PCI: Export pcie_flr()

Currently we opencode the FLR sequence in lots of place; export a core
helper instead.  We split out the probing for FLR support as all the
non-core callers already know their hardware.

Note that in the new pci_has_flr() function the quirk check has been moved
before the capability check as there is no point in reading the capability
in this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index bef14777bb305861836a8b5e0701e84650770bb5..957a11a6a840ad0eb538eb3d9d26b97b7a1af953 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3773,27 +3773,41 @@ static void pci_flr_wait(struct pci_dev *dev)
                         (i - 1) * 100);
 }
 
-static int pcie_flr(struct pci_dev *dev, int probe)
+/**
+ * pcie_has_flr - check if a device supports function level resets
+ * @dev:       device to check
+ *
+ * Returns true if the device advertises support for PCIe function level
+ * resets.
+ */
+static bool pcie_has_flr(struct pci_dev *dev)
 {
        u32 cap;
 
-       pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
-       if (!(cap & PCI_EXP_DEVCAP_FLR))
-               return -ENOTTY;
-
        if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
-               return -ENOTTY;
+               return false;
 
-       if (probe)
-               return 0;
+       pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
+       return cap & PCI_EXP_DEVCAP_FLR;
+}
 
+/**
+ * pcie_flr - initiate a PCIe function level reset
+ * @dev:       device to reset
+ *
+ * Initiate a function level reset on @dev.  The caller should ensure the
+ * device supports FLR before calling this function, e.g. by using the
+ * pcie_has_flr() helper.
+ */
+void pcie_flr(struct pci_dev *dev)
+{
        if (!pci_wait_for_pending_transaction(dev))
                dev_err(&dev->dev, "timed out waiting for pending transaction; performing function level reset anyway\n");
 
        pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
        pci_flr_wait(dev);
-       return 0;
 }
+EXPORT_SYMBOL_GPL(pcie_flr);
 
 static int pci_af_flr(struct pci_dev *dev, int probe)
 {
@@ -3977,9 +3991,12 @@ static int __pci_dev_reset(struct pci_dev *dev, int probe)
        if (rc != -ENOTTY)
                goto done;
 
-       rc = pcie_flr(dev, probe);
-       if (rc != -ENOTTY)
+       if (pcie_has_flr(dev)) {
+               if (!probe)
+                       pcie_flr(dev);
+               rc = 0;
                goto done;
+       }
 
        rc = pci_af_flr(dev, probe);
        if (rc != -ENOTTY)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 22cad2c66d59da2456b73d38031435fb2317e43a..a9ff99c916014a0df5da6f02191fe16379850ed7 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1054,6 +1054,7 @@ int pcie_get_mps(struct pci_dev *dev);
 int pcie_set_mps(struct pci_dev *dev, int mps);
 int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed,
                          enum pcie_link_width *width);
+void pcie_flr(struct pci_dev *dev);
 int __pci_reset_function(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);