PCI: fix ARI code to be compatible with mixed ARI/non-ARI systems
The original ARI support code has a compatibility problem with non-ARI devices. If a device doesn't support ARI, turning on ARI forwarding on its upper level bridge will cause undefined behavior. This fix turns on ARI forwarding only when the subordinate devices support it. Tested-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Yu Zhao <yu.zhao@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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1 changed files with 15 additions and 10 deletions
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@ -1309,27 +1309,32 @@ void pci_enable_ari(struct pci_dev *dev)
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int pos;
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u32 cap;
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u16 ctrl;
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struct pci_dev *bridge;
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if (!dev->is_pcie)
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if (!dev->is_pcie || dev->devfn)
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return;
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if (dev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
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dev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
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return;
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pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
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pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
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if (!pos)
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return;
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pci_read_config_dword(dev, pos + PCI_EXP_DEVCAP2, &cap);
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bridge = dev->bus->self;
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if (!bridge || !bridge->is_pcie)
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return;
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pos = pci_find_capability(bridge, PCI_CAP_ID_EXP);
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if (!pos)
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return;
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pci_read_config_dword(bridge, pos + PCI_EXP_DEVCAP2, &cap);
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if (!(cap & PCI_EXP_DEVCAP2_ARI))
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return;
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pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &ctrl);
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pci_read_config_word(bridge, pos + PCI_EXP_DEVCTL2, &ctrl);
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ctrl |= PCI_EXP_DEVCTL2_ARI;
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pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, ctrl);
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pci_write_config_word(bridge, pos + PCI_EXP_DEVCTL2, ctrl);
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dev->ari_enabled = 1;
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bridge->ari_enabled = 1;
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}
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int
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