From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3B802482.80086FC8@mvista.com> Date: Sun, 19 Aug 2001 16:41:38 -0400 From: Dan Malek MIME-Version: 1.0 To: John Francis Cc: linuxppc-embedded@lists.linuxppc.org Subject: Re: Using IDMA1 ( or IDMA2 ) on 860 References: <20010819203359.28639.qmail@web20104.mail.yahoo.com> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: John Francis wrote: > May be I should have been more specific, yes I have > setup the PC15 pin to have correct direction. Well, your description indicated you were expecting the transition of DREQ to generate an interrupt. This isn't the case. Have you connected a logic analyzer to the bus and determined the DMA is working correctly? > /* version2 of GetChipAddress this WORKS why? */ Because you can't directly access physical bus addresses from the kernel. They have to be mapped to some virtual address. The IMMR is mapped to a well known address that can generally be used anywhere in the kernel. Anything else must be mapped, as your example shows. Just make sure you do this _once_, don't keep calling ioremap() over and over or you will exhaust the VM space and get a different address every time. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/