PCI: mvebu: Disallow mapping interrupts on emulated bridges

Interrupt support on mvebu emulated bridges is not implemented yet.

So properly indicate return value to callers that they cannot request
interrupts from emulated bridge.

Link: https://lore.kernel.org/r/20211125124605.25915-6-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/pci/controller/pci-mvebu.c

@@ -686,6 +686,15 @@ static struct pci_ops mvebu_pcie_ops = {
 	.write = mvebu_pcie_wr_conf,
 };
 
+static int mvebu_pcie_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
+{
+	/* Interrupt support on mvebu emulated bridges is not implemented yet */
+	if (dev->bus->number == 0)
+		return 0; /* Proper return code 0 == NO_IRQ */
+
+	return of_irq_parse_and_map_pci(dev, slot, pin);
+}
+
 static resource_size_t mvebu_pcie_align_resource(struct pci_dev *dev,
 						 const struct resource *res,
 						 resource_size_t start,
@@ -1102,6 +1111,7 @@ static int mvebu_pcie_probe(struct platform_device *pdev)
 	bridge->sysdata = pcie;
 	bridge->ops = &mvebu_pcie_ops;
 	bridge->align_resource = mvebu_pcie_align_resource;
+	bridge->map_irq = mvebu_pcie_map_irq;
 
 	return pci_host_probe(bridge);
 }