Merge tag 'pci-v4.9-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI fixes from Bjorn Helgaas:
 "PCI fixes:

   - Fix Read Completion Boundary setting, which fixes a boot failure on
     IBM x3850 with Mellanox MT27500 ConnectX-3

   - Update some MAINTAINERS entries and email addresses"

* tag 'pci-v4.9-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Set Read Completion Boundary to 128 iff Root Port supports it (_HPX)
  PCI: Export pcie_find_root_port
  PCI: designware-plat: Update author email
  PCI: designware: Change maintainer to Joao Pinto
  MAINTAINERS: Add devicetree binding to PCI i.MX6 entry
  MAINTAINERS: Update Richard Zhu's email address

1 files changed, 27 insertions, 1 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ab002671fa60..104c46d53121 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1439,6 +1439,21 @@ static void program_hpp_type1(struct pci_dev *dev, struct hpp_type1 *hpp)
 		dev_warn(&dev->dev, "PCI-X settings not supported\n");
 }
 
+static bool pcie_root_rcb_set(struct pci_dev *dev)
+{
+	struct pci_dev *rp = pcie_find_root_port(dev);
+	u16 lnkctl;
+
+	if (!rp)
+		return false;
+
+	pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl);
+	if (lnkctl & PCI_EXP_LNKCTL_RCB)
+		return true;
+
+	return false;
+}
+
 static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp)
 {
 	int pos;
@@ -1468,9 +1483,20 @@ static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp)
 			~hpp->pci_exp_devctl_and, hpp->pci_exp_devctl_or);
 
 	/* Initialize Link Control Register */
-	if (pcie_cap_has_lnkctl(dev))
+	if (pcie_cap_has_lnkctl(dev)) {
+
+		/*
+		 * If the Root Port supports Read Completion Boundary of
+		 * 128, set RCB to 128.  Otherwise, clear it.
+		 */
+		hpp->pci_exp_lnkctl_and |= PCI_EXP_LNKCTL_RCB;
+		hpp->pci_exp_lnkctl_or &= ~PCI_EXP_LNKCTL_RCB;
+		if (pcie_root_rcb_set(dev))
+			hpp->pci_exp_lnkctl_or |= PCI_EXP_LNKCTL_RCB;
+
 		pcie_capability_clear_and_set_word(dev, PCI_EXP_LNKCTL,
 			~hpp->pci_exp_lnkctl_and, hpp->pci_exp_lnkctl_or);
+	}
 
 	/* Find Advanced Error Reporting Enhanced Capability */
 	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);