must have the appropriate FIT tools installed, as well as Wine (sudo apt-get install wine) to run the FIT tools. Obtain the FIT tools directly from Intel's Resource & Design Center
Please ensure that you have successfully synced your tree, and that your toolchain is up-to-date:
$ cd ~/chromiumos $ cros_sdk -- bash -c "repo sync && ./update_chroot"
new_variant.py must run inside the ChromeOS chroot environment.
A bug number to track the creation of the firmware for the new variant, e.g. b/133181366 to create the Kindred variant of Hatch.
This example shows how to ceate the “Sushi” variant of the Hatch reference board.
Enter the chroot and start the variant by running ./new_variant.py and providing the name of the reference board (Hatch), the name of the new variant (Sushi), and the bug number (or “None”). new_variant.py will create CLs for a new coreboot variant, a new coreboot configuration, and a new FIT image. The program will then ask you to generate the FIT image outside the chroot environment.
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --board=hatch --variant=sushi --bug=None [... some messages about creating a new coreboot variant and configuation ...] [... the source files for the new FIT image are created, and then the ...] [... program exits with a message about building the FIT image ...] ERROR:root:The following files need to be generated: ERROR:root:* fitimage-sushi.bin ERROR:root:* fitimage-sushi-versions.txt ERROR:root:The fitimage sources are ready for gen_fit_image.sh to process. ERROR:root:gen_fit_image.sh cannot run inside the chroot. Please open a new terminal ERROR:root:window, change to the directory where gen_fit_image.sh is located, and run ERROR:root:./gen_fit_image.sh sushi <path_to_fit_kit> -b ERROR:root:Then re-start this program with --continue. ERROR:root:If your chroot is based in ~/chromiumos, then the folder you want is ERROR:root:~/chromiumos/src/private-overlays/baseboard-hatch-private/sys-boot/coreboot-private-files-hatch/asset_generation
Open a new terminal and do not enter the chroot environment. Hatch uses version 14.0.0.1065 of Intel's FIT tools, so this example assumes that you have unzipped the Intel FIT tool files in the directory ~/TXE1065.
$ cd ~/chromiumos/src/private-overlays/baseboard-hatch-private/sys-boot/coreboot-private-files-hatch/asset_generation $ ./gen_fit_image.sh sushi ~/TXE1065 -b
When FIT image generation is done, you can close this terminal
Switch back to the terminal still in the chroot environment and run new_variant.py --continue. new_variant.py will add the generated FIT image to a CL, then create CLs for a new EC image and to modify the public and private model.yaml files. It will then ask you to push the coreboot CL to review.coreboot.org.
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --continue [... lots of messages about various commits being created ...] [... the EC code builds ...] [... the firmware boot image builds (using emerge) ...] [... the program exits with a message about pushing to coreboot ...] INFO:root:Running step push_coreboot ERROR:root:The following commit needs to be pushed to coreboot.org: ERROR:root: Branch "create_sushi_20200320" ERROR:root: in directory "/mnt/host/source/src/third_party/coreboot" ERROR:root: with change-id "Ie900d09ff55e695527eafe68a5a75cd4a0b6d340" ERROR:root:Please push the branch to review.coreboot.org, and then re-start this program with --continue
Push the commit to coreboot as instructed. There are multiple ways to push a CL to review.coreboot.org; if you have a method that works for you, do that. If not, see the References section for documents that explain some possible workflows for pushing to coreboot. Because your setup may vary, the specific commands are beyond the scope of this document.
After the coreboot CL has been pushed, run new_variant.py --continue again. The program will determine that the coreboot CL has been pushed, and then move on to uploading the other CLs by calling repo upload.
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --continue INFO:root:Running step push_coreboot INFO:root:Running step upload_CLs INFO:root:Running step find_coreboot_upstream ERROR:root:Program cannot continue until coreboot CL is upstreamed. ERROR:root:(coreboot:39892, change-id Ie900d09ff55e695527eafe68a5a75cd4a0b6d340) ERROR:root:Please wait for the CL to be upstreamed, then run this program again with --continue
As part of developing for coreboot in ChromeOS, we have to push our changes to review.coreboot.org and then wait for those CLs to be reviewed, approved, merged, and upstreamed into the chromiumos tree. new_variant.py will try to locate the upstreamed CL in the chromiumos tree. If it is not found, the program will ask you to wait for the CL to be upstreamed before continuing.
Once the coreboot CL has been upstreamed into the chromiumos tree, you are ready to re-upload the CLs with new commit messages that add Cq-Depend information. Again, new_variant.py will call repo upload to upload new patchsets on any CL that has Cq-Depend added. Once the uploads are done, the program will clean up some internal housekeeping information and you are ready to get the CLs reviewed, approved, and merged.
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --continue INFO:root:Running step find_coreboot_upstream INFO:root:Running step add_cq_depend INFO:root:Running step re_upload INFO:root:Running step clean_up
The clean_up step will remove all of the state information that new_variant.py has been tracking during this process.
The following CLs were created and uplodaded by new_variant.py:
The process for Volteer is similar to Hatch, but not quite identical. Hatch uses public and private model.yaml files for configuration, while Volteer uses the new per-project configuration repository (in src/project/volteer/${VARIANT}).
A new variant for Hatch involves the following steps:
A new variant for Volteer involves the following steps:
Note that steps 1-6 for Hatch are the same as steps 2-7 for Volteer.
Rather than duplicate the explanatory text in each section, we have opted to only provide the headings, the commands, and any important notes. Refer to the same-named sections in the Hatch tutorial for explanatory text.
A gerrit administrator must create the project configuration repository before you can begin the process to create a new variant of Volteer. Please file a bug in Infra > ChromeOS > Product > Device to have the project configuration updated.
This example shows how to create the “Gnastygnorc” variant of the Volteer reference board. Note that there is no project configuration repository for gnastygnorc, but this example proceeds as if it does exist.
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --board=volteer --variant=gnastygnorc --bug=b:12345 [... some messages about creating a new coreboot variant and configuation ...] [... the source files for the new FIT image are created, and then the ...] [... program exits with a message about building the FIT image ...] ERROR:root:The following files need to be generated: ERROR:root:* fitimage-gnastygnorc.bin ERROR:root:* fitimage-gnastygnorc-versions.txt ERROR:root:The fitimage sources are ready for gen_fit_image.sh to process. ERROR:root:gen_fit_image.sh cannot run inside the chroot. Please open a new terminal ERROR:root:window, change to the directory where gen_fit_image.sh is located, and run ERROR:root:./gen_fit_image.sh gnastygnorc <path_to_fit_kit> -b ERROR:root:Then re-start this program with --continue. ERROR:root:If your chroot is based in ~/chromiumos, then the folder you want is ERROR:root:~/chromiumos/src/private-overlays/baseboard-volteer-private/sys-boot/coreboot-private-files-baseboard-volteer/asset_generation
Volteer uses version 15.0.0.1166 of Intel's FIT tools, so this example assumes that you have unzipped the Intel FIT tool files in the directory ~/TXE1166.
$ cd ~/chromiumos/src/private-overlays/baseboard-volteer-private/sys-boot/coreboot-private-files-baseboard-volteer/asset_generation $ ./gen_fit_image.sh gnastygnorc ~/TXE1166 -b
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --continue [... lots of messages about various commits being created ...] [... the EC code builds ...] [... the firmware boot image builds (using emerge) ...] [... the program exits with a message about pushing to coreboot ...] INFO:root:Running step push_coreboot ERROR:root:The following commit needs to be pushed to coreboot.org: ERROR:root: Branch "create_gnastygnorc_20200424" ERROR:root: in directory "/mnt/host/source/src/third_party/coreboot" ERROR:root: with change-id "Ie900d09ff55e695527eafe68a5a75cd4a0b6d340" ERROR:root:Please push the branch to review.coreboot.org, and then re-start this program with --continue
Note that the change-id is the same as Sushi in this example, because the Gnastygnorc CLs have not been (and will not be) uploaded.
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --continue INFO:root:Running step push_coreboot INFO:root:Running step upload_CLs INFO:root:Running step find_coreboot_upstream ERROR:root:Program cannot continue until coreboot CL is upstreamed. ERROR:root:(coreboot:39892, change-id Ie900d09ff55e695527eafe68a5a75cd4a0b6d340) ERROR:root:Please wait for the CL to be upstreamed, then run this program again with --continue
Note that the CL number and change-id is the same as Sushi in this example, because the Gnastygnorc CLs have not been (and will not be) uploaded.
(cr) $ cd ~/trunk/src/platform/src/contrib/variant (cr) $ ./new_variant.py --continue INFO:root:Running step find_coreboot_upstream INFO:root:Running step add_cq_depend INFO:root:Running step re_upload INFO:root:Running step clean_up
new_variant.py keeps track of its state inside the chroot in the user's home directory. The state is stored in a file named .new_variant.yaml. The --continue option uses the state to continue the creation of the new variant.
If you want to abort the creation of the new variant, use the --abort flag, e.g. ./new_variant.py --abort. All of the branches and commits that were created on your local disk for the new variant will be abandoned and deleted, and the stored state (.new_variant.yaml) will be cleaned up.
Any CLs that have been uploaded will continue to exist on the gerrit servers; make sure to abandon the CLs using the gerrit interface.