From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <392D47A4.DEFFD152@motorola.com> Date: Thu, 25 May 2000 10:32:52 -0500 From: "Richard Hendricks" MIME-Version: 1.0 To: Linux PPC Mailing List Subject: Re: IDMA: Setting Up Parameter RAM. References: <20000525060239.3F99C3C989@elph.research.canon.com.au> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Have you tried looking at the IDMA section in the MPC823 User's Manual? An electronic copy of that portion is at http://www.mot.com/SPS/ADC/pps/download/823/823RM/16-cpm2.pdf Also, you could try the IDMA demo under Engineer's Toolbox at http://www.mot.com/mpc823 It sounds to me like you're not executing the INIT_IDMA command after setting up. Greg Johnson wrote: > > Hi all, > > I am having a little problem with IDMA parameter RAM on the 855T/860. > The problem is that when I set up the parameter RAM's DMA Channel > Mode Register, and the IDMA BD Base Address pointer, the CPM does not > appear to recognise these new values. I am quite confident that I > am setting up the ports etc for our board correctly. I shall elaborate. > > When I power on our board, boot, load our driver for the hardware, > setup the IDMA/Parameter RAM/Buffer Descriptors and attempt to start > an IDMA transfer, nothing happens. (reloading driver and retries > do not work) > > When I then hit the reset button (no power cycle) and go through the > same ritual, IDMA works fine. > > The reason being is that values for the IDMA Parameter RAM DMA Channel > mode register (DCMR) and IDMA BD Base Address pointer (IBASE) that > were written in the first attempt on power-on are preserved in > DPRAM over the reboot. Why would these value apparently be written > in the first attempt, but appear not to be recognised by the CPM??? > > In addition, if I power on, and use the boot loader to program the > IDMA Parameter RAM DCMR and IBASE elements, then boot Linux, load > the driver and attempt a DMA operation, It all works fine. The > reason I don't want to be content with setting this information up > in the boot loader is that we want to be able to eventually allocate > and release buffer descriptors. > > I suspect that I am not setting up something correctly that affects > the way that the Communications Processor responds to changes in the > Parameter RAM. > > Can anyoue offer any clues/hints/guesses??? > > Thanks in advance. > > Greg. > > -- > +------------------------------------------------------+ > | Do you want to know more? www.geocities.com/worfsom/ | > | ..ooOO Greg Johnson OOoo.. | > | HW/SW Engineer gjohnson@research.canon.com.au | > | Canon Information Systems Research Australia (CISRA) | > | 1 Thomas Holt Dr., North Ryde, NSW, 2113, Australia | > | "I FLEXed my BISON and it went YACC!" - me. | > +------------------------------------------------------+ > -- MPC823 Applications Engineering Development Get help from other MPC823 customers on the comp.sys.powerpc.tech newsgroup! ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/