5 files changed, 85 insertions, 38 deletions

diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index 728cc30d04ea..fe0b09dceb7d 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -36,9 +36,6 @@ extern atomic_t ppc_n_lost_interrupts;
 /* Total number of virq in the platform */
 #define NR_IRQS         CONFIG_NR_IRQS
 
-/* Number of irqs reserved for the legacy controller */
-#define NUM_ISA_INTERRUPTS      16
-
 /* Same thing, used by the generic IRQ code */
 #define NR_IRQS_LEGACY          NUM_ISA_INTERRUPTS
 
diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
index 573a73bd954a..997df6a7ab5d 100644
--- a/arch/powerpc/sysdev/i8259.c
+++ b/arch/powerpc/sysdev/i8259.c
@@ -263,7 +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_domain_add_legacy(node, &i8259_host_ops, NULL);
+        i8259_host = irq_domain_add_legacy_isa(node, &i8259_host_ops, NULL);
         if (i8259_host == NULL) {
                 printk(KERN_ERR "i8259: failed to allocate irq host !\n");
                 return;
diff --git a/arch/powerpc/sysdev/tsi108_pci.c b/arch/powerpc/sysdev/tsi108_pci.c
index 1be26f4b9c96..188012c58f7f 100644
--- a/arch/powerpc/sysdev/tsi108_pci.c
+++ b/arch/powerpc/sysdev/tsi108_pci.c
@@ -419,7 +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_domain_add_legacy(node, &pci_irq_domain_ops, NULL);
+        pci_irq_host = irq_domain_add_legacy_isa(node, &pci_irq_domain_ops, NULL);
         if (pci_irq_host == NULL) {
                 printk(KERN_ERR "pci_irq_host: failed to allocate irq domain!\n");
                 return;
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index f95553fa6872..7fef39ed5523 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -39,6 +39,9 @@ struct device_node;
 struct irq_domain;
 struct of_device_id;
 
+/* Number of irqs reserved for a legacy isa controller */
+#define NUM_ISA_INTERRUPTS      16
+
 /* This type is the placeholder for a hardware interrupt number. It has to
  * be big enough to enclose whatever representation is used by a given
  * platform.
@@ -98,6 +101,11 @@ struct irq_domain {
         union {
                 struct {
                         unsigned int size;
+                        unsigned int first_irq;
+                        irq_hw_number_t first_hwirq;
+                } legacy;
+                struct {
+                        unsigned int size;
                         unsigned int *revmap;
                 } linear;
                 struct radix_tree_root tree;
@@ -117,6 +125,9 @@ struct irq_domain {
 #ifdef CONFIG_IRQ_DOMAIN
 #ifdef CONFIG_PPC
 struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
+                                         unsigned int size,
+                                         unsigned int first_irq,
+                                         irq_hw_number_t first_hwirq,
                                          struct irq_domain_ops *ops,
                                          void *host_data);
 struct irq_domain *irq_domain_add_linear(struct device_node *of_node,
@@ -130,11 +141,18 @@ struct irq_domain *irq_domain_add_tree(struct device_node *of_node,
                                          struct irq_domain_ops *ops,
                                          void *host_data);
 
-
 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);
 
+static inline struct irq_domain *irq_domain_add_legacy_isa(
+                                struct device_node *of_node,
+                                struct irq_domain_ops *ops,
+                                void *host_data)
+{
+        return irq_domain_add_legacy(of_node, NUM_ISA_INTERRUPTS, 0, 0, ops,
+                                     host_data);
+}
 
 extern unsigned int irq_create_mapping(struct irq_domain *host,
                                        irq_hw_number_t hwirq);
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index acedba1a2651..c6740d72073e 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -13,7 +13,8 @@
 #include <linux/smp.h>
 #include <linux/fs.h>
 
-#define IRQ_DOMAIN_MAP_LEGACY 0 /* legacy 8259, gets irqs 1..15 */
+#define IRQ_DOMAIN_MAP_LEGACY 0 /* driver allocated fixed range of irqs.
+                                 * ie. legacy 8259, gets irqs 1..15 */
 #define IRQ_DOMAIN_MAP_NOMAP 1 /* no fast reverse mapping */
 #define IRQ_DOMAIN_MAP_LINEAR 2 /* linear map of interrupts */
 #define IRQ_DOMAIN_MAP_TREE 3 /* radix tree */
@@ -74,9 +75,25 @@ static void irq_domain_add(struct irq_domain *domain)
                  domain->revmap_type, domain);
 }
 
+static unsigned int irq_domain_legacy_revmap(struct irq_domain *domain,
+                                             irq_hw_number_t hwirq)
+{
+        irq_hw_number_t first_hwirq = domain->revmap_data.legacy.first_hwirq;
+        int size = domain->revmap_data.legacy.size;
+
+        if (WARN_ON(hwirq < first_hwirq || hwirq >= first_hwirq + size))
+                return 0;
+        return hwirq - first_hwirq + domain->revmap_data.legacy.first_irq;
+}
+
 /**
  * irq_domain_add_legacy() - Allocate and register a legacy revmap irq_domain.
  * @of_node: pointer to interrupt controller's device tree node.
+ * @size: total number of irqs in legacy mapping
+ * @first_irq: first number of irq block assigned to the domain
+ * @first_hwirq: first hwirq number to use for the translation. Should normally
+ *               be '0', but a positive integer can be used if the effective
+ *               hwirqs numbering does not begin at zero.
  * @ops: map/unmap domain callbacks
  * @host_data: Controller private data pointer
  *
@@ -85,44 +102,64 @@ static void irq_domain_add(struct irq_domain *domain)
  * a legacy controller).
  */
 struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
+                                         unsigned int size,
+                                         unsigned int first_irq,
+                                         irq_hw_number_t first_hwirq,
                                          struct irq_domain_ops *ops,
                                          void *host_data)
 {
-        struct irq_domain *domain, *h;
+        struct irq_domain *domain;
         unsigned int i;
 
         domain = irq_domain_alloc(of_node, IRQ_DOMAIN_MAP_LEGACY, ops, host_data);
         if (!domain)
                 return NULL;
 
+        domain->revmap_data.legacy.first_irq = first_irq;
+        domain->revmap_data.legacy.first_hwirq = first_hwirq;
+        domain->revmap_data.legacy.size = size;
+
         mutex_lock(&irq_domain_mutex);
-        /* Make sure only one legacy controller can be created */
-        list_for_each_entry(h, &irq_domain_list, link) {
-                if (WARN_ON(h->revmap_type == IRQ_DOMAIN_MAP_LEGACY)) {
+        /* Verify that all the irqs are available */
+        for (i = 0; i < size; i++) {
+                int irq = first_irq + i;
+                struct irq_data *irq_data = irq_get_irq_data(irq);
+
+                if (WARN_ON(!irq_data || irq_data->domain)) {
                         mutex_unlock(&irq_domain_mutex);
                         of_node_put(domain->of_node);
                         kfree(domain);
                         return NULL;
                 }
         }
-        list_add(&domain->link, &irq_domain_list);
-        mutex_unlock(&irq_domain_mutex);
 
-        /* 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;
+        /* Claim all of the irqs before registering a legacy domain */
+        for (i = 0; i < size; i++) {
+                struct irq_data *irq_data = irq_get_irq_data(first_irq + i);
+                irq_data->hwirq = first_hwirq + i;
                 irq_data->domain = domain;
+        }
+        mutex_unlock(&irq_domain_mutex);
+
+        for (i = 0; i < size; i++) {
+                int irq = first_irq + i;
+                int hwirq = first_hwirq + i;
+
+                /* IRQ0 gets ignored */
+                if (!irq)
+                        continue;
 
                 /* 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);
+                ops->map(domain, irq, hwirq);
 
                 /* Clear norequest flags */
-                irq_clear_status_flags(i, IRQ_NOREQUEST);
+                irq_clear_status_flags(irq, IRQ_NOREQUEST);
         }
+
+        irq_domain_add(domain);
         return domain;
 }
 
@@ -338,24 +375,19 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
         }
 
         /* Get a virtual interrupt number */
-        if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY) {
-                /* Handle legacy */
-                virq = (unsigned int)hwirq;
-                if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
-                        return 0;
-                return virq;
-        } else {
-                /* Allocate a virtual interrupt number */
-                hint = hwirq % irq_virq_count;
-                if (hint == 0)
-                        hint++;
-                virq = irq_alloc_desc_from(hint, 0);
-                if (!virq)
-                        virq = irq_alloc_desc_from(1, 0);
-                if (!virq) {
-                        pr_debug("irq: -> virq allocation failed\n");
-                        return 0;
-                }
+        if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY)
+                return irq_domain_legacy_revmap(domain, hwirq);
+
+        /* Allocate a virtual interrupt number */
+        hint = hwirq % irq_virq_count;
+        if (hint == 0)
+                hint++;
+        virq = irq_alloc_desc_from(hint, 0);
+        if (!virq)
+                virq = irq_alloc_desc_from(1, 0);
+        if (!virq) {
+                pr_debug("irq: -> virq allocation failed\n");
+                return 0;
         }
 
         if (irq_setup_virq(domain, virq, hwirq)) {
@@ -483,7 +515,7 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 
         /* legacy -> bail early */
         if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY)
-                return hwirq;
+                return irq_domain_legacy_revmap(domain, hwirq);
 
         /* Slow path does a linear search of the map */
         if (hint == 0)