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, 49 insertions, 1 deletions

diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index 5617150fd8fb..c306421d86c1 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -345,7 +345,7 @@ void panic_if_irq_remap(const char *msg)
 		panic(msg);
 }
 
-static void ir_ack_apic_edge(struct irq_data *data)
+void ir_ack_apic_edge(struct irq_data *data)
 {
 	ack_APIC_irq();
 }
@@ -356,6 +356,19 @@ static void ir_ack_apic_level(struct irq_data *data)
 	eoi_ioapic_irq(data->irq, irqd_cfg(data));
 }
 
+void irq_remapping_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	/*
+	 * Assume interrupt is remapped if the parent irqdomain isn't the
+	 * vector domain, which is true for MSI, HPET and IOAPIC on x86
+	 * platforms.
+	 */
+	if (data->domain && data->domain->parent != arch_get_ir_parent_domain())
+		seq_printf(p, " IR-%s", data->chip->name);
+	else
+		seq_printf(p, " %s", data->chip->name);
+}
+
 static void ir_print_prefix(struct irq_data *data, struct seq_file *p)
 {
 	seq_printf(p, " IR-%s", data->chip->name);
@@ -377,3 +390,38 @@ bool setup_remapped_irq(int irq, struct irq_cfg *cfg, struct irq_chip *chip)
 	irq_remap_modify_chip_defaults(chip);
 	return true;
 }
+
+/**
+ * irq_remapping_get_ir_irq_domain - Get the irqdomain associated with the IOMMU
+ *				     device serving request @info
+ * @info: interrupt allocation information, used to identify the IOMMU device
+ *
+ * It's used to get parent irqdomain for HPET and IOAPIC irqdomains.
+ * Returns pointer to IRQ domain, or NULL on failure.
+ */
+struct irq_domain *
+irq_remapping_get_ir_irq_domain(struct irq_alloc_info *info)
+{
+	if (!remap_ops || !remap_ops->get_ir_irq_domain)
+		return NULL;
+
+	return remap_ops->get_ir_irq_domain(info);
+}
+
+/**
+ * irq_remapping_get_irq_domain - Get the irqdomain serving the request @info
+ * @info: interrupt allocation information, used to identify the IOMMU device
+ *
+ * There will be one PCI MSI/MSIX irqdomain associated with each interrupt
+ * remapping device, so this interface is used to retrieve the PCI MSI/MSIX
+ * irqdomain serving request @info.
+ * Returns pointer to IRQ domain, or NULL on failure.
+ */
+struct irq_domain *
+irq_remapping_get_irq_domain(struct irq_alloc_info *info)
+{
+	if (!remap_ops || !remap_ops->get_irq_domain)
+		return NULL;
+
+	return remap_ops->get_irq_domain(info);
+}