PCI: Handle FLR failure and allow other reset types

pci_flr_wait() and pci_af_flr() functions assume graceful return even
though the device is inaccessible under error conditions.

Return -ENOTTY in error cases so that __pci_reset_function_locked() can
try other reset types if AF_FLR/FLR reset fails.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 660c848..7aa11b1 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4017,7 +4017,7 @@ int pci_wait_for_pending_transaction(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_wait_for_pending_transaction);
 
-static void pci_flr_wait(struct pci_dev *dev)
+static int pci_flr_wait(struct pci_dev *dev)
 {
        int delay = 1, timeout = 60000;
        u32 id;
@@ -4046,7 +4046,7 @@ static void pci_flr_wait(struct pci_dev *dev)
                if (delay > timeout) {
                        pci_warn(dev, "not ready %dms after FLR; giving up\n",
                                 100 + delay - 1);
-                       return;
+                       return -ENOTTY;
                }
 
                if (delay > 1000)
@@ -4060,6 +4060,8 @@ static void pci_flr_wait(struct pci_dev *dev)
 
        if (delay > 1000)
                pci_info(dev, "ready %dms after FLR\n", 100 + delay - 1);
+
+       return 0;
 }
 
 /**
@@ -4088,13 +4090,13 @@ static bool pcie_has_flr(struct pci_dev *dev)
  * device supports FLR before calling this function, e.g. by using the
  * pcie_has_flr() helper.
  */
-void pcie_flr(struct pci_dev *dev)
+int pcie_flr(struct pci_dev *dev)
 {
        if (!pci_wait_for_pending_transaction(dev))
                pci_err(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 pci_flr_wait(dev);
 }
 EXPORT_SYMBOL_GPL(pcie_flr);
 
@@ -4127,8 +4129,7 @@ static int pci_af_flr(struct pci_dev *dev, int probe)
                pci_err(dev, "timed out waiting for pending transaction; performing AF function level reset anyway\n");
 
        pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
-       pci_flr_wait(dev);
-       return 0;
+       return pci_flr_wait(dev);
 }
 
 /**
@@ -4379,8 +4380,9 @@ int __pci_reset_function_locked(struct pci_dev *dev)
        if (rc != -ENOTTY)
                return rc;
        if (pcie_has_flr(dev)) {
-               pcie_flr(dev);
-               return 0;
+               rc = pcie_flr(dev);
+               if (rc != -ENOTTY)
+                       return rc;
        }
        rc = pci_af_flr(dev, 0);
        if (rc != -ENOTTY)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 024a1be..af75d9d 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1082,7 +1082,7 @@ 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 pcie_flr(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);
 int pci_reset_function_locked(struct pci_dev *dev);