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
24 static DEFINE_IDA(cxl_nvdimm_bridge_ida);
25
cxl_nvdimm_bridge_release(struct device * dev)26 static 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
34 static const struct attribute_group *cxl_nvdimm_bridge_attribute_groups[] = {
35 &cxl_base_attribute_group,
36 NULL,
37 };
38
39 const 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
to_cxl_nvdimm_bridge(struct device * dev)45 struct 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 }
52 EXPORT_SYMBOL_NS_GPL(to_cxl_nvdimm_bridge, CXL);
53
is_cxl_nvdimm_bridge(struct device * dev)54 bool is_cxl_nvdimm_bridge(struct device *dev)
55 {
56 return dev->type == &cxl_nvdimm_bridge_type;
57 }
58 EXPORT_SYMBOL_NS_GPL(is_cxl_nvdimm_bridge, CXL);
59
match_nvdimm_bridge(struct device * dev,void * data)60 static 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 */
cxl_find_nvdimm_bridge(struct cxl_port * port)70 struct 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 }
85 EXPORT_SYMBOL_NS_GPL(cxl_find_nvdimm_bridge, CXL);
86
87 static struct lock_class_key cxl_nvdimm_bridge_key;
88
cxl_nvdimm_bridge_alloc(struct cxl_port * port)89 static 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
115 err:
116 kfree(cxl_nvb);
117 return ERR_PTR(rc);
118 }
119
unregister_nvb(void * _cxl_nvb)120 static 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 */
devm_cxl_add_nvdimm_bridge(struct device * host,struct cxl_port * port)134 struct 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
163 err:
164 put_device(dev);
165 return ERR_PTR(rc);
166 }
167 EXPORT_SYMBOL_NS_GPL(devm_cxl_add_nvdimm_bridge, CXL);
168
cxl_nvdimm_release(struct device * dev)169 static 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
176 static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {
177 &cxl_base_attribute_group,
178 NULL,
179 };
180
181 const struct device_type cxl_nvdimm_type = {
182 .name = "cxl_nvdimm",
183 .release = cxl_nvdimm_release,
184 .groups = cxl_nvdimm_attribute_groups,
185 };
186
is_cxl_nvdimm(struct device * dev)187 bool is_cxl_nvdimm(struct device *dev)
188 {
189 return dev->type == &cxl_nvdimm_type;
190 }
191 EXPORT_SYMBOL_NS_GPL(is_cxl_nvdimm, CXL);
192
to_cxl_nvdimm(struct device * dev)193 struct 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 }
200 EXPORT_SYMBOL_NS_GPL(to_cxl_nvdimm, CXL);
201
202 static struct lock_class_key cxl_nvdimm_key;
203
cxl_nvdimm_alloc(struct cxl_nvdimm_bridge * cxl_nvb,struct cxl_memdev * cxlmd)204 static 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
cxlmd_release_nvdimm(void * _cxlmd)234 static 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 */
devm_cxl_add_nvdimm(struct cxl_port * parent_port,struct cxl_memdev * cxlmd)254 int 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
287 err:
288 put_device(dev);
289 err_alloc:
290 cxlmd->cxl_nvb = NULL;
291 cxlmd->cxl_nvd = NULL;
292 put_device(&cxl_nvb->dev);
293
294 return rc;
295 }
296 EXPORT_SYMBOL_NS_GPL(devm_cxl_add_nvdimm, CXL);
297