Messages in this thread |  | | Date | Fri, 10 Feb 2012 11:15:56 +0100 | From | Michal Simek <> | Subject | Re: CMA on arm from zero address |
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Russell King - ARM Linux wrote: > On Wed, Feb 08, 2012 at 02:21:26PM +0100, Michal Simek wrote: >> First of all I have found how to do it (by CONFIG_PHYS_OFFSET) so the >> problem is in QEMU. > > So you're basically not telling the kernel about the first 32MB of memory.
It is not a problem.
> >> Currently experimenting how to convince CMA to allocate that memory for >> my purpose. > > Which means it won't be part of the kernels normal memory map, and so > won't be in the page pool. So CMA won't be able to help. > > Instead, just ignore the first 32MB of RAM, and map it like any other > peripheral to gain access to it. You might need to use ioremap_wc() > to avoid treating the memory as a 'device type' in ARMv6+.
I switched from cma to dma_declare_coherent_memory which does exactly what I wanted to do.
Thanks, Michal
-- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/ Microblaze U-BOOT custodian
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