On Thu, Dec 11, 2014 at 08:02:27PM +0800, Zhou Wang wrote: > I have tested this NAND controller driver on the MTD test modules > (drivers/mtd/tests/*). All tests passed except mtd_nandbiterrs.ko. > > Here is the test log for mtd_nandbiterrs: > /home # insmod mtd_nandbiterrs.ko dev=2 page_offset=1 seed=110 mode=0 > [ 100.484995] > [ 100.490082] ================================================== > [ 100.509657] mtd_nandbiterrs: MTD device: 2 > [ 100.523413] mtd_nandbiterrs: MTD device size 8388608, > eraseblock=131072, page=2048, oob=64 > [ 100.551134] mtd_nandbiterrs: Device uses 2 subpages of 1024 bytes > [ 100.571585] mtd_nandbiterrs: Using page=1, offset=2048, eraseblock=0 > [ 104.431136] mtd_nandbiterrs: incremental biterrors test > [ 104.448872] mtd_nandbiterrs: write_page > [ 104.463193] mtd_nandbiterrs: rewrite page > [ 104.477620] mtd_nandbiterrs: read_page > [ 104.490898] mtd_nandbiterrs: verify_page > [ 104.504338] mtd_nandbiterrs: Successfully corrected 0 bit errors > per subpage > [ 104.527985] mtd_nandbiterrs: Inserted biterror @ 0/5 > [ 104.544673] mtd_nandbiterrs: Inserted biterror @ 1024/2 > [ 104.562197] mtd_nandbiterrs: rewrite page > [ 104.576766] mtd_nandbiterrs: read_page > [ 104.590052] mtd_nandbiterrs: verify_page > [ 104.603252] mtd_nandbiterrs: Error: page offset 0, expected 23, got 03 > [ 104.625203] mtd_nandbiterrs: Error: page offset 1024, expected 06, got 02 > [ 104.648056] mtd_nandbiterrs: ECC failure, read data is incorrect > despite read success > insmod: can't insert 'mtd_nandbiterrs.ko': Input/output error > > The reason for above failure is that: > In ECC mode, when rewriting page data to NAND flash, the NAND > controller will also produce ECC code and write them to NAND flash > as well. So when we read data from NAND flash, there is no need to > correct the error bit. We read what we write to the flash. BTW, your explanation doesn't seem quite right. The problem is that even though mtd_read() didn't report errors, the data doesn't match what's written. It's not that there was "no need to correct the error bit". I'd recommend digging a little more to figure out what's wrong here. You might need to instrument the nandbiterrs test. This is possibly highlighting a driver bug [1]. Brian [1] Besised simply that you didn't implement write_page_raw(). The default nand_write_page_raw() implementation looks just like your non-raw version. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
