accessing paged physical memory

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#2998

From: E312 Genshirt
Date: Tue, 17 Nov 1992 10:13

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We want to run a device-driver written for OS2-V1.3 under OS2-V2.0. The
driver uses DMA-transfer. V1.3 does not page physical memory. How does V2.0
make the adress-convertions for a memory block.

   virtual adress  --> linear adress --> physical adress

The DMA-controller needs physical contiguous memory. The OS2-system will
map the virtual data-buffer adress used in a DosRead() or DosWrite() to
a physical (or linear?) adress for the driver. Also the system will lock
the memory. Do we have to bother that the locked physical memory might not
be contiguous? Could IO-memory be parted in separeted 4k-pages?

Are there additional device-helper-functions? What can be done to get and
to verify contiguous memory?

Any information on OS2-2.x adress-mapping and paging would be highly
appreciated.

Thomas

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Path: arc1-ca.pugleaf.net!sparky!uunet!usc!rpi!uwm.edu!caen!sol.ctr.columbia.edu!ira.uka.de!math.fu-berlin.de!news.netmbx.de!Germany.EU.net!aegsg!genshirt
From: genshirt@aegsg.UUCP (E312 Genshirt)
Newsgroups: comp.os.os2.programmer
Subject: accessing paged physical memory
Keywords: device driver, memory mapping, paging
Message-ID: <486@aegsg.UUCP>
Date: 17 Nov 92 10:13:54 GMT
Organization: AEG-Seligenstadt, W. Germany
Lines: 19