[PATCH v4 0/3] Add Renesas RZ/N1x EDAC driver

[Paul Louvel]

The Cadence memory controller found on Renesas RZ/N1x SoCs supports ECC
with SECDED.

The memory controller found on the r9a06g032 supports at most a single
DIMM of DDR2/3, up to 2GB.

Add the EDAC driver for this memory controller, and the relevant
device-tree binding. Also add the EDAC node to the existing r9a06g032
SoC base device-tree.

Signed-off-by: Paul Louvel (Schneider Electric) <paul.louvel@xxxxxxxxxxx>
---
Changes in v4:
- Patch 1 and 3: drop the RZN1 family compatible, as requested by Geert.
- Patch 2:

    - Instead of using FIELD_MODIFY macro that expect a compile-time
      constant mask, use binary operators instead. Note that the new
      code is doing exactly what FIELD_MODIFY do, minus the error if
      cdns_rmw() is not inlined.

    - Use a spinlock instead of mutex since the locked region will be
      really fast to execute. Only lock it once for two register rmw.

    - Use edac_debugfs_* facility instead of sysfs attributes. Use a
      separate "bits" and "inject" file instead of just a single file.
      This is better since clients can read the previously set syndrome.

    - Cleaned up the probe function in separate functions. Use a remove
      function instead of registering custom devm action. Use a goto for
      resources cleaning.

    - Mask all interrupts before un-registering the memory controller.

- Link to v3: https://patch.msgid.link/20260924-paul-v7-3-rc1-edac-v3-0-bd8054a5b180@xxxxxxxxxxx

Changes in v3:
- Patch 2:

    - Added trailing newline to end message.

    - Forgot mutex_init() in probe...

    - Registering the MC at the end of the probe.

- Link to v2: https://patch.msgid.link/20260924-paul-v7-3-rc1-edac-v2-0-bc1406161ecc@xxxxxxxxxxx

Changes in v2:
- Patch 2:

    - FIELD_MODIFY() is always called with a compile-time constant mask
      in this driver. I see no problem here.

    - Use devm_clk_get_enabled() so the driver does not need to store
      struct clk_bulk_data outside the stack space.
      Clocks are not manipulated outside of probe.

    - Introduced a mutex for rmw operations in inject_ctrl_store() sysfs
      callback. Rename drv to priv in cdns_rmw().

    - Return IRQ_NONE if the stat int register is empty.

    - I see no reason to follow Sashiko last remark on this patch.
      Is an unhandled interrupt a big deal in this case ?

- Link to v1: https://patch.msgid.link/20260924-paul-v7-3-rc1-edac-v1-0-70be37c41a18@xxxxxxxxxxx

---
Paul Louvel (3):
      dt-bindings: edac: cdns,ddr-edac: add Cadence DDR EDAC binding
      EDAC/cadence: Add Cadence DDR EDAC driver
      ARM: dts: renesas: r9a06g032: add EDAC node

 .../devicetree/bindings/edac/cdns,ddr-edac.yaml    |  61 ++++
 MAINTAINERS                                        |   7 +
 arch/arm/boot/dts/renesas/r9a06g032.dtsi           |   9 +
 drivers/edac/Kconfig                               |  10 +
 drivers/edac/Makefile                              |   1 +
 drivers/edac/cadence_edac.c                        | 390 +++++++++++++++++++++
 6 files changed, 478 insertions(+)
---
base-commit: d9f39b2c0579f313d14954a9ec584511c543aab5
change-id: 20260916-paul-v7-3-rc1-edac-1f479f96fc57

Best regards,
--  
Paul Louvel, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com