From patchwork Fri Sep 7 16:48:09 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [-next, v4, 4/5] mtd: mtd_nandecctest: add single bit error correction test Date: Fri, 07 Sep 2012 06:48:09 -0000 From: Akinobu Mita X-Patchwork-Id: 182425 Message-Id: <1347036490-18258-5-git-send-email-akinobu.mita@gmail.com> To: linux-mtd@lists.infradead.org Cc: Artem Bityutskiy , David Woodhouse , Akinobu Mita This adds the single bit error correction test case listed below: Prepare data block without corruption and ECC data with single bit error, and verify that the data block is preserved by __nand_correct_data(). Signed-off-by: Akinobu Mita Cc: David Woodhouse Cc: linux-mtd@lists.infradead.org Cc: Artem Bityutskiy --- No changes from previous version drivers/mtd/tests/mtd_nandecctest.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c index ff97b10..caaeb64 100644 --- a/drivers/mtd/tests/mtd_nandecctest.c +++ b/drivers/mtd/tests/mtd_nandecctest.c @@ -48,6 +48,31 @@ static void single_bit_error_data(void *error_data, void *correct_data, __change_bit_le(offset, error_data); } +static unsigned int random_ecc_bit(size_t size) +{ + unsigned int offset = random32() % (3 * BITS_PER_BYTE); + + if (size == 256) { + /* + * Don't inject a bit error into the insignificant bits (16th + * and 17th bit) in ECC code for 256 byte data block + */ + while (offset == 16 || offset == 17) + offset = random32() % (3 * BITS_PER_BYTE); + } + + return offset; +} + +static void single_bit_error_ecc(void *error_ecc, void *correct_ecc, + size_t size) +{ + unsigned int offset = random_ecc_bit(size); + + memcpy(error_ecc, correct_ecc, 3); + __change_bit_le(offset, error_ecc); +} + static void no_bit_error(void *error_data, void *error_ecc, void *correct_data, void *correct_ecc, const size_t size) { @@ -76,6 +101,13 @@ static void single_bit_error_in_data(void *error_data, void *error_ecc, memcpy(error_ecc, correct_ecc, 3); } +static void single_bit_error_in_ecc(void *error_data, void *error_ecc, + void *correct_data, void *correct_ecc, const size_t size) +{ + memcpy(error_data, correct_data, size); + single_bit_error_ecc(error_ecc, correct_ecc, size); +} + static int single_bit_error_correct(void *error_data, void *error_ecc, void *correct_data, const size_t size) { @@ -101,6 +133,11 @@ static const struct nand_ecc_test nand_ecc_test[] = { .prepare = single_bit_error_in_data, .verify = single_bit_error_correct, }, + { + .name = "single-bit-error-in-ecc-correct", + .prepare = single_bit_error_in_ecc, + .verify = single_bit_error_correct, + }, }; static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data,