[PATCH v3 3/3] PCI: Avoid slot reset for Cavium cn8xxx root ports

[Jan Glauber <jglauber@cavium.com>]

Root ports of cn8xxx do not function after a slot reset when used with
some e1000e and LSI HBA devices. Add a quirk to prevent slot reset on
these root ports.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
---
 drivers/pci/quirks.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 85191b8..6679971 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -845,6 +845,22 @@ static void quirk_cavium_sriov_rnm_link(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CAVIUM, 0xa018, quirk_cavium_sriov_rnm_link);
 #endif
 
+/*
+ * Root port on some Cavium CN8xxx chips do not successfully complete
+ * a bus reset when used with certain types of child devices. Config
+ * space access to the child may quit responding. Flag all devices under
+ * the secondary bus as non-resettable.
+ */
+static void quirk_CN8xxx_secondary_bus(struct pci_dev *dev)
+{
+	struct pci_dev *pdev;
+
+	dev_warn(&dev->dev, "Cavium CN8xxx quirk detected; reset for devices on secondary bus disabled\n");
+	list_for_each_entry(pdev, &dev->subordinate->devices, bus_list)
+		pdev->dev_flags |= PCI_DEV_FLAGS_NO_BUS_RESET;
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CAVIUM, 0xa100, quirk_CN8xxx_secondary_bus);
+
 /*
  * Some settings of MMRBC can lead to data corruption so block changes.
  * See AMD 8131 HyperTransport PCI-X Tunnel Revision Guide
-- 
2.9.0.rc0.21.g7777322