Hi Trevor, On 2/19/24 18:48, Trevor Woerner via lists.yoctoproject.org wrote:
In order to boot successfully, most Rockchip SoCs require a specific partitioning scheme which was defined many years (and many SoCs) ago. That partitioning scheme places the SPL and U-Boot at specific offsets at the start of the boot block device:https://opensource.rock-chips.com/wiki_Partitions The Rockchip partitioning scheme goes on to also define the locations of a number of additional partitions, including the "boot" and "root" partitions. Since both the SPL and U-Boot have already been placed on the block device, the "boot" partition only contains the extlinux config file and the kernel+dtb/fitImage; it doesn't contain any bootloader artifacts (other than the extlinux config). The location of the SPL partition is a hard dependency since the BOOTROM etched inside the Rockchip SoCs is programmed to load and run a validated binary it finds at this location. The locations of the "boot" and "root" partitions are not so rigid since it is U-Boot which interacts with them. U-Boot is very flexible with how it finds boot components, and in its support for various devices, filesystems, sizes, etc. Both oe-core's U-Boot metadata and wic's bootimg-partition script contain logic to generate the extlinux pieces required for a bootloader to boot a Linux system. If both are enabled, the wic pieces silently clobber the U-Boot pieces. However, the mechanisms contained in the U-Boot metadata are much more flexible, from a user's point of view, than the mechanisms in wic's bootimg-partition. If a user wishes to setup some sort of A/B redundant update mechanism, they must have redundant root partitions (in order to update their filesystem contents) but they also need to have redundant boot partitions if they wish to update the kernel as part of their update mechanism. Pairing redundant kernel partitions with redundant filesystem partitions becomes unnecessarily complicated. Therefore it makes sense to combine the kernel and the filesystem into the same partition so that both the kernel and filesystem are updated, or rolled back, in lock-step as one unit. Specific kernel versions and configurations often have dependencies on user-space components and versions. The /boot location is not going away. This patch simply transfers responsibility for its creation to the more flexible U-Boot mechanism and includes the kernel as part of the same partition as the root filesystem. Not only does it add flexibility, it also makes update schemes more straightforward. Although having a separate /boot partition is a "requirement" of the Rockchip partitioning scheme, it is not an actual hard requirement when using a flexible, open-source bootloader (such as U-Boot) instead of using Rockchip's proprietary miniloader, preloader, and trust.img. Build-tested for all boards. Run-tested on: nanopi-m4-2gb, nanopi-m4b, nanopi-r2s, nanopi-r4s, roc-rk3328-cc, rock-3a, rock-5a, rock-5b, rock-pi-4b, rock-pi-e, rock-pi-s, rock64 Signed-off-by: Trevor Woerner <twoer...@gmail.com>
Reviewed-by: Quentin Schulz <quentin.sch...@theobroma-systems.com> Thanks, Quentin
-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#62557): https://lists.yoctoproject.org/g/yocto/message/62557 Mute This Topic: https://lists.yoctoproject.org/mt/104451459/21656 Group Owner: yocto+ow...@lists.yoctoproject.org Unsubscribe: https://lists.yoctoproject.org/g/yocto/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
