I had a few boards with NAND related problems. In Linux a file was written to a JFFS2 partition in NAND, but u-boot was unable to read the same file correctly from the JFFS2. This happened to be often the case if the NAND had a few bad blocks in the JFFS2 partition. Upon further examination it turned out Linux still was able to read the file 100% correctly from the partition, but u-boot wasn't. I did get a lot of "read_nand_cache: error reading nand off ..." messages in u-boot.
When debugging further it appears that read_nand_cached(...) in /fs/jffs2/jffs2_1pass.c throws away the data if nand_read (/drivers/ mtd/nand/nand_base.c) doesn't return 0. This happens in case of an uncorrectable ECC error (-EBADMSG) or a correctable ECC error(-EUCLEAN). (see nand_do_read_ops in /drivers/ mtd/nand/nand_base.c) So this would mean that data gets thrown away in case of a correctable ECC error, which doesn't seem the right thing to do and probably does not match with how linux is behaving. I patched the code to not throw away data with correctable ECC errors and this seems to fix it for the two boards that had this issue. If it matters: the correctable ECC errors appeared in good blocks (but often close to a bad block). So would my understanding be 'correct'? Regards, Stephane Deltour PS: Sorry about the disclaimer, it is out of my control DISCLAIMER: Unless indicated otherwise, the information contained in this message is privileged and confidential, and is intended only for the use of the addressee(s) named above and others who have been specifically authorized to receive it. If you are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this message and/or attachments is strictly prohibited. The company accepts no liability for any damage caused by any virus transmitted by this email. Furthermore, the company does not warrant a proper and complete transmission of this information, nor does it accept liability for any delays. If you have received this message in error, please contact the sender and delete the message. Thank you. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
