1 files changed, 121 insertions, 0 deletions

diff --git a/drivers/cxl/core.c b/drivers/cxl/core.c
index 68d6afea363b..aaffb390d168 100644
--- a/drivers/cxl/core.c
+++ b/drivers/cxl/core.c
@@ -187,6 +187,12 @@ static const struct device_type cxl_decoder_root_type = {
 	.groups = cxl_decoder_root_attribute_groups,
 };
 
+bool is_root_decoder(struct device *dev)
+{
+	return dev->type == &cxl_decoder_root_type;
+}
+EXPORT_SYMBOL_GPL(is_root_decoder);
+
 struct cxl_decoder *to_cxl_decoder(struct device *dev)
 {
 	if (dev_WARN_ONCE(dev, dev->type->release != cxl_decoder_release,
@@ -194,6 +200,7 @@ struct cxl_decoder *to_cxl_decoder(struct device *dev)
 		return NULL;
 	return container_of(dev, struct cxl_decoder, dev);
 }
+EXPORT_SYMBOL_GPL(to_cxl_decoder);
 
 static void cxl_dport_release(struct cxl_dport *dport)
 {
@@ -611,6 +618,118 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 }
 EXPORT_SYMBOL_GPL(cxl_probe_component_regs);
 
+static void cxl_nvdimm_bridge_release(struct device *dev)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
+
+	kfree(cxl_nvb);
+}
+
+static const struct attribute_group *cxl_nvdimm_bridge_attribute_groups[] = {
+	&cxl_base_attribute_group,
+	NULL,
+};
+
+static const struct device_type cxl_nvdimm_bridge_type = {
+	.name = "cxl_nvdimm_bridge",
+	.release = cxl_nvdimm_bridge_release,
+	.groups = cxl_nvdimm_bridge_attribute_groups,
+};
+
+struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev)
+{
+	if (dev_WARN_ONCE(dev, dev->type != &cxl_nvdimm_bridge_type,
+			  "not a cxl_nvdimm_bridge device\n"))
+		return NULL;
+	return container_of(dev, struct cxl_nvdimm_bridge, dev);
+}
+EXPORT_SYMBOL_GPL(to_cxl_nvdimm_bridge);
+
+static struct cxl_nvdimm_bridge *
+cxl_nvdimm_bridge_alloc(struct cxl_port *port)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb;
+	struct device *dev;
+
+	cxl_nvb = kzalloc(sizeof(*cxl_nvb), GFP_KERNEL);
+	if (!cxl_nvb)
+		return ERR_PTR(-ENOMEM);
+
+	dev = &cxl_nvb->dev;
+	cxl_nvb->port = port;
+	cxl_nvb->state = CXL_NVB_NEW;
+	device_initialize(dev);
+	device_set_pm_not_required(dev);
+	dev->parent = &port->dev;
+	dev->bus = &cxl_bus_type;
+	dev->type = &cxl_nvdimm_bridge_type;
+
+	return cxl_nvb;
+}
+
+static void unregister_nvb(void *_cxl_nvb)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb = _cxl_nvb;
+	bool flush;
+
+	/*
+	 * If the bridge was ever activated then there might be in-flight state
+	 * work to flush. Once the state has been changed to 'dead' then no new
+	 * work can be queued by user-triggered bind.
+	 */
+	device_lock(&cxl_nvb->dev);
+	flush = cxl_nvb->state != CXL_NVB_NEW;
+	cxl_nvb->state = CXL_NVB_DEAD;
+	device_unlock(&cxl_nvb->dev);
+
+	/*
+	 * Even though the device core will trigger device_release_driver()
+	 * before the unregister, it does not know about the fact that
+	 * cxl_nvdimm_bridge_driver defers ->remove() work. So, do the driver
+	 * release not and flush it before tearing down the nvdimm device
+	 * hierarchy.
+	 */
+	device_release_driver(&cxl_nvb->dev);
+	if (flush)
+		flush_work(&cxl_nvb->state_work);
+	device_unregister(&cxl_nvb->dev);
+}
+
+struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
+						     struct cxl_port *port)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb;
+	struct device *dev;
+	int rc;
+
+	if (!IS_ENABLED(CONFIG_CXL_PMEM))
+		return ERR_PTR(-ENXIO);
+
+	cxl_nvb = cxl_nvdimm_bridge_alloc(port);
+	if (IS_ERR(cxl_nvb))
+		return cxl_nvb;
+
+	dev = &cxl_nvb->dev;
+	rc = dev_set_name(dev, "nvdimm-bridge");
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	rc = devm_add_action_or_reset(host, unregister_nvb, cxl_nvb);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return cxl_nvb;
+
+err:
+	put_device(dev);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm_bridge);
+
 /**
  * cxl_probe_device_regs() - Detect CXL Device register blocks
  * @dev: Host device of the @base mapping
@@ -808,6 +927,8 @@ EXPORT_SYMBOL_GPL(cxl_driver_unregister);
 
 static int cxl_device_id(struct device *dev)
 {
+	if (dev->type == &cxl_nvdimm_bridge_type)
+		return CXL_DEVICE_NVDIMM_BRIDGE;
 	return 0;
 }