From 68a286dda22b9f4ade8d4fab18b55a4bc7ee4b33 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Fri, 1 May 2020 12:39:21 +0100
Subject: [PATCH] PCI: dwc: Fix inner MSI IRQ domain registration

commit 0414b93e78d87ecc24ae1a7e61fe97deb29fa2f4 upstream.

On a system that uses the internal DWC MSI widget, I get this
warning from debugfs when CONFIG_GENERIC_IRQ_DEBUGFS is selected:

  debugfs: File ':soc:pcie@fc000000' in directory 'domains' already present!

This is due to the fact that the DWC MSI code tries to register two
IRQ domains for the same firmware node, without telling the low
level code how to distinguish them (by setting a bus token). This
further confuses debugfs which tries to create corresponding
files for each domain.

Fix it by tagging the inner domain as DOMAIN_BUS_NEXUS, which is
the closest thing we have as to "generic MSI".

Link: https://lore.kernel.org/r/20200501113921.366597-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 96f3e373279a..c8b93aae77ed 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -263,6 +263,8 @@ int dw_pcie_allocate_domains(struct pcie_port *pp)
 		return -ENOMEM;
 	}
 
+	irq_domain_update_bus_token(pp->irq_domain, DOMAIN_BUS_NEXUS);
+
 	pp->msi_domain = pci_msi_create_irq_domain(fwnode,
 						   &dw_pcie_msi_domain_info,
 						   pp->irq_domain);
-- 
2.27.0