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From e921d59a75c7932fd33bfa64c156fd40d7ba4da9 Mon Sep 17 00:00:00 2001
From: Ben Widawsky <ben.widawsky@intel.com>
Date: Mon, 2 Aug 2021 10:29:38 -0700
Subject: [PATCH] cxl: Move cxl_core to new directory
Git-commit: 5161a55c069f53d88da49274cbef6e3c74eadea9
Patch-mainline: v5.15-rc1
References: stable-5.14.8

[ backport note: fixed remove callback to void for build fix -- tiwai ]

[ Upstream commit 5161a55c069f53d88da49274cbef6e3c74eadea9 ]

CXL core is growing, and it's already arguably unmanageable. To support
future growth, move core functionality to a new directory and rename the
file to represent just bus support. Future work will remove non-bus
functionality.

Note that mem.h is renamed to cxlmem.h to avoid a namespace collision
with the global ARCH=um mem.h header.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/162792537866.368511.8915631504621088321.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 Documentation/driver-api/cxl/memory-devices.rst |    2 
 drivers/cxl/Makefile                            |    4 
 drivers/cxl/core/Makefile                       |    5 
 drivers/cxl/core/bus.c                          | 1066 ++++++++++++++++++++++++
 drivers/cxl/cxlmem.h                            |   81 +
 drivers/cxl/mem.h                               |   81 -
 drivers/cxl/pci.c                               |    2 
 drivers/cxl/pmem.c                              |    2 
 8 files changed, 1156 insertions(+), 87 deletions(-)
 delete mode 100644 drivers/cxl/core.c
 create mode 100644 drivers/cxl/core/Makefile
 create mode 100644 drivers/cxl/core/bus.c
 create mode 100644 drivers/cxl/cxlmem.h
 delete mode 100644 drivers/cxl/mem.h

--- a/Documentation/driver-api/cxl/memory-devices.rst
+++ b/Documentation/driver-api/cxl/memory-devices.rst
@@ -36,7 +36,7 @@ CXL Core
 .. kernel-doc:: drivers/cxl/cxl.h
    :internal:
 
-.. kernel-doc:: drivers/cxl/core.c
+.. kernel-doc:: drivers/cxl/core/bus.c
    :doc: cxl core
 
 External Interfaces
--- a/drivers/cxl/Makefile
+++ b/drivers/cxl/Makefile
@@ -1,11 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_CXL_BUS) += cxl_core.o
+obj-$(CONFIG_CXL_BUS) += core/
 obj-$(CONFIG_CXL_MEM) += cxl_pci.o
 obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
 obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
 
-ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL
-cxl_core-y := core.o
 cxl_pci-y := pci.o
 cxl_acpi-y := acpi.o
 cxl_pmem-y := pmem.o
--- /dev/null
+++ b/drivers/cxl/core/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CXL_BUS) += cxl_core.o
+
+ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL -I$(srctree)/drivers/cxl
+cxl_core-y := bus.o
--- /dev/null
+++ b/drivers/cxl/core/bus.c
@@ -0,0 +1,1066 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <cxlmem.h>
+#include <cxl.h>
+
+/**
+ * DOC: cxl core
+ *
+ * The CXL core provides a sysfs hierarchy for control devices and a rendezvous
+ * point for cross-device interleave coordination through cxl ports.
+ */
+
+static DEFINE_IDA(cxl_port_ida);
+
+static ssize_t devtype_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	return sysfs_emit(buf, "%s\n", dev->type->name);
+}
+static DEVICE_ATTR_RO(devtype);
+
+static struct attribute *cxl_base_attributes[] = {
+	&dev_attr_devtype.attr,
+	NULL,
+};
+
+static struct attribute_group cxl_base_attribute_group = {
+	.attrs = cxl_base_attributes,
+};
+
+static ssize_t start_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+
+	return sysfs_emit(buf, "%#llx\n", cxld->range.start);
+}
+static DEVICE_ATTR_RO(start);
+
+static ssize_t size_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+
+	return sysfs_emit(buf, "%#llx\n", range_len(&cxld->range));
+}
+static DEVICE_ATTR_RO(size);
+
+#define CXL_DECODER_FLAG_ATTR(name, flag)                            \
+static ssize_t name##_show(struct device *dev,                       \
+			   struct device_attribute *attr, char *buf) \
+{                                                                    \
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);              \
+                                                                     \
+	return sysfs_emit(buf, "%s\n",                               \
+			  (cxld->flags & (flag)) ? "1" : "0");       \
+}                                                                    \
+static DEVICE_ATTR_RO(name)
+
+CXL_DECODER_FLAG_ATTR(cap_pmem, CXL_DECODER_F_PMEM);
+CXL_DECODER_FLAG_ATTR(cap_ram, CXL_DECODER_F_RAM);
+CXL_DECODER_FLAG_ATTR(cap_type2, CXL_DECODER_F_TYPE2);
+CXL_DECODER_FLAG_ATTR(cap_type3, CXL_DECODER_F_TYPE3);
+CXL_DECODER_FLAG_ATTR(locked, CXL_DECODER_F_LOCK);
+
+static ssize_t target_type_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+
+	switch (cxld->target_type) {
+	case CXL_DECODER_ACCELERATOR:
+		return sysfs_emit(buf, "accelerator\n");
+	case CXL_DECODER_EXPANDER:
+		return sysfs_emit(buf, "expander\n");
+	}
+	return -ENXIO;
+}
+static DEVICE_ATTR_RO(target_type);
+
+static ssize_t target_list_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+	ssize_t offset = 0;
+	int i, rc = 0;
+
+	device_lock(dev);
+	for (i = 0; i < cxld->interleave_ways; i++) {
+		struct cxl_dport *dport = cxld->target[i];
+		struct cxl_dport *next = NULL;
+
+		if (!dport)
+			break;
+
+		if (i + 1 < cxld->interleave_ways)
+			next = cxld->target[i + 1];
+		rc = sysfs_emit_at(buf, offset, "%d%s", dport->port_id,
+				   next ? "," : "");
+		if (rc < 0)
+			break;
+		offset += rc;
+	}
+	device_unlock(dev);
+
+	if (rc < 0)
+		return rc;
+
+	rc = sysfs_emit_at(buf, offset, "\n");
+	if (rc < 0)
+		return rc;
+
+	return offset + rc;
+}
+static DEVICE_ATTR_RO(target_list);
+
+static struct attribute *cxl_decoder_base_attrs[] = {
+	&dev_attr_start.attr,
+	&dev_attr_size.attr,
+	&dev_attr_locked.attr,
+	&dev_attr_target_list.attr,
+	NULL,
+};
+
+static struct attribute_group cxl_decoder_base_attribute_group = {
+	.attrs = cxl_decoder_base_attrs,
+};
+
+static struct attribute *cxl_decoder_root_attrs[] = {
+	&dev_attr_cap_pmem.attr,
+	&dev_attr_cap_ram.attr,
+	&dev_attr_cap_type2.attr,
+	&dev_attr_cap_type3.attr,
+	NULL,
+};
+
+static struct attribute_group cxl_decoder_root_attribute_group = {
+	.attrs = cxl_decoder_root_attrs,
+};
+
+static const struct attribute_group *cxl_decoder_root_attribute_groups[] = {
+	&cxl_decoder_root_attribute_group,
+	&cxl_decoder_base_attribute_group,
+	&cxl_base_attribute_group,
+	NULL,
+};
+
+static struct attribute *cxl_decoder_switch_attrs[] = {
+	&dev_attr_target_type.attr,
+	NULL,
+};
+
+static struct attribute_group cxl_decoder_switch_attribute_group = {
+	.attrs = cxl_decoder_switch_attrs,
+};
+
+static const struct attribute_group *cxl_decoder_switch_attribute_groups[] = {
+	&cxl_decoder_switch_attribute_group,
+	&cxl_decoder_base_attribute_group,
+	&cxl_base_attribute_group,
+	NULL,
+};
+
+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);
+	kfree(cxld);
+}
+
+static const struct device_type cxl_decoder_switch_type = {
+	.name = "cxl_decoder_switch",
+	.release = cxl_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,
+	.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,
+			  "not a cxl_decoder device\n"))
+		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)
+{
+	list_del(&dport->list);
+	put_device(dport->dport);
+	kfree(dport);
+}
+
+static void cxl_port_release(struct device *dev)
+{
+	struct cxl_port *port = to_cxl_port(dev);
+	struct cxl_dport *dport, *_d;
+
+	device_lock(dev);
+	list_for_each_entry_safe(dport, _d, &port->dports, list)
+		cxl_dport_release(dport);
+	device_unlock(dev);
+	ida_free(&cxl_port_ida, port->id);
+	kfree(port);
+}
+
+static const struct attribute_group *cxl_port_attribute_groups[] = {
+	&cxl_base_attribute_group,
+	NULL,
+};
+
+static const struct device_type cxl_port_type = {
+	.name = "cxl_port",
+	.release = cxl_port_release,
+	.groups = cxl_port_attribute_groups,
+};
+
+struct cxl_port *to_cxl_port(struct device *dev)
+{
+	if (dev_WARN_ONCE(dev, dev->type != &cxl_port_type,
+			  "not a cxl_port device\n"))
+		return NULL;
+	return container_of(dev, struct cxl_port, dev);
+}
+
+static void unregister_port(void *_port)
+{
+	struct cxl_port *port = _port;
+	struct cxl_dport *dport;
+
+	device_lock(&port->dev);
+	list_for_each_entry(dport, &port->dports, list) {
+		char link_name[CXL_TARGET_STRLEN];
+
+		if (snprintf(link_name, CXL_TARGET_STRLEN, "dport%d",
+			     dport->port_id) >= CXL_TARGET_STRLEN)
+			continue;
+		sysfs_remove_link(&port->dev.kobj, link_name);
+	}
+	device_unlock(&port->dev);
+	device_unregister(&port->dev);
+}
+
+static void cxl_unlink_uport(void *_port)
+{
+	struct cxl_port *port = _port;
+
+	sysfs_remove_link(&port->dev.kobj, "uport");
+}
+
+static int devm_cxl_link_uport(struct device *host, struct cxl_port *port)
+{
+	int rc;
+
+	rc = sysfs_create_link(&port->dev.kobj, &port->uport->kobj, "uport");
+	if (rc)
+		return rc;
+	return devm_add_action_or_reset(host, cxl_unlink_uport, port);
+}
+
+static struct cxl_port *cxl_port_alloc(struct device *uport,
+				       resource_size_t component_reg_phys,
+				       struct cxl_port *parent_port)
+{
+	struct cxl_port *port;
+	struct device *dev;
+	int rc;
+
+	port = kzalloc(sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return ERR_PTR(-ENOMEM);
+
+	rc = ida_alloc(&cxl_port_ida, GFP_KERNEL);
+	if (rc < 0)
+		goto err;
+	port->id = rc;
+
+	/*
+	 * The top-level cxl_port "cxl_root" does not have a cxl_port as
+	 * its parent and it does not have any corresponding component
+	 * registers as its decode is described by a fixed platform
+	 * description.
+	 */
+	dev = &port->dev;
+	if (parent_port)
+		dev->parent = &parent_port->dev;
+	else
+		dev->parent = uport;
+
+	port->uport = uport;
+	port->component_reg_phys = component_reg_phys;
+	ida_init(&port->decoder_ida);
+	INIT_LIST_HEAD(&port->dports);
+
+	device_initialize(dev);
+	device_set_pm_not_required(dev);
+	dev->bus = &cxl_bus_type;
+	dev->type = &cxl_port_type;
+
+	return port;
+
+err:
+	kfree(port);
+	return ERR_PTR(rc);
+}
+
+/**
+ * devm_cxl_add_port - register a cxl_port in CXL memory decode hierarchy
+ * @host: host device for devm operations
+ * @uport: "physical" device implementing this upstream port
+ * @component_reg_phys: (optional) for configurable cxl_port instances
+ * @parent_port: next hop up in the CXL memory decode hierarchy
+ */
+struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
+				   resource_size_t component_reg_phys,
+				   struct cxl_port *parent_port)
+{
+	struct cxl_port *port;
+	struct device *dev;
+	int rc;
+
+	port = cxl_port_alloc(uport, component_reg_phys, parent_port);
+	if (IS_ERR(port))
+		return port;
+
+	dev = &port->dev;
+	if (parent_port)
+		rc = dev_set_name(dev, "port%d", port->id);
+	else
+		rc = dev_set_name(dev, "root%d", port->id);
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	rc = devm_add_action_or_reset(host, unregister_port, port);
+	if (rc)
+		return ERR_PTR(rc);
+
+	rc = devm_cxl_link_uport(host, port);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return port;
+
+err:
+	put_device(dev);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_port);
+
+static struct cxl_dport *find_dport(struct cxl_port *port, int id)
+{
+	struct cxl_dport *dport;
+
+	device_lock_assert(&port->dev);
+	list_for_each_entry (dport, &port->dports, list)
+		if (dport->port_id == id)
+			return dport;
+	return NULL;
+}
+
+static int add_dport(struct cxl_port *port, struct cxl_dport *new)
+{
+	struct cxl_dport *dup;
+
+	device_lock(&port->dev);
+	dup = find_dport(port, new->port_id);
+	if (dup)
+		dev_err(&port->dev,
+			"unable to add dport%d-%s non-unique port id (%s)\n",
+			new->port_id, dev_name(new->dport),
+			dev_name(dup->dport));
+	else
+		list_add_tail(&new->list, &port->dports);
+	device_unlock(&port->dev);
+
+	return dup ? -EEXIST : 0;
+}
+
+/**
+ * cxl_add_dport - append downstream port data to a cxl_port
+ * @port: the cxl_port that references this dport
+ * @dport_dev: firmware or PCI device representing the dport
+ * @port_id: identifier for this dport in a decoder's target list
+ * @component_reg_phys: optional location of CXL component registers
+ *
+ * Note that all allocations and links are undone by cxl_port deletion
+ * and release.
+ */
+int cxl_add_dport(struct cxl_port *port, struct device *dport_dev, int port_id,
+		  resource_size_t component_reg_phys)
+{
+	char link_name[CXL_TARGET_STRLEN];
+	struct cxl_dport *dport;
+	int rc;
+
+	if (snprintf(link_name, CXL_TARGET_STRLEN, "dport%d", port_id) >=
+	    CXL_TARGET_STRLEN)
+		return -EINVAL;
+
+	dport = kzalloc(sizeof(*dport), GFP_KERNEL);
+	if (!dport)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&dport->list);
+	dport->dport = get_device(dport_dev);
+	dport->port_id = port_id;
+	dport->component_reg_phys = component_reg_phys;
+	dport->port = port;
+
+	rc = add_dport(port, dport);
+	if (rc)
+		goto err;
+
+	rc = sysfs_create_link(&port->dev.kobj, &dport_dev->kobj, link_name);
+	if (rc)
+		goto err;
+
+	return 0;
+err:
+	cxl_dport_release(dport);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(cxl_add_dport);
+
+static struct cxl_decoder *
+cxl_decoder_alloc(struct cxl_port *port, int nr_targets, resource_size_t base,
+		  resource_size_t len, int interleave_ways,
+		  int interleave_granularity, enum cxl_decoder_type type,
+		  unsigned long flags)
+{
+	struct cxl_decoder *cxld;
+	struct device *dev;
+	int rc = 0;
+
+	if (interleave_ways < 1)
+		return ERR_PTR(-EINVAL);
+
+	device_lock(&port->dev);
+	if (list_empty(&port->dports))
+		rc = -EINVAL;
+	device_unlock(&port->dev);
+	if (rc)
+		return ERR_PTR(rc);
+
+	cxld = kzalloc(struct_size(cxld, target, nr_targets), GFP_KERNEL);
+	if (!cxld)
+		return ERR_PTR(-ENOMEM);
+
+	rc = ida_alloc(&port->decoder_ida, GFP_KERNEL);
+	if (rc < 0)
+		goto err;
+
+	*cxld = (struct cxl_decoder) {
+		.id = rc,
+		.range = {
+			.start = base,
+			.end = base + len - 1,
+		},
+		.flags = flags,
+		.interleave_ways = interleave_ways,
+		.interleave_granularity = interleave_granularity,
+		.target_type = type,
+	};
+
+	/* handle implied target_list */
+	if (interleave_ways == 1)
+		cxld->target[0] =
+			list_first_entry(&port->dports, struct cxl_dport, list);
+	dev = &cxld->dev;
+	device_initialize(dev);
+	device_set_pm_not_required(dev);
+	dev->parent = &port->dev;
+	dev->bus = &cxl_bus_type;
+
+	/* root ports do not have a cxl_port_type parent */
+	if (port->dev.parent->type == &cxl_port_type)
+		dev->type = &cxl_decoder_switch_type;
+	else
+		dev->type = &cxl_decoder_root_type;
+
+	return cxld;
+err:
+	kfree(cxld);
+	return ERR_PTR(rc);
+}
+
+static void unregister_dev(void *dev)
+{
+	device_unregister(dev);
+}
+
+struct cxl_decoder *
+devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
+		     resource_size_t base, resource_size_t len,
+		     int interleave_ways, int interleave_granularity,
+		     enum cxl_decoder_type type, unsigned long flags)
+{
+	struct cxl_decoder *cxld;
+	struct device *dev;
+	int rc;
+
+	cxld = cxl_decoder_alloc(port, nr_targets, base, len, interleave_ways,
+				 interleave_granularity, type, flags);
+	if (IS_ERR(cxld))
+		return cxld;
+
+	dev = &cxld->dev;
+	rc = dev_set_name(dev, "decoder%d.%d", port->id, cxld->id);
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	rc = devm_add_action_or_reset(host, unregister_dev, dev);
+	if (rc)
+		return ERR_PTR(rc);
+	return cxld;
+
+err:
+	put_device(dev);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_decoder);
+
+/**
+ * cxl_probe_component_regs() - Detect CXL Component register blocks
+ * @dev: Host device of the @base mapping
+ * @base: Mapping containing the HDM Decoder Capability Header
+ * @map: Map object describing the register block information found
+ *
+ * See CXL 2.0 8.2.4 Component Register Layout and Definition
+ * See CXL 2.0 8.2.5.5 CXL Device Register Interface
+ *
+ * Probe for component register information and return it in map object.
+ */
+void cxl_probe_component_regs(struct device *dev, void __iomem *base,
+			      struct cxl_component_reg_map *map)
+{
+	int cap, cap_count;
+	u64 cap_array;
+
+	*map = (struct cxl_component_reg_map) { 0 };
+
+	/*
+	 * CXL.cache and CXL.mem registers are at offset 0x1000 as defined in
+	 * CXL 2.0 8.2.4 Table 141.
+	 */
+	base += CXL_CM_OFFSET;
+
+	cap_array = readq(base + CXL_CM_CAP_HDR_OFFSET);
+
+	if (FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, cap_array) != CM_CAP_HDR_CAP_ID) {
+		dev_err(dev,
+			"Couldn't locate the CXL.cache and CXL.mem capability array header./n");
+		return;
+	}
+
+	/* It's assumed that future versions will be backward compatible */
+	cap_count = FIELD_GET(CXL_CM_CAP_HDR_ARRAY_SIZE_MASK, cap_array);
+
+	for (cap = 1; cap <= cap_count; cap++) {
+		void __iomem *register_block;
+		u32 hdr;
+		int decoder_cnt;
+		u16 cap_id, offset;
+		u32 length;
+
+		hdr = readl(base + cap * 0x4);
+
+		cap_id = FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, hdr);
+		offset = FIELD_GET(CXL_CM_CAP_PTR_MASK, hdr);
+		register_block = base + offset;
+
+		switch (cap_id) {
+		case CXL_CM_CAP_CAP_ID_HDM:
+			dev_dbg(dev, "found HDM decoder capability (0x%x)\n",
+				offset);
+
+			hdr = readl(register_block);
+
+			decoder_cnt = cxl_hdm_decoder_count(hdr);
+			length = 0x20 * decoder_cnt + 0x10;
+
+			map->hdm_decoder.valid = true;
+			map->hdm_decoder.offset = CXL_CM_OFFSET + offset;
+			map->hdm_decoder.size = length;
+			break;
+		default:
+			dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
+				offset);
+			break;
+		}
+	}
+}
+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);
+
+static void cxl_nvdimm_release(struct device *dev)
+{
+	struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
+
+	kfree(cxl_nvd);
+}
+
+static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {
+	&cxl_base_attribute_group,
+	NULL,
+};
+
+static const struct device_type cxl_nvdimm_type = {
+	.name = "cxl_nvdimm",
+	.release = cxl_nvdimm_release,
+	.groups = cxl_nvdimm_attribute_groups,
+};
+
+bool is_cxl_nvdimm(struct device *dev)
+{
+	return dev->type == &cxl_nvdimm_type;
+}
+EXPORT_SYMBOL_GPL(is_cxl_nvdimm);
+
+struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev)
+{
+	if (dev_WARN_ONCE(dev, !is_cxl_nvdimm(dev),
+			  "not a cxl_nvdimm device\n"))
+		return NULL;
+	return container_of(dev, struct cxl_nvdimm, dev);
+}
+EXPORT_SYMBOL_GPL(to_cxl_nvdimm);
+
+static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)
+{
+	struct cxl_nvdimm *cxl_nvd;
+	struct device *dev;
+
+	cxl_nvd = kzalloc(sizeof(*cxl_nvd), GFP_KERNEL);
+	if (!cxl_nvd)
+		return ERR_PTR(-ENOMEM);
+
+	dev = &cxl_nvd->dev;
+	cxl_nvd->cxlmd = cxlmd;
+	device_initialize(dev);
+	device_set_pm_not_required(dev);
+	dev->parent = &cxlmd->dev;
+	dev->bus = &cxl_bus_type;
+	dev->type = &cxl_nvdimm_type;
+
+	return cxl_nvd;
+}
+
+int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd)
+{
+	struct cxl_nvdimm *cxl_nvd;
+	struct device *dev;
+	int rc;
+
+	cxl_nvd = cxl_nvdimm_alloc(cxlmd);
+	if (IS_ERR(cxl_nvd))
+		return PTR_ERR(cxl_nvd);
+
+	dev = &cxl_nvd->dev;
+	rc = dev_set_name(dev, "pmem%d", cxlmd->id);
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	dev_dbg(host, "%s: register %s\n", dev_name(dev->parent),
+		dev_name(dev));
+
+	return devm_add_action_or_reset(host, unregister_dev, dev);
+
+err:
+	put_device(dev);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm);
+
+/**
+ * cxl_probe_device_regs() - Detect CXL Device register blocks
+ * @dev: Host device of the @base mapping
+ * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
+ * @map: Map object describing the register block information found
+ *
+ * Probe for device register information and return it in map object.
+ */
+void cxl_probe_device_regs(struct device *dev, void __iomem *base,
+			   struct cxl_device_reg_map *map)
+{
+	int cap, cap_count;
+	u64 cap_array;
+
+	*map = (struct cxl_device_reg_map){ 0 };
+
+	cap_array = readq(base + CXLDEV_CAP_ARRAY_OFFSET);
+	if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
+	    CXLDEV_CAP_ARRAY_CAP_ID)
+		return;
+
+	cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
+
+	for (cap = 1; cap <= cap_count; cap++) {
+		u32 offset, length;
+		u16 cap_id;
+
+		cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
+				   readl(base + cap * 0x10));
+		offset = readl(base + cap * 0x10 + 0x4);
+		length = readl(base + cap * 0x10 + 0x8);
+
+		switch (cap_id) {
+		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
+			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
+
+			map->status.valid = true;
+			map->status.offset = offset;
+			map->status.size = length;
+			break;
+		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
+			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
+			map->mbox.valid = true;
+			map->mbox.offset = offset;
+			map->mbox.size = length;
+			break;
+		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
+			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
+			break;
+		case CXLDEV_CAP_CAP_ID_MEMDEV:
+			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
+			map->memdev.valid = true;
+			map->memdev.offset = offset;
+			map->memdev.size = length;
+			break;
+		default:
+			if (cap_id >= 0x8000)
+				dev_dbg(dev, "Vendor cap ID: %#x offset: %#x\n", cap_id, offset);
+			else
+				dev_dbg(dev, "Unknown cap ID: %#x offset: %#x\n", cap_id, offset);
+			break;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(cxl_probe_device_regs);
+
+static void __iomem *devm_cxl_iomap_block(struct device *dev,
+					  resource_size_t addr,
+					  resource_size_t length)
+{
+	void __iomem *ret_val;
+	struct resource *res;
+
+	res = devm_request_mem_region(dev, addr, length, dev_name(dev));
+	if (!res) {
+		resource_size_t end = addr + length - 1;
+
+		dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end);
+		return NULL;
+	}
+
+	ret_val = devm_ioremap(dev, addr, length);
+	if (!ret_val)
+		dev_err(dev, "Failed to map region %pr\n", res);
+
+	return ret_val;
+}
+
+int cxl_map_component_regs(struct pci_dev *pdev,
+			   struct cxl_component_regs *regs,
+			   struct cxl_register_map *map)
+{
+	struct device *dev = &pdev->dev;
+	resource_size_t phys_addr;
+	resource_size_t length;
+
+	phys_addr = pci_resource_start(pdev, map->barno);
+	phys_addr += map->block_offset;
+
+	phys_addr += map->component_map.hdm_decoder.offset;
+	length = map->component_map.hdm_decoder.size;
+	regs->hdm_decoder = devm_cxl_iomap_block(dev, phys_addr, length);
+	if (!regs->hdm_decoder)
+		return -ENOMEM;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_map_component_regs);
+
+int cxl_map_device_regs(struct pci_dev *pdev,
+			struct cxl_device_regs *regs,
+			struct cxl_register_map *map)
+{
+	struct device *dev = &pdev->dev;
+	resource_size_t phys_addr;
+
+	phys_addr = pci_resource_start(pdev, map->barno);
+	phys_addr += map->block_offset;
+
+	if (map->device_map.status.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.status.offset;
+		length = map->device_map.status.size;
+		regs->status = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->status)
+			return -ENOMEM;
+	}
+
+	if (map->device_map.mbox.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.mbox.offset;
+		length = map->device_map.mbox.size;
+		regs->mbox = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->mbox)
+			return -ENOMEM;
+	}
+
+	if (map->device_map.memdev.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.memdev.offset;
+		length = map->device_map.memdev.size;
+		regs->memdev = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->memdev)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_map_device_regs);
+
+/**
+ * __cxl_driver_register - register a driver for the cxl bus
+ * @cxl_drv: cxl driver structure to attach
+ * @owner: owning module/driver
+ * @modname: KBUILD_MODNAME for parent driver
+ */
+int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner,
+			  const char *modname)
+{
+	if (!cxl_drv->probe) {
+		pr_debug("%s ->probe() must be specified\n", modname);
+		return -EINVAL;
+	}
+
+	if (!cxl_drv->name) {
+		pr_debug("%s ->name must be specified\n", modname);
+		return -EINVAL;
+	}
+
+	if (!cxl_drv->id) {
+		pr_debug("%s ->id must be specified\n", modname);
+		return -EINVAL;
+	}
+
+	cxl_drv->drv.bus = &cxl_bus_type;
+	cxl_drv->drv.owner = owner;
+	cxl_drv->drv.mod_name = modname;
+	cxl_drv->drv.name = cxl_drv->name;
+
+	return driver_register(&cxl_drv->drv);
+}
+EXPORT_SYMBOL_GPL(__cxl_driver_register);
+
+void cxl_driver_unregister(struct cxl_driver *cxl_drv)
+{
+	driver_unregister(&cxl_drv->drv);
+}
+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;
+	if (dev->type == &cxl_nvdimm_type)
+		return CXL_DEVICE_NVDIMM;
+	return 0;
+}
+
+static int cxl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	return add_uevent_var(env, "MODALIAS=" CXL_MODALIAS_FMT,
+			      cxl_device_id(dev));
+}
+
+static int cxl_bus_match(struct device *dev, struct device_driver *drv)
+{
+	return cxl_device_id(dev) == to_cxl_drv(drv)->id;
+}
+
+static int cxl_bus_probe(struct device *dev)
+{
+	return to_cxl_drv(dev->driver)->probe(dev);
+}
+
+static void cxl_bus_remove(struct device *dev)
+{
+	struct cxl_driver *cxl_drv = to_cxl_drv(dev->driver);
+
+	if (cxl_drv->remove)
+		cxl_drv->remove(dev);
+}
+
+struct bus_type cxl_bus_type = {
+	.name = "cxl",
+	.uevent = cxl_bus_uevent,
+	.match = cxl_bus_match,
+	.probe = cxl_bus_probe,
+	.remove = cxl_bus_remove,
+};
+EXPORT_SYMBOL_GPL(cxl_bus_type);
+
+static __init int cxl_core_init(void)
+{
+	return bus_register(&cxl_bus_type);
+}
+
+static void cxl_core_exit(void)
+{
+	bus_unregister(&cxl_bus_type);
+}
+
+module_init(cxl_core_init);
+module_exit(cxl_core_exit);
+MODULE_LICENSE("GPL v2");
--- /dev/null
+++ b/drivers/cxl/cxlmem.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2020-2021 Intel Corporation. */
+#ifndef __CXL_MEM_H__
+#define __CXL_MEM_H__
+#include <linux/cdev.h>
+#include "cxl.h"
+
+/* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
+#define CXLMDEV_STATUS_OFFSET 0x0
+#define   CXLMDEV_DEV_FATAL BIT(0)
+#define   CXLMDEV_FW_HALT BIT(1)
+#define   CXLMDEV_STATUS_MEDIA_STATUS_MASK GENMASK(3, 2)
+#define     CXLMDEV_MS_NOT_READY 0
+#define     CXLMDEV_MS_READY 1
+#define     CXLMDEV_MS_ERROR 2
+#define     CXLMDEV_MS_DISABLED 3
+#define CXLMDEV_READY(status)                                                  \
+	(FIELD_GET(CXLMDEV_STATUS_MEDIA_STATUS_MASK, status) ==                \
+	 CXLMDEV_MS_READY)
+#define   CXLMDEV_MBOX_IF_READY BIT(4)
+#define   CXLMDEV_RESET_NEEDED_MASK GENMASK(7, 5)
+#define     CXLMDEV_RESET_NEEDED_NOT 0
+#define     CXLMDEV_RESET_NEEDED_COLD 1
+#define     CXLMDEV_RESET_NEEDED_WARM 2
+#define     CXLMDEV_RESET_NEEDED_HOT 3
+#define     CXLMDEV_RESET_NEEDED_CXL 4
+#define CXLMDEV_RESET_NEEDED(status)                                           \
+	(FIELD_GET(CXLMDEV_RESET_NEEDED_MASK, status) !=                       \
+	 CXLMDEV_RESET_NEEDED_NOT)
+
+/*
+ * An entire PCI topology full of devices should be enough for any
+ * config
+ */
+#define CXL_MEM_MAX_DEVS 65536
+
+/**
+ * struct cxl_memdev - CXL bus object representing a Type-3 Memory Device
+ * @dev: driver core device object
+ * @cdev: char dev core object for ioctl operations
+ * @cxlm: pointer to the parent device driver data
+ * @id: id number of this memdev instance.
+ */
+struct cxl_memdev {
+	struct device dev;
+	struct cdev cdev;
+	struct cxl_mem *cxlm;
+	int id;
+};
+
+/**
+ * struct cxl_mem - A CXL memory device
+ * @pdev: The PCI device associated with this CXL device.
+ * @cxlmd: Logical memory device chardev / interface
+ * @regs: Parsed register blocks
+ * @payload_size: Size of space for payload
+ *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
+ * @lsa_size: Size of Label Storage Area
+ *                (CXL 2.0 8.2.9.5.1.1 Identify Memory Device)
+ * @mbox_mutex: Mutex to synchronize mailbox access.
+ * @firmware_version: Firmware version for the memory device.
+ * @enabled_cmds: Hardware commands found enabled in CEL.
+ * @pmem_range: Persistent memory capacity information.
+ * @ram_range: Volatile memory capacity information.
+ */
+struct cxl_mem {
+	struct pci_dev *pdev;
+	struct cxl_memdev *cxlmd;
+
+	struct cxl_regs regs;
+
+	size_t payload_size;
+	size_t lsa_size;
+	struct mutex mbox_mutex; /* Protects device mailbox and firmware */
+	char firmware_version[0x10];
+	unsigned long *enabled_cmds;
+
+	struct range pmem_range;
+	struct range ram_range;
+};
+#endif /* __CXL_MEM_H__ */
--- a/drivers/cxl/mem.h
+++ /dev/null
@@ -1,81 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/* Copyright(c) 2020-2021 Intel Corporation. */
-#ifndef __CXL_MEM_H__
-#define __CXL_MEM_H__
-#include <linux/cdev.h>
-#include "cxl.h"
-
-/* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
-#define CXLMDEV_STATUS_OFFSET 0x0
-#define   CXLMDEV_DEV_FATAL BIT(0)
-#define   CXLMDEV_FW_HALT BIT(1)
-#define   CXLMDEV_STATUS_MEDIA_STATUS_MASK GENMASK(3, 2)
-#define     CXLMDEV_MS_NOT_READY 0
-#define     CXLMDEV_MS_READY 1
-#define     CXLMDEV_MS_ERROR 2
-#define     CXLMDEV_MS_DISABLED 3
-#define CXLMDEV_READY(status)                                                  \
-	(FIELD_GET(CXLMDEV_STATUS_MEDIA_STATUS_MASK, status) ==                \
-	 CXLMDEV_MS_READY)
-#define   CXLMDEV_MBOX_IF_READY BIT(4)
-#define   CXLMDEV_RESET_NEEDED_MASK GENMASK(7, 5)
-#define     CXLMDEV_RESET_NEEDED_NOT 0
-#define     CXLMDEV_RESET_NEEDED_COLD 1
-#define     CXLMDEV_RESET_NEEDED_WARM 2
-#define     CXLMDEV_RESET_NEEDED_HOT 3
-#define     CXLMDEV_RESET_NEEDED_CXL 4
-#define CXLMDEV_RESET_NEEDED(status)                                           \
-	(FIELD_GET(CXLMDEV_RESET_NEEDED_MASK, status) !=                       \
-	 CXLMDEV_RESET_NEEDED_NOT)
-
-/*
- * An entire PCI topology full of devices should be enough for any
- * config
- */
-#define CXL_MEM_MAX_DEVS 65536
-
-/**
- * struct cxl_memdev - CXL bus object representing a Type-3 Memory Device
- * @dev: driver core device object
- * @cdev: char dev core object for ioctl operations
- * @cxlm: pointer to the parent device driver data
- * @id: id number of this memdev instance.
- */
-struct cxl_memdev {
-	struct device dev;
-	struct cdev cdev;
-	struct cxl_mem *cxlm;
-	int id;
-};
-
-/**
- * struct cxl_mem - A CXL memory device
- * @pdev: The PCI device associated with this CXL device.
- * @cxlmd: Logical memory device chardev / interface
- * @regs: Parsed register blocks
- * @payload_size: Size of space for payload
- *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
- * @lsa_size: Size of Label Storage Area
- *                (CXL 2.0 8.2.9.5.1.1 Identify Memory Device)
- * @mbox_mutex: Mutex to synchronize mailbox access.
- * @firmware_version: Firmware version for the memory device.
- * @enabled_cmds: Hardware commands found enabled in CEL.
- * @pmem_range: Persistent memory capacity information.
- * @ram_range: Volatile memory capacity information.
- */
-struct cxl_mem {
-	struct pci_dev *pdev;
-	struct cxl_memdev *cxlmd;
-
-	struct cxl_regs regs;
-
-	size_t payload_size;
-	size_t lsa_size;
-	struct mutex mbox_mutex; /* Protects device mailbox and firmware */
-	char firmware_version[0x10];
-	unsigned long *enabled_cmds;
-
-	struct range pmem_range;
-	struct range ram_range;
-};
-#endif /* __CXL_MEM_H__ */
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -12,9 +12,9 @@
 #include <linux/pci.h>
 #include <linux/io.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
+#include "cxlmem.h"
 #include "pci.h"
 #include "cxl.h"
-#include "mem.h"
 
 /**
  * DOC: cxl pci
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -6,7 +6,7 @@
 #include <linux/ndctl.h>
 #include <linux/async.h>
 #include <linux/slab.h>
-#include "mem.h"
+#include "cxlmem.h"
 #include "cxl.h"
 
 /*