3 files changed, 28 insertions, 1 deletions

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index ab9d455e8579..1990a5940b7c 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -1272,6 +1272,7 @@ struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev)
 	mutex_init(&mds->mbox_mutex);
 	mutex_init(&mds->event.log_lock);
 	mds->cxlds.dev = dev;
+	mds->cxlds.type = CXL_DEVTYPE_CLASSMEM;
 
 	return mds;
 }
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 15434b1b4909..3f2d54f30548 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -41,6 +41,8 @@ static ssize_t firmware_version_show(struct device *dev,
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
 
+	if (!mds)
+		return sysfs_emit(buf, "\n");
 	return sysfs_emit(buf, "%.16s\n", mds->firmware_version);
 }
 static DEVICE_ATTR_RO(firmware_version);
@@ -52,6 +54,8 @@ static ssize_t payload_max_show(struct device *dev,
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
 
+	if (!mds)
+		return sysfs_emit(buf, "\n");
 	return sysfs_emit(buf, "%zu\n", mds->payload_size);
 }
 static DEVICE_ATTR_RO(payload_max);
@@ -63,6 +67,8 @@ static ssize_t label_storage_size_show(struct device *dev,
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
 
+	if (!mds)
+		return sysfs_emit(buf, "\n");
 	return sysfs_emit(buf, "%zu\n", mds->lsa_size);
 }
 static DEVICE_ATTR_RO(label_storage_size);
@@ -517,10 +523,12 @@ static long cxl_memdev_ioctl(struct file *file, unsigned int cmd,
 			     unsigned long arg)
 {
 	struct cxl_memdev *cxlmd = file->private_data;
+	struct cxl_dev_state *cxlds;
 	int rc = -ENXIO;
 
 	down_read(&cxl_memdev_rwsem);
-	if (cxlmd->cxlds)
+	cxlds = cxlmd->cxlds;
+	if (cxlds && cxlds->type == CXL_DEVTYPE_CLASSMEM)
 		rc = __cxl_memdev_ioctl(cxlmd, cmd, arg);
 	up_read(&cxl_memdev_rwsem);
 
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index b1a72e01e4de..1b39afeb369e 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -254,6 +254,20 @@ struct cxl_poison_state {
 	struct mutex lock;  /* Protect reads of poison list */
 };
 
+/*
+ * enum cxl_devtype - delineate type-2 from a generic type-3 device
+ * @CXL_DEVTYPE_DEVMEM - Vendor specific CXL Type-2 device implementing HDM-D or
+ *			 HDM-DB, no requirement that this device implements a
+ *			 mailbox, or other memory-device-standard manageability
+ *			 flows.
+ * @CXL_DEVTYPE_CLASSMEM - Common class definition of a CXL Type-3 device with
+ *			   HDM-H and class-mandatory memory device registers
+ */
+enum cxl_devtype {
+	CXL_DEVTYPE_DEVMEM,
+	CXL_DEVTYPE_CLASSMEM,
+};
+
 /**
  * struct cxl_dev_state - The driver device state
  *
@@ -272,6 +286,7 @@ struct cxl_poison_state {
  * @ram_res: Active Volatile memory capacity configuration
  * @component_reg_phys: register base of component registers
  * @serial: PCIe Device Serial Number
+ * @type: Generic Memory Class device or Vendor Specific Memory device
  */
 struct cxl_dev_state {
 	struct device *dev;
@@ -285,6 +300,7 @@ struct cxl_dev_state {
 	struct resource ram_res;
 	resource_size_t component_reg_phys;
 	u64 serial;
+	enum cxl_devtype type;
 };
 
 /**
@@ -343,6 +359,8 @@ struct cxl_memdev_state {
 static inline struct cxl_memdev_state *
 to_cxl_memdev_state(struct cxl_dev_state *cxlds)
 {
+	if (cxlds->type != CXL_DEVTYPE_CLASSMEM)
+		return NULL;
 	return container_of(cxlds, struct cxl_memdev_state, cxlds);
 }