irq_remapping: Introduce new interfaces to support hierarchical irqdomains

Introduce new interfaces for interrupt remapping drivers to support
hierarchical irqdomains:

1) irq_remapping_get_ir_irq_domain(): get irqdomain associated with an
   interrupt remapping unit. IOAPIC/HPET drivers use this interface to
   get parent interrupt remapping irqdomain.

2) irq_remapping_get_irq_domain(): get irqdomain for an IRQ allocation.
   This is mainly used to support MSI irqdomain. We must build one MSI
   irqdomain for each interrupt remapping unit. MSI driver calls this
   interface to get MSI irqdomain associated with an IR irqdomain which
   manages the PCI devices. In a further step we will store the irqdomain
   pointer in the device struct to avoid this call in the irq allocation
   path.

Architecture specific hooks:
1) arch_get_ir_parent_domain(): get parent irqdomain for IR irqdomain,
   which is x86_vector_domain on x86 platforms.
2) arch_create_msi_irq_domain(): create an MSI irqdomain associated with
   the interrupt remapping unit.

We also add following callbacks into struct irq_remap_ops:
	struct irq_domain *(*get_ir_irq_domain)(struct irq_alloc_info *);
	struct irq_domain *(*get_irq_domain)(struct irq_alloc_info *);

Once all clients of IR have been converted to the new hierarchical irqdomain
interfaces, we will:
1) Remove set_ioapic_entry, set_affinity, free_irq, compose_msi_msg,
   msi_alloc_irq, msi_setup_irq, setup_hpet_msi from struct remap_osp
2) Remove setup_ioapic_remapped_entry, free_remapped_irq,
   compose_remapped_msi_msg, setup_hpet_msi_remapped, setup_remapped_irq.
3) Simplify x86_io_apic_ops and x86_msi.

We can achieve a way clearer architecture with all these changes
applied.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: iommu@lists.linux-foundation.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Joerg Roedel <joro@8bytes.org>
Link: http://lkml.kernel.org/r/1428905519-23704-9-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 36 insertions, 0 deletions

diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index 86d897bc15dd..0cd6195cc375 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -22,6 +22,8 @@
 #ifndef __X86_IRQ_REMAPPING_H
 #define __X86_IRQ_REMAPPING_H
 
+#include <linux/irqdomain.h>
+#include <asm/hw_irq.h>
 #include <asm/io_apic.h>
 
 struct IO_APIC_route_entry;
@@ -30,6 +32,7 @@ struct irq_chip;
 struct msi_msg;
 struct pci_dev;
 struct irq_cfg;
+struct irq_alloc_info;
 
 #ifdef CONFIG_IRQ_REMAP
 
@@ -56,6 +59,25 @@ extern bool setup_remapped_irq(int irq,
 
 void irq_remap_modify_chip_defaults(struct irq_chip *chip);
 
+extern struct irq_domain *
+irq_remapping_get_ir_irq_domain(struct irq_alloc_info *info);
+extern struct irq_domain *
+irq_remapping_get_irq_domain(struct irq_alloc_info *info);
+extern void irq_remapping_print_chip(struct irq_data *data, struct seq_file *p);
+
+/* Create PCI MSI/MSIx irqdomain, use @parent as the parent irqdomain. */
+static inline struct irq_domain *
+arch_create_msi_irq_domain(struct irq_domain *parent)
+{
+	return NULL;
+}
+
+/* Get parent irqdomain for interrupt remapping irqdomain */
+static inline struct irq_domain *arch_get_ir_parent_domain(void)
+{
+	return x86_vector_domain;
+}
+
 #else  /* CONFIG_IRQ_REMAP */
 
 static inline void set_irq_remapping_broken(void) { }
@@ -97,6 +119,20 @@ static inline bool setup_remapped_irq(int irq,
 {
 	return false;
 }
+
+static inline struct irq_domain *
+irq_remapping_get_ir_irq_domain(struct irq_alloc_info *info)
+{
+	return NULL;
+}
+
+static inline struct irq_domain *
+irq_remapping_get_irq_domain(struct irq_alloc_info *info)
+{
+	return NULL;
+}
+
+#define	irq_remapping_print_chip	NULL
 #endif /* CONFIG_IRQ_REMAP */
 
 extern int dmar_alloc_hwirq(void);