On Tue, Nov 09, 2004 at 07:27:09PM +0200, Felix Radensky wrote: > Hi, folks > > I have a 405GPr based board with 512M of RAM. > My kernel is 2.4.17 from Monta Vista Linux 2.1. > I'm trying to reserve 64M on boot using mem=448M > and map it later by > > ioremap(__pa(high_memory), 64*(1<<20)); > > This worked fine when system had 256M of RAM, > but now ioremap fails. If I understand the kernel > code correctly, by adding more RAM I've reduced > the vmalloc/ioremap space. I can also see that this > space is reduced dramatically on boot by mappings > done in arch/ppc/kernel/ppc4xx_setup.c:m4xx_map_io() > > Is there any way to fix problem ? Is it necessary to have > a 1:1 virtual to physical mappings as its done in m4xx_map_io() > or maybe higher virtual addresses can be used, thus > allowing to save some precious ioremap space.
This is exactly why the PPC44x ports don't use io_block_map()... it can interfere with dynamic mappings. It is not necessary to have 1:1 virtual to physical mappings nor is it necessary to have m4xx_map_io() at all. One can use ioremap() to map any space and let the kernel place things intelligently. In order to use serial console you'll have to use early_serial_setup() after you've ioremapped the UART...once you've removed the io_block_map() call. Look at other ports to see how this is done. Someday I might get down my list to cleaning up 40x stuff in 2.6. -Matt
