On Tue, Mar 08, 2005 at 05:20:38PM -0600, Rune Torgersen wrote: > > -----Original Message----- > > From: Kumar Gala [mailto:kumar.gala at freescale.com] > > Sent: Tuesday, March 08, 2005 17:14 > > To: Rune Torgersen > > Cc: linuxppc-embedded at ozlabs.org; Matt Porter > > Subject: Re: Lots of memory on 826x > > > > Hmm, I think there is an expectation that virt->phys is a simple > > translation (ie, subtract KERNELBASE) for lowmem. lowmem most parts > > tops out at 768M. So changing VMALLOC_START would break that. > > Yep noticed..... (tried changing it...)
Yeah, sorry, got busy and couldn't reply to say, "don't do that!". :) > > Is there an issue with moving the IMMR virt address up higher? > Not really. Will have to redo a whole lot of address maps for some > external devices, but not too bad... > > I did change the kernel start address, and that seems to work better, > except that things is still broken when CONFIG_HIGHMEM is set > When that option is set, it maps the highmem to 0xFE000000, which is in > the IO area mapped for IMMR and other memory mapped devices. > (0xF0000000-0xFFFFFFFF) > > This can be changed by CONFIG_HIGHMEM_START. Any good ideas on where to > move it to? > > (Maybe change IMMR/IO to 0xF8000000 and up, and set HIGHMEM_START to > 0xF0000000?) Ahh, but early ioremaps (before mm is inited) grow down from PKMAP_BASE, so you will be overlapping the top of lowmem with those allocations. It wants to be above vmalloc space. Set HIGHMEM_START to 0xF6000000, IMMR/IO to 0xF8000000 and you then have vmalloc space between 0xF1000000-0xF5FFFFFF. -Matt
