On Wed, 2015-05-20 at 22:11 -0500, Scott Wood wrote:
On Wed, 2015-05-20 at 20:03 -0700, Andrei Yakimov wrote:
On Wed, 2015-05-20 at 21:46 -0500, Scott Wood wrote:
On Wed, 2015-05-20 at 19:42 -0700, Andrei Yakimov wrote:
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.
Again, I'm a reluctant to use RNDOUT in the default read_param() because that would change the flow for all controllers and chips, and while the chip manual I'm looking at says it's OK, it introduces risk that it doesn't work everywhere (e.g. some controller drivers that provide their own cmdfunc don't implement RNDOUT).
RNDOUT is already used by nand_flash_detect_ext_param_page(), so this isn't as much of a concern for ONFI, but it could be an issue with nand_flash_detect_jedec().
Forget about read_param(),
Then how will it work on controllers like eLBC/IFC which is the whole point?
just like this:
I miss this line: chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
for (i = 0; i < 3; i++) { for (j = 0; j < sizeof(*p); j++) ((uint8_t *)p)[j] = chip->read_byte(mtd); if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) == le16_to_cpu(p->crc)) { break; } chip->cmdfunc(mtd, NAND_CMD_RNDOUT, <offest>, -1); }
and this is good - will be "no op" or "bad command" error, which could be ignored - so for this drivers operation flow is unchanged.
RNDOUT needs to come before read_buf() and it needs to specify the offset you want.
column address - it is exactly offset for RNDOUT. First param read 256/512 bytes, if it fail, we do RNDOUT to get next. we will not do extra RNDOUT - it is for() loop.
I can test it on my board. This is really good solution if it work. it is just 1 line, and only when ONFI mark already read from flash.
And we can leave (NAND_CMD_PARAM, 0x40) (JDEC label) handling for kernel folks.
My problem only jesd230B do not specify PARAM command, ONFI4.0 - do not expect column address for PARAM.
Linux kernel cleary doing (NAND_CMD_PARAM, 0x40).
This is bit annoying.
Question is elbc/ifc old controllers - is it worth the effort?
-Scott