x86/msi: Provide new iommu irqdomain interface

Provide a new interface for creating the iommu remapping domains, so that
the caller can supply a name and a id in order to create named irqdomains.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: iommu@lists.linux-foundation.org
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235443.986661206@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/irq_remapping.h

@@ -56,6 +56,8 @@ irq_remapping_get_irq_domain(struct irq_alloc_info *info);
 
 /* Create PCI MSI/MSIx irqdomain, use @parent as the parent irqdomain. */
 extern struct irq_domain *arch_create_msi_irq_domain(struct irq_domain *parent);
+extern struct irq_domain *
+arch_create_remap_msi_irq_domain(struct irq_domain *par, const char *n, int id);
 
 /* Get parent irqdomain for interrupt remapping irqdomain */
 static inline struct irq_domain *arch_get_ir_parent_domain(void)

arch/x86/kernel/apic/msi.c

@@ -167,10 +167,25 @@ static struct msi_domain_info pci_msi_ir_domain_info = {
 	.handler_name	= "edge",
 };
 
+struct irq_domain *arch_create_remap_msi_irq_domain(struct irq_domain *parent,
+						    const char *name, int id)
+{
+	struct fwnode_handle *fn;
+	struct irq_domain *d;
+
+	fn = irq_domain_alloc_named_id_fwnode(name, id);
+	if (!fn)
+		return NULL;
+	d = pci_msi_create_irq_domain(fn, &pci_msi_ir_domain_info, parent);
+	irq_domain_free_fwnode(fn);
+	return d;
+}
+
 struct irq_domain *arch_create_msi_irq_domain(struct irq_domain *parent)
 {
 	return pci_msi_create_irq_domain(NULL, &pci_msi_ir_domain_info, parent);
 }
+
 #endif
 
 #ifdef CONFIG_DMAR_TABLE