> Just write a small kernel module that does a mmio mapping the physical
> memory on the card into the virtual memory of the userspace
> application.
> You do need a kernel module driver loaded to do this task though.
> There would simply be a few IOCTL calls so that userspace can request
> a pointer to the virtual memory location, and also to release the
> memory.
>
> Take a look at some of the PCI passthru code in qemu. qemu is a
> userspace app and can be used to passthru mmio from the hardware into
> the qemu vm.
>From a while back...
Having managed to get the PCI analyser back up and running, it appears that using devmem2 on the base address as reported in the /sys/bus/pci/devices/.../resource file, it does indeed result in reads across the PCI bus at the expected address (and return the data that I expect to see there); however, writes are not currently showing any accesses at all. My guess at the moment is the mapping that is going on - may be caching, I need to investigate further - I'll have a look at what Qemu does too.
Note that this is not using a custom kernel module to handle the mapping, just what is provided by sysfs.
Hope this is of some use to someone!
Peter
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