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Linux - Embedded & Single-board computer This forum is for the discussion of Linux on both embedded devices and single-board computers (such as the Raspberry Pi, BeagleBoard and PandaBoard). Discussions involving Arduino, plug computers and other micro-controller like devices are also welcome.

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Old 09-27-2010, 03:57 PM   #1
timboar
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Declaring a specific RAM section as used


I have an embedded system, where the main processor is running linux. A sub processor is running in parallel, and assumes it controls a specific section of RAM. The kernel must still be able to read/write to this section of RAM, but must never allocate it, or use it for anything else.

I'm wondering if there is a simple way to do this.
 
Old 09-28-2010, 08:32 AM   #2
neonsignal
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My understanding (and I haven't tried this, so this is just an outline) is:

1. that you use the 'memmap=nn$ss' parameter to the kernel at boot (nn is size, ss is offset, with optional K/M/G suffixes) to reserve the area of memory that you are using for the dual port to the secondary processor

2. you then create a driver to 'remap_pfn_range' this physical area into user space so that you can access it
 
Old 09-29-2010, 10:45 AM   #3
timboar
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Thanks, I'll give that a try.

Last edited by timboar; 09-29-2010 at 11:07 AM.
 
  


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