PCI MSI: Add support for multiple MSI

Add the new API pci_enable_msi_block() to allow drivers to
request multiple MSI and reimplement pci_enable_msi in terms of
pci_enable_msi_block.  Ensure that the architecture back ends don't
have to know about multiple MSI.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 8 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/msi.c b/arch/powerpc/kernel/msi.c
index 3bb7d3dd28be..0c16e2a854e5 100644
--- a/arch/powerpc/kernel/msi.c
+++ b/arch/powerpc/kernel/msi.c
@@ -19,6 +19,10 @@ int arch_msi_check_device(struct pci_dev* dev, int nvec, int type)
                 return -ENOSYS;
         }
 
+        /* PowerPC doesn't support multiple MSI yet */
+        if (type == PCI_CAP_ID_MSI && nvec > 1)
+                return 1;
+
         if (ppc_md.msi_check_device) {
                 pr_debug("msi: Using platform check routine.\n");
                 return ppc_md.msi_check_device(dev, nvec, type);
diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index bc7ac4da90d7..a09549a6321b 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -3510,6 +3510,10 @@ int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
         int index = 0;
 #endif
 
+        /* x86 doesn't support multiple MSI yet */
+        if (type == PCI_CAP_ID_MSI && nvec > 1)
+                return 1;
+
         irq_want = nr_irqs_gsi;
         sub_handle = 0;
         list_for_each_entry(msidesc, &dev->msi_list, list) {