On Wednesday 17 September 2008 09:39:19 pm KAHO Toshikazu wrote:
> Hello,
>
> > Well, bus_alloc_resource() will allocate resources for the BAR and update
the
> > BAR for you, the question is if you need to hardcode the range to
> > bus_alloc_resource() or not.
>
> It is necessary for a pci device to set the BAR, if the device
> would use memory or I/O space, isn't it? I don't know why the
> BAR is not settable, but I think it is disabled by some reasons
> and the BAR may be settable if the device could be enabled.
The BIOS simply may have not set a range for the BAR and left it at 0. In
that case, the BAR can probably be enabled by just programming it to a valid
range. You can try doing that via
rid = PCIR_BAR(x);
/* Or SYS_RES_IOPORT */
res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid);
This will allocate fresh resources for the BAR if possible. However, if the
BAR is "special" and only works with a certain hard-coded address, then you
can try specifying the start/end/count using bus_alloc_resource() rather than
bus_alloc_resource_any().
--
John Baldwin
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