[PATCH v3 00/15] mtd: rawnand: sunxi: support the Allwinner randomized OOB format

[James Hilliard]

Allwinner NAND firmware leaves the bad-block marker in the randomizer
data stream. On H6/H616 it also places all protected user data before the
first ECC step. These choices differ from the mainline format, which
keeps the physical marker plain and maximizes the H6/H616 user-data area.

Add allwinner,randomized-oob to select the firmware format for the
configured hardware-ECC geometry. Older controllers keep their fixed
four-byte-per-step user-data layout; H6/H616 use four bytes per 1 KiB
step, capped at 16 bytes, packed before the first ECC step. Without the
property, retain the existing marker handling and OOB layout.

Normal hardware-ECC accesses use the controller randomizer. MTD_OPS_RAW
continues to bypass both ECC and randomization and expose physical data
and OOB, including randomized markers stored by firmware.

Address the ECC-error paths as well. In randomized-OOB mode, use the
controller-specific vendor spare-byte erased-page heuristic on the
protected user data from the original hardware read. Older controllers
use exact erased-spare checks, including their first-page and page-127
signatures; H616 requires byte zero and at least nine of ten spare bytes
to be 0xff. Accepted erased pages return all-0xff data and OOB without a
raw reread. An all-zero physical page instead returns a bad marker and
an ECC failure.

Other ECC failures retain the original decoded data and protected OOB for
bad-block and flash-BBT pattern scans. PIO and DMA share this page-wide
classification, including randomized-format subpage reads. Plain-marker
mode keeps its existing physical erased-chunk check.

Prepend independent fixes for PIO OOB lengths, per-step pattern IDs,
read/write error handling and duplicate OOB program confirms, followed by
OOB-helper cleanups.
These fixes also apply when randomized-OOB mode is disabled.

Also combine contiguous unprotected OOB reads and reduce repeated chip
setup and register accesses without changing the page format.

Assisted-by: Codex:gpt-6-astra
Signed-off-by: James Hilliard <james.hilliard1 at gmail.com>
---
Changes in v3:
- add a prerequisite fix for the logical OOB length used by PIO transfers
- clarify logical ECC steps versus hardware slots and share protected-OOB
  register indexing
- select the controller-specific vendor spare-byte erased-page check from
  the SoC capabilities, only in randomized-OOB mode and without rereading
  the main data
- retain hardware-decoded data and protected OOB on other ECC failures
  for bad-block and BBT pattern scans (reported by Miquel Raynal)
- retain a bad marker and ECC failure for all-zero physical pages, and
  disable the ECC exception for the vendor format
- share page classification between PIO and DMA, reading complete pages
  for randomized-format subpage requests
- propagate OOB read errors and defer randomized-format ECC accounting
  until those reads have succeeded
- propagate read/program setup, column-change and buffer-transfer errors,
  including extra OOB; stop failed writes and disable ECC and randomization
- discard partial DMA ECC statistics before retrying in PIO, and keep
  correction counts separate from successful OOB-transfer status
- select the current hardware step's pattern ID instead of slot zero
- avoid a second program confirm after an OOB-only write
- avoid redundant column changes before writing extra OOB bytes
- reject oversized ECC steps in randomized-OOB mode before the core can
  fall back to software ECC
- combine adjacent parity and trailing OOB reads in randomized-OOB mode
- remove duplicate chip setup immediately before core page commands
- program each packed DMA user-data length register once per operation,
  and write PIO slot zero directly without read-modify-write
- reuse pattern IDs and packed error counters within a DMA read, while
  refreshing the snapshot after every PIO ECC operation
- Link to v2: https://patch.msgid.link/20260904-submit-sunxi-nand-vendor-oob-layout-v1-v2-0-b12074f4aca7@gmail.com

Changes in v2:
- rebase on the current MTD nand/next branch
- retain the merged protected-OOB allocation, BBM reservation and
  stack-buffer fixes
- clarify that randomization is part of the normal hardware-ECC page
  format while MTD_OPS_RAW continues to expose physical bytes
- explain why a BSP-compatible BBM remains randomized in physical raw data
- document the decoded bad-block and flash-BBT access paths
- reject the firmware OOB format with software or disabled ECC
- document the BSP page-format compatibility contract and the
  older-controller format audit
- Link to v1: https://patch.msgid.link/20260810-submit-sunxi-nand-vendor-oob-layout-v1-v1-0-463853a14ad9@gmail.com

To: Miquel Raynal <miquel.raynal at bootlin.com>
To: Richard Weinberger <richard at nod.at>
To: Vignesh Raghavendra <vigneshr at ti.com>
To: Chen-Yu Tsai <wens at kernel.org>
To: Jernej Skrabec <jernej.skrabec at gmail.com>
To: Samuel Holland <samuel at sholland.org>
To: Richard Genoud <richard.genoud at bootlin.com>
To: Rob Herring <robh at kernel.org>
To: Krzysztof Kozlowski <krzk+dt at kernel.org>
To: Conor Dooley <conor+dt at kernel.org>
To: Maxime Ripard <mripard at kernel.org>
To: Masahiro Yamada <yamada.masahiro at socionext.com>
To: Boris Brezillon <bbrezillon at kernel.org>
To: Brian Norris <computersforpeace at gmail.com>
Cc: linux-mtd at lists.infradead.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-sunxi at lists.linux.dev
Cc: linux-kernel at vger.kernel.org
Cc: devicetree at vger.kernel.org

---
James Hilliard (15):
      mtd: rawnand: sunxi: use the logical step's OOB length in PIO
      mtd: rawnand: sunxi: propagate page-setup and erased-check errors
      mtd: rawnand: sunxi: stop failed program operations and disable ECC
      mtd: rawnand: sunxi: select the pattern ID for the current ECC step
      mtd: rawnand: sunxi: propagate buffer and column transfer errors
      mtd: rawnand: sunxi: avoid a second program confirm for OOB writes
      mtd: rawnand: sunxi: avoid redundant column changes for extra OOB
      mtd: rawnand: sunxi: clarify OOB register and step handling
      dt-bindings: mtd: sunxi: Add randomized OOB flag
      mtd: rawnand: sunxi: support randomized OOB formats
      mtd: rawnand: sunxi: select the packed H6/H616 OOB layout
      mtd: rawnand: sunxi: combine contiguous unprotected OOB reads
      mtd: rawnand: sunxi: avoid duplicate chip setup before page commands
      mtd: rawnand: sunxi: reduce user-data length register accesses
      mtd: rawnand: sunxi: reuse ECC status within each DMA read

 .../bindings/mtd/allwinner,sun4i-a10-nand.yaml     |  10 +
 drivers/mtd/nand/raw/sunxi_nand.c                  | 948 +++++++++++++++------
 2 files changed, 689 insertions(+), 269 deletions(-)
---
base-commit: 7e874b1750a40f3dc9a629aeb72eba09c77f77e9
change-id: 20260810-submit-sunxi-nand-vendor-oob-layout-v1-e3114d10cc9c

Best regards,
--  
James Hilliard <james.hilliard1 at gmail.com>