Commit 85aabbd7 authored by Jean-Philippe Brucker's avatar Jean-Philippe Brucker Committed by Bjorn Helgaas
Browse files

PCI/MSI: Fix MSIs for generic hosts that use device-tree's "msi-map" 

Since commit 9ec37efb ("PCI/MSI: Make pci_host_common_probe() declare
its reliance on MSI domains"), platforms that rely on the "msi-map"
device-tree property don't get MSIs anymore.

On the Arm Fast Model for example [1], the host bridge doesn't have a
"msi-parent" property since it doesn't itself generate MSIs, and so doesn't
get a MSI domain. It has an "msi-map" property instead to describe MSI
controllers of child devices. As a result, due to the new msi_domain check
in pci_register_host_bridge(), the whole bus gets PCI_BUS_FLAGS_NO_MSI.

Check whether the root complex has an "msi-map" property before giving
up on MSIs.

[1] arch/arm64/boot/dts/arm/fvp-base-revc.dts

Fixes: 9ec37efb ("PCI/MSI: Make pci_host_common_probe() declare its reliance on MSI domains")
Link: https://lore.kernel.org/r/20210510173129.750496-1-jean-philippe@linaro.org


Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Acked-by: default avatarMarc Zyngier <maz@kernel.org>
parent 2ee4c8a2

drivers/pci/of.c

+7 −0
Original line number Diff line number Diff line
@@ -103,6 +103,13 @@ struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus) 
#endif

}



bool pci_host_of_has_msi_map(struct device *dev)

{

	if (dev && dev->of_node)

		return of_get_property(dev->of_node, "msi-map", NULL);

	return false;

}



static inline int __of_pci_pci_compare(struct device_node *node,

				       unsigned int data)

{

drivers/pci/probe.c

+2 −1
Original line number Diff line number Diff line
@@ -925,7 +925,8 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) 
	device_enable_async_suspend(bus->bridge);

	pci_set_bus_of_node(bus);

	pci_set_bus_msi_domain(bus);

	if (bridge->msi_domain && !dev_get_msi_domain(&bus->dev))

	if (bridge->msi_domain && !dev_get_msi_domain(&bus->dev) &&

	    !pci_host_of_has_msi_map(parent))

		bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;



	if (!parent)

include/linux/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -2344,6 +2344,7 @@ int pci_vpd_find_info_keyword(const u8 *buf, unsigned int off, 
struct device_node;

struct irq_domain;

struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus);

bool pci_host_of_has_msi_map(struct device *dev);



/* Arch may override this (weak) */

struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus);
@@ -2351,6 +2352,7 @@ struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus); 
#else	/* CONFIG_OF */

static inline struct irq_domain *

pci_host_bridge_of_msi_domain(struct pci_bus *bus) { return NULL; }

static inline bool pci_host_of_has_msi_map(struct device *dev) { return false; }

#endif  /* CONFIG_OF */



static inline struct device_node *