[PATCH v3 0/8] mtd: ubi: allow UBI volumes to provide NVMEM

From: Daniel Golle
Date: Tue Aug 08 2023 - 13:15:46 EST


The series is a follow-up and contains all patches of the previous
series "mtd: ubi: behave like a good MTD citizen"[1] which was meant in
preparation for implementing the NVMEM provider.

The goal is to support embedded Linux devices which got NVMEM bits
stored inside a UBI volume. Representing the UBI volume in the Device
Tree, adding a phandle to be referenced by NVMEM consumers allows such
devices to come up with their correct MAC addresses and device-specific
Wi-Fi calibration data loaded.

In order to be available for other drivers, attaching UBI devices has
to be moved from late_initcall (which is too late for other drivers) to
happen earlier. As an alternative to the existing kernel cmdline
parameter the Device Tree property 'compatible = "linux,ubi";' inside
an MTD partition can be used to have that MTD device attached as UBI
device. MTD partitions which serve as UBI devices may have a "volumes"
firmware subnode with volumes which may be compatible with
"nvmem-cells".

In this way, other drivers (think: Ethernet, Wi-Fi) can resolve and
acquire NVMEM bits using the usual device tree phandle, just this time
the NVMEM content is read from a UBI volume.

[1]: https://patchwork.ozlabs.org/project/linux-mtd/list/?series=353177&state=%2A&archive=both

Changes since v2:
* include dt-bindings additions

Changes since v1:
* include patch to fix exiting Kconfig formatting issues
* fix typo and indentation in Kconfig

Daniel Golle (8):
dt-bindings: mtd: add basic bindings for UBI
dt-bindings: mtd: nvmem-cells: allow UBI volumes to provide NVMEM
mtd: ubi: block: don't return on error when removing
mtd: ubi: block: use notifier to create ubiblock from parameter
mtd: ubi: attach MTD partition from device-tree
mtd: ubi: introduce pre-removal notification for UBI volumes
mtd: ubi: populate ubi volume fwnode
mtd: ubi: provide NVMEM layer over UBI volumes

.../bindings/mtd/partitions/linux,ubi.yaml | 66 ++++++
.../bindings/mtd/partitions/nvmem-cells.yaml | 5 +-
.../bindings/mtd/partitions/ubi-volume.yaml | 35 ++++
drivers/mtd/ubi/Kconfig | 12 ++
drivers/mtd/ubi/Makefile | 1 +
drivers/mtd/ubi/block.c | 186 ++++++++++-------
drivers/mtd/ubi/build.c | 160 +++++++++++----
drivers/mtd/ubi/cdev.c | 4 +-
drivers/mtd/ubi/nvmem.c | 189 ++++++++++++++++++
drivers/mtd/ubi/ubi.h | 6 +-
drivers/mtd/ubi/vmt.c | 32 +++
include/linux/mtd/ubi.h | 2 +
12 files changed, 578 insertions(+), 120 deletions(-)
create mode 100644 Documentation/devicetree/bindings/mtd/partitions/linux,ubi.yaml
create mode 100644 Documentation/devicetree/bindings/mtd/partitions/ubi-volume.yaml
create mode 100644 drivers/mtd/ubi/nvmem.c

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2.41.0