[PATCH V6 07/16] PCI: Disable MSI for Tegra234 root ports

From: Vidya Sagar <vidyas@nvidia.com>
To: <bhelgaas@google.com>, <lpieralisi@kernel.org>,
	<robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
	<thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
	<jingoohan1@gmail.com>, <gustavo.pimentel@synopsys.com>
Cc: <kw@linux.com>, <kishon@ti.com>, <linux-pci@vger.kernel.org>,
	<devicetree@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <kthota@nvidia.com>,
	<mmaddireddy@nvidia.com>, <vidyas@nvidia.com>,
	<sagar.tv@gmail.com>
Subject: [PATCH V6 07/16] PCI: Disable MSI for Tegra234 root ports
Date: Thu, 21 Jul 2022 19:50:43 +0530	[thread overview]
Message-ID: <20220721142052.25971-8-vidyas@nvidia.com> (raw)
In-Reply-To: <20220721142052.25971-1-vidyas@nvidia.com>

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>
---
V6:
* None

V5:
* None

V4:
* None

V3:
* None

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 2e68f50bc7ae..5b532449ac4f 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

