[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
Re: PXA2x0 DMAC alignment check
> My pxa255 machine happens error when start write DMA to MMC.
> Error message is
> pxamci0: couldn't start dma xfer. (error=14)
> This reason is fault alignment on pxadmac. It checks alignment
> to 8bytes boundary always. But PXA255/270 datasheets describing
> 4byte allowed, if internal peripherals.
Looks okay, but have a few comments:
- it's better to put some comments about DMA alignment constraints
as you mentioned above
- inconsistent use of nsegs vs xd->xd_nsegs
- I wonder if we should bother to check periph_end; I guess DMA xfer
across peripherals appearntly invalid, if so periph_end check could
be KASSERT() or inside #ifdef DIAGNOSTIC?
> However pxa2x0 DMAC has more constraints for alignment.
> We need more check?
No idea, but different problems should be handled separately, I think.
("best or nothing" strategy is always bad ;-p)
It's still worth to put XXX comments about such unhandled constraints,
Main Index |
Thread Index |