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    copied!<p>/dev/mem is okay for simple register peeks and pokes, but once you cross into interrupts and DMA territory, you really should write a kernel-mode driver. What you did for your previous memory-management-less OSes simply doesn't graft well to an General Purpose OS like Linux. </p> <p>You've already thought about the DMA buffer allocation issue. Now, think about the "DMA done" interrupt from your device. How are you going to install an Interrupt Service Routine?</p> <p>Besides, /dev/mem is typically locked out for non-root users, so it's not very practical for general use. Sure, you could chmod it, but then you've opened a big security hole in the system.</p> <p>If you are trying to keep the driver code base similar between the OSes, you should consider refactoring it into separate user &amp; kernel mode layers with an IOCTL-like interface in-between. If you write the user-mode portion as a generic library of C code, it should be easy to port between Linux and other OSes. The OS-specific part is the kernel-mode code. (We use this kind of approach for our drivers.)</p> <p>It seems like you have already concluded that it's time to write a kernel-driver, so you're on the right track. The only advice I can add is to read these books cover-to-cover.</p> <p><a href="http://oreilly.com/catalog/9780596005900/" rel="nofollow noreferrer">Linux Device Drivers</a></p> <p><a href="http://oreilly.com/catalog/9780596005658/?CMP=AFC-ak_book&amp;ATT=Understanding+the+Linux+Kernel" rel="nofollow noreferrer">Understanding the Linux Kernel</a></p> <p>(Keep in mind that these books are circa-2005, so the information is a bit dated.)</p>
 

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