PCI/MSI: Only use the generic MSI layer when domain is hierarchical

Since d8a1cb757550 ("PCI/MSI: Let pci_msi_get_domain use struct
device::msi_domain"), we use the MSI domain associated with the PCI device.

But finding an MSI domain doesn't mean that the domain is implemented using
the generic MSI domain API, and a number of MSI controllers are still using
arch_setup_msi_irq() and arch_teardown_msi_irqs().

Check that the domain we just obtained is hierarchical.  If it is, we can
use the new generic MSI stuff.  Otherwise we have to fall back to the old
arch_setup_msi_irq() and arch_teardown_msi_irqs() interfaces.

This avoids an oops in msi_domain_alloc_irqs() on systems with R-Car,
Tegra, Armada 370, and probably other DesignWare-based host controllers.

Fixes: d8a1cb757550 ("PCI/MSI: Let pci_msi_get_domain use struct device::msi_domain")
Reported-by: Phil Edworthy <[email protected]>
Tested-by: Phil Edworthy <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
CC: [email protected]	# v4.3+

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 53e463244bb7e35ac368ff088a4976c2153fce3d..7eaa4c87fec71c8dd792ccffc919b322711d91dd 100644 (file)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -54,7 +54,7 @@ static int pci_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
        struct irq_domain *domain;
 
        domain = pci_msi_get_domain(dev);
-       if (domain)
+       if (domain && irq_domain_is_hierarchy(domain))
                return pci_msi_domain_alloc_irqs(domain, dev, nvec, type);
 
        return arch_setup_msi_irqs(dev, nvec, type);
@@ -65,7 +65,7 @@ static void pci_msi_teardown_msi_irqs(struct pci_dev *dev)
        struct irq_domain *domain;
 
        domain = pci_msi_get_domain(dev);
-       if (domain)
+       if (domain && irq_domain_is_hierarchy(domain))
                pci_msi_domain_free_irqs(domain, dev);
        else
                arch_teardown_msi_irqs(dev);