[PATCH] PCI: handle subtractive decode pci-pci bridge better
With the number of PCI bus resources increased to 8, we can handle the subtractive decode PCI-PCI bridge like a normal bridge, taking into account standard PCI-PCI bridge windows (resources 0-2). This helps to avoid problems with peer-to-peer DMA behind such bridges, poor performance for MMIO ranges outside bridge windows and prefetchable vs. non-prefetchable memory issues. To reflect the fact that such bridges do forward all addresses to the secondary bus (transparency), remaining bus resources 3-7 are linked to resources 0-4 of the primary bus. These resources will be used as fallback by resource management code if allocation from standard bridge windows fails for some reason. Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Acked-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -239,9 +239,8 @@ void __devinit pci_read_bridge_bases(struct pci_bus *child)
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if (dev->transparent) {
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printk(KERN_INFO "PCI: Transparent bridge - %s\n", pci_name(dev));
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for(i = 0; i < PCI_BUS_NUM_RESOURCES; i++)
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child->resource[i] = child->parent->resource[i];
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return;
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for(i = 3; i < PCI_BUS_NUM_RESOURCES; i++)
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child->resource[i] = child->parent->resource[i - 3];
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}
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for(i=0; i<3; i++)
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