UDMA for Compact Flash over PC Card?
s_j_newbury at yahoo.co.uk
Fri Apr 6 12:56:42 EDT 2007
--- Piotras <piotras at gmail.com> wrote:
> Am I correct to assume that the PXA DMA engine is using
> DMA signaling on the PCMCIA bus? Do you use WIN_READDMA*/
> WIN_WRITEDMA* commands to access the CF card?
> Could you provide the details of your CF card?
The former, the PXA DMA engine is very flexible. The card is initialised
normally and then subsequent IO requests are sent and recieved in mutli-byte
bursts over the bus. The CF card just operates normally. Similar performance
can be achieved by using multi-sector IDE transers if your CF card supports it
although with more CPU load.
I've attached a patch that is also integrated with Thomas' MMIO patch although
as I said I couldn't get it going unfortunately.
By the way I didn't originally write the PXA PIODMA patch I just cleaned it up
and fixed a few bugs, and I'm not sure who did. I got it from Richard Purdie's
archive in the tosort directory, it was part of a larger somewhat broken patch
tof random local changes that somebody had sent to Richard. He may remember
who it was...
[Yahoo mail isn't letting me send with attachments I'll try sending it again
later if you're interested in taking a look]
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