[PATCH 0/9] Support for block device NVMEM providers

Loic Poulain
2026-04-28T14:23:12Z

On embedded devices, it is common for factory provisioning to store
device-specific information, such as Ethernet or WiFi MAC addresses,
in a dedicated area of an eMMC partition. This avoids the need for
and additional EEPROM/OTP and leverages the persistence of eMMC.

One example is the Arduino UNO-Q, where the WiFi MAC address and the
Bluetooth Device address are stored in the eMMC Boot1 partition.

Until now, accessing this information required a custom bootloader
to read the data and inject it into the Device Tree before handing
control over to the kernel. This approach is fragile and leads to
device-specific workarounds.

Rather than adding a new NVMEM provider specifically to the eMMC
subsystem, the new support operates at the block layer, allowing any
block device to behave like other non-volatile memories such as EEPROM
or OTP.

This series builds on earlier work by Daniel Golle that enables block
devices to act as NVMEM providers:
https://lore.kernel.org/all/6061aa4201030b9bb2f8d03ef32a564fdb786ed1.1709667858.git.daniel@makrotopia.org/

It also introduces an NVMEM layout description for the Arduino UNO-Q,
allowing device-specific data stored in the eMMC Boot1 partition to
be accessed in a standard way.

WiFi and Ethernet already support retrieving MAC addresses from NVMEM.
Bluetooth requires similar support, which is also addressed.

Note that this is currently limited to eMMC-backed block devices, as
only the eMMC core associates a firmware node with the block device
(add_disk_fwnode). This can be easily extended in the future to
support additional block drivers.

Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
---
Daniel Golle (1):
block: implement NVMEM provider

Loic Poulain (8):
dt-bindings: mmc: Document support for nvmem-layout
arm64: dts: qcom: arduino-imola: Describe boot1 NVMEM layout
dt-bindings: net: wireless: qcom,ath10k: Add NVMEM MAC address cell
arm64: dts: qcom: arduino-imola: Get WiFi MAC from NVMEM
dt-bindings: bluetooth: qcom: Add NVMEM BD address cell
Bluetooth: hci_sync: Add NVMEM-backed BD address retrieval
Bluetooth: qca: Set NVMEM BD address quirks when address is invalid
arm64: dts: qcom: arduino-imola: Get Bluetooth BD address from NVMEM

.../devicetree/bindings/mmc/mmc-card.yaml | 20 +++
.../net/bluetooth/qcom,bluetooth-common.yaml | 10 ++
.../bindings/net/wireless/qcom,ath10k.yaml | 10 ++
arch/arm64/boot/dts/qcom/qrb2210-arduino-imola.dts | 30 ++++
block/Kconfig | 9 ++
block/Makefile | 1 +
block/blk-nvmem.c | 164 +++++++++++++++++++++
drivers/bluetooth/btqca.c | 5 +-
include/net/bluetooth/hci.h | 18 +++
net/bluetooth/hci_sync.c | 56 ++++++-
10 files changed, 321 insertions(+), 2 deletions(-)
---
base-commit: 47c4835fc0fed583d01d90387b67633950eba2b2
change-id: 20260428-block-as-nvmem-4b308e8bda9a

Best regards,
--
Loic Poulain <loic.poulain@oss.qualcomm.com>