From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Norris Subject: Re: [PATCH v4 0/2] mtd: hisilicon: add a new driver for NAND controller of hisilicon hip04 Soc Date: Tue, 16 Dec 2014 17:03:58 -0800 Message-ID: <20141217010358.GM9759@ld-irv-0074> References: <1415105221-7732-1-git-send-email-wangzhou.bry@gmail.com> <20141130090853.GG3608@norris-Latitude-E6410> <548987D3.3060407@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <548987D3.3060407-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Zhou Wang Cc: David Woodhouse , linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, caizhiyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, haojian.zhuang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, xuwei5-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org, wangzhou1-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org, liguozhu-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org, yubingxu-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org List-Id: devicetree@vger.kernel.org On Thu, Dec 11, 2014 at 08:02:27PM +0800, Zhou Wang wrote: > On 2014=E5=B9=B411=E6=9C=8830=E6=97=A5 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-u= tils > >package. >=20 > I have tested this NAND controller driver on the MTD test modules > (drivers/mtd/tests/*). All tests passed except mtd_nandbiterrs.ko. >=20 > Here is the test log for mtd_nandbiterrs: > /home # insmod mtd_nandbiterrs.ko dev=3D2 page_offset=3D1 seed=3D110 = mode=3D0 > [ 100.484995] > [ 100.490082] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D > [ 100.509657] mtd_nandbiterrs: MTD device: 2 > [ 100.523413] mtd_nandbiterrs: MTD device size 8388608, > eraseblock=3D131072, page=3D2048, oob=3D64 > [ 100.551134] mtd_nandbiterrs: Device uses 2 subpages of 1024 bytes > [ 100.571585] mtd_nandbiterrs: Using page=3D1, offset=3D2048, eraseb= lock=3D0 > [ 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, go= t 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 >=20 > 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. >=20 > In mtd_nandbiterrs test, We call nand_write_page_raw indeed to perfor= m > rewrite operation. My question is that: in this NAND controller hardw= are > 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, wit= h 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.h= tml http://article.gmane.org/gmane.linux.drivers.mtd/52183/ Brian -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html