For now lets stick with 1536 in u-boot. I will send a patch. At least it will not loosing flash over time as nand ages.
I understand what you wish, and will take a look on it inside fresh new kernel. I found one more driver - marvel looks like have same problem. I will check how NAND_CMD_RNDOUT is working. Perhaps we do not need extra read_param(), and use only NAND_CMD_RNDOUT to get next block inside page loop. Andrei On Wed, 2015-05-20 at 21:27 -0500, Scott Wood wrote: > On Wed, 2015-05-20 at 18:55 -0700, Andrei Yakimov wrote: > > On Wed, 2015-05-20 at 20:37 -0500, Scott Wood wrote: > > > On Wed, 2015-05-20 at 18:27 -0700, Andrei Yakimov wrote: > > > > For elbc and imx due to we reading all at once, it can not be stateless, > > > > we need to read more and more each time > > > > > > Why do we need to? Why can't we read all three copies at once? > > > > > > > reissuing command or relay on different way to ID chip - and this make > > > > it pointless if it can not be done universally. > > > > > > Or, we can reissue the command. I don't see any big problem either way. > > > This is not performance critical. > > lets say 1 time you read 256 ( or 512) it go bad, next time you read > > 512 (or 1024) next time you read 768 ( or 1536). > > I was thinking read_param() would take the offset as a parameter and use > NAND_CMD_RNDOUT to skip ahead -- but that would change the default flow > which I'd rather avoid. Another option is that read_param() just sets > up the read for the specified number of bytes, but the caller still uses > read_byte() to extract the data. This way the code could specify > sizeof(struct)*3 as the size up front without needing three separate > buffers. > > Note that whatever gets done should first be accepted in Linux, rather > than being a local U-Boot change. If you want a short-term fix, just > stick 1536 in the eLBC driver. > > > Upper layer can maintain it. > > Roughly like this: > > > > Was: > > chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1); > > for (i = 0; i < 3; i++) { > > chip->read_buf(mtd, (uint8_t *)p, sizeof(*p)); > > You're looking at old code. It uses read_byte() now. > > > if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) == > > le16_to_cpu(p->crc)) { > > break; > > } > > } > > if (i == 3) > > return 0; > > > > new: > > int read_size, offset; > > read_size = 256; > > offset =0; > > if(!chip->read_param) > > chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1); > > I don't want "if (chip->read_param)" all over the place; there should be > a default read_param() that does what the existing code does. > > > for (i = 0; i < 3; i++) { > > if(chip->read_param) chip->read_param( 0, read_size); > > chip->read_buf(mtd, (uint8_t *)p + offest, sizeof(*p)); > > This isn't going to read the second or third copy; it's going to read > the first copy and write beyond the end of your buffer. > > -Scott > > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot