I have a PC device that has a Dual ported memory interface with an
addressing limit of 24 bits (a Deltatau PMAC motion control card).
I need to memory map this into the kernel space for my RTL processes.
My problem is that I can't figure out how to get RTLinux to leave
me a free page so I can map this device within this 24bit (16Mb)
limit. My computer has 32Mb of physical memory.
Effectively, I need RTL to ignore a page in the middle of its physical
memory. The instructions posted for shared memory communications in
RTL do not help because they are based on freeing space by limiting the
total memory used by the OS (and hence the free page is at the top
of the physical memory). In my case, the device's 24bit limit will
force me to kill half of my available memory.
It has been suggested that I try to hide my device somewhere in low
memory where PC bios's have traditionally kept space for currently
out of date devices. This seems a precarious, and certainly not
portable solution. Am I mistaken?
Any help would be appreciated, even if someone has tried this and
can confirm that it is not do-able without losing my memory past 16Mb.
thanks in advance
Rich
*------------------------------------------------------------------*
| INTELLIGENT MACHINES AND MANUFACTURING RESEARCH CENTRE (IMMRC) |
*------------------------------------------------------------------*
| Richard Teltz, | Dept. of Mechanical Engineering,|
| principal research engineer, | McMaster University, |
| tel: (905) 525-9140, x27351 | Hamilton, Ontario, |
| fax: (905) 572-7944 | Canada, |
| email: [EMAIL PROTECTED] | L8S 4L7 |
*------------------------------------------------------------------*
--- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
----
For more information on Real-Time Linux see:
http://www.rtlinux.org/~rtlinux/
