Messages in this thread | | | From | Michael Baumann <> | Subject | Problem trying to implement mmap for device on 2.4 | Date | Wed, 6 Oct 2004 09:50:39 -0700 |
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Sorry if this is too much of a noob question - do point me to the right place if you can. System: PPC on VME Attempting driver for 3rd party NVRAM board - it's meant to be used as a data-store/system-state recorder. Will be used by more than one processor in the system - each processor is to use a "chunk" of the RAM as it's scratch space. Or that's the plan.
Based on what I thought I understood from Rubini&Corbet 2nd Edition I created a simple module, that provided a mmap method - after reserving the region via request_mem_region.
mapping was done with a simple remap_page_range()
In userland, the mmap system call is made, with MAP_FIXED and the kernel immediately fails the call with "cannot allocate memory" - never even getting to my implementation of the mmap call. Apparently dying somewhere during "the good deal of work" Rubini talks about. If I don't use MAP_FIXED, things 'work', but I need that fixed location, I'm obviously trying to map the RAM into user space for access.
I'm assuming I'm missing something simple in the setup, somewhere. Any help/pointers/ even insults accepted - I'm in a tough spot here.
-- -- #include <std_disclaimer> Michael Baumann 9518974841 Optivus Technology, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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