[v4,00/12] External ECC engines & Macronix support

Hello all,

This series is now stable and brings support for external/modular ECC
engines, and let SPI controller using the ECC framework.

As a first example, Macronix ECC engine can be used as an
external engine (takes the data, proceeds to the calculations, writes
back the ECC bytes) or as a pipelined engine doing on-the-fly
calculations (which is very common in the raw NAND world).

In the device tree, the ECC engine should be described as a separated DT
node. Then:
* external case: the flash node should provide a nand-ecc-engine
  property pointing to the ECC engine node.
* pipelined case: the flash node should provide a nand-ecc-engine
  property pointing to the SPI controller, itself with another
  nand-ecc-engine property pointing at the ECC engine node.

This series comes with a bunch of improvements on the binding side as
well.

Cheers,
Miquèl

Changes in v4:
* The first half of the series has been left aside (all the binding
  changes + the external mode in the Macronix driver), now let's focus
  on the pipelined mode.
* Added the ecc_en spi_mem_op structure parameter in a dedicated commit.
* Introduced a new helper for supporting generically the supported ops.
* Used this new helper in the macronix driver.
* By default all the other drivers would refuse a spi_mem_op with ecc_en
  enabled.

Changes in v3:
* Added Mark's R-by.
* Added a commit changing the initialization order between the dirmaps
  and the ECC engine so that the core might now if we are using a
  pipelined engine or not.
* Stopped creating additional dirmaps with ECC if the engine is not a
  pipelined engine.
* Solved the kernel test robot reports. In particular, I added a
  dependency on MTD_NAND_ECC to Macronix SPI controller driver.
* Added a patch to clean the NAND controller yaml file before moving
  some bits to nand-chip.yaml. This addresses the comments made by Rob
  about the useless allOf's.
* Used platform_get_irq_byname_optional() in order to avoid useless
  warnings when there is no IRQ.

Changes in v2:
* Fixed the bindings and added Rob's acks when relevant.
* Added locking in the ECC engine driver.
* Brought more changes in the core in order to bring the ECC information
  into the spi_mem_op structure with the idea of avoiding any races
  between parallel calls on the same engine.
* Reorganized the ECC driver entirely in order to have a per-engine mxic
  structure plus a per-NAND context. This lead to a number of changes
  internally which cannot all be listed.

Changes since the RFC:
* Rebased on top of v5.15-rc1.
* Fixed the dirmap configuration.
* Added the various tags received.
* Fixed the bindings as reported by the robots.
* Fixed the return value of the helper counting bitflips.
* Included a fix from Jaime Liao in the external pattern logic.
* Added the yaml conversion of Macronix SPI controller description.
* Added the yaml conversion of the SPI-NAND description.
* Created a nand-chip.yaml file to share properties between SPI-NAND and
  raw NAND.

Miquel Raynal (12):
  mtd: nand: mxic-ecc: Support SPI pipelined mode
  mtd: spinand: Delay a little bit the dirmap creation
  spi: spi-mem: Create a helper to gather all the supports_op checks
  spi: spi-mem: Add an ecc_en parameter to the spi_mem_op structure
  spi: spi-mem: Export the spi_mem_generic_supports_op() helper
  mtd: spinand: Create direct mapping descriptors for ECC operations
  spi: mxic: Fix the transmit path
  spi: mxic: Create a helper to configure the controller before an
    operation
  spi: mxic: Create a helper to ease the start of an operation
  spi: mxic: Add support for direct mapping
  spi: mxic: Use spi_mem_generic_supports_op()
  spi: mxic: Add support for pipelined ECC operations

 drivers/mtd/nand/ecc-mxic.c       | 210 ++++++++++++++++++-
 drivers/mtd/nand/spi/core.c       |  51 ++++-
 drivers/spi/Kconfig               |   2 +-
 drivers/spi/spi-mem.c             |  38 +++-
 drivers/spi/spi-mxic.c            | 337 ++++++++++++++++++++++++------
 include/linux/mtd/nand-ecc-mxic.h |  49 +++++
 include/linux/mtd/spinand.h       |   2 +
 include/linux/spi/spi-mem.h       |  16 ++
 8 files changed, 623 insertions(+), 82 deletions(-)
 create mode 100644 include/linux/mtd/nand-ecc-mxic.h