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| author | Boris BREZILLON <boris.brezillon@free-electrons.com> | 2014-10-20 10:46:14 +0200 |
|---|---|---|
| committer | Brian Norris <computersforpeace@gmail.com> | 2014-11-20 00:02:46 -0800 |
| commit | 62d956dc3e11138c5ffd4b2c62e4f909c5180a12 (patch) | |
| tree | d122faefaed35017d623325e4ffc52321ef2705c /include/linux | |
| parent | afc0ea1b8e1e27b2cb77e7023d917f3aa5971d17 (diff) | |
| download | linux-62d956dc3e11138c5ffd4b2c62e4f909c5180a12.tar.gz linux-62d956dc3e11138c5ffd4b2c62e4f909c5180a12.tar.bz2 linux-62d956dc3e11138c5ffd4b2c62e4f909c5180a12.zip | |
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>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/mtd/nand.h | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index e4d451e4600b..b14d190b593a 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 |