diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index f37ad34c80ec..dbd19f329354 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -13,6 +13,8 @@
 #include <linux/msi.h>
 #include <linux/slab.h>
 
+/* Begin of removal area. Once everything is converted over. Cleanup the includes too! */
+
 #define DEV_ID_SHIFT	21
 #define MAX_DEV_MSIS	(1 << (32 - DEV_ID_SHIFT))
 
@@ -350,3 +352,98 @@ int platform_msi_device_domain_alloc(struct irq_domain *domain, unsigned int vir
 
 	return msi_domain_populate_irqs(domain->parent, dev, virq, nr_irqs, &data->arg);
 }
+
+/* End of removal area */
+
+/* Real per device domain interfaces */
+
+/*
+ * This indirection can go when platform_device_ims_init_and_alloc_irqs()
+ * is switched to a proper irq_chip::irq_write_msi_msg() callback. Keep it
+ * simple for now.
+ */
+static void platform_msi_write_msi_msg(struct irq_data *d, struct msi_msg *msg)
+{
+	irq_write_msi_msg_t cb = d->chip_data;
+
+	cb(irq_data_get_msi_desc(d), msg);
+}
+
+static void platform_msi_set_desc_byindex(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = desc->msi_index;
+}
+
+static const struct msi_domain_template platform_msi_template = {
+	.chip = {
+		.name			= "pMSI",
+		.irq_mask		= irq_chip_mask_parent,
+		.irq_unmask		= irq_chip_unmask_parent,
+		.irq_write_msi_msg	= platform_msi_write_msi_msg,
+		/* The rest is filled in by the platform MSI parent */
+	},
+
+	.ops = {
+		.set_desc		= platform_msi_set_desc_byindex,
+	},
+
+	.info = {
+		.bus_token		= DOMAIN_BUS_DEVICE_IMS,
+	},
+};
+
+/**
+ * platform_device_ims_init_and_alloc_irqs - Initialize platform device IMS
+ *					     and allocate interrupts for @dev
+ * @dev:		The device for which to allocate interrupts
+ * @nvec:		The number of interrupts to allocate
+ * @write_msi_msg:	Callback to write an interrupt message for @dev
+ *
+ * Returns:
+ * Zero for success, or an error code in case of failure
+ *
+ * This creates a MSI domain on @dev which has @dev->msi.domain as
+ * parent. The parent domain sets up the new domain. The domain has
+ * a fixed size of @nvec. The domain is managed by devres and will
+ * be removed when the device is removed.
+ *
+ * Note: For migration purposes this falls back to the original platform_msi code
+ *	 up to the point where all platforms have been converted to the MSI
+ *	 parent model.
+ */
+int platform_device_ims_init_and_alloc_irqs(struct device *dev, unsigned int nvec,
+					    irq_write_msi_msg_t write_msi_msg)
+{
+	struct irq_domain *domain = dev->msi.domain;
+
+	if (!domain || !write_msi_msg)
+		return -EINVAL;
+
+	/* Migration support. Will go away once everything is converted */
+	if (!irq_domain_is_msi_parent(domain))
+		return platform_msi_domain_alloc_irqs(dev, nvec, write_msi_msg);
+
+	/*
+	 * @write_msi_msg is stored in the resulting msi_domain_info::data.
+	 * The underlying domain creation mechanism will assign that
+	 * callback to the resulting irq chip.
+	 */
+	if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN,
+					  &platform_msi_template,
+					  nvec, NULL, write_msi_msg))
+		return -ENODEV;
+
+	return msi_domain_alloc_irqs_range(dev, MSI_DEFAULT_DOMAIN, 0, nvec - 1);
+}
+EXPORT_SYMBOL_GPL(platform_device_ims_init_and_alloc_irqs);
+
+/**
+ * platform_device_ims_free_irqs_all - Free all interrupts for @dev
+ * @dev:	The device for which to free interrupts
+ */
+void platform_device_ims_free_irqs_all(struct device *dev)
+{
+	msi_domain_free_irqs_all(dev, MSI_DEFAULT_DOMAIN);
+}
+EXPORT_SYMBOL_GPL(platform_device_ims_free_irqs_all);
diff --git a/include/linux/msi.h b/include/linux/msi.h
index d5d1513ef4d6..9bec9ca19800 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -664,6 +664,10 @@ int platform_msi_device_domain_alloc(struct irq_domain *domain, unsigned int vir
 void platform_msi_device_domain_free(struct irq_domain *domain, unsigned int virq,
 				     unsigned int nvec);
 void *platform_msi_get_host_data(struct irq_domain *domain);
+/* Per device platform MSI */
+int platform_device_ims_init_and_alloc_irqs(struct device *dev, unsigned int nvec,
+					    irq_write_msi_msg_t write_msi_msg);
+void platform_device_ims_free_irqs_all(struct device *dev);
 
 bool msi_device_has_isolated_msi(struct device *dev);
 #else /* CONFIG_GENERIC_MSI_IRQ */
