I am developing a module for a PCI device. In order to get large enough
DMA buffers, I am reserving the upper N megabytes of RAM (via the
kernel parameter "mem=") and using ioremap to get at the buffer from
within the kernel. This is all fine and dandy, I can do DMA transfers
to/from my device just fine. My question is, is it possible to map
this DMA buffer into user space?
For smaller, kmalloc'd DMA buffers I can map into user space easily by
manually returning the correct page with VM no_page operation. It
doesn't look like I can do this using reserved buffers because the
page structures don't appear to be valid. (Reserved buffer page indices
>= max_mapnr).
Thanks for your time,
Mike DeKoker
Signatec, Inc.
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