+static int pcie_flr(struct pci_dev *dev, int probe)
+{
+ int i;
+ int pos;
+ u32 cap;
+ u16 status;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (!pos)
+ return -ENOTTY;
+
+ pci_read_config_dword(dev, pos + PCI_EXP_DEVCAP, &cap);
+ if (!(cap & PCI_EXP_DEVCAP_FLR))
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ /* Wait for Transaction Pending bit clean */
+ for (i = 0; i < 4; i++) {
+ if (i)
+ msleep((1 << (i - 1)) * 100);
+
+ pci_read_config_word(dev, pos + PCI_EXP_DEVSTA, &status);
+ if (!(status & PCI_EXP_DEVSTA_TRPND))
+ goto clear;
+ }
+
+ dev_err(&dev->dev, "transaction is not cleared; "
+ "proceeding with reset anyway\n");
+
+clear:
+ pci_write_config_word(dev, pos + PCI_EXP_DEVCTL,
+ PCI_EXP_DEVCTL_BCR_FLR);
+ msleep(100);
+
+ return 0;
+}
+
+static int pci_af_flr(struct pci_dev *dev, int probe)
+{
+ int i;
+ int pos;
+ u8 cap;
+ u8 status;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_AF);
+ if (!pos)
+ return -ENOTTY;
+
+ pci_read_config_byte(dev, pos + PCI_AF_CAP, &cap);
+ if (!(cap & PCI_AF_CAP_TP) || !(cap & PCI_AF_CAP_FLR))
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ /* Wait for Transaction Pending bit clean */
+ for (i = 0; i < 4; i++) {
+ if (i)
+ msleep((1 << (i - 1)) * 100);
+
+ pci_read_config_byte(dev, pos + PCI_AF_STATUS, &status);
+ if (!(status & PCI_AF_STATUS_TP))
+ goto clear;
+ }
+
+ dev_err(&dev->dev, "transaction is not cleared; "
+ "proceeding with reset anyway\n");
+
+clear:
+ pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
+ msleep(100);
+
+ return 0;
+}
+
+static int pci_pm_reset(struct pci_dev *dev, int probe)
+{
+ u16 csr;
+
+ if (!dev->pm_cap)
+ return -ENOTTY;
+
+ pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &csr);
+ if (csr & PCI_PM_CTRL_NO_SOFT_RESET)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ if (dev->current_state != PCI_D0)
+ return -EINVAL;
+
+ csr &= ~PCI_PM_CTRL_STATE_MASK;
+ csr |= PCI_D3hot;
+ pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
+ msleep(pci_pm_d3_delay);
+
+ csr &= ~PCI_PM_CTRL_STATE_MASK;
+ csr |= PCI_D0;
+ pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
+ msleep(pci_pm_d3_delay);
+
+ return 0;
+}
+
+static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
+{
+ u16 ctrl;
+ struct pci_dev *pdev;
+
+ if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self)
+ return -ENOTTY;
+
+ list_for_each_entry(pdev, &dev->bus->devices, bus_list)
+ if (pdev != dev)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, &ctrl);
+ ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
+ pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
+ msleep(100);
+
+ ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
+ pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
+ msleep(100);
+
+ return 0;
+}
+
+static int pci_dev_reset(struct pci_dev *dev, int probe)
+{
+ int rc;
+
+ might_sleep();
+
+ if (!probe) {
+ pci_block_user_cfg_access(dev);
+ /* block PM suspend, driver probe, etc. */
+ down(&dev->dev.sem);
+ }
+
+ rc = pcie_flr(dev, probe);
+ if (rc != -ENOTTY)
+ goto done;
+
+ rc = pci_af_flr(dev, probe);
+ if (rc != -ENOTTY)
+ goto done;
+
+ rc = pci_pm_reset(dev, probe);
+ if (rc != -ENOTTY)
+ goto done;
+
+ rc = pci_parent_bus_reset(dev, probe);
+done:
+ if (!probe) {
+ up(&dev->dev.sem);
+ pci_unblock_user_cfg_access(dev);
+ }
+
+ return rc;
+}
+
+/**
+ * __pci_reset_function - reset a PCI device function
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * The device function is presumed to be unused when this function is called.
+ * Resetting the device will make the contents of PCI configuration space
+ * random, so any caller of this must be prepared to reinitialise the
+ * device including MSI, bus mastering, BARs, decoding IO and memory spaces,
+ * etc.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int __pci_reset_function(struct pci_dev *dev)
+{
+ return pci_dev_reset(dev, 0);
+}
+EXPORT_SYMBOL_GPL(__pci_reset_function);
+
+/**
+ * pci_reset_function - quiesce and reset a PCI device function
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * This function does not just reset the PCI portion of a device, but
+ * clears all the state associated with the device. This function differs
+ * from __pci_reset_function in that it saves and restores device state
+ * over the reset.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int pci_reset_function(struct pci_dev *dev)
+{
+ int rc;
+
+ rc = pci_dev_reset(dev, 1);
+ if (rc)
+ return rc;
+
+ pci_save_state(dev);
+
+ /*
+ * both INTx and MSI are disabled after the Interrupt Disable bit
+ * is set and the Bus Master bit is cleared.
+ */
+ pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
+
+ rc = pci_dev_reset(dev, 0);
+
+ pci_restore_state(dev);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pci_reset_function);
+