[RFC 10/14] irq_domain: Replace irq_alloc_host() with revmap-specific initializers

@@ -190,8 +190,7 @@ mpc5121_ads_cpld_pic_init(void)
 
 	cpld_pic_node = of_node_get(np);
 
-	cpld_pic_host =
-	    irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR, 16, &cpld_pic_host_ops, 16);
+	cpld_pic_host = irq_domain_add_linear(np, 16, &cpld_pic_host_ops);
 	if (!cpld_pic_host) {
 		printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
 		goto end;

@@ -173,9 +173,9 @@ static void __init media5200_init_irq(void)
 
 	spin_lock_init(&media5200_irq.lock);
 
-	media5200_irq.irqhost = irq_alloc_host(fpga_np, IRQ_DOMAIN_MAP_LINEAR,
-					       MEDIA5200_NUM_IRQS,
-					       &media5200_irq_ops, -1);
+	media5200_irq.irqhost = irq_domain_add_linear(fpga_np,
+						MEDIA5200_NUM_IRQS,
+						&media5200_irq_ops);
 	if (!media5200_irq.irqhost)
 		goto out;
 	pr_debug("%s: allocated irqhost\n", __func__);

@@ -252,10 +252,9 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
 	if (!cascade_virq)
 		return;
 
-	gpt->irqhost = irq_alloc_host(node, IRQ_DOMAIN_MAP_LINEAR, 1,
-				      &mpc52xx_gpt_irq_ops, -1);
+	gpt->irqhost = irq_domain_add_linear(node, 1, &mpc52xx_gpt_irq_ops);
 	if (!gpt->irqhost) {
-		dev_err(gpt->dev, "irq_alloc_host() failed\n");
+		dev_err(gpt->dev, "irq_domain_add_linear() failed\n");
 		return;
 	}
 

@@ -444,9 +444,9 @@ void __init mpc52xx_init_irq(void)
 	 * As last step, add an irq host to translate the real
 	 * hw irq information provided by the ofw to linux virq
 	 */
-	mpc52xx_irqhost = irq_alloc_host(picnode, IRQ_DOMAIN_MAP_LINEAR,
+	mpc52xx_irqhost = irq_domain_add_linear(picnode,
 	                                 MPC52xx_IRQ_HIGHTESTHWIRQ,
-	                                 &mpc52xx_irqhost_ops, -1);
+	                                 &mpc52xx_irqhost_ops);
 
 	if (!mpc52xx_irqhost)
 		panic(__FILE__ ": Cannot allocate the IRQ host\n");

@@ -156,8 +156,7 @@ int __init pq2ads_pci_init_irq(void)
 	out_be32(&priv->regs->mask, ~0);
 	mb();
 
-	host = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR, NUM_IRQS,
-	                      &pci_pic_host_ops, NUM_IRQS);
+	host = irq_domain_add_linear(np, NUM_IRQS, &pci_pic_host_ops);
 	if (!host) {
 		ret = -ENOMEM;
 		goto out_unmap_regs;

@@ -280,9 +280,8 @@ void socrates_fpga_pic_init(struct device_node *pic)
 	int i;
 
 	/* Setup an irq_domain structure */
-	socrates_fpga_pic_irq_host = irq_alloc_host(pic, IRQ_DOMAIN_MAP_LINEAR,
-			SOCRATES_FPGA_NUM_IRQS,	&socrates_fpga_pic_host_ops,
-			SOCRATES_FPGA_NUM_IRQS);
+	socrates_fpga_pic_irq_host = irq_domain_add_linear(pic,
+			SOCRATES_FPGA_NUM_IRQS, &socrates_fpga_pic_host_ops);
 	if (socrates_fpga_pic_irq_host == NULL) {
 		pr_err("FPGA PIC: Unable to allocate host\n");
 		return;

@@ -212,9 +212,8 @@ void __init gef_pic_init(struct device_node *np)
 	}
 
 	/* Setup an irq_domain structure */
-	gef_pic_irq_host = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR,
-					  GEF_PIC_NUM_IRQS,
-					  &gef_pic_host_ops, NO_IRQ);
+	gef_pic_irq_host = irq_domain_add_linear(np, GEF_PIC_NUM_IRQS,
+					  &gef_pic_host_ops);
 	if (gef_pic_irq_host == NULL)
 		return;
 

@@ -392,8 +392,7 @@ static int axon_msi_probe(struct platform_device *device)
 	}
 	memset(msic->fifo_virt, 0xff, MSIC_FIFO_SIZE_BYTES);
 
-	msic->irq_domain = irq_alloc_host(dn, IRQ_DOMAIN_MAP_NOMAP,
-					NR_IRQS, &msic_host_ops, 0);
+	msic->irq_domain = irq_domain_add_nomap(dn, &msic_host_ops);
 	if (!msic->irq_domain) {
 		printk(KERN_ERR "axon_msi: couldn't allocate irq_domain for %s\n",
 		       dn->full_name);

@@ -239,9 +239,7 @@ void __init beatic_init_IRQ(void)
 	ppc_md.get_irq = beatic_get_irq;
 
 	/* Allocate an irq host */
-	beatic_host = irq_alloc_host(NULL, IRQ_DOMAIN_MAP_NOMAP, 0,
-				     &beatic_pic_host_ops,
-					 0);
+	beatic_host = irq_domain_add_nomap(NULL, &beatic_pic_host_ops);
 	BUG_ON(beatic_host == NULL);
 	irq_set_default_host(beatic_host);
 }

@@ -378,8 +378,7 @@ static int __init setup_iic(void)
 void __init iic_init_IRQ(void)
 {
 	/* Setup an irq host data structure */
-	iic_host = irq_alloc_host(NULL, IRQ_DOMAIN_MAP_LINEAR, IIC_SOURCE_COUNT,
-				  &iic_host_ops, IIC_IRQ_INVALID);
+	iic_host = irq_domain_add_linear(NULL, IIC_SOURCE_COUNT, &iic_host_ops);
 	BUG_ON(iic_host == NULL);
 	irq_set_default_host(iic_host);
 

@@ -299,9 +299,7 @@ static void __init spider_init_one(struct device_node *of_node, int chip,
 		panic("spider_pic: can't map registers !");
 
 	/* Allocate a host */
-	pic->host = irq_alloc_host(of_node, IRQ_DOMAIN_MAP_LINEAR,
-				   SPIDER_SRC_COUNT, &spider_host_ops,
-				   SPIDER_IRQ_INVALID);
+	pic->host = irq_domain_add_linear(of_node, SPIDER_SRC_COUNT, &spider_host_ops);
 	if (pic->host == NULL)
 		panic("spider_pic: can't allocate irq host !");
 	pic->host->host_data = pic;

@@ -159,8 +159,8 @@ struct irq_domain * __init flipper_pic_init(struct device_node *np)
 
 	__flipper_quiesce(io_base);
 
-	irq_domain = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR, FLIPPER_NR_IRQS,
-				  &flipper_irq_domain_ops, -1);
+	irq_domain = irq_domain_add_linear(np, FLIPPER_NR_IRQS,
+				  &flipper_irq_domain_ops);
 	if (!irq_domain) {
 		pr_err("failed to allocate irq_domain\n");
 		return NULL;

@@ -177,8 +177,7 @@ struct irq_domain *hlwd_pic_init(struct device_node *np)
 
 	__hlwd_quiesce(io_base);
 
-	irq_domain = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR, HLWD_NR_IRQS,
-				  &hlwd_irq_domain_ops, -1);
+	irq_domain = irq_domain_add_linear(np, HLWD_NR_IRQS, &hlwd_irq_domain_ops);
 	if (!irq_domain) {
 		pr_err("failed to allocate irq_domain\n");
 		return NULL;

@@ -380,8 +380,7 @@ void __init iSeries_init_IRQ(void)
 	/* Create irq host. No need for a revmap since HV will give us
 	 * back our virtual irq number
 	 */
-	host = irq_alloc_host(NULL, IRQ_DOMAIN_MAP_NOMAP, 0,
-			      &iseries_irq_domain_ops, 0);
+	host = irq_domain_add_nomap(NULL, &iseries_irq_domain_ops);
 	BUG_ON(host == NULL);
 	irq_set_default_host(host);
 

@@ -352,9 +352,7 @@ static void __init pmac_pic_probe_oldstyle(void)
 	/*
 	 * Allocate an irq host
 	 */
-	pmac_pic_host = irq_alloc_host(master, IRQ_DOMAIN_MAP_LINEAR, max_irqs,
-				       &pmac_pic_host_ops,
-				       max_irqs);
+	pmac_pic_host = irq_domain_add_linear(master, max_irqs, &pmac_pic_host_ops);
 	BUG_ON(pmac_pic_host == NULL);
 	irq_set_default_host(pmac_pic_host);
 

@@ -192,8 +192,7 @@ static int psurge_secondary_ipi_init(void)
 {
 	int rc = -ENOMEM;
 
-	psurge_host = irq_alloc_host(NULL, IRQ_DOMAIN_MAP_NOMAP, 0,
-		&psurge_host_ops, 0);
+	psurge_host = irq_domain_add_nomap(NULL, &psurge_host_ops);
 
 	if (psurge_host)
 		psurge_secondary_virq = irq_create_direct_mapping(psurge_host);

@@ -753,8 +753,7 @@ void __init ps3_init_IRQ(void)
 	unsigned cpu;
 	struct irq_domain *host;
 
-	host = irq_alloc_host(NULL, IRQ_DOMAIN_MAP_NOMAP, 0, &ps3_host_ops,
-		PS3_INVALID_OUTLET);
+	host = irq_domain_add_nomap(NULL, &ps3_host_ops);
 	irq_set_default_host(host);
 	irq_set_virq_count(PS3_PLUG_MAX + 1);
 

@@ -263,12 +263,11 @@ struct opb_pic *opb_pic_init_one(struct device_node *dn)
 		goto free_opb;
 	}
 
-	/* Allocate an irq host so that Linux knows that despite only
+	/* Allocate an irq domain so that Linux knows that despite only
 	 * having one interrupt to issue, we're the controller for multiple
 	 * hardware IRQs, so later we can lookup their virtual IRQs. */
 
-	opb->host = irq_alloc_host(dn, IRQ_DOMAIN_MAP_LINEAR,
-			OPB_NR_IRQS, &opb_host_ops, -1);
+	opb->host = irq_domain_add_linear(dn, OPB_NR_IRQS, &opb_host_ops);
 
 	if (!opb->host) {
 		printk(KERN_ERR "opb: Failed to allocate IRQ host!\n");

@@ -164,8 +164,7 @@ unsigned int cpm_pic_init(void)
 
 	out_be32(&cpic_reg->cpic_cimr, 0);
 
-	cpm_pic_host = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR,
-				      64, &cpm_pic_host_ops, 64);
+	cpm_pic_host = irq_domain_add_linear(np, 64, &cpm_pic_host_ops);
 	if (cpm_pic_host == NULL) {
 		printk(KERN_ERR "CPM2 PIC: failed to allocate irq host!\n");
 		sirq = NO_IRQ;

@@ -275,8 +275,7 @@ void cpm2_pic_init(struct device_node *node)
 	out_be32(&cpm2_intctl->ic_scprrl, 0x05309770);
 
 	/* create a legacy host */
-	cpm2_pic_host = irq_alloc_host(node, IRQ_DOMAIN_MAP_LINEAR,
-				       64, &cpm2_pic_host_ops, 64);
+	cpm2_pic_host = irq_domain_add_linear(node, 64, &cpm2_pic_host_ops);
 	if (cpm2_pic_host == NULL) {
 		printk(KERN_ERR "CPM2 PIC: failed to allocate irq host!\n");
 		return;

@@ -275,9 +275,7 @@ void __init ehv_pic_init(void)
 		return;
 	}
 
-	ehv_pic->irqhost = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR,
-		NR_EHV_PIC_INTS, &ehv_pic_host_ops, 0);
-
+	ehv_pic->irqhost = irq_domain_add_linear(np, NR_EHV_PIC_INTS, &ehv_pic_host_ops);
 	if (!ehv_pic->irqhost) {
 		of_node_put(np);
 		kfree(ehv_pic);

@@ -387,8 +387,8 @@ static int __devinit fsl_of_msi_probe(struct platform_device *dev)
 	}
 	platform_set_drvdata(dev, msi);
 
-	msi->irqhost = irq_alloc_host(dev->dev.of_node, IRQ_DOMAIN_MAP_LINEAR,
-				      NR_MSI_IRQS, &fsl_msi_host_ops, 0);
+	msi->irqhost = irq_domain_add_linear(dev->dev.of_node,
+				      NR_MSI_IRQS, &fsl_msi_host_ops);
 
 	if (msi->irqhost == NULL) {
 		dev_err(&dev->dev, "No memory for MSI irqhost\n");

@@ -263,8 +263,7 @@ void i8259_init(struct device_node *node, unsigned long intack_addr)
 	raw_spin_unlock_irqrestore(&i8259_lock, flags);
 
 	/* create a legacy host */
-	i8259_host = irq_alloc_host(node, IRQ_DOMAIN_MAP_LEGACY,
-				    0, &i8259_host_ops, 0);
+	i8259_host = irq_domain_add_legacy(node, &i8259_host_ops);
 	if (i8259_host == NULL) {
 		printk(KERN_ERR "i8259: failed to allocate irq host !\n");
 		return;

@@ -728,9 +728,7 @@ struct ipic * __init ipic_init(struct device_node *node, unsigned int flags)
 	if (ipic == NULL)
 		return NULL;
 
-	ipic->irqhost = irq_alloc_host(node, IRQ_DOMAIN_MAP_LINEAR,
-				       NR_IPIC_INTS,
-				       &ipic_host_ops, 0);
+	ipic->irqhost = irq_domain_add_linear(node, NR_IPIC_INTS, &ipic_host_ops);
 	if (ipic->irqhost == NULL) {
 		kfree(ipic);
 		return NULL;

@@ -171,8 +171,7 @@ int mpc8xx_pic_init(void)
 		goto out;
 	}
 
-	mpc8xx_pic_host = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR,
-					 64, &mpc8xx_pic_host_ops, 64);
+	mpc8xx_pic_host = irq_domain_add_linear(np, 64, &mpc8xx_pic_host_ops);
 	if (mpc8xx_pic_host == NULL) {
 		printk(KERN_ERR "MPC8xx PIC: failed to allocate irq host!\n");
 		ret = -ENOMEM;

@@ -1345,10 +1345,9 @@ struct mpic * __init mpic_alloc(struct device_node *node,
 	mpic->isu_shift = 1 + __ilog2(mpic->isu_size - 1);
 	mpic->isu_mask = (1 << mpic->isu_shift) - 1;
 
-	mpic->irqhost = irq_alloc_host(mpic->node, IRQ_DOMAIN_MAP_LINEAR,
+	mpic->irqhost = irq_domain_add_linear(mpic->node,
 				       isu_size ? isu_size : mpic->num_sources,
-				       &mpic_host_ops,
-				       flags & MPIC_LARGE_VECTORS ? 2048 : 256);
+				       &mpic_host_ops);
 
 	/*
 	 * FIXME: The code leaks the MPIC object and mappings here; this

@@ -250,9 +250,8 @@ void __init mv64x60_init_irq(void)
 	paddr = of_translate_address(np, reg);
 	mv64x60_irq_reg_base = ioremap(paddr, reg[1]);
 
-	mv64x60_irq_host = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR,
-					  MV64x60_NUM_IRQS,
-					  &mv64x60_host_ops, MV64x60_NUM_IRQS);
+	mv64x60_irq_host = irq_domain_add_linear(np, MV64x60_NUM_IRQS,
+					  &mv64x60_host_ops);
 
 	spin_lock_irqsave(&mv64x60_lock, flags);
 	out_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_MASK,

@@ -339,8 +339,7 @@ void __init qe_ic_init(struct device_node *node, unsigned int flags,
 	if (qe_ic == NULL)
 		return;
 
-	qe_ic->irqhost = irq_alloc_host(node, IRQ_DOMAIN_MAP_LINEAR,
-					NR_QE_IC_INTS, &qe_ic_host_ops, 0);
+	qe_ic->irqhost = irq_domain_add_linear(node, NR_QE_IC_INTS, &qe_ic_host_ops);
 	if (qe_ic->irqhost == NULL) {
 		kfree(qe_ic);
 		return;

@@ -419,8 +419,7 @@ void __init tsi108_pci_int_init(struct device_node *node)
 {
 	DBG("Tsi108_pci_int_init: initializing PCI interrupts\n");
 
-	pci_irq_host = irq_alloc_host(node, IRQ_DOMAIN_MAP_LEGACY,
-				      0, &pci_irq_domain_ops, 0);
+	pci_irq_host = irq_domain_add_legacy(node, &pci_irq_domain_ops);
 	if (pci_irq_host == NULL) {
 		printk(KERN_ERR "pci_irq_host: failed to allocate irq domain!\n");
 		return;

@@ -270,8 +270,7 @@ static struct uic * __init uic_init_one(struct device_node *node)
 	}
 	uic->dcrbase = *dcrreg;
 
-	uic->irqhost = irq_alloc_host(node, IRQ_DOMAIN_MAP_LINEAR,
-				      NR_UIC_INTS, &uic_host_ops, -1);
+	uic->irqhost = irq_domain_add_linear(node, NR_UIC_INTS, &uic_host_ops);
 	if (! uic->irqhost)
 		return NULL; /* FIXME: panic? */
 

@@ -374,8 +374,7 @@ static struct irq_domain_ops xics_host_ops = {
 
 static void __init xics_init_host(void)
 {
-	xics_host = irq_alloc_host(NULL, IRQ_DOMAIN_MAP_TREE, 0, &xics_host_ops,
-				   XICS_IRQ_SPURIOUS);
+	xics_host = irq_domain_add_tree(NULL, &xics_host_ops);
 	BUG_ON(xics_host == NULL);
 	irq_set_default_host(xics_host);
 }

@@ -201,8 +201,7 @@ xilinx_intc_init(struct device_node *np)
 	out_be32(regs + XINTC_MER, 0x3UL); /* Turn on the Master Enable. */
 
 	/* Allocate and initialize an irq_domain structure. */
-	irq = irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR, XILINX_INTC_MAXIRQS,
-			     &xilinx_intc_ops, -1);
+	irq = irq_domain_add_linear(np, XILINX_INTC_MAXIRQS, &xilinx_intc_ops);
 	if (!irq)
 		panic(__FILE__ ": Cannot allocate IRQ host\n");
 	irq->host_data = regs;

@@ -364,9 +364,8 @@ static void __init mpc8xxx_add_controller(struct device_node *np)
 	if (hwirq == NO_IRQ)
 		goto skip_irq;
 
-	mpc8xxx_gc->irq =
-		irq_alloc_host(np, IRQ_DOMAIN_MAP_LINEAR, MPC8XXX_GPIO_PINS,
-			       &mpc8xxx_gpio_irq_ops, MPC8XXX_GPIO_PINS);
+	mpc8xxx_gc->irq = irq_domain_add_linear(np, MPC8XXX_GPIO_PINS,
+						&mpc8xxx_gpio_irq_ops);
 	if (!mpc8xxx_gc->irq)
 		goto skip_irq;
 

@@ -120,11 +120,17 @@ struct irq_domain {
 
 #ifdef CONFIG_IRQ_DOMAIN
 #ifdef CONFIG_PPC
-extern struct irq_domain *irq_alloc_host(struct device_node *of_node,
-				       unsigned int revmap_type,
-				       unsigned int revmap_arg,
-				       struct irq_domain_ops *ops,
-				       irq_hw_number_t inval_irq);
+struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
+					 struct irq_domain_ops *ops);
+struct irq_domain *irq_domain_add_linear(struct device_node *of_node,
+					 unsigned int size,
+					 struct irq_domain_ops *ops);
+struct irq_domain *irq_domain_add_nomap(struct device_node *of_node,
+					 struct irq_domain_ops *ops);
+struct irq_domain *irq_domain_add_tree(struct device_node *of_node,
+					 struct irq_domain_ops *ops);
+
+
 extern struct irq_domain *irq_find_host(struct device_node *node);
 extern void irq_set_default_host(struct irq_domain *host);
 extern void irq_set_virq_count(unsigned int count);

@@ -22,48 +22,69 @@ static int default_irq_domain_match(struct irq_domain *d, struct device_node *np
 }
 
 /**
- * irq_alloc_host() - Allocate a new irq_domain data structure
+ * irq_domain_alloc() - Allocate a new irq_domain data structure
  * @of_node: optional device-tree node of the interrupt controller
  * @revmap_type: type of reverse mapping to use
- * @revmap_arg: for IRQ_DOMAIN_MAP_LINEAR linear only: size of the map
  * @ops: map/unmap domain callbacks
- * @inval_irq: provide a hw number in that domain space that is always invalid
  *
- * Allocates and initialize and irq_domain structure. Note that in the case of
- * IRQ_DOMAIN_MAP_LEGACY, the map() callback will be called before this returns
- * for all legacy interrupts except 0 (which is always the invalid irq for
- * a legacy controller). For a IRQ_DOMAIN_MAP_LINEAR, the map is allocated by
- * this call as well. For a IRQ_DOMAIN_MAP_TREE, the radix tree will be
- * allocated later during boot automatically (the reverse mapping will use the
- * slow path until that happens).
+ * Allocates and initialize and irq_domain structure.  Caller is expected to
+ * register allocated irq_domain with irq_domain_register().  Returns pointer
+ * to IRQ domain, or NULL on failure.
  */
-struct irq_domain *irq_alloc_host(struct device_node *of_node,
-				unsigned int revmap_type,
-				unsigned int revmap_arg,
-				struct irq_domain_ops *ops,
-				irq_hw_number_t inval_irq)
+static struct irq_domain *irq_domain_alloc(struct device_node *of_node,
+					   unsigned int revmap_type,
+					   struct irq_domain_ops *ops)
 {
 	struct irq_domain *domain, *h;
-	unsigned int size = sizeof(struct irq_domain);
-	unsigned int i;
-	unsigned int *rmap;
 
-	/* Allocate structure and revmap table if using linear mapping */
-	if (revmap_type == IRQ_DOMAIN_MAP_LINEAR)
-		size += revmap_arg * sizeof(unsigned int);
-	domain = kzalloc(size, GFP_KERNEL);
-	if (domain == NULL)
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+	if (WARN_ON(!domain))
 		return NULL;
 
 	/* Fill structure */
 	domain->revmap_type = revmap_type;
-	domain->inval_irq = inval_irq;
 	domain->ops = ops;
 	domain->of_node = of_node_get(of_node);
 
 	if (domain->ops->match == NULL)
 		domain->ops->match = default_irq_domain_match;
 
+	return domain;
+}
+
+static struct irq_domain *irq_domain_add(struct device_node *of_node,
+					 unsigned int revmap_type,
+					 struct irq_domain_ops *ops)
+{
+	struct irq_domain *domain = irq_domain_alloc(of_node, revmap_type, ops);
+	if (!domain)
+		return NULL;
+
+	mutex_lock(&irq_domain_mutex);
+	list_add(&domain->link, &irq_domain_list);
+	mutex_unlock(&irq_domain_mutex);
+	pr_debug("irq: Allocated domain of type %d @0x%p\n", revmap_type, domain);
+	return domain;
+}
+
+/**
+ * irq_domain_add_legacy() - Allocate and register a legacy revmap irq_domain.
+ * @of_node: pointer to interrupt controller's device tree node.
+ * @ops: map/unmap domain callbacks
+ *
+ * Note: the map() callback will be called before this function returns
+ * for all legacy interrupts except 0 (which is always the invalid irq for
+ * a legacy controller).
+ */
+struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
+					 struct irq_domain_ops *ops)
+{
+	struct irq_domain *domain = irq_domain_alloc(of_node, IRQ_DOMAIN_MAP_LEGACY, ops);
+	unsigned int i;
+
+	if (!domain)
+		return NULL;
+
 	mutex_lock(&irq_domain_mutex);
 	/* Make sure only one legacy controller can be created */
 	if (revmap_type == IRQ_DOMAIN_MAP_LEGACY) {

@@ -79,43 +100,70 @@ struct irq_domain *irq_alloc_host(struct device_node *of_node,
 	list_add(&domain->link, &irq_domain_list);
 	mutex_unlock(&irq_domain_mutex);
 
-	/* Additional setups per revmap type */
-	switch(revmap_type) {
-	case IRQ_DOMAIN_MAP_LEGACY:
-		/* 0 is always the invalid number for legacy */
-		domain->inval_irq = 0;
-		/* setup us as the domain for all legacy interrupts */
-		for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
-			struct irq_data *irq_data = irq_get_irq_data(i);
-			irq_data->hwirq = i;
-			irq_data->domain = domain;
-
-			/* Legacy flags are left to default at this point,
-			 * one can then use irq_create_mapping() to
-			 * explicitly change them
-			 */
-			ops->map(domain, i, i);
-
-			/* Clear norequest flags */
-			irq_clear_status_flags(i, IRQ_NOREQUEST);
-		}
-		break;
-	case IRQ_DOMAIN_MAP_LINEAR:
-		rmap = (unsigned int *)(domain + 1);
-		for (i = 0; i < revmap_arg; i++)
-			rmap[i] = 0;
-		domain->revmap_data.linear.size = revmap_arg;
-		domain->revmap_data.linear.revmap = rmap;
-		break;
-	case IRQ_DOMAIN_MAP_TREE:
-		INIT_RADIX_TREE(&domain->revmap_data.tree, GFP_KERNEL);
-		break;
-	default:
-		break;
+	/* setup us as the domain for all legacy interrupts */
+	for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
+		struct irq_data *irq_data = irq_get_irq_data(i);
+		irq_data->hwirq = i;
+		irq_data->domain = domain;
+
+		/* Legacy flags are left to default at this point,
+		 * one can then use irq_create_mapping() to
+		 * explicitly change them
+		 */
+		ops->map(domain, i, i);
+
+		/* Clear norequest flags */
+		irq_clear_status_flags(i, IRQ_NOREQUEST);
 	}
+	return domain;
+}
 
-	pr_debug("irq: Allocated domain of type %d @0x%p\n", revmap_type, domain);
+/**
+ * irq_domain_add_linear() - Allocate and register a legacy revmap irq_domain.
+ * @of_node: pointer to interrupt controller's device tree node.
+ * @ops: map/unmap domain callbacks
+ */
+struct irq_domain *irq_domain_add_linear(struct device_node *of_node,
+					 unsigned int size,
+					 struct irq_domain_ops *ops)
+{
+	struct irq_domain *domain;
+	unsigned int *revmap;
+
+	revmap = kzalloc(sizeof(*revmap) * size, GFP_KERNEL);
+	if (WARN_ON(!revmap))
+		return NULL;
 
+	domain = irq_domain_add(of_node, IRQ_DOMAIN_MAP_LINEAR, ops);
+	if (!domain) {
+		kfree(revmap);
+		return NULL;
+	}
+	domain->revmap_data.linear.size = size;
+	domain->revmap_data.linear.revmap = revmap;
+	return domain;
+}
+
+struct irq_domain *irq_domain_add_nomap(struct device_node *of_node,
+					 struct irq_domain_ops *ops)
+{
+	return irq_domain_add(of_node, IRQ_DOMAIN_MAP_NOMAP, ops);
+}
+
+/**
+ * irq_domain_add_tree()
+ * @of_node: pointer to interrupt controller's device tree node.
+ * @ops: map/unmap domain callbacks
+ *
+ * Note: The radix tree will be allocated later during boot automatically
+ * (the reverse mapping will use the slow path until that happens).
+ */
+struct irq_domain *irq_domain_add_tree(struct device_node *of_node,
+					 struct irq_domain_ops *ops)
+{
+	struct irq_domain *domain = irq_domain_add(of_node, IRQ_DOMAIN_MAP_TREE, ops);
+	if (domain)
+		INIT_RADIX_TREE(&domain->revmap_data.tree, GFP_KERNEL);
 	return domain;
 }
 

@@ -380,9 +428,6 @@ void irq_dispose_mapping(unsigned int virq)
 		break;
 	}
 
-	/* Destroy map */
-	irq_data->hwirq = domain->inval_irq;
-
 	irq_free_desc(virq);
 }
 EXPORT_SYMBOL_GPL(irq_dispose_mapping);