genirq/msi: Add msi_domain_populate_irqs

To be able to allocate interrupts from the MSI layer down,
add a new msi_domain_populate_irqs entry point.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

2 files changed, 42 insertions, 0 deletions

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 1c0bb2c0b211..cee102b1916d 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -283,6 +283,8 @@ void platform_msi_domain_free_irqs(struct device *dev);
 /* When an MSI domain is used as an intermediate domain */
 int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
                             int nvec, msi_alloc_info_t *args);
+int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
+                             int virq, int nvec, msi_alloc_info_t *args);
 #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
 
 #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 9a85613d4227..15b249e7c673 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -266,6 +266,46 @@ int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
         return ret;
 }
 
+int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
+                             int virq, int nvec, msi_alloc_info_t *arg)
+{
+        struct msi_domain_info *info = domain->host_data;
+        struct msi_domain_ops *ops = info->ops;
+        struct msi_desc *desc;
+        int ret = 0;
+
+        for_each_msi_entry(desc, dev) {
+                /* Don't even try the multi-MSI brain damage. */
+                if (WARN_ON(!desc->irq || desc->nvec_used != 1)) {
+                        ret = -EINVAL;
+                        break;
+                }
+
+                if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
+                        continue;
+
+                ops->set_desc(arg, desc);
+                /* Assumes the domain mutex is held! */
+                ret = irq_domain_alloc_irqs_recursive(domain, virq, 1, arg);
+                if (ret)
+                        break;
+
+                irq_set_msi_desc_off(virq, 0, desc);
+        }
+
+        if (ret) {
+                /* Mop up the damage */
+                for_each_msi_entry(desc, dev) {
+                        if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
+                                continue;
+
+                        irq_domain_free_irqs_common(domain, desc->irq, 1);
+                }
+        }
+
+        return ret;
+}
+
 /**
  * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
  * @domain:     The domain to allocate from