mapping small parts of a pci card to conserve KVA
gallatin at cs.duke.edu
Tue Feb 15 12:05:27 PST 2005
I maintain drivers for a PCI card which presents itself as having
16MB of address space. Eg:
mx0: <Myrinet PCIXE> mem 0xf9000000-0xf9ffffff irq 20 at device 3.0 on pci1
However, most of that address space does not need to be mapped into
the host. Really, only a little over 2MB needs to be mapped (3 regions
with length 1024 bytes, 256 bytes, and 2MB).
I've tried to re-write things so that I make multiple calls
to bus_alloc_resource() with the (hopefully) appropriate offset and
rid = PCIR_MAPS;
*res = bus_alloc_resource(is->arch.dev, SYS_RES_MEMORY, &rid,
(u_long)(offset + len - 1), len,
At least on 5.3R, I seem to get back the same struct resource * from
each call. rman_get_virtual() returns a different kva for each
mapping, yet they all seem to map to the same physical address.
Eg, I call vtophys() on the results of rman_get_virtual(),
for each segment, and they all map to 0xf9000000.
Is there a way to just map what I need?
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