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   1 From 7ae6478b304bc004c3139b422665b0e23b57f05c Mon Sep 17 00:00:00 2001
   2 From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
   3 Date: Wed, 13 Oct 2021 14:19:55 +0100
   4 Subject: [PATCH] nvmem: core: rework nvmem cell instance creation
   5
   6 In the existing design, we do not create a instance per nvmem cell consumer
   7 but we directly refer cell from nvmem cell list that are added to provider.
   8
   9 However this design has some limitations when consumers want to assign name
  10 or connection id the nvmem cell instance, ex: via "nvmem-cell-names" or
  11 id in nvmem_cell_get(id).
  12
  13 Having a name associated with nvmem cell consumer instance will help
  14 provider drivers in performing post processing of nvmem cell data if required
  15 before data is seen by the consumers. This is pretty normal with some vendors
  16 storing nvmem cells like mac-address in a vendor specific data layouts that
  17 are not directly usable by the consumer drivers.
  18
  19 With this patch nvmem cell will be created dynamically during nvmem_cell_get
  20 and destroyed in nvmem_cell_put, allowing consumers to associate name with
  21 nvmem cell consumer instance.
  22
  23 With this patch a new struct nvmem_cell_entry replaces struct nvmem_cell
  24 for storing nvmem cell information within the core.
  25 This patch does not change nvmem-consumer interface based on nvmem_cell.
  26
  27 Tested-by: Joakim Zhang <qiangqing.zhang@nxp.com>
  28 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  29 Link: https://lore.kernel.org/r/20211013131957.30271-2-srinivas.kandagatla@linaro.org
  30 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  31 ---
  32  drivers/nvmem/core.c | 165 +++++++++++++++++++++++++++----------------
  33  1 file changed, 105 insertions(+), 60 deletions(-)
  34
  35 --- a/drivers/nvmem/core.c
  36 +++ b/drivers/nvmem/core.c
  37 @@ -45,8 +45,7 @@ struct nvmem_device {
  38  #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
  39
  40  #define FLAG_COMPAT            BIT(0)
  41 -
  42 -struct nvmem_cell {
  43 +struct nvmem_cell_entry {
  44         const char              *name;
  45         int                     offset;
  46         int                     bytes;
  47 @@ -57,6 +56,11 @@ struct nvmem_cell {
  48         struct list_head        node;
  49  };
  50
  51 +struct nvmem_cell {
  52 +       struct nvmem_cell_entry *entry;
  53 +       const char              *id;
  54 +};
  55 +
  56  static DEFINE_MUTEX(nvmem_mutex);
  57  static DEFINE_IDA(nvmem_ida);
  58
  59 @@ -424,7 +428,7 @@ static struct bus_type nvmem_bus_type =
  60         .name           = "nvmem",
  61  };
  62
  63 -static void nvmem_cell_drop(struct nvmem_cell *cell)
  64 +static void nvmem_cell_entry_drop(struct nvmem_cell_entry *cell)
  65  {
  66         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
  67         mutex_lock(&nvmem_mutex);
  68 @@ -437,13 +441,13 @@ static void nvmem_cell_drop(struct nvmem
  69
  70  static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
  71  {
  72 -       struct nvmem_cell *cell, *p;
  73 +       struct nvmem_cell_entry *cell, *p;
  74
  75         list_for_each_entry_safe(cell, p, &nvmem->cells, node)
  76 -               nvmem_cell_drop(cell);
  77 +               nvmem_cell_entry_drop(cell);
  78  }
  79
  80 -static void nvmem_cell_add(struct nvmem_cell *cell)
  81 +static void nvmem_cell_entry_add(struct nvmem_cell_entry *cell)
  82  {
  83         mutex_lock(&nvmem_mutex);
  84         list_add_tail(&cell->node, &cell->nvmem->cells);
  85 @@ -451,9 +455,9 @@ static void nvmem_cell_add(struct nvmem_
  86         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
  87  }
  88
  89 -static int nvmem_cell_info_to_nvmem_cell_nodup(struct nvmem_device *nvmem,
  90 -                                       const struct nvmem_cell_info *info,
  91 -                                       struct nvmem_cell *cell)
  92 +static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
  93 +                                                    const struct nvmem_cell_info *info,
  94 +                                                    struct nvmem_cell_entry *cell)
  95  {
  96         cell->nvmem = nvmem;
  97         cell->offset = info->offset;
  98 @@ -477,13 +481,13 @@ static int nvmem_cell_info_to_nvmem_cell
  99         return 0;
 100  }
 101
 102 -static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
 103 -                               const struct nvmem_cell_info *info,
 104 -                               struct nvmem_cell *cell)
 105 +static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem,
 106 +                                              const struct nvmem_cell_info *info,
 107 +                                              struct nvmem_cell_entry *cell)
 108  {
 109         int err;
 110
 111 -       err = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, cell);
 112 +       err = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, cell);
 113         if (err)
 114                 return err;
 115
 116 @@ -507,7 +511,7 @@ static int nvmem_add_cells(struct nvmem_
 117                     const struct nvmem_cell_info *info,
 118                     int ncells)
 119  {
 120 -       struct nvmem_cell **cells;
 121 +       struct nvmem_cell_entry **cells;
 122         int i, rval;
 123
 124         cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
 125 @@ -521,13 +525,13 @@ static int nvmem_add_cells(struct nvmem_
 126                         goto err;
 127                 }
 128
 129 -               rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
 130 +               rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, &info[i], cells[i]);
 131                 if (rval) {
 132                         kfree(cells[i]);
 133                         goto err;
 134                 }
 135
 136 -               nvmem_cell_add(cells[i]);
 137 +               nvmem_cell_entry_add(cells[i]);
 138         }
 139
 140         /* remove tmp array */
 141 @@ -536,7 +540,7 @@ static int nvmem_add_cells(struct nvmem_
 142         return 0;
 143  err:
 144         while (i--)
 145 -               nvmem_cell_drop(cells[i]);
 146 +               nvmem_cell_entry_drop(cells[i]);
 147
 148         kfree(cells);
 149
 150 @@ -573,7 +577,7 @@ static int nvmem_add_cells_from_table(st
 151  {
 152         const struct nvmem_cell_info *info;
 153         struct nvmem_cell_table *table;
 154 -       struct nvmem_cell *cell;
 155 +       struct nvmem_cell_entry *cell;
 156         int rval = 0, i;
 157
 158         mutex_lock(&nvmem_cell_mutex);
 159 @@ -588,15 +592,13 @@ static int nvmem_add_cells_from_table(st
 160                                         goto out;
 161                                 }
 162
 163 -                               rval = nvmem_cell_info_to_nvmem_cell(nvmem,
 164 -                                                                    info,
 165 -                                                                    cell);
 166 +                               rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
 167                                 if (rval) {
 168                                         kfree(cell);
 169                                         goto out;
 170                                 }
 171
 172 -                               nvmem_cell_add(cell);
 173 +                               nvmem_cell_entry_add(cell);
 174                         }
 175                 }
 176         }
 177 @@ -606,10 +608,10 @@ out:
 178         return rval;
 179  }
 180
 181 -static struct nvmem_cell *
 182 -nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id)
 183 +static struct nvmem_cell_entry *
 184 +nvmem_find_cell_entry_by_name(struct nvmem_device *nvmem, const char *cell_id)
 185  {
 186 -       struct nvmem_cell *iter, *cell = NULL;
 187 +       struct nvmem_cell_entry *iter, *cell = NULL;
 188
 189         mutex_lock(&nvmem_mutex);
 190         list_for_each_entry(iter, &nvmem->cells, node) {
 191 @@ -680,7 +682,7 @@ static int nvmem_add_cells_from_of(struc
 192  {
 193         struct device_node *parent, *child;
 194         struct device *dev = &nvmem->dev;
 195 -       struct nvmem_cell *cell;
 196 +       struct nvmem_cell_entry *cell;
 197         const __be32 *addr;
 198         int len;
 199
 200 @@ -729,7 +731,7 @@ static int nvmem_add_cells_from_of(struc
 201                 }
 202
 203                 cell->np = of_node_get(child);
 204 -               nvmem_cell_add(cell);
 205 +               nvmem_cell_entry_add(cell);
 206         }
 207
 208         return 0;
 209 @@ -1142,9 +1144,33 @@ struct nvmem_device *devm_nvmem_device_g
 210  }
 211  EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
 212
 213 +static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry, const char *id)
 214 +{
 215 +       struct nvmem_cell *cell;
 216 +       const char *name = NULL;
 217 +
 218 +       cell = kzalloc(sizeof(*cell), GFP_KERNEL);
 219 +       if (!cell)
 220 +               return ERR_PTR(-ENOMEM);
 221 +
 222 +       if (id) {
 223 +               name = kstrdup_const(id, GFP_KERNEL);
 224 +               if (!name) {
 225 +                       kfree(cell);
 226 +                       return ERR_PTR(-ENOMEM);
 227 +               }
 228 +       }
 229 +
 230 +       cell->id = name;
 231 +       cell->entry = entry;
 232 +
 233 +       return cell;
 234 +}
 235 +
 236  static struct nvmem_cell *
 237  nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
 238  {
 239 +       struct nvmem_cell_entry *cell_entry;
 240         struct nvmem_cell *cell = ERR_PTR(-ENOENT);
 241         struct nvmem_cell_lookup *lookup;
 242         struct nvmem_device *nvmem;
 243 @@ -1169,11 +1195,15 @@ nvmem_cell_get_from_lookup(struct device
 244                                 break;
 245                         }
 246
 247 -                       cell = nvmem_find_cell_by_name(nvmem,
 248 -                                                      lookup->cell_name);
 249 -                       if (!cell) {
 250 +                       cell_entry = nvmem_find_cell_entry_by_name(nvmem,
 251 +                                                                  lookup->cell_name);
 252 +                       if (!cell_entry) {
 253                                 __nvmem_device_put(nvmem);
 254                                 cell = ERR_PTR(-ENOENT);
 255 +                       } else {
 256 +                               cell = nvmem_create_cell(cell_entry, con_id);
 257 +                               if (IS_ERR(cell))
 258 +                                       __nvmem_device_put(nvmem);
 259                         }
 260                         break;
 261                 }
 262 @@ -1184,10 +1214,10 @@ nvmem_cell_get_from_lookup(struct device
 263  }
 264
 265  #if IS_ENABLED(CONFIG_OF)
 266 -static struct nvmem_cell *
 267 -nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np)
 268 +static struct nvmem_cell_entry *
 269 +nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np)
 270  {
 271 -       struct nvmem_cell *iter, *cell = NULL;
 272 +       struct nvmem_cell_entry *iter, *cell = NULL;
 273
 274         mutex_lock(&nvmem_mutex);
 275         list_for_each_entry(iter, &nvmem->cells, node) {
 276 @@ -1217,6 +1247,7 @@ struct nvmem_cell *of_nvmem_cell_get(str
 277  {
 278         struct device_node *cell_np, *nvmem_np;
 279         struct nvmem_device *nvmem;
 280 +       struct nvmem_cell_entry *cell_entry;
 281         struct nvmem_cell *cell;
 282         int index = 0;
 283
 284 @@ -1237,12 +1268,16 @@ struct nvmem_cell *of_nvmem_cell_get(str
 285         if (IS_ERR(nvmem))
 286                 return ERR_CAST(nvmem);
 287
 288 -       cell = nvmem_find_cell_by_node(nvmem, cell_np);
 289 -       if (!cell) {
 290 +       cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
 291 +       if (!cell_entry) {
 292                 __nvmem_device_put(nvmem);
 293                 return ERR_PTR(-ENOENT);
 294         }
 295
 296 +       cell = nvmem_create_cell(cell_entry, id);
 297 +       if (IS_ERR(cell))
 298 +               __nvmem_device_put(nvmem);
 299 +
 300         return cell;
 301  }
 302  EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
 303 @@ -1348,13 +1383,17 @@ EXPORT_SYMBOL(devm_nvmem_cell_put);
 304   */
 305  void nvmem_cell_put(struct nvmem_cell *cell)
 306  {
 307 -       struct nvmem_device *nvmem = cell->nvmem;
 308 +       struct nvmem_device *nvmem = cell->entry->nvmem;
 309 +
 310 +       if (cell->id)
 311 +               kfree_const(cell->id);
 312
 313 +       kfree(cell);
 314         __nvmem_device_put(nvmem);
 315  }
 316  EXPORT_SYMBOL_GPL(nvmem_cell_put);
 317
 318 -static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
 319 +static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void *buf)
 320  {
 321         u8 *p, *b;
 322         int i, extra, bit_offset = cell->bit_offset;
 323 @@ -1388,8 +1427,8 @@ static void nvmem_shift_read_buffer_in_p
 324  }
 325
 326  static int __nvmem_cell_read(struct nvmem_device *nvmem,
 327 -                     struct nvmem_cell *cell,
 328 -                     void *buf, size_t *len)
 329 +                     struct nvmem_cell_entry *cell,
 330 +                     void *buf, size_t *len, const char *id)
 331  {
 332         int rc;
 333
 334 @@ -1420,18 +1459,18 @@ static int __nvmem_cell_read(struct nvme
 335   */
 336  void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
 337  {
 338 -       struct nvmem_device *nvmem = cell->nvmem;
 339 +       struct nvmem_device *nvmem = cell->entry->nvmem;
 340         u8 *buf;
 341         int rc;
 342
 343         if (!nvmem)
 344                 return ERR_PTR(-EINVAL);
 345
 346 -       buf = kzalloc(cell->bytes, GFP_KERNEL);
 347 +       buf = kzalloc(cell->entry->bytes, GFP_KERNEL);
 348         if (!buf)
 349                 return ERR_PTR(-ENOMEM);
 350
 351 -       rc = __nvmem_cell_read(nvmem, cell, buf, len);
 352 +       rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id);
 353         if (rc) {
 354                 kfree(buf);
 355                 return ERR_PTR(rc);
 356 @@ -1441,7 +1480,7 @@ void *nvmem_cell_read(struct nvmem_cell
 357  }
 358  EXPORT_SYMBOL_GPL(nvmem_cell_read);
 359
 360 -static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
 361 +static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
 362                                              u8 *_buf, int len)
 363  {
 364         struct nvmem_device *nvmem = cell->nvmem;
 365 @@ -1494,16 +1533,7 @@ err:
 366         return ERR_PTR(rc);
 367  }
 368
 369 -/**
 370 - * nvmem_cell_write() - Write to a given nvmem cell
 371 - *
 372 - * @cell: nvmem cell to be written.
 373 - * @buf: Buffer to be written.
 374 - * @len: length of buffer to be written to nvmem cell.
 375 - *
 376 - * Return: length of bytes written or negative on failure.
 377 - */
 378 -int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
 379 +static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, size_t len)
 380  {
 381         struct nvmem_device *nvmem = cell->nvmem;
 382         int rc;
 383 @@ -1529,6 +1559,21 @@ int nvmem_cell_write(struct nvmem_cell *
 384
 385         return len;
 386  }
 387 +
 388 +/**
 389 + * nvmem_cell_write() - Write to a given nvmem cell
 390 + *
 391 + * @cell: nvmem cell to be written.
 392 + * @buf: Buffer to be written.
 393 + * @len: length of buffer to be written to nvmem cell.
 394 + *
 395 + * Return: length of bytes written or negative on failure.
 396 + */
 397 +int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
 398 +{
 399 +       return __nvmem_cell_entry_write(cell->entry, buf, len);
 400 +}
 401 +
 402  EXPORT_SYMBOL_GPL(nvmem_cell_write);
 403
 404  static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
 405 @@ -1631,7 +1676,7 @@ static const void *nvmem_cell_read_varia
 406         if (IS_ERR(cell))
 407                 return cell;
 408
 409 -       nbits = cell->nbits;
 410 +       nbits = cell->entry->nbits;
 411         buf = nvmem_cell_read(cell, len);
 412         nvmem_cell_put(cell);
 413         if (IS_ERR(buf))
 414 @@ -1727,18 +1772,18 @@ EXPORT_SYMBOL_GPL(nvmem_cell_read_variab
 415  ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
 416                            struct nvmem_cell_info *info, void *buf)
 417  {
 418 -       struct nvmem_cell cell;
 419 +       struct nvmem_cell_entry cell;
 420         int rc;
 421         ssize_t len;
 422
 423         if (!nvmem)
 424                 return -EINVAL;
 425
 426 -       rc = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, &cell);
 427 +       rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
 428         if (rc)
 429                 return rc;
 430
 431 -       rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
 432 +       rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL);
 433         if (rc)
 434                 return rc;
 435
 436 @@ -1758,17 +1803,17 @@ EXPORT_SYMBOL_GPL(nvmem_device_cell_read
 437  int nvmem_device_cell_write(struct nvmem_device *nvmem,
 438                             struct nvmem_cell_info *info, void *buf)
 439  {
 440 -       struct nvmem_cell cell;
 441 +       struct nvmem_cell_entry cell;
 442         int rc;
 443
 444         if (!nvmem)
 445                 return -EINVAL;
 446
 447 -       rc = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, &cell);
 448 +       rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
 449         if (rc)
 450                 return rc;
 451
 452 -       return nvmem_cell_write(&cell, buf, cell.bytes);
 453 +       return __nvmem_cell_entry_write(&cell, buf, cell.bytes);
 454  }
 455  EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
 456