drivers/misc/sram.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic on-chip SRAM allocation driver
   4  *
   5  * Copyright (C) 2012 Philipp Zabel, Pengutronix
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/delay.h>
  10 #include <linux/genalloc.h>
  11 #include <linux/io.h>
  12 #include <linux/list_sort.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_device.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regmap.h>
  17 #include <linux/slab.h>
  18 #include <linux/mfd/syscon.h>
  19 #include <soc/at91/atmel-secumod.h>
  20
  21 #include "sram.h"
  22
  23 #define SRAM_GRANULARITY        32
  24
  25 static ssize_t sram_read(struct file *filp, struct kobject *kobj,
  26                          struct bin_attribute *attr,
  27                          char *buf, loff_t pos, size_t count)
  28 {
  29         struct sram_partition *part;
  30
  31         part = container_of(attr, struct sram_partition, battr);
  32
  33         mutex_lock(&part->lock);
  34         memcpy_fromio(buf, part->base + pos, count);
  35         mutex_unlock(&part->lock);
  36
  37         return count;
  38 }
  39
  40 static ssize_t sram_write(struct file *filp, struct kobject *kobj,
  41                           struct bin_attribute *attr,
  42                           char *buf, loff_t pos, size_t count)
  43 {
  44         struct sram_partition *part;
  45
  46         part = container_of(attr, struct sram_partition, battr);
  47
  48         mutex_lock(&part->lock);
  49         memcpy_toio(part->base + pos, buf, count);
  50         mutex_unlock(&part->lock);
  51
  52         return count;
  53 }
  54
  55 static int sram_add_pool(struct sram_dev *sram, struct sram_reserve *block,
  56                          phys_addr_t start, struct sram_partition *part)
  57 {
  58         int ret;
  59
  60         part->pool = devm_gen_pool_create(sram->dev, ilog2(SRAM_GRANULARITY),
  61                                           NUMA_NO_NODE, block->label);
  62         if (IS_ERR(part->pool))
  63                 return PTR_ERR(part->pool);
  64
  65         ret = gen_pool_add_virt(part->pool, (unsigned long)part->base, start,
  66                                 block->size, NUMA_NO_NODE);
  67         if (ret < 0) {
  68                 dev_err(sram->dev, "failed to register subpool: %d\n", ret);
  69                 return ret;
  70         }
  71
  72         return 0;
  73 }
  74
  75 static int sram_add_export(struct sram_dev *sram, struct sram_reserve *block,
  76                            phys_addr_t start, struct sram_partition *part)
  77 {
  78         sysfs_bin_attr_init(&part->battr);
  79         part->battr.attr.name = devm_kasprintf(sram->dev, GFP_KERNEL,
  80                                                "%llx.sram",
  81                                                (unsigned long long)start);
  82         if (!part->battr.attr.name)
  83                 return -ENOMEM;
  84
  85         part->battr.attr.mode = S_IRUSR | S_IWUSR;
  86         part->battr.read = sram_read;
  87         part->battr.write = sram_write;
  88         part->battr.size = block->size;
  89
  90         return device_create_bin_file(sram->dev, &part->battr);
  91 }
  92
  93 static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block,
  94                               phys_addr_t start)
  95 {
  96         int ret;
  97         struct sram_partition *part = &sram->partition[sram->partitions];
  98
  99         mutex_init(&part->lock);
 100         part->base = sram->virt_base + block->start;
 101
 102         if (block->pool) {
 103                 ret = sram_add_pool(sram, block, start, part);
 104                 if (ret)
 105                         return ret;
 106         }
 107         if (block->export) {
 108                 ret = sram_add_export(sram, block, start, part);
 109                 if (ret)
 110                         return ret;
 111         }
 112         if (block->protect_exec) {
 113                 ret = sram_check_protect_exec(sram, block, part);
 114                 if (ret)
 115                         return ret;
 116
 117                 ret = sram_add_pool(sram, block, start, part);
 118                 if (ret)
 119                         return ret;
 120
 121                 sram_add_protect_exec(part);
 122         }
 123
 124         sram->partitions++;
 125
 126         return 0;
 127 }
 128
 129 static void sram_free_partitions(struct sram_dev *sram)
 130 {
 131         struct sram_partition *part;
 132
 133         if (!sram->partitions)
 134                 return;
 135
 136         part = &sram->partition[sram->partitions - 1];
 137         for (; sram->partitions; sram->partitions--, part--) {
 138                 if (part->battr.size)
 139                         device_remove_bin_file(sram->dev, &part->battr);
 140
 141                 if (part->pool &&
 142                     gen_pool_avail(part->pool) < gen_pool_size(part->pool))
 143                         dev_err(sram->dev, "removed pool while SRAM allocated\n");
 144         }
 145 }
 146
 147 static int sram_reserve_cmp(void *priv, struct list_head *a,
 148                                         struct list_head *b)
 149 {
 150         struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
 151         struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
 152
 153         return ra->start - rb->start;
 154 }
 155
 156 static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
 157 {
 158         struct device_node *np = sram->dev->of_node, *child;
 159         unsigned long size, cur_start, cur_size;
 160         struct sram_reserve *rblocks, *block;
 161         struct list_head reserve_list;
 162         unsigned int nblocks, exports = 0;
 163         const char *label;
 164         int ret = 0;
 165
 166         INIT_LIST_HEAD(&reserve_list);
 167
 168         size = resource_size(res);
 169
 170         /*
 171          * We need an additional block to mark the end of the memory region
 172          * after the reserved blocks from the dt are processed.
 173          */
 174         nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
 175         rblocks = kcalloc(nblocks, sizeof(*rblocks), GFP_KERNEL);
 176         if (!rblocks)
 177                 return -ENOMEM;
 178
 179         block = &rblocks[0];
 180         for_each_available_child_of_node(np, child) {
 181                 struct resource child_res;
 182
 183                 ret = of_address_to_resource(child, 0, &child_res);
 184                 if (ret < 0) {
 185                         dev_err(sram->dev,
 186                                 "could not get address for node %pOF\n",
 187                                 child);
 188                         goto err_chunks;
 189                 }
 190
 191                 if (child_res.start < res->start || child_res.end > res->end) {
 192                         dev_err(sram->dev,
 193                                 "reserved block %pOF outside the sram area\n",
 194                                 child);
 195                         ret = -EINVAL;
 196                         goto err_chunks;
 197                 }
 198
 199                 block->start = child_res.start - res->start;
 200                 block->size = resource_size(&child_res);
 201                 list_add_tail(&block->list, &reserve_list);
 202
 203                 if (of_find_property(child, "export", NULL))
 204                         block->export = true;
 205
 206                 if (of_find_property(child, "pool", NULL))
 207                         block->pool = true;
 208
 209                 if (of_find_property(child, "protect-exec", NULL))
 210                         block->protect_exec = true;
 211
 212                 if ((block->export || block->pool || block->protect_exec) &&
 213                     block->size) {
 214                         exports++;
 215
 216                         label = NULL;
 217                         ret = of_property_read_string(child, "label", &label);
 218                         if (ret && ret != -EINVAL) {
 219                                 dev_err(sram->dev,
 220                                         "%pOF has invalid label name\n",
 221                                         child);
 222                                 goto err_chunks;
 223                         }
 224                         if (!label)
 225                                 label = child->name;
 226
 227                         block->label = devm_kstrdup(sram->dev,
 228                                                     label, GFP_KERNEL);
 229                         if (!block->label) {
 230                                 ret = -ENOMEM;
 231                                 goto err_chunks;
 232                         }
 233
 234                         dev_dbg(sram->dev, "found %sblock '%s' 0x%x-0x%x\n",
 235                                 block->export ? "exported " : "", block->label,
 236                                 block->start, block->start + block->size);
 237                 } else {
 238                         dev_dbg(sram->dev, "found reserved block 0x%x-0x%x\n",
 239                                 block->start, block->start + block->size);
 240                 }
 241
 242                 block++;
 243         }
 244         child = NULL;
 245
 246         /* the last chunk marks the end of the region */
 247         rblocks[nblocks - 1].start = size;
 248         rblocks[nblocks - 1].size = 0;
 249         list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
 250
 251         list_sort(NULL, &reserve_list, sram_reserve_cmp);
 252
 253         if (exports) {
 254                 sram->partition = devm_kcalloc(sram->dev,
 255                                        exports, sizeof(*sram->partition),
 256                                        GFP_KERNEL);
 257                 if (!sram->partition) {
 258                         ret = -ENOMEM;
 259                         goto err_chunks;
 260                 }
 261         }
 262
 263         cur_start = 0;
 264         list_for_each_entry(block, &reserve_list, list) {
 265                 /* can only happen if sections overlap */
 266                 if (block->start < cur_start) {
 267                         dev_err(sram->dev,
 268                                 "block at 0x%x starts after current offset 0x%lx\n",
 269                                 block->start, cur_start);
 270                         ret = -EINVAL;
 271                         sram_free_partitions(sram);
 272                         goto err_chunks;
 273                 }
 274
 275                 if ((block->export || block->pool || block->protect_exec) &&
 276                     block->size) {
 277                         ret = sram_add_partition(sram, block,
 278                                                  res->start + block->start);
 279                         if (ret) {
 280                                 sram_free_partitions(sram);
 281                                 goto err_chunks;
 282                         }
 283                 }
 284
 285                 /* current start is in a reserved block, so continue after it */
 286                 if (block->start == cur_start) {
 287                         cur_start = block->start + block->size;
 288                         continue;
 289                 }
 290
 291                 /*
 292                  * allocate the space between the current starting
 293                  * address and the following reserved block, or the
 294                  * end of the region.
 295                  */
 296                 cur_size = block->start - cur_start;
 297
 298                 dev_dbg(sram->dev, "adding chunk 0x%lx-0x%lx\n",
 299                         cur_start, cur_start + cur_size);
 300
 301                 ret = gen_pool_add_virt(sram->pool,
 302                                 (unsigned long)sram->virt_base + cur_start,
 303                                 res->start + cur_start, cur_size, -1);
 304                 if (ret < 0) {
 305                         sram_free_partitions(sram);
 306                         goto err_chunks;
 307                 }
 308
 309                 /* next allocation after this reserved block */
 310                 cur_start = block->start + block->size;
 311         }
 312
 313 err_chunks:
 314         of_node_put(child);
 315         kfree(rblocks);
 316
 317         return ret;
 318 }
 319
 320 static int atmel_securam_wait(void)
 321 {
 322         struct regmap *regmap;
 323         u32 val;
 324
 325         regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-secumod");
 326         if (IS_ERR(regmap))
 327                 return -ENODEV;
 328
 329         return regmap_read_poll_timeout(regmap, AT91_SECUMOD_RAMRDY, val,
 330                                         val & AT91_SECUMOD_RAMRDY_READY,
 331                                         10000, 500000);
 332 }
 333
 334 static const struct of_device_id sram_dt_ids[] = {
 335         { .compatible = "mmio-sram" },
 336         { .compatible = "atmel,sama5d2-securam", .data = atmel_securam_wait },
 337         {}
 338 };
 339
 340 static int sram_probe(struct platform_device *pdev)
 341 {
 342         struct sram_dev *sram;
 343         struct resource *res;
 344         size_t size;
 345         int ret;
 346         int (*init_func)(void);
 347
 348         sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
 349         if (!sram)
 350                 return -ENOMEM;
 351
 352         sram->dev = &pdev->dev;
 353
 354         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 355         if (!res) {
 356                 dev_err(sram->dev, "found no memory resource\n");
 357                 return -EINVAL;
 358         }
 359
 360         size = resource_size(res);
 361
 362         if (!devm_request_mem_region(sram->dev, res->start, size, pdev->name)) {
 363                 dev_err(sram->dev, "could not request region for resource\n");
 364                 return -EBUSY;
 365         }
 366
 367         if (of_property_read_bool(pdev->dev.of_node, "no-memory-wc"))
 368                 sram->virt_base = devm_ioremap(sram->dev, res->start, size);
 369         else
 370                 sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size);
 371         if (!sram->virt_base)
 372                 return -ENOMEM;
 373
 374         sram->pool = devm_gen_pool_create(sram->dev, ilog2(SRAM_GRANULARITY),
 375                                           NUMA_NO_NODE, NULL);
 376         if (IS_ERR(sram->pool))
 377                 return PTR_ERR(sram->pool);
 378
 379         sram->clk = devm_clk_get(sram->dev, NULL);
 380         if (IS_ERR(sram->clk))
 381                 sram->clk = NULL;
 382         else
 383                 clk_prepare_enable(sram->clk);
 384
 385         ret = sram_reserve_regions(sram, res);
 386         if (ret)
 387                 goto err_disable_clk;
 388
 389         platform_set_drvdata(pdev, sram);
 390
 391         init_func = of_device_get_match_data(&pdev->dev);
 392         if (init_func) {
 393                 ret = init_func();
 394                 if (ret)
 395                         goto err_free_partitions;
 396         }
 397
 398         dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n",
 399                 gen_pool_size(sram->pool) / 1024, sram->virt_base);
 400
 401         return 0;
 402
 403 err_free_partitions:
 404         sram_free_partitions(sram);
 405 err_disable_clk:
 406         if (sram->clk)
 407                 clk_disable_unprepare(sram->clk);
 408
 409         return ret;
 410 }
 411
 412 static int sram_remove(struct platform_device *pdev)
 413 {
 414         struct sram_dev *sram = platform_get_drvdata(pdev);
 415
 416         sram_free_partitions(sram);
 417
 418         if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
 419                 dev_err(sram->dev, "removed while SRAM allocated\n");
 420
 421         if (sram->clk)
 422                 clk_disable_unprepare(sram->clk);
 423
 424         return 0;
 425 }
 426
 427 static struct platform_driver sram_driver = {
 428         .driver = {
 429                 .name = "sram",
 430                 .of_match_table = sram_dt_ids,
 431         },
 432         .probe = sram_probe,
 433         .remove = sram_remove,
 434 };
 435
 436 static int __init sram_init(void)
 437 {
 438         return platform_driver_register(&sram_driver);
 439 }
 440
 441 postcore_initcall(sram_init);