On Thu, Feb 19, 2026 at 06:09:27AM -0700, Simon Glass wrote: > Hi Daniel, > > On Mon, 16 Feb 2026 at 14:22, Daniel Golle <[email protected]> wrote: > > > > Add a UBI volume storage backend for the image_loader framework. > > > > image_loader_init_ubi() takes a volume name, ensures the UBI device > > is attached (auto-attaching if needed), and installs a .read() callback > > wrapping ubi_volume_read(). > > > > Auto-attach works by scanning the device tree for the first MTD > > partition with compatible = "linux,ubi", then calling ubi_part() on > > that partition. The partition name is resolved using the same > > precedence as the MTD partition parser: the "label" property first, > > then "name", then the node name. Since U-Boot only supports a single > > attached UBI device at a time, only the first matching partition is > > used. If a UBI device is already attached, the auto-attach step is > > skipped. > > > > UBI handles bad-block management and wear leveling internally, so the > > read callback is a straightforward passthrough. Note that > > ubi_volume_read() returns positive errno values; the wrapper negates > > them for the image_loader convention. > > > > Gated by CONFIG_IMAGE_LOADER_UBI (depends on CMD_UBI && IMAGE_LOADER). > > > > Signed-off-by: Daniel Golle <[email protected]> > > --- > > boot/Kconfig | 8 +++ > > boot/Makefile | 1 + > > boot/image-loader-ubi.c | 112 ++++++++++++++++++++++++++++++++++++++++ > > include/image-loader.h | 13 +++++ > > 4 files changed, 134 insertions(+) > > create mode 100644 boot/image-loader-ubi.c > > > > diff --git a/boot/Kconfig b/boot/Kconfig > > index 23848a0f57e..89832014af6 100644 > > --- a/boot/Kconfig > > +++ b/boot/Kconfig > > @@ -1203,6 +1203,14 @@ config IMAGE_LOADER_MTD > > parallel NAND, etc.) using the image_loader framework. > > NAND bad blocks are skipped transparently. > > > > +config IMAGE_LOADER_UBI > > + bool "UBI volume backend for image loader" > > + depends on IMAGE_LOADER && CMD_UBI > > + help > > + Allows loading images from UBI volumes using the image_loader > > + framework. Auto-attaches the UBI device from the device tree > > + if not already attached. > > + > > config DISTRO_DEFAULTS > > bool "(deprecated) Script-based booting of Linux distributions" > > select CMDLINE > > diff --git a/boot/Makefile b/boot/Makefile > > index 1dde16db694..7d1d4a28106 100644 > > --- a/boot/Makefile > > +++ b/boot/Makefile > > @@ -76,6 +76,7 @@ obj-$(CONFIG_$(PHASE_)BOOTMETH_ANDROID) += > > bootmeth_android.o > > obj-$(CONFIG_IMAGE_LOADER) += image-loader.o > > obj-$(CONFIG_IMAGE_LOADER_BLK) += image-loader-blk.o > > obj-$(CONFIG_IMAGE_LOADER_MTD) += image-loader-mtd.o > > +obj-$(CONFIG_IMAGE_LOADER_UBI) += image-loader-ubi.o > > > > obj-$(CONFIG_$(PHASE_)BOOTMETH_VBE_ABREC) += vbe_abrec.o vbe_common.o > > obj-$(CONFIG_$(PHASE_)BOOTMETH_VBE_ABREC_FW) += vbe_abrec_fw.o > > diff --git a/boot/image-loader-ubi.c b/boot/image-loader-ubi.c > > new file mode 100644 > > index 00000000000..64901a13378 > > --- /dev/null > > +++ b/boot/image-loader-ubi.c > > @@ -0,0 +1,112 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * UBI volume backend for image_loader > > + * > > + * Copyright (C) 2026 Daniel Golle <[email protected]> > > + */ > > + > > +#include <dm/ofnode.h> > > +#include <image-loader.h> > > +#include <log.h> > > +#include <malloc.h> > > +#include <mtd.h> > > +#include <ubi_uboot.h> > > + > > +struct image_loader_ubi_priv { > > + char *vol_name; > > +}; > > + > > +/** > > + * ubi_auto_attach() - attach UBI if not already attached > > + * > > + * If no UBI device is currently attached, walk the device tree for the > > + * first MTD partition node with compatible = "linux,ubi", find the > > + * corresponding MTD device by matching flash_node, and attach UBI to > > + * it via ubi_part_from_mtd(). > > + * > > + * Since U-Boot only supports a single attached UBI device at a time, > > + * only the first matching partition is used. > > + * > > + * Return: 0 on success or if already attached, negative errno on failure > > + */ > > +static int ubi_auto_attach(void) > > +{ > > + struct mtd_info *mtd; > > + ofnode node; > > + > > + /* Already attached? */ > > + if (ubi_devices[0]) > > + return 0; > > + > > + mtd_probe_devices(); > > This should be handled by your new ubi driver for your uclass. > > > + > > + ofnode_for_each_compatible_node(node, "linux,ubi") { > > + mtd_for_each_device(mtd) { > > + if (ofnode_equal(mtd->flash_node, node)) > > + goto found; > > + } > > + } > > Eek this is really strange. There should be a device so you can use > uclass_first_device(UCLASS_...).
I carefully considered turning UBI devices into a UCLASS, but it would be a huge major rewrite of how UBI works in U-Boot, and while that would be a good thing to do, I consider far beyond the scope of supporting a boot method for OpenWrt. Or did you mean the to-be-create UCLASS_IMAGE_MAPPER?
