4 files changed, 66 insertions, 1 deletions

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index fcf14b8a3c87..391aadf9e7fa 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -13,14 +13,26 @@ extern struct attribute_group cxl_base_attribute_group;
 extern struct device_attribute dev_attr_create_pmem_region;
 extern struct device_attribute dev_attr_delete_region;
 extern struct device_attribute dev_attr_region;
+extern const struct device_type cxl_region_type;
 void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled);
 #define CXL_REGION_ATTR(x) (&dev_attr_##x.attr)
+#define CXL_REGION_TYPE(x) (&cxl_region_type)
 #define SET_CXL_REGION_ATTR(x) (&dev_attr_##x.attr),
+int cxl_region_init(void);
+void cxl_region_exit(void);
 #else
 static inline void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled)
 {
 }
+static inline int cxl_region_init(void)
+{
+	return 0;
+}
+static inline void cxl_region_exit(void)
+{
+}
 #define CXL_REGION_ATTR(x) NULL
+#define CXL_REGION_TYPE(x) NULL
 #define SET_CXL_REGION_ATTR(x)
 #endif
 
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 40b4a72d6539..ba66ce25de30 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -51,6 +51,8 @@ static int cxl_device_id(struct device *dev)
 	}
 	if (is_cxl_memdev(dev))
 		return CXL_DEVICE_MEMORY_EXPANDER;
+	if (dev->type == CXL_REGION_TYPE())
+		return CXL_DEVICE_REGION;
 	return 0;
 }
 
@@ -1864,8 +1866,14 @@ static __init int cxl_core_init(void)
 	if (rc)
 		goto err_bus;
 
+	rc = cxl_region_init();
+	if (rc)
+		goto err_region;
+
 	return 0;
 
+err_region:
+	bus_unregister(&cxl_bus_type);
 err_bus:
 	destroy_workqueue(cxl_bus_wq);
 err_wq:
@@ -1875,6 +1883,7 @@ err_wq:
 
 static void cxl_core_exit(void)
 {
+	cxl_region_exit();
 	bus_unregister(&cxl_bus_type);
 	destroy_workqueue(cxl_bus_wq);
 	cxl_memdev_exit();
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 800085300779..bf4e7f5499c1 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1450,7 +1450,7 @@ static void cxl_region_release(struct device *dev)
 	kfree(cxlr);
 }
 
-static const struct device_type cxl_region_type = {
+const struct device_type cxl_region_type = {
 	.name = "cxl_region",
 	.release = cxl_region_release,
 	.groups = region_groups
@@ -1650,4 +1650,47 @@ static ssize_t delete_region_store(struct device *dev,
 }
 DEVICE_ATTR_WO(delete_region);
 
+static int cxl_region_probe(struct device *dev)
+{
+	struct cxl_region *cxlr = to_cxl_region(dev);
+	struct cxl_region_params *p = &cxlr->params;
+	int rc;
+
+	rc = down_read_interruptible(&cxl_region_rwsem);
+	if (rc) {
+		dev_dbg(&cxlr->dev, "probe interrupted\n");
+		return rc;
+	}
+
+	if (p->state < CXL_CONFIG_COMMIT) {
+		dev_dbg(&cxlr->dev, "config state: %d\n", p->state);
+		rc = -ENXIO;
+	}
+
+	/*
+	 * From this point on any path that changes the region's state away from
+	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
+	 */
+	up_read(&cxl_region_rwsem);
+
+	return rc;
+}
+
+static struct cxl_driver cxl_region_driver = {
+	.name = "cxl_region",
+	.probe = cxl_region_probe,
+	.id = CXL_DEVICE_REGION,
+};
+
+int cxl_region_init(void)
+{
+	return cxl_driver_register(&cxl_region_driver);
+}
+
+void cxl_region_exit(void)
+{
+	cxl_driver_unregister(&cxl_region_driver);
+}
+
 MODULE_IMPORT_NS(CXL);
+MODULE_ALIAS_CXL(CXL_DEVICE_REGION);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 01095d78784d..e96bf8ccccf2 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -599,6 +599,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv);
 #define CXL_DEVICE_PORT			3
 #define CXL_DEVICE_ROOT			4
 #define CXL_DEVICE_MEMORY_EXPANDER	5
+#define CXL_DEVICE_REGION		6
 
 #define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
 #define CXL_MODALIAS_FMT "cxl:t%d"