PCI: Disable MSI for Tegra root ports

Tegra PCIe rootports don't generate MSI interrupts for PME and AER events.
Since PCIe spec (Ref: r4.0 sec 7.7.1.2 and 7.7.2.2) doesn't support using
a mix of INTx and MSI/MSI-X, MSI needs to be disabled to avoid root ports
service drivers registering their respective ISRs with MSI interrupt and
to let only INTx be used for all events.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 208aacf39329..168782c5d23b 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2593,6 +2593,59 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA,
                         nvenet_msi_disable);
 
 /*
+ * PCIe spec r4.0 sec 7.7.1.2 and sec 7.7.2.2 say that if MSI/MSI-X is enabled,
+ * then the device can't use INTx interrupts. Tegra's PCIe root ports don't
+ * generate MSI interrupts for PME and AER events instead only INTx interrupts
+ * are generated. Though Tegra's PCIe root ports can generate MSI interrupts
+ * for other events, since PCIe specificiation doesn't support using a mix of
+ * INTx and MSI/MSI-X, it is required to disable MSI interrupts to avoid port
+ * service drivers registering their respective ISRs for MSIs.
+ */
+static void pci_quirk_nvidia_tegra_disable_rp_msi(struct pci_dev *dev)
+{
+        dev->no_msi = 1;
+}
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x1ad0,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x1ad1,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x1ad2,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf0,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf1,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1c,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1d,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e12,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e13,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0fae,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0faf,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x10e5,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x10e6,
+                              PCI_CLASS_BRIDGE_PCI, 8,
+                              pci_quirk_nvidia_tegra_disable_rp_msi);
+
+/*
  * Some versions of the MCP55 bridge from Nvidia have a legacy IRQ routing
  * config register.  This register controls the routing of legacy
  * interrupts from devices that route through the MCP55.  If this register