mtd: nand: provide detailed description for raw read/write page methods

read_page_raw and write_page_raw method description is not clear enough.
It clearly specifies that ECC correction should not be involved but does
not talk about specific layout (by layout I mean where in-band and
out-of-band data are stored on the NAND media) used by NAND/ECC
controllers.

Those specific layouts might impact MTD users and thus should be hidden (as
already done in the standard NAND_ECC_HW_SYNDROME implementation).

Clearly state this constraint in the nand_ecc_ctrl struct documentation.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Boris BREZILLON 2014-10-20 10:46:14 +02:00 committed by Brian Norris
parent afc0ea1b8e
commit 62d956dc3e

View File

@ -455,8 +455,21 @@ struct nand_hw_control {
* be provided if an hardware ECC is available
* @calculate: function for ECC calculation or readback from ECC hardware
* @correct: function for ECC correction, matching to ECC generator (sw/hw)
* @read_page_raw: function to read a raw page without ECC
* @write_page_raw: function to write a raw page without ECC
* @read_page_raw: function to read a raw page without ECC. This function
* should hide the specific layout used by the ECC
* controller and always return contiguous in-band and
* out-of-band data even if they're not stored
* contiguously on the NAND chip (e.g.
* NAND_ECC_HW_SYNDROME interleaves in-band and
* out-of-band data).
* @write_page_raw: function to write a raw page without ECC. This function
* should hide the specific layout used by the ECC
* controller and consider the passed data as contiguous
* in-band and out-of-band data. ECC controller is
* responsible for doing the appropriate transformations
* to adapt to its specific layout (e.g.
* NAND_ECC_HW_SYNDROME interleaves in-band and
* out-of-band data).
* @read_page: function to read a page according to the ECC generator
* requirements; returns maximum number of bitflips corrected in
* any single ECC step, 0 if bitflips uncorrectable, -EIO hw error