MT7621 NAND vs MMC (was: MT7621 NAND OOB misdetect)

[Peter Naulls]

On 2/21/23 11:02, Peter Naulls wrote:
> On 2/15/23 10:17, Chuanhong Guo wrote:
>> Hi!
>>
> 
>>>
>>> What to try next, thanks!
>>
>> It looks like the detected spare size and ECC strength matches between the
>> two drivers, according to the u-boot message and kernel log.
>> Maybe you can try dumping the nand controller setup registers and compare
>> the register values between the two drivers?
>> I don't have any other easier ideas now :(
>>

After some marathon debug, I have an answer to this.

It seems that once the MT7621 MMC driver gets loaded, then the NAND driver's
busy flag becomes stuck on forever. This was loaded as a module, so the
first few flash lookups (such as MAC addresses) would work, and then failure
after.

Why this might be, I don't know, and I don't have the appetite to look into the 
MMC driver - I disabled it in my build.  I'm sure someone has some insight
into this.  I was able to get both the legacy driver and the current kernel
driver working - but the former is rife with problems, so there's no cause
to use it.

Thanks again to Chuanhong.