MIPS: Octeon: Disallow MSI-X interrupt and fall back to MSI interrupts.

MSI-X interrupts are not supported yet for Octeon, return error if
MSI-X interrupts are requested by driver so that the driver will fall
back to use MSI interrupts.

Signed-off-by: Chandrakala Chavva <cchavva@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: David Daney <ddaney@caviumnetworks.com>
Patchwork: https://patchwork.linux-mips.org/patch/1506/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>

arch/mips/include/asm/pci.h

@@ -140,6 +140,11 @@ static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
 	return channel ? 15 : 14;
 }
 
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+/* MSI arch hook for OCTEON */
+#define arch_setup_msi_irqs arch_setup_msi_irqs
+#endif
+
 extern int pci_probe_only;
 
 extern char * (*pcibios_plat_setup)(char *str);

arch/mips/pci/msi-octeon.c

@@ -177,6 +177,34 @@ msi_irq_allocated:
 	return 0;
 }
 
+int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+	struct msi_desc *entry;
+	int ret;
+
+	/*
+	 * MSI-X is not supported.
+	 */
+	if (type == PCI_CAP_ID_MSIX)
+		return -EINVAL;
+
+	/*
+	 * If an architecture wants to support multiple MSI, it needs to
+	 * override arch_setup_msi_irqs()
+	 */
+	if (type == PCI_CAP_ID_MSI && nvec > 1)
+		return 1;
+
+	list_for_each_entry(entry, &dev->msi_list, list) {
+		ret = arch_setup_msi_irq(dev, entry);
+		if (ret < 0)
+			return ret;
+		if (ret > 0)
+			return -ENOSPC;
+	}
+
+	return 0;
+}
 
 /**
  * Called when a device no longer needs its MSI interrupts. All