OMAP query about GPMC FIFOTHRESHOLDSTATUS bit

Woodruff, Richard r-woodruff2 at ti.com
Mon Dec 13 13:32:11 UTC 2010


> From: Peter Maydell [mailto:peter.maydell at linaro.org]
> Sent: Sunday, December 12, 2010 3:02 PM

> In case you're collecting things to clean up for the next issue,
> here's
> another :-)  The Rev M OMAP35x TRM says on page 1139:
>
> "In both prefetch and write-posting modes, the engine respectivelly
> uses byte or Word16 access requests for an 8- or 16-bit wide NAND
> device attached to the linked chip-select. The FIFOTHRESHOLD and
> TRANSFERCOUNT fields must be programmed accordingly as a
> number of bytes or a number of Word16."

Yes that appears wrong in all TRM and underlying specs.

> However the register descriptions just say that FIFOTHRESHOLD
> and TRANSFERCOUNT are byte counts.
>
> In this case I'm going to trust the register descriptions because
> that's how Linux programs them (and it doesn't boot if you model
> them as Word16 counts...)

A search on TRANSFERCOUNT does show 3 spots where it explicitly says bytes.

I'll forward to TRM owners.  I know the right folks for 34xx,36xx,44xx, I think that should propagate to 35xx and other variants.

Regards,
Richard W.


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