1// SPDX-License-Identifier: GPL-2.0-only
  2/* Copyright(c) 2020 Intel Corporation. */
  3#include <linux/device.h>
  4#include <linux/slab.h>
  5#include <linux/idr.h>
  6#include <cxlmem.h>
  7#include <cxl.h>
  8#include "core.h"
  9
 10/**
 11 * DOC: cxl pmem
 12 *
 13 * The core CXL PMEM infrastructure supports persistent memory
 14 * provisioning and serves as a bridge to the LIBNVDIMM subsystem. A CXL
 15 * 'bridge' device is added at the root of a CXL device topology if
 16 * platform firmware advertises at least one persistent memory capable
 17 * CXL window. That root-level bridge corresponds to a LIBNVDIMM 'bus'
 18 * device. Then for each cxl_memdev in the CXL device topology a bridge
 19 * device is added to host a LIBNVDIMM dimm object. When these bridges
 20 * are registered native LIBNVDIMM uapis are translated to CXL
 21 * operations, for example, namespace label access commands.
 22 */
 23
 24static DEFINE_IDA(cxl_nvdimm_bridge_ida);
 25
 26static void cxl_nvdimm_bridge_release(struct device *dev)
 27{
 28	struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
 29
 30	ida_free(&cxl_nvdimm_bridge_ida, cxl_nvb->id);
 31	kfree(cxl_nvb);
 32}
 33
 34static const struct attribute_group *cxl_nvdimm_bridge_attribute_groups[] = {
 35	&cxl_base_attribute_group,
 36	NULL,
 37};
 38
 39const struct device_type cxl_nvdimm_bridge_type = {
 40	.name = "cxl_nvdimm_bridge",
 41	.release = cxl_nvdimm_bridge_release,
 42	.groups = cxl_nvdimm_bridge_attribute_groups,
 43};
 44
 45struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev)
 46{
 47	if (dev_WARN_ONCE(dev, dev->type != &cxl_nvdimm_bridge_type,
 48			  "not a cxl_nvdimm_bridge device\n"))
 49		return NULL;
 50	return container_of(dev, struct cxl_nvdimm_bridge, dev);
 51}
 52EXPORT_SYMBOL_NS_GPL(to_cxl_nvdimm_bridge, "CXL");
 53
 54bool is_cxl_nvdimm_bridge(struct device *dev)
 55{
 56	return dev->type == &cxl_nvdimm_bridge_type;
 57}
 58EXPORT_SYMBOL_NS_GPL(is_cxl_nvdimm_bridge, "CXL");
 59
 60static int match_nvdimm_bridge(struct device *dev, void *data)
 61{
 62	return is_cxl_nvdimm_bridge(dev);
 63}
 64
 65/**
 66 * cxl_find_nvdimm_bridge() - find a bridge device relative to a port
 67 * @port: any descendant port of an nvdimm-bridge associated
 68 *        root-cxl-port
 69 */
 70struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_port *port)
 71{
 72	struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
 73	struct device *dev;
 74
 75	if (!cxl_root)
 76		return NULL;
 77
 78	dev = device_find_child(&cxl_root->port.dev, NULL, match_nvdimm_bridge);
 79
 80	if (!dev)
 81		return NULL;
 82
 83	return to_cxl_nvdimm_bridge(dev);
 84}
 85EXPORT_SYMBOL_NS_GPL(cxl_find_nvdimm_bridge, "CXL");
 86
 87static struct lock_class_key cxl_nvdimm_bridge_key;
 88
 89static struct cxl_nvdimm_bridge *cxl_nvdimm_bridge_alloc(struct cxl_port *port)
 90{
 91	struct cxl_nvdimm_bridge *cxl_nvb;
 92	struct device *dev;
 93	int rc;
 94
 95	cxl_nvb = kzalloc(sizeof(*cxl_nvb), GFP_KERNEL);
 96	if (!cxl_nvb)
 97		return ERR_PTR(-ENOMEM);
 98
 99	rc = ida_alloc(&cxl_nvdimm_bridge_ida, GFP_KERNEL);
100	if (rc < 0)
101		goto err;
102	cxl_nvb->id = rc;
103
104	dev = &cxl_nvb->dev;
105	cxl_nvb->port = port;
106	device_initialize(dev);
107	lockdep_set_class(&dev->mutex, &cxl_nvdimm_bridge_key);
108	device_set_pm_not_required(dev);
109	dev->parent = &port->dev;
110	dev->bus = &cxl_bus_type;
111	dev->type = &cxl_nvdimm_bridge_type;
112
113	return cxl_nvb;
114
115err:
116	kfree(cxl_nvb);
117	return ERR_PTR(rc);
118}
119
120static void unregister_nvb(void *_cxl_nvb)
121{
122	struct cxl_nvdimm_bridge *cxl_nvb = _cxl_nvb;
123
124	device_unregister(&cxl_nvb->dev);
125}
126
127/**
128 * devm_cxl_add_nvdimm_bridge() - add the root of a LIBNVDIMM topology
129 * @host: platform firmware root device
130 * @port: CXL port at the root of a CXL topology
131 *
132 * Return: bridge device that can host cxl_nvdimm objects
133 */
134struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
135						     struct cxl_port *port)
136{
137	struct cxl_nvdimm_bridge *cxl_nvb;
138	struct device *dev;
139	int rc;
140
141	if (!IS_ENABLED(CONFIG_CXL_PMEM))
142		return ERR_PTR(-ENXIO);
143
144	cxl_nvb = cxl_nvdimm_bridge_alloc(port);
145	if (IS_ERR(cxl_nvb))
146		return cxl_nvb;
147
148	dev = &cxl_nvb->dev;
149	rc = dev_set_name(dev, "nvdimm-bridge%d", cxl_nvb->id);
150	if (rc)
151		goto err;
152
153	rc = device_add(dev);
154	if (rc)
155		goto err;
156
157	rc = devm_add_action_or_reset(host, unregister_nvb, cxl_nvb);
158	if (rc)
159		return ERR_PTR(rc);
160
161	return cxl_nvb;
162
163err:
164	put_device(dev);
165	return ERR_PTR(rc);
166}
167EXPORT_SYMBOL_NS_GPL(devm_cxl_add_nvdimm_bridge, "CXL");
168
169static void cxl_nvdimm_release(struct device *dev)
170{
171	struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
172
173	kfree(cxl_nvd);
174}
175
176static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {
177	&cxl_base_attribute_group,
178	NULL,
179};
180
181const struct device_type cxl_nvdimm_type = {
182	.name = "cxl_nvdimm",
183	.release = cxl_nvdimm_release,
184	.groups = cxl_nvdimm_attribute_groups,
185};
186
187bool is_cxl_nvdimm(struct device *dev)
188{
189	return dev->type == &cxl_nvdimm_type;
190}
191EXPORT_SYMBOL_NS_GPL(is_cxl_nvdimm, "CXL");
192
193struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev)
194{
195	if (dev_WARN_ONCE(dev, !is_cxl_nvdimm(dev),
196			  "not a cxl_nvdimm device\n"))
197		return NULL;
198	return container_of(dev, struct cxl_nvdimm, dev);
199}
200EXPORT_SYMBOL_NS_GPL(to_cxl_nvdimm, "CXL");
201
202static struct lock_class_key cxl_nvdimm_key;
203
204static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_nvdimm_bridge *cxl_nvb,
205					   struct cxl_memdev *cxlmd)
206{
207	struct cxl_nvdimm *cxl_nvd;
208	struct device *dev;
209
210	cxl_nvd = kzalloc(sizeof(*cxl_nvd), GFP_KERNEL);
211	if (!cxl_nvd)
212		return ERR_PTR(-ENOMEM);
213
214	dev = &cxl_nvd->dev;
215	cxl_nvd->cxlmd = cxlmd;
216	cxlmd->cxl_nvd = cxl_nvd;
217	device_initialize(dev);
218	lockdep_set_class(&dev->mutex, &cxl_nvdimm_key);
219	device_set_pm_not_required(dev);
220	dev->parent = &cxlmd->dev;
221	dev->bus = &cxl_bus_type;
222	dev->type = &cxl_nvdimm_type;
223	/*
224	 * A "%llx" string is 17-bytes vs dimm_id that is max
225	 * NVDIMM_KEY_DESC_LEN
226	 */
227	BUILD_BUG_ON(sizeof(cxl_nvd->dev_id) < 17 ||
228		     sizeof(cxl_nvd->dev_id) > NVDIMM_KEY_DESC_LEN);
229	sprintf(cxl_nvd->dev_id, "%llx", cxlmd->cxlds->serial);
230
231	return cxl_nvd;
232}
233
234static void cxlmd_release_nvdimm(void *_cxlmd)
235{
236	struct cxl_memdev *cxlmd = _cxlmd;
237	struct cxl_nvdimm *cxl_nvd = cxlmd->cxl_nvd;
238	struct cxl_nvdimm_bridge *cxl_nvb = cxlmd->cxl_nvb;
239
240	cxl_nvd->cxlmd = NULL;
241	cxlmd->cxl_nvd = NULL;
242	cxlmd->cxl_nvb = NULL;
243	device_unregister(&cxl_nvd->dev);
244	put_device(&cxl_nvb->dev);
245}
246
247/**
248 * devm_cxl_add_nvdimm() - add a bridge between a cxl_memdev and an nvdimm
249 * @parent_port: parent port for the (to be added) @cxlmd endpoint port
250 * @cxlmd: cxl_memdev instance that will perform LIBNVDIMM operations
251 *
252 * Return: 0 on success negative error code on failure.
253 */
254int devm_cxl_add_nvdimm(struct cxl_port *parent_port,
255			struct cxl_memdev *cxlmd)
256{
257	struct cxl_nvdimm_bridge *cxl_nvb;
258	struct cxl_nvdimm *cxl_nvd;
259	struct device *dev;
260	int rc;
261
262	cxl_nvb = cxl_find_nvdimm_bridge(parent_port);
263	if (!cxl_nvb)
264		return -ENODEV;
265
266	cxl_nvd = cxl_nvdimm_alloc(cxl_nvb, cxlmd);
267	if (IS_ERR(cxl_nvd)) {
268		rc = PTR_ERR(cxl_nvd);
269		goto err_alloc;
270	}
271	cxlmd->cxl_nvb = cxl_nvb;
272
273	dev = &cxl_nvd->dev;
274	rc = dev_set_name(dev, "pmem%d", cxlmd->id);
275	if (rc)
276		goto err;
277
278	rc = device_add(dev);
279	if (rc)
280		goto err;
281
282	dev_dbg(&cxlmd->dev, "register %s\n", dev_name(dev));
283
284	/* @cxlmd carries a reference on @cxl_nvb until cxlmd_release_nvdimm */
285	return devm_add_action_or_reset(&cxlmd->dev, cxlmd_release_nvdimm, cxlmd);
286
287err:
288	put_device(dev);
289err_alloc:
290	cxlmd->cxl_nvb = NULL;
291	cxlmd->cxl_nvd = NULL;
292	put_device(&cxl_nvb->dev);
293
294	return rc;
295}
296EXPORT_SYMBOL_NS_GPL(devm_cxl_add_nvdimm, "CXL");