On 2014年12月17日 09:03, Brian Norris wrote:
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
Got it, thanks for your explanation, Brian. I will resend the new
version of patchset based on v3.19-rc1 later.
Regards,
Zhou
--
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
