[POWERPC] PowerPC MSI infrastructure

This provides the architecture specific hooks to support MSI on
powerpc.  We implement the newly added arch_setup_msi_irqs() and
arch_teardown_msi_irqs(), and then delegate to ppc_md routines.

Platforms that don't implement MSI will leave the ppc_md calls blank,
arch_msi_check_device() will detect this and return ENOSYS. Drivers
should detect this error and continue to use LSI.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/Makefile

@@ -68,6 +68,7 @@ obj-$(CONFIG_MODULES)		+= $(module-y)
 pci64-$(CONFIG_PPC64)		+= pci_64.o pci_dn.o
 pci32-$(CONFIG_PPC32)		:= pci_32.o
 obj-$(CONFIG_PCI)		+= $(pci64-y) $(pci32-y)
+obj-$(CONFIG_PCI_MSI)		+= msi.o
 kexec-$(CONFIG_PPC64)		:= machine_kexec_64.o
 kexec-$(CONFIG_PPC32)		:= machine_kexec_32.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o crash.o $(kexec-y)

arch/powerpc/kernel/msi.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/msi.h>
+
+#include <asm/machdep.h>
+
+int arch_msi_check_device(struct pci_dev* dev, int nvec, int type)
+{
+	if (!ppc_md.setup_msi_irqs || !ppc_md.teardown_msi_irqs) {
+		pr_debug("msi: Platform doesn't provide MSI callbacks.\n");
+		return -ENOSYS;
+	}
+
+	if (ppc_md.msi_check_device) {
+		pr_debug("msi: Using platform check routine.\n");
+		return ppc_md.msi_check_device(dev, nvec, type);
+	}
+
+        return 0;
+}
+
+int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+	return ppc_md.setup_msi_irqs(dev, nvec, type);
+}
+
+void arch_teardown_msi_irqs(struct pci_dev *dev)
+{
+	return ppc_md.teardown_msi_irqs(dev);
+}