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This part is wrong in multiple ways: [1] is_erased() is called against "buf" twice, so the OOB area is not checked at all. The second call should check chip->oob_poi. [2] This code block is nested by double "if (check_erase_page)". The inner one is redundant. [3] The ECC_ERROR_ADDRESS register reports which sector(s) had uncorrectable ECC errors. It is pointless to check the whole page if only one sector contains errors. [4] Unfortunately, the Denali ECC correction engine has already manipulated the data buffer before it decides the bitflips are uncorrectable. That is, not all of the data are 0xFF after an erased page is processed by the ECC engine. The current is_erased() helper could report false-positive ECC errors. Actually, a certain mount of bitflips are allowed in an erased page. The core framework provides nand_check_erased_ecc_chunk() that takes the threshold into account. Let's use this. This commit reworks the code to solve those problems. Please note the erased page checking is implemented as a separate helper function instead of embedding it in the loop in handle_ecc(). The reason is that OOB data are needed for the erased page checking, but the controller can not start a new transaction until all ECC error information is read out from the registers. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.