how to allocate 9MB of memory in kernel ?
misbah_khan at engineer.com
Wed Jul 23 17:30:36 EST 2008
If you SDRAM is you main memory, you need vmalloc and remap_vmalloc_range.
If the SDRAM is not your main memory but some I/O attached buffer, you need
ioremap/of_iomap and remap_pfn_range.
My SDRAM is the main memory of which 9MB i have to allocate in the driver.
If i allocate 9BM using vmalloc and remap to user space how should it
address to the 9MB
SDRAM contigues address which i need to map for user access ?
Arnd Bergmann wrote:
> On Tuesday 22 July 2008, Misbah khan wrote:
>> First of all let me thank you for your valuable suggessions ...
>> 1. I wanted to allocate 9MB in kernel and wanted that memory to be mapped
>> the physically continews SDRAM memory. but till now i could not found a
>> to do so ???
>> 2. So i thought to use ioremap to map SDRAM and make it accessible to
>> using mmap technique but there is only one doubt and that is will it be
>> secure and stable and whether it is a right way of doing ???
> As I have told you a few times now, you *either* allocate the memory *or*
> ioremap it, NOT BOTH!!!
> If you SDRAM is you main memory, you need vmalloc and remap_vmalloc_range.
> If the SDRAM is not your main memory but some I/O attached buffer, you
> ioremap/of_iomap and remap_pfn_range.
> Arnd <><
> Linuxppc-embedded mailing list
> Linuxppc-embedded at ozlabs.org
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