[PATCH v4 1/4] mtd: nand: provide detailed description for raw read/write page methods
From: Boris Brezillon <hidden>
Date: 2014-10-20 08:55:25
Also in:
lkml
Subsystem:
memory technology devices (mtd), nand flash subsystem, the rest · Maintainers:
Miquel Raynal, Richard Weinberger, Vignesh Raghavendra, Linus Torvalds
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 <redacted> --- include/linux/mtd/nand.h | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index e4d451e..b14d190 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h@@ -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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1.9.1