[PATCH v2 0/8] Support for block device NVMEM providers

[Loic Poulain]

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 MMC-backed block devices, as
only the MMC 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 at oss.qualcomm.com>
---
Changes in v2:
- Fix example nvmem-layout cells to use compatible = "mac-base"
- Squash WiFi MAC and Bluetooth BD address consumer patches into the nvmem layout patch
- Fix possible use-after-free in blk-nvmem: bnv (nvmem priv) linked to nvmem lifetime
- Simplify nvmem-cell-names from items: - const: to plain const:
- Factor out common NVMEM EUI-48 retrieval logic
- Reorder changes
- Link to v1: https://lore.kernel.org/r/20260428-block-as-nvmem-v1-0-6ad23e75190a@oss.qualcomm.com

---
Daniel Golle (1):
      block: implement NVMEM provider

Loic Poulain (7):
      dt-bindings: mmc: Document support for nvmem-layout
      dt-bindings: net: wireless: qcom,ath10k: Add NVMEM MAC address cell
      dt-bindings: bluetooth: qcom: Add NVMEM BD address cell
      net: of_net: Add of_get_nvmem_eui48() helper for EUI-48 lookup
      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: Describe NVMEM layout for WiFi/BT addresses

 .../devicetree/bindings/mmc/mmc-card.yaml          |  24 +++
 .../net/bluetooth/qcom,bluetooth-common.yaml       |   9 +
 .../bindings/net/wireless/qcom,ath10k.yaml         |   9 +
 arch/arm64/boot/dts/qcom/qrb2210-arduino-imola.dts |  34 ++++
 block/Kconfig                                      |   9 +
 block/Makefile                                     |   1 +
 block/blk-nvmem.c                                  | 188 +++++++++++++++++++++
 drivers/bluetooth/btqca.c                          |   5 +-
 drivers/nvmem/core.c                               |  13 ++
 include/linux/nvmem-consumer.h                     |   6 +
 include/linux/of_net.h                             |   7 +
 include/net/bluetooth/hci.h                        |  18 ++
 net/bluetooth/hci_sync.c                           |  39 ++++-
 net/core/of_net.c                                  |  47 ++++--
 14 files changed, 395 insertions(+), 14 deletions(-)
---
base-commit: 47c4835fc0fed583d01d90387b67633950eba2b2
change-id: 20260428-block-as-nvmem-4b308e8bda9a

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