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>

2 files changed, 33 insertions, 0 deletions

diff --git a/arch/mips/include/asm/pci.h b/arch/mips/include/asm/pci.h
index 3beea1479b43..576397c69920 100644
--- a/arch/mips/include/asm/pci.h
+++ b/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);
diff --git a/arch/mips/pci/msi-octeon.c b/arch/mips/pci/msi-octeon.c
index 7c756408b85d..d8080499872a 100644
--- a/arch/mips/pci/msi-octeon.c
+++ b/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