MingLiu wrote:
> Dear Dave,
>
>> If you are using memory that is not under the kernel's memory management>
>> you will need to use something other than remap_pfn_range.>
>>
> Happenly and unfortunately we are using the memory space out of the control
> from the kernel. We have 2GB memory on the board and only 64(or 32) MB is
> reserved for the kernel. The rest large space is for the data buffering or
> LUT use. In my question, the LUT memory is located in the rest part rather
> than the kernel memory area.
>
> Any more suggestion on how to mmap this LUT area? Any idea will be valuable
> for a beginner like me. Thanks in advance.
>
If this is physical memory that is not controlled by the kernel you
could also use the /dev/mem device. You could do something like:
memFd = open("/dev/mem", O_RDWR);
memBuf = mmap(0, <Memory size>, PROT_READ | PROT_WRITE, MAP_SHARED,
memFd, <Physical address of memory);
which maps the physical memory into user space, without the need for a
special device driver or mmap implementation.
Kind regards,
Johan Borkhuis
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