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11fbb00c67
Currently our code to set up the data structures for a PCI host bridge and create the mapping for its I/O window assumes that the window starts at I/O port 0 on the PCI side. If this is not true, we can end up with I/O port numbers in the resources for PCI devices which will cause an oops if a driver tries to access them via inb/outb etc., because there is no mapping for the corresponding addresses. Normally the I/O window starts at 0, but there are some situations on partitioned machines with a hypervisor where the window may not start at 0. This fixes the problem by allocating space for the range from 0 to the end of the I/O window. That is, hose->io_base_virt contains the virtual address for I/O port 0 on the PCI bus, and thus the assumption that hose->io_base_virt - pci_io_base is the offset between the "global" I/O port numbers (those in the PCI device resources) and the I/O port numbers on the PCI bus is maintained. For PCI host bridges that are present at boot, we only map the portion of that range that correspond to the bridge's I/O window. For bridges added after boot we ioremap the range from 0 to the end of the I/O window, for now; in fact hot-added bridges should be using reserve_phb_iospace() and __ioremap_explicit (so they get sensible global port numbers), but we don't have the infrastructure yet to do that (basically a free_phb_iospace() routine plus appropriate locking). Interestingly, this makes the two arms of the if statement in get_bus_io_range do almost exactly the same thing; that function could now be simplified in a further patch. Signed-off-by: Paul Mackerras <paulus@samba.org> |
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