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PCI: support Secondary Bus Reset
PCI-to-PCI Bridge 1.2 specifies that the Secondary Bus Reset bit can force the assertion of RST# on the secondary interface, which can be used to reset all devices including subordinates under this bus. This can be used to reset a function if this function is the only device under this bus. Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Yu Zhao <yu.zhao@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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@ -2162,6 +2162,33 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
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return 0;
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}
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static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
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{
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u16 ctrl;
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struct pci_dev *pdev;
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if (dev->subordinate)
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return -ENOTTY;
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list_for_each_entry(pdev, &dev->bus->devices, bus_list)
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if (pdev != dev)
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return -ENOTTY;
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if (probe)
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return 0;
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pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, &ctrl);
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ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
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pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
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msleep(100);
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ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
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pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
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msleep(100);
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return 0;
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}
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static int pci_dev_reset(struct pci_dev *dev, int probe)
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{
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int rc;
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@ -2183,6 +2210,10 @@ static int pci_dev_reset(struct pci_dev *dev, int probe)
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goto done;
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rc = pci_pm_reset(dev, probe);
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if (rc != -ENOTTY)
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goto done;
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rc = pci_parent_bus_reset(dev, probe);
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done:
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if (!probe) {
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up(&dev->dev.sem);
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