PCI: Set Read Completion Boundary to 128 iff Root Port supports it (_HPX)

[firefly-linux-kernel-4.4.55.git] / drivers / pci / probe.c

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 9757cf9037a2b0e9e917ac454b0f107e0e3b3b04..b5843c255263df2d04c12f36e819b60bab47369f 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1415,6 +1415,21 @@ 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;
@@ -1444,9 +1459,20 @@ 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);