drivers/cxl/core/pmem.c

   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
  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
  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
  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
  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  */
  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
  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
 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  */
 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
 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
 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
 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
 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
 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  */
 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);