Re: LPC bus in a geode sc1200

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, May 10, 2006 at 09:55:47AM +0200, Carlos Ojea Castro wrote:
> Thank you very much for your reply, Len.
> I will also have an FPGA (I think it will be on port 0x1400 or so). I
> am writing to LPC using 'outb' like this: outb (data, port);
> So I see an I/O write on the LPC bus, that is: 2 bytes for address and
> 1 byte for data (it tooks one microsecond per transfer).
> 
> To speed up things, I wish to transmit more than 1 byte for data in
> each transfer (if possible).
> Accordingly with page 194 of the sc1200 processor data book, it is
> also possible to do a "Bus Master Memory Write" to transmit 1,2 or 4
> bytes.
> Do you know how can I make a "Bus Master Memory Write" to the LPC?

Well I know we don't do that.  We have very little data, just board
status information from various places on the board.  LPC does support
doing DMA, which I believe is done in the same way it was done on ISA at
least as far as the software is concerned.  How to implement DMA for LPC
in the FPGA I have no idea.  The LPC specifications would probably tell
you.  I imagine it involves setting up a DMA buffer in RAM (in the first
16MB probably) and then sending a command to the FPGA telling it to do a
DMA transfer from that memory location using the LPC DMA commands.

Len Sorensen
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux