[PATCH V2 6/8] PCI: Disable MSI for Tegra234 root ports

Vidya Sagar
2022-04-23T12:50:56Z

Tegra234 PCIe rootports don't generate MSI interrupts for PME and AER
events. Since PCIe spec (Ref: r4.0 sec 6.1.4.3) 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>
---
V2:
* Addressed review comments from Bjorn i.e. changed the PCIe spec reference
to a more relevant section and modified commit message accordingly

drivers/pci/quirks.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 41aeaa235132..6ebb4301eb43 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2709,8 +2709,8 @@ 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
+ * PCIe spec r4.0 sec 6.1.4.3 says 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 specification doesn't support using a mix of
@@ -2760,6 +2760,15 @@ DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x10e5,
DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x10e6,
PCI_CLASS_BRIDGE_PCI, 8,
pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x229a,
+ PCI_CLASS_BRIDGE_PCI, 8,
+ pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x229c,
+ PCI_CLASS_BRIDGE_PCI, 8,
+ pci_quirk_nvidia_tegra_disable_rp_msi);
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_NVIDIA, 0x229e,
+ 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
--
2.17.1