On Thu, Dec 11, 2014 at 08:02:27PM +0800, Zhou Wang wrote: > On 2014年11月30日 17:08, Brian Norris wrote: > >Have you tested on the MTD test modules (drivers/mtd/tests/*)? This is > >important, as we seem to regularly get UBIFS bug reports from users > >whose drivers have not even passed some of the simple tests. > > > >Also, it might be worth testing out the UBI tests found in the mtd-utils > >package. > > 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. > > In mtd_nandbiterrs test, We call nand_write_page_raw indeed to perform > rewrite operation. My question is that: in this NAND controller hardware > design, it is hard to implement hardware specific write_page_raw to > write page data without producing ECC code, will this bring some bad > effects somewhere? It will be very nice if you and anyone can give > me some advice. As of now, read_page_raw()/write_page_raw() are not required for any normal operation. They are useful for debugging and testing though, with tests like this one. In the future, we might use read_page_raw() for implementing (optional) software-based detection of blank/erased pages that have bitflips in them -- i.e., all 0xff but with a few bitflips. See: http://lists.infradead.org/pipermail/linux-mtd/2014-December/056749.html http://article.gmane.org/gmane.linux.drivers.mtd/52183/ Brian -- 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
