'struct nand_ecc_engine_ops' are not modified in these drivers.
Constifying this structure moves some data to a read-only section, so
increases overall security, especially when the structure holds some
function pointers.
Update the prototype of mxic_ecc_get_pipelined_ops() accordingly.
On a x86_64, with allmodconfig, as an example:
Before:
======
text data bss dec hex filename
16709 1374 16 18099 46b3 drivers/mtd/nand/ecc-mxic.o
After:
=====
text data bss dec hex filename
16789 1294 16 18099 46b3 drivers/mtd/nand/ecc-mxic.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/72597e9de2320a4109be2112e696399592edacd4.1729271136.git.christophe.jaillet@wanadoo.fr
Some SPI-NAND chips do not have a proper on-die ECC engine providing
error correction/detection. This is particularly an issue on embedded
devices with limited resources because all the computations must
happen in software, unless an external hardware engine is provided.
These external engines are new and can be of two categories: external
or pipelined. Macronix is providing both, the former being already
supported. The second, however, is very SoC implementation dependent
and must be instantiated by the SPI host controller directly.
An entire subsystem has been contributed to support these engines which
makes the insertion into another subsystem such as SPI quite
straightforward without the need for a lot of specific functions.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/linux-mtd/20220202144536.393792-1-miquel.raynal@bootlin.com
Introduce the support for another possible configuration: the ECC
engine may work as DMA master (pipelined) and move itself the data
to/from the NAND chip into the buffer, applying the necessary
corrections/computations on the fly.
This driver offers an ECC engine implementation that must be
instatiated from a SPI controller driver.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211216111654.238086-17-miquel.raynal@bootlin.com
