I can tell you now the mapping between physical and virtual not as important as you make out. I have Linux running on a board I described to you and there is no RAM mapped at 0xc0000000. I suggest you read your chip manual more carefully. In my 860 PowerQUICC Users manual chapters 13,14 and 16.
I also remember reading somewhere at IO should be mapped above 0x80000000 but I have not been able to find where I read it in the last two years so that could be another urban myth that need the cold light of day on it. Regards, Rod Boyce -----Original Message----- From: jgdon [mailto:[EMAIL PROTECTED] Sent: Wednesday, 22 January 2003 2:56 p.m. To: Rod Boyce Cc: 'James Don'; linuxppc-embedded at lists.linuxppc.org Subject: RE: My Memory map ... how do i pick the virtual address (Aside fr om i mmr and sdram) Hi, I think the the mapping of virtual to physical address may be important ... i believe ram should be at 0xc0000000 for a number of reasons ... there is lots of posts regarding this ... What I am worried about is "rules of thumb" for example i have an ASIC on cs4 ... at BR4 0x08000000 ... I would like to map it to 0x08000000 in the MMU ... i would just like to be sure this is an ok address to check ... or if there is some generally accepts address range for "non memeory" device stuff ... I assume 'no' ... but i also assume the immr address and sdram address didn't matter at one time ... Jim On Wed, 22 Jan 2003, Rod Boyce wrote: > > I think you have the wrong end of the stick. Our boards have 32MB of RAM > located at 0. We have placed IMMR at 0xfa200000. The address of 0xc0000000 > is a virtual address it does not have to have any relation to a physical > address this is done by the memory manager. The only constant is that the > boot flash MUST be connected to chip select 0. Everything else is mostly > software configurable. > > Regards, > Rod Boyce. > > -----Original Message----- > From: James Don [mailto:JDon at spacebridge.com] > Sent: Wednesday, 22 January 2003 12:58 p.m. > To: linuxppc-embedded at lists.linuxppc.org > Subject: My Memory map ... how do i pick the virtual address (Aside > from i mmr and sdram) > > > Hi, > > I am just looking at adding my other mem mapped devices to Linux for my > custom MPC860 board ... > > I know RAM has to be at 0xc0000000 and immr at 0xff000000 ... is there any > rule of thumb for anything else? > > Jim > > > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
