Merge pull request #251 from krishnachaitanya-linux/usbhux-aspm-fix

WORKAROUND: pci: quirks: Disable L1.1 and L1.2 for USB hub attach

Author: sgaud-quic

drivers/pci/quirks.c

@@ -2533,6 +2533,49 @@ static void quirk_disable_aspm_l1ss(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_QCOM, 0x1103, quirk_disable_aspm_l1ss);
 
+static int disable_aspm_l1ss(struct pci_dev *dev, void *data)
+{
+        pci_disable_link_state(dev, PCIE_LINK_STATE_L1_1 | PCIE_LINK_STATE_L1_2);
+        return 0;
+}
+
+static void quirk_disable_l1ss(struct pci_dev *dev)
+{
+        struct pci_dev *root_port;
+        struct pci_dev *upstream;
+
+        pci_info(dev, "Disabling ASPM L1ss\n");
+
+        upstream = dev->bus->self;
+        while (upstream) {
+                if (pci_pcie_type(upstream) == PCI_EXP_TYPE_ROOT_PORT) {
+                        root_port = upstream;
+                        break;
+                }
+
+                /* Move further up the hierarchy */
+                upstream = upstream->bus->self;
+        }
+
+        if (!root_port) {
+                pci_err(dev, "Could not find root port, cannot disable L1ss\n");
+                return;
+        }
+
+        pci_info(dev, "Found root-port with VID: %04x PID: %04x, disabling l1ss\n",
+                root_port->vendor, root_port->device);
+
+        pci_walk_bus(root_port->subordinate, disable_aspm_l1ss, NULL);
+}
+
+/*
+ * When ASPM L1.1/L1.2 is enabled on the upstream link of QPS615 switch,
+ * and Renesas uPD720201 USB 3.0 Controller is connected to one of the switch
+ * downstream ports, then uPD dies down and stops responding to host commands;
+ * disabling l1 sub-states in uPD attach case helps mitigate this issue.
+ */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_RENESAS, 0x0014, quirk_disable_l1ss);
+
 /*
  * Some Pericom PCIe-to-PCI bridges in reverse mode need the PCIe Retrain
  * Link bit cleared after starting the link retrain process to allow this