Clean up the pci host generic driver

[andrew]

Summary

• Support Prefetchable Memory
• Use the correct rman when allocating memory and ioports
• Translate PCI addresses in bus_alloc_resource to allow physical addresses that are different than pci addresses.

[crowston_protonmail.com]

I am not an expert by any means but these changes look good to me.

[crowston_protonmail.com]

sys/dev/pci/pci_host_generic.c

364

Actually, another niggle I find while trying to adopt this patch today.

In pci_pci.c, when allocating the bridge window, we try to allocate start=0x0, end=0xfffff.

That's always going to fail if the pci memory range is [0xf8000000,0xfbffffff] (as in the case of the rpi controller). Somehow we need to adjust that bridge window region into a pci address range.

Also, it seems that we don't actually check if sc->ranges[i] is large enough to hold the requested [start, end] resource.

[andrew]

sys/dev/pci/pci_host_generic.c

364

Can you get the raw values of the PCIR_MEMBASE_1 and PCIR_MEMLIMIT_1 registers.