x86/irq: Export functions to allow MSI domains in modules

The Linux kernel already has the concept of IRQ domain, wherein a
component can expose a set of IRQs which are managed by a particular
interrupt controller chip or other subsystem. The PCI driver exposes
the notion of an IRQ domain for Message-Signaled Interrupts (MSI) from
PCI Express devices. This patch exposes the functions which are
necessary for creating a MSI IRQ domain within a module.

[ tglx: Split it into x86 and core irq parts ]

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Cc: gregkh@linuxfoundation.org
Cc: kys@microsoft.com
Cc: devel@linuxdriverproject.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: vkuznets@redhat.com
Cc: haiyangz@microsoft.com
Cc: marc.zyngier@arm.com
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1449769983-12948-4-git-send-email-jakeo@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index 5f1feb6..ade2532 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -96,8 +96,8 @@
 	return arg->msi_hwirq;
 }
 
-static int pci_msi_prepare(struct irq_domain *domain, struct device *dev,
-			   int nvec, msi_alloc_info_t *arg)
+int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
+		    msi_alloc_info_t *arg)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct msi_desc *desc = first_pci_msi_entry(pdev);
@@ -113,11 +113,13 @@
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(pci_msi_prepare);
 
-static void pci_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+void pci_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
 {
 	arg->msi_hwirq = pci_msi_domain_calc_hwirq(arg->msi_dev, desc);
 }
+EXPORT_SYMBOL_GPL(pci_msi_set_desc);
 
 static struct msi_domain_ops pci_msi_domain_ops = {
 	.get_hwirq	= pci_msi_get_hwirq,