I'm thinking part of the problem I was having was my command is bring up a bug: nand write 10008000 0 200

This will result in nand_rw calling nand_write_ecc with an eccbuf = NULL, as the size and alignment check does not work for the first block (noecc = (start!=start... ). Nand_rw passes this to nand_write_ecc which passes it onto nand_write page. Which then acts like its valid and starts trying to read and write to address 0. As I have ROM there what ends up going into the oob is my rom's first instruction.

I've feeling a bit slow at the moment, and am wondering if the rounding to see if we are starting on an aligned address is even correct.

As far as R/B goes, I have two types of systems, one has it and the other doesn't. I've inserted code which seems to allow things to work without a R/B connected...mainly using the status read to wait till not busy followed by a read to check for success or failure. The only real pain with out having a RB and doing this all with GPIOs is my ARM does not have anything which allows the equivalent of a ppc "sync" instruction, so dependencies on the memory controller's scheduling creep up.

Regards/Thanks,

Richard W.

-----Original Message----- From: Dave Ellis [mailto:dge@sixnetio.com] Sent: Wednesday, July 23, 2003 1:38 PM To: Woodruff, Richard Cc: u-boot-users@lists.sourceforge.net Subject: RE: [U-Boot-Users] ECC code used in cmd_nand.c

Richard Woodruff wrote:

...

Can anyone verify that the write using "nand write aaaa offf ssss" should work with ECC enabled? I'm finding that if I disable the ECC generation I can write uImages and compare them and get what I expect and boot from them.

It has been working fine for me using the SXNI855T configuration. I built this morning's CVS version and it also seems OK.

...

If I enable ECC generation, on read it complains that they are all wrong (but there is no errors on the write which I think it should give if the written ecc does not match the calculated one). If I disregard the ecc warnings and then "cmp" the data starting which was loaded, the first 16k are indeed the same (16k is my block size), however, there is some differences at the end of the first block. Again, if I disable ECC no such problem.

If you write if with ECC, but read it back without ECC is the data still corrupted? The data may be OK until the bad ECC data is used to 'correct' it.

...

...If I do a read.oob of the first block, it appears that the data_buf[0] is written to the first position of the oob, instead of the expected data.

Are you sure NanD_WaitReady() is working? If it isn't, you could start to read the oob data before it is ready, and would see some old data from the start of the buffer.

Dave

Dave Ellis

SIXNET - "Leading the Industrial Ethernet Revolution"
331 Ushers Road,   P.O. Box 767, Clifton Park, NY 12065 USA
Tel +1 (518) 877-5173   Fax +1 (518) 877-8346
Email me at: dge@sixnetio.com 
Detailed product info: www.sixnetio.com