Hi Eric,
On Wed, Apr 3, 2013 at 8:17 PM, Eric Nelson eric.nelson@boundarydevices.com wrote:
Actually, I'm a little confused by PRSSTAT_DLA checking: currently the loop exits when either IRQSTAT_TC occurs _or_ PRSSTAT_DLA flag comes to 0. Is that correct? I'm not quite familiar with using this flag, but should the loop exit when both IRQSTAT_TC occurs _and_ PRSSTAT_DLA flag comes to 0 (i.e. in current code '&&' should be replaced by '||')? And then the modified loop condition (with DMA check) would be
} while (!(irqstat & IRQSTAT_TC) || !(irqstat & IRQSTAT_DINT) || (esdhc_read32(®s->prsstat) & PRSSTAT_DLA));Can you advise anything on using this flag?
That is weird, and suspect. The reference manual indicates that this bit (Data line active) will go low when the data lines are done with the transaction, but that will happen before the DMA completes, so it seems like a bad way to short-circuit the loop.
Fabio, can you comment on this?
I am not very familiar with the mmc driver. Adding Andy in case he has some insight about it.
The code appears to have been like this since the beginning of main-line support for i.MX so there's no history to go on.
The same goes in Freescale's git tree.
Do you mean FSL U-boot or kernel tree? Is it the same with the mainline kernel driver?
Regards,
Fabio Estevam