Commit 62d956dc authored by Boris BREZILLON's avatar Boris BREZILLON Committed by Brian Norris
Browse files

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: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent afc0ea1b

include/linux/mtd/nand.h

+15 −2
Original line number Diff line number Diff line
@@ -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

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