PCI: Add pci_wait_for_pending_transaction()

New routine to avoid duplication of code to wait for pending PCI
transactions to complete.

Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Vipul Pandya <vipul@chelsio.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

@@ -3098,19 +3098,17 @@ int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask)
 }
 EXPORT_SYMBOL(pci_set_dma_seg_boundary);
 
-static int pcie_flr(struct pci_dev *dev, int probe)
+/**
+ * pci_wait_for_pending_transaction - waits for pending transaction
+ * @dev: the PCI device to operate on
+ *
+ * Return 0 if transaction is pending 1 otherwise.
+ */
+int pci_wait_for_pending_transaction(struct pci_dev *dev)
 {
 	int i;
-	u32 cap;
 	u16 status;
 
-	pcie_capability_read_dword(dev, 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)
@@ -3118,13 +3116,27 @@ static int pcie_flr(struct pci_dev *dev, int probe)
 
 		pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &status);
 		if (!(status & PCI_EXP_DEVSTA_TRPND))
-			goto clear;
+			return 1;
 	}
 
-	dev_err(&dev->dev, "transaction is not cleared; "
-			"proceeding with reset anyway\n");
+	return 0;
+}
+EXPORT_SYMBOL(pci_wait_for_pending_transaction);
+
+static int pcie_flr(struct pci_dev *dev, int probe)
+{
+	u32 cap;
+
+	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
+	if (!(cap & PCI_EXP_DEVCAP_FLR))
+		return -ENOTTY;
+
+	if (probe)
+		return 0;
+
+	if (!pci_wait_for_pending_transaction(dev))
+		dev_err(&dev->dev, "transaction is not cleared; proceeding with reset anyway\n");
 
-clear:
 	pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
 
 	msleep(100);

include/linux/pci.h

@@ -914,6 +914,7 @@ bool pci_check_and_unmask_intx(struct pci_dev *dev);
 void pci_msi_off(struct pci_dev *dev);
 int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size);
 int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask);
+int pci_wait_for_pending_transaction(struct pci_dev *dev);
 int pcix_get_max_mmrbc(struct pci_dev *dev);
 int pcix_get_mmrbc(struct pci_dev *dev);
 int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc);