}
 static DEVICE_ATTR_RO(target_type);
 
-static ssize_t emit_target_list(struct cxl_decoder *cxld, char *buf)
+static ssize_t emit_target_list(struct cxl_switch_decoder *cxlsd, char *buf)
 {
+       struct cxl_decoder *cxld = &cxlsd->cxld;
        ssize_t offset = 0;
        int i, rc = 0;
 
        for (i = 0; i < cxld->interleave_ways; i++) {
-               struct cxl_dport *dport = cxld->target[i];
+               struct cxl_dport *dport = cxlsd->target[i];
                struct cxl_dport *next = NULL;
 
                if (!dport)
                        break;
 
                if (i + 1 < cxld->interleave_ways)
-                       next = cxld->target[i + 1];
+                       next = cxlsd->target[i + 1];
                rc = sysfs_emit_at(buf, offset, "%d%s", dport->port_id,
                                   next ? "," : "");
                if (rc < 0)
        return offset;
 }
 
+static struct cxl_switch_decoder *to_cxl_switch_decoder(struct device *dev);
+
 static ssize_t target_list_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
-       struct cxl_decoder *cxld = to_cxl_decoder(dev);
+       struct cxl_switch_decoder *cxlsd = to_cxl_switch_decoder(dev);
        ssize_t offset;
        unsigned int seq;
        int rc;
 
        do {
-               seq = read_seqbegin(&cxld->target_lock);
-               rc = emit_target_list(cxld, buf);
-       } while (read_seqretry(&cxld->target_lock, seq));
+               seq = read_seqbegin(&cxlsd->target_lock);
+               rc = emit_target_list(cxlsd, buf);
+       } while (read_seqretry(&cxlsd->target_lock, seq));
 
        if (rc < 0)
                return rc;
        NULL,
 };
 
+static void __cxl_decoder_release(struct cxl_decoder *cxld)
+{
+       struct cxl_port *port = to_cxl_port(cxld->dev.parent);
+
+       ida_free(&port->decoder_ida, cxld->id);
+       put_device(&port->dev);
+}
+
 static void cxl_decoder_release(struct device *dev)
 {
        struct cxl_decoder *cxld = to_cxl_decoder(dev);
-       struct cxl_port *port = to_cxl_port(dev->parent);
 
-       ida_free(&port->decoder_ida, cxld->id);
+       __cxl_decoder_release(cxld);
        kfree(cxld);
-       put_device(&port->dev);
+}
+
+static void cxl_switch_decoder_release(struct device *dev)
+{
+       struct cxl_switch_decoder *cxlsd = to_cxl_switch_decoder(dev);
+
+       __cxl_decoder_release(&cxlsd->cxld);
+       kfree(cxlsd);
 }
 
 static const struct device_type cxl_decoder_endpoint_type = {
 
 static const struct device_type cxl_decoder_switch_type = {
        .name = "cxl_decoder_switch",
-       .release = cxl_decoder_release,
+       .release = cxl_switch_decoder_release,
        .groups = cxl_decoder_switch_attribute_groups,
 };
 
 static const struct device_type cxl_decoder_root_type = {
        .name = "cxl_decoder_root",
-       .release = cxl_decoder_release,
+       .release = cxl_switch_decoder_release,
        .groups = cxl_decoder_root_attribute_groups,
 };
 
 }
 EXPORT_SYMBOL_NS_GPL(is_root_decoder, CXL);
 
+static bool is_switch_decoder(struct device *dev)
+{
+       return is_root_decoder(dev) || dev->type == &cxl_decoder_switch_type;
+}
+
 struct cxl_decoder *to_cxl_decoder(struct device *dev)
 {
-       if (dev_WARN_ONCE(dev, dev->type->release != cxl_decoder_release,
+       if (dev_WARN_ONCE(dev,
+                         !is_switch_decoder(dev) && !is_endpoint_decoder(dev),
                          "not a cxl_decoder device\n"))
                return NULL;
        return container_of(dev, struct cxl_decoder, dev);
 }
 EXPORT_SYMBOL_NS_GPL(to_cxl_decoder, CXL);
 
+static struct cxl_switch_decoder *to_cxl_switch_decoder(struct device *dev)
+{
+       if (dev_WARN_ONCE(dev, !is_switch_decoder(dev),
+                         "not a cxl_switch_decoder device\n"))
+               return NULL;
+       return container_of(dev, struct cxl_switch_decoder, cxld.dev);
+}
+
 static void cxl_ep_release(struct cxl_ep *ep)
 {
        if (!ep)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_find_dport_by_dev, CXL);
 
-static int decoder_populate_targets(struct cxl_decoder *cxld,
+static int decoder_populate_targets(struct cxl_switch_decoder *cxlsd,
                                    struct cxl_port *port, int *target_map)
 {
        int i, rc = 0;
        if (list_empty(&port->dports))
                return -EINVAL;
 
-       write_seqlock(&cxld->target_lock);
-       for (i = 0; i < cxld->nr_targets; i++) {
+       write_seqlock(&cxlsd->target_lock);
+       for (i = 0; i < cxlsd->nr_targets; i++) {
                struct cxl_dport *dport = find_dport(port, target_map[i]);
 
                if (!dport) {
                        rc = -ENXIO;
                        break;
                }
-               cxld->target[i] = dport;
+               cxlsd->target[i] = dport;
        }
-       write_sequnlock(&cxld->target_lock);
+       write_sequnlock(&cxlsd->target_lock);
 
        return rc;
 }
 static struct lock_class_key cxl_decoder_key;
 
 /**
- * cxl_decoder_alloc - Allocate a new CXL decoder
+ * cxl_decoder_init - Common decoder setup / initialization
  * @port: owning port of this decoder
- * @nr_targets: downstream targets accessible by this decoder. All upstream
- *             ports and root ports must have at least 1 target. Endpoint
- *             devices will have 0 targets. Callers wishing to register an
- *             endpoint device should specify 0.
- *
- * A port should contain one or more decoders. Each of those decoders enable
- * some address space for CXL.mem utilization. A decoder is expected to be
- * configured by the caller before registering.
+ * @cxld: common decoder properties to initialize
  *
- * Return: A new cxl decoder to be registered by cxl_decoder_add(). The decoder
- *        is initialized to be a "passthrough" decoder.
+ * A port may contain one or more decoders. Each of those decoders
+ * enable some address space for CXL.mem utilization. A decoder is
+ * expected to be configured by the caller before registering via
+ * cxl_decoder_add()
  */
-static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port,
-                                            unsigned int nr_targets)
+static int cxl_decoder_init(struct cxl_port *port, struct cxl_decoder *cxld)
 {
-       struct cxl_decoder *cxld;
        struct device *dev;
-       int rc = 0;
-
-       if (nr_targets > CXL_DECODER_MAX_INTERLEAVE)
-               return ERR_PTR(-EINVAL);
-
-       cxld = kzalloc(struct_size(cxld, target, nr_targets), GFP_KERNEL);
-       if (!cxld)
-               return ERR_PTR(-ENOMEM);
+       int rc;
 
        rc = ida_alloc(&port->decoder_ida, GFP_KERNEL);
        if (rc < 0)
-               goto err;
+               return rc;
 
        /* need parent to stick around to release the id */
        get_device(&port->dev);
        cxld->id = rc;
 
-       cxld->nr_targets = nr_targets;
-       seqlock_init(&cxld->target_lock);
        dev = &cxld->dev;
        device_initialize(dev);
        lockdep_set_class(&dev->mutex, &cxl_decoder_key);
        device_set_pm_not_required(dev);
        dev->parent = &port->dev;
        dev->bus = &cxl_bus_type;
-       if (is_cxl_root(port))
-               cxld->dev.type = &cxl_decoder_root_type;
-       else if (is_cxl_endpoint(port))
-               cxld->dev.type = &cxl_decoder_endpoint_type;
-       else
-               cxld->dev.type = &cxl_decoder_switch_type;
 
        /* Pre initialize an "empty" decoder */
        cxld->interleave_ways = 1;
                .end = -1,
        };
 
-       return cxld;
-err:
-       kfree(cxld);
-       return ERR_PTR(rc);
+       return 0;
+}
+
+static int cxl_switch_decoder_init(struct cxl_port *port,
+                                  struct cxl_switch_decoder *cxlsd,
+                                  int nr_targets)
+{
+       if (nr_targets > CXL_DECODER_MAX_INTERLEAVE)
+               return -EINVAL;
+
+       cxlsd->nr_targets = nr_targets;
+       seqlock_init(&cxlsd->target_lock);
+       return cxl_decoder_init(port, &cxlsd->cxld);
 }
 
 /**
  * firmware description of CXL resources into a CXL standard decode
  * topology.
  */
-struct cxl_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
-                                          unsigned int nr_targets)
+struct cxl_switch_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
+                                                 unsigned int nr_targets)
 {
+       struct cxl_switch_decoder *cxlsd;
+       struct cxl_decoder *cxld;
+       int rc;
+
        if (!is_cxl_root(port))
                return ERR_PTR(-EINVAL);
 
-       return cxl_decoder_alloc(port, nr_targets);
+       cxlsd = kzalloc(struct_size(cxlsd, target, nr_targets), GFP_KERNEL);
+       if (!cxlsd)
+               return ERR_PTR(-ENOMEM);
+
+       rc = cxl_switch_decoder_init(port, cxlsd, nr_targets);
+       if (rc) {
+               kfree(cxlsd);
+               return ERR_PTR(rc);
+       }
+
+       cxld = &cxlsd->cxld;
+       cxld->dev.type = &cxl_decoder_root_type;
+       return cxlsd;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_root_decoder_alloc, CXL);
 
  * that sit between Switch Upstream Ports / Switch Downstream Ports and
  * Host Bridges / Root Ports.
  */
-struct cxl_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
-                                            unsigned int nr_targets)
+struct cxl_switch_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
+                                                   unsigned int nr_targets)
 {
+       struct cxl_switch_decoder *cxlsd;
+       struct cxl_decoder *cxld;
+       int rc;
+
        if (is_cxl_root(port) || is_cxl_endpoint(port))
                return ERR_PTR(-EINVAL);
 
-       return cxl_decoder_alloc(port, nr_targets);
+       cxlsd = kzalloc(struct_size(cxlsd, target, nr_targets), GFP_KERNEL);
+       if (!cxlsd)
+               return ERR_PTR(-ENOMEM);
+
+       rc = cxl_switch_decoder_init(port, cxlsd, nr_targets);
+       if (rc) {
+               kfree(cxlsd);
+               return ERR_PTR(rc);
+       }
+
+       cxld = &cxlsd->cxld;
+       cxld->dev.type = &cxl_decoder_switch_type;
+       return cxlsd;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_switch_decoder_alloc, CXL);
 
  */
 struct cxl_decoder *cxl_endpoint_decoder_alloc(struct cxl_port *port)
 {
+       struct cxl_decoder *cxld;
+       int rc;
+
        if (!is_cxl_endpoint(port))
                return ERR_PTR(-EINVAL);
 
-       return cxl_decoder_alloc(port, 0);
+       cxld = kzalloc(sizeof(*cxld), GFP_KERNEL);
+       if (!cxld)
+               return ERR_PTR(-ENOMEM);
+
+       rc = cxl_decoder_init(port, cxld);
+       if (rc)  {
+               kfree(cxld);
+               return ERR_PTR(rc);
+       }
+
+       cxld->dev.type = &cxl_decoder_endpoint_type;
+       return cxld;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_endpoint_decoder_alloc, CXL);
 
 /**
  * cxl_decoder_add_locked - Add a decoder with targets
- * @cxld: The cxl decoder allocated by cxl_decoder_alloc()
+ * @cxld: The cxl decoder allocated by cxl_<type>_decoder_alloc()
  * @target_map: A list of downstream ports that this decoder can direct memory
  *              traffic to. These numbers should correspond with the port number
  *              in the PCIe Link Capabilities structure.
 
        port = to_cxl_port(cxld->dev.parent);
        if (!is_endpoint_decoder(dev)) {
-               rc = decoder_populate_targets(cxld, port, target_map);
+               struct cxl_switch_decoder *cxlsd = to_cxl_switch_decoder(dev);
+
+               rc = decoder_populate_targets(cxlsd, port, target_map);
                if (rc && (cxld->flags & CXL_DECODER_F_ENABLE)) {
                        dev_err(&port->dev,
                                "Failed to populate active decoder targets\n");
 
 /**
  * cxl_decoder_add - Add a decoder with targets
- * @cxld: The cxl decoder allocated by cxl_decoder_alloc()
+ * @cxld: The cxl decoder allocated by cxl_<type>_decoder_alloc()
  * @target_map: A list of downstream ports that this decoder can direct memory
  *              traffic to. These numbers should correspond with the port number
  *              in the PCIe Link Capabilities structure.
 
 #define CXL_DECODER_MAX_INTERLEAVE 16
 
 /**
- * struct cxl_decoder - CXL address range decode configuration
+ * struct cxl_decoder - Common CXL HDM Decoder Attributes
  * @dev: this decoder's device
  * @id: kernel device name id
  * @hpa_range: Host physical address range mapped by this decoder
  * @interleave_granularity: data stride per dport
  * @target_type: accelerator vs expander (type2 vs type3) selector
  * @flags: memory type capabilities and locking
- * @target_lock: coordinate coherent reads of the target list
- * @nr_targets: number of elements in @target
- * @target: active ordered target list in current decoder configuration
  */
 struct cxl_decoder {
        struct device dev;
        int interleave_granularity;
        enum cxl_decoder_type target_type;
        unsigned long flags;
+};
+
+/**
+ * struct cxl_switch_decoder - Switch specific CXL HDM Decoder
+ * @cxld: base cxl_decoder object
+ * @target_lock: coordinate coherent reads of the target list
+ * @nr_targets: number of elements in @target
+ * @target: active ordered target list in current decoder configuration
+ *
+ * The 'switch' decoder type represents the decoder instances of cxl_port's that
+ * route from the root of a CXL memory decode topology to the endpoints. They
+ * come in two flavors, root-level decoders, statically defined by platform
+ * firmware, and mid-level decoders, where interleave-granularity,
+ * interleave-width, and the target list are mutable.
+ */
+struct cxl_switch_decoder {
+       struct cxl_decoder cxld;
        seqlock_t target_lock;
        int nr_targets;
        struct cxl_dport *target[];
 struct cxl_decoder *to_cxl_decoder(struct device *dev);
 bool is_root_decoder(struct device *dev);
 bool is_endpoint_decoder(struct device *dev);
-struct cxl_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
-                                          unsigned int nr_targets);
-struct cxl_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
-                                            unsigned int nr_targets);
+struct cxl_switch_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
+                                                 unsigned int nr_targets);
+struct cxl_switch_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
+                                                   unsigned int nr_targets);
 int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
 struct cxl_decoder *cxl_endpoint_decoder_alloc(struct cxl_port *port);
 int cxl_decoder_add_locked(struct cxl_decoder *cxld, int *target_map);