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 struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_memdev *cxlmd)
  66 {
  67         struct cxl_port *port = find_cxl_root(cxlmd->endpoint);
  68         struct device *dev;
  69
  70         if (!port)
  71                 return NULL;
  72
  73         dev = device_find_child(&port->dev, NULL, match_nvdimm_bridge);
  74         put_device(&port->dev);
  75
  76         if (!dev)
  77                 return NULL;
  78
  79         return to_cxl_nvdimm_bridge(dev);
  80 }
  81 EXPORT_SYMBOL_NS_GPL(cxl_find_nvdimm_bridge, CXL);
  82
  83 static struct lock_class_key cxl_nvdimm_bridge_key;
  84
  85 static struct cxl_nvdimm_bridge *cxl_nvdimm_bridge_alloc(struct cxl_port *port)
  86 {
  87         struct cxl_nvdimm_bridge *cxl_nvb;
  88         struct device *dev;
  89         int rc;
  90
  91         cxl_nvb = kzalloc(sizeof(*cxl_nvb), GFP_KERNEL);
  92         if (!cxl_nvb)
  93                 return ERR_PTR(-ENOMEM);
  94
  95         rc = ida_alloc(&cxl_nvdimm_bridge_ida, GFP_KERNEL);
  96         if (rc < 0)
  97                 goto err;
  98         cxl_nvb->id = rc;
  99
 100         dev = &cxl_nvb->dev;
 101         cxl_nvb->port = port;
 102         device_initialize(dev);
 103         lockdep_set_class(&dev->mutex, &cxl_nvdimm_bridge_key);
 104         device_set_pm_not_required(dev);
 105         dev->parent = &port->dev;
 106         dev->bus = &cxl_bus_type;
 107         dev->type = &cxl_nvdimm_bridge_type;
 108
 109         return cxl_nvb;
 110
 111 err:
 112         kfree(cxl_nvb);
 113         return ERR_PTR(rc);
 114 }
 115
 116 static void unregister_nvb(void *_cxl_nvb)
 117 {
 118         struct cxl_nvdimm_bridge *cxl_nvb = _cxl_nvb;
 119
 120         device_unregister(&cxl_nvb->dev);
 121 }
 122
 123 /**
 124  * devm_cxl_add_nvdimm_bridge() - add the root of a LIBNVDIMM topology
 125  * @host: platform firmware root device
 126  * @port: CXL port at the root of a CXL topology
 127  *
 128  * Return: bridge device that can host cxl_nvdimm objects
 129  */
 130 struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
 131                                                      struct cxl_port *port)
 132 {
 133         struct cxl_nvdimm_bridge *cxl_nvb;
 134         struct device *dev;
 135         int rc;
 136
 137         if (!IS_ENABLED(CONFIG_CXL_PMEM))
 138                 return ERR_PTR(-ENXIO);
 139
 140         cxl_nvb = cxl_nvdimm_bridge_alloc(port);
 141         if (IS_ERR(cxl_nvb))
 142                 return cxl_nvb;
 143
 144         dev = &cxl_nvb->dev;
 145         rc = dev_set_name(dev, "nvdimm-bridge%d", cxl_nvb->id);
 146         if (rc)
 147                 goto err;
 148
 149         rc = device_add(dev);
 150         if (rc)
 151                 goto err;
 152
 153         rc = devm_add_action_or_reset(host, unregister_nvb, cxl_nvb);
 154         if (rc)
 155                 return ERR_PTR(rc);
 156
 157         return cxl_nvb;
 158
 159 err:
 160         put_device(dev);
 161         return ERR_PTR(rc);
 162 }
 163 EXPORT_SYMBOL_NS_GPL(devm_cxl_add_nvdimm_bridge, CXL);
 164
 165 static void cxl_nvdimm_release(struct device *dev)
 166 {
 167         struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
 168
 169         kfree(cxl_nvd);
 170 }
 171
 172 static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {
 173         &cxl_base_attribute_group,
 174         NULL,
 175 };
 176
 177 const struct device_type cxl_nvdimm_type = {
 178         .name = "cxl_nvdimm",
 179         .release = cxl_nvdimm_release,
 180         .groups = cxl_nvdimm_attribute_groups,
 181 };
 182
 183 bool is_cxl_nvdimm(struct device *dev)
 184 {
 185         return dev->type == &cxl_nvdimm_type;
 186 }
 187 EXPORT_SYMBOL_NS_GPL(is_cxl_nvdimm, CXL);
 188
 189 struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev)
 190 {
 191         if (dev_WARN_ONCE(dev, !is_cxl_nvdimm(dev),
 192                           "not a cxl_nvdimm device\n"))
 193                 return NULL;
 194         return container_of(dev, struct cxl_nvdimm, dev);
 195 }
 196 EXPORT_SYMBOL_NS_GPL(to_cxl_nvdimm, CXL);
 197
 198 static struct lock_class_key cxl_nvdimm_key;
 199
 200 static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_nvdimm_bridge *cxl_nvb,
 201                                            struct cxl_memdev *cxlmd)
 202 {
 203         struct cxl_nvdimm *cxl_nvd;
 204         struct device *dev;
 205
 206         cxl_nvd = kzalloc(sizeof(*cxl_nvd), GFP_KERNEL);
 207         if (!cxl_nvd)
 208                 return ERR_PTR(-ENOMEM);
 209
 210         dev = &cxl_nvd->dev;
 211         cxl_nvd->cxlmd = cxlmd;
 212         cxlmd->cxl_nvd = cxl_nvd;
 213         device_initialize(dev);
 214         lockdep_set_class(&dev->mutex, &cxl_nvdimm_key);
 215         device_set_pm_not_required(dev);
 216         dev->parent = &cxlmd->dev;
 217         dev->bus = &cxl_bus_type;
 218         dev->type = &cxl_nvdimm_type;
 219         /*
 220          * A "%llx" string is 17-bytes vs dimm_id that is max
 221          * NVDIMM_KEY_DESC_LEN
 222          */
 223         BUILD_BUG_ON(sizeof(cxl_nvd->dev_id) < 17 ||
 224                      sizeof(cxl_nvd->dev_id) > NVDIMM_KEY_DESC_LEN);
 225         sprintf(cxl_nvd->dev_id, "%llx", cxlmd->cxlds->serial);
 226
 227         return cxl_nvd;
 228 }
 229
 230 static void cxlmd_release_nvdimm(void *_cxlmd)
 231 {
 232         struct cxl_memdev *cxlmd = _cxlmd;
 233         struct cxl_nvdimm *cxl_nvd = cxlmd->cxl_nvd;
 234         struct cxl_nvdimm_bridge *cxl_nvb = cxlmd->cxl_nvb;
 235
 236         cxl_nvd->cxlmd = NULL;
 237         cxlmd->cxl_nvd = NULL;
 238         cxlmd->cxl_nvb = NULL;
 239         device_unregister(&cxl_nvd->dev);
 240         put_device(&cxl_nvb->dev);
 241 }
 242
 243 /**
 244  * devm_cxl_add_nvdimm() - add a bridge between a cxl_memdev and an nvdimm
 245  * @cxlmd: cxl_memdev instance that will perform LIBNVDIMM operations
 246  *
 247  * Return: 0 on success negative error code on failure.
 248  */
 249 int devm_cxl_add_nvdimm(struct cxl_memdev *cxlmd)
 250 {
 251         struct cxl_nvdimm_bridge *cxl_nvb;
 252         struct cxl_nvdimm *cxl_nvd;
 253         struct device *dev;
 254         int rc;
 255
 256         cxl_nvb = cxl_find_nvdimm_bridge(cxlmd);
 257         if (!cxl_nvb)
 258                 return -ENODEV;
 259
 260         cxl_nvd = cxl_nvdimm_alloc(cxl_nvb, cxlmd);
 261         if (IS_ERR(cxl_nvd)) {
 262                 rc = PTR_ERR(cxl_nvd);
 263                 goto err_alloc;
 264         }
 265         cxlmd->cxl_nvb = cxl_nvb;
 266
 267         dev = &cxl_nvd->dev;
 268         rc = dev_set_name(dev, "pmem%d", cxlmd->id);
 269         if (rc)
 270                 goto err;
 271
 272         rc = device_add(dev);
 273         if (rc)
 274                 goto err;
 275
 276         dev_dbg(&cxlmd->dev, "register %s\n", dev_name(dev));
 277
 278         /* @cxlmd carries a reference on @cxl_nvb until cxlmd_release_nvdimm */
 279         return devm_add_action_or_reset(&cxlmd->dev, cxlmd_release_nvdimm, cxlmd);
 280
 281 err:
 282         put_device(dev);
 283 err_alloc:
 284         cxlmd->cxl_nvb = NULL;
 285         cxlmd->cxl_nvd = NULL;
 286         put_device(&cxl_nvb->dev);
 287
 288         return rc;
 289 }
 290 EXPORT_SYMBOL_NS_GPL(devm_cxl_add_nvdimm, CXL);