drivers/misc/sram.c

   1 /*
   2  * Generic on-chip SRAM allocation driver
   3  *
   4  * Copyright (C) 2012 Philipp Zabel, Pengutronix
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  18  * MA 02110-1301, USA.
  19  */
  20
  21 #include <linux/clk.h>
  22 #include <linux/delay.h>
  23 #include <linux/genalloc.h>
  24 #include <linux/io.h>
  25 #include <linux/list_sort.h>
  26 #include <linux/of_address.h>
  27 #include <linux/of_device.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/regmap.h>
  30 #include <linux/slab.h>
  31 #include <linux/mfd/syscon.h>
  32 #include <soc/at91/atmel-secumod.h>
  33
  34 #include "sram.h"
  35
  36 #define SRAM_GRANULARITY        32
  37
  38 static ssize_t sram_read(struct file *filp, struct kobject *kobj,
  39                          struct bin_attribute *attr,
  40                          char *buf, loff_t pos, size_t count)
  41 {
  42         struct sram_partition *part;
  43
  44         part = container_of(attr, struct sram_partition, battr);
  45
  46         mutex_lock(&part->lock);
  47         memcpy_fromio(buf, part->base + pos, count);
  48         mutex_unlock(&part->lock);
  49
  50         return count;
  51 }
  52
  53 static ssize_t sram_write(struct file *filp, struct kobject *kobj,
  54                           struct bin_attribute *attr,
  55                           char *buf, loff_t pos, size_t count)
  56 {
  57         struct sram_partition *part;
  58
  59         part = container_of(attr, struct sram_partition, battr);
  60
  61         mutex_lock(&part->lock);
  62         memcpy_toio(part->base + pos, buf, count);
  63         mutex_unlock(&part->lock);
  64
  65         return count;
  66 }
  67
  68 static int sram_add_pool(struct sram_dev *sram, struct sram_reserve *block,
  69                          phys_addr_t start, struct sram_partition *part)
  70 {
  71         int ret;
  72
  73         part->pool = devm_gen_pool_create(sram->dev, ilog2(SRAM_GRANULARITY),
  74                                           NUMA_NO_NODE, block->label);
  75         if (IS_ERR(part->pool))
  76                 return PTR_ERR(part->pool);
  77
  78         ret = gen_pool_add_virt(part->pool, (unsigned long)part->base, start,
  79                                 block->size, NUMA_NO_NODE);
  80         if (ret < 0) {
  81                 dev_err(sram->dev, "failed to register subpool: %d\n", ret);
  82                 return ret;
  83         }
  84
  85         return 0;
  86 }
  87
  88 static int sram_add_export(struct sram_dev *sram, struct sram_reserve *block,
  89                            phys_addr_t start, struct sram_partition *part)
  90 {
  91         sysfs_bin_attr_init(&part->battr);
  92         part->battr.attr.name = devm_kasprintf(sram->dev, GFP_KERNEL,
  93                                                "%llx.sram",
  94                                                (unsigned long long)start);
  95         if (!part->battr.attr.name)
  96                 return -ENOMEM;
  97
  98         part->battr.attr.mode = S_IRUSR | S_IWUSR;
  99         part->battr.read = sram_read;
 100         part->battr.write = sram_write;
 101         part->battr.size = block->size;
 102
 103         return device_create_bin_file(sram->dev, &part->battr);
 104 }
 105
 106 static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block,
 107                               phys_addr_t start)
 108 {
 109         int ret;
 110         struct sram_partition *part = &sram->partition[sram->partitions];
 111
 112         mutex_init(&part->lock);
 113         part->base = sram->virt_base + block->start;
 114
 115         if (block->pool) {
 116                 ret = sram_add_pool(sram, block, start, part);
 117                 if (ret)
 118                         return ret;
 119         }
 120         if (block->export) {
 121                 ret = sram_add_export(sram, block, start, part);
 122                 if (ret)
 123                         return ret;
 124         }
 125         if (block->protect_exec) {
 126                 ret = sram_check_protect_exec(sram, block, part);
 127                 if (ret)
 128                         return ret;
 129
 130                 ret = sram_add_pool(sram, block, start, part);
 131                 if (ret)
 132                         return ret;
 133
 134                 sram_add_protect_exec(part);
 135         }
 136
 137         sram->partitions++;
 138
 139         return 0;
 140 }
 141
 142 static void sram_free_partitions(struct sram_dev *sram)
 143 {
 144         struct sram_partition *part;
 145
 146         if (!sram->partitions)
 147                 return;
 148
 149         part = &sram->partition[sram->partitions - 1];
 150         for (; sram->partitions; sram->partitions--, part--) {
 151                 if (part->battr.size)
 152                         device_remove_bin_file(sram->dev, &part->battr);
 153
 154                 if (part->pool &&
 155                     gen_pool_avail(part->pool) < gen_pool_size(part->pool))
 156                         dev_err(sram->dev, "removed pool while SRAM allocated\n");
 157         }
 158 }
 159
 160 static int sram_reserve_cmp(void *priv, struct list_head *a,
 161                                         struct list_head *b)
 162 {
 163         struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
 164         struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
 165
 166         return ra->start - rb->start;
 167 }
 168
 169 static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
 170 {
 171         struct device_node *np = sram->dev->of_node, *child;
 172         unsigned long size, cur_start, cur_size;
 173         struct sram_reserve *rblocks, *block;
 174         struct list_head reserve_list;
 175         unsigned int nblocks, exports = 0;
 176         const char *label;
 177         int ret = 0;
 178
 179         INIT_LIST_HEAD(&reserve_list);
 180
 181         size = resource_size(res);
 182
 183         /*
 184          * We need an additional block to mark the end of the memory region
 185          * after the reserved blocks from the dt are processed.
 186          */
 187         nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
 188         rblocks = kcalloc(nblocks, sizeof(*rblocks), GFP_KERNEL);
 189         if (!rblocks)
 190                 return -ENOMEM;
 191
 192         block = &rblocks[0];
 193         for_each_available_child_of_node(np, child) {
 194                 struct resource child_res;
 195
 196                 ret = of_address_to_resource(child, 0, &child_res);
 197                 if (ret < 0) {
 198                         dev_err(sram->dev,
 199                                 "could not get address for node %pOF\n",
 200                                 child);
 201                         goto err_chunks;
 202                 }
 203
 204                 if (child_res.start < res->start || child_res.end > res->end) {
 205                         dev_err(sram->dev,
 206                                 "reserved block %pOF outside the sram area\n",
 207                                 child);
 208                         ret = -EINVAL;
 209                         goto err_chunks;
 210                 }
 211
 212                 block->start = child_res.start - res->start;
 213                 block->size = resource_size(&child_res);
 214                 list_add_tail(&block->list, &reserve_list);
 215
 216                 if (of_find_property(child, "export", NULL))
 217                         block->export = true;
 218
 219                 if (of_find_property(child, "pool", NULL))
 220                         block->pool = true;
 221
 222                 if (of_find_property(child, "protect-exec", NULL))
 223                         block->protect_exec = true;
 224
 225                 if ((block->export || block->pool || block->protect_exec) &&
 226                     block->size) {
 227                         exports++;
 228
 229                         label = NULL;
 230                         ret = of_property_read_string(child, "label", &label);
 231                         if (ret && ret != -EINVAL) {
 232                                 dev_err(sram->dev,
 233                                         "%pOF has invalid label name\n",
 234                                         child);
 235                                 goto err_chunks;
 236                         }
 237                         if (!label)
 238                                 label = child->name;
 239
 240                         block->label = devm_kstrdup(sram->dev,
 241                                                     label, GFP_KERNEL);
 242                         if (!block->label) {
 243                                 ret = -ENOMEM;
 244                                 goto err_chunks;
 245                         }
 246
 247                         dev_dbg(sram->dev, "found %sblock '%s' 0x%x-0x%x\n",
 248                                 block->export ? "exported " : "", block->label,
 249                                 block->start, block->start + block->size);
 250                 } else {
 251                         dev_dbg(sram->dev, "found reserved block 0x%x-0x%x\n",
 252                                 block->start, block->start + block->size);
 253                 }
 254
 255                 block++;
 256         }
 257         child = NULL;
 258
 259         /* the last chunk marks the end of the region */
 260         rblocks[nblocks - 1].start = size;
 261         rblocks[nblocks - 1].size = 0;
 262         list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
 263
 264         list_sort(NULL, &reserve_list, sram_reserve_cmp);
 265
 266         if (exports) {
 267                 sram->partition = devm_kcalloc(sram->dev,
 268                                        exports, sizeof(*sram->partition),
 269                                        GFP_KERNEL);
 270                 if (!sram->partition) {
 271                         ret = -ENOMEM;
 272                         goto err_chunks;
 273                 }
 274         }
 275
 276         cur_start = 0;
 277         list_for_each_entry(block, &reserve_list, list) {
 278                 /* can only happen if sections overlap */
 279                 if (block->start < cur_start) {
 280                         dev_err(sram->dev,
 281                                 "block at 0x%x starts after current offset 0x%lx\n",
 282                                 block->start, cur_start);
 283                         ret = -EINVAL;
 284                         sram_free_partitions(sram);
 285                         goto err_chunks;
 286                 }
 287
 288                 if ((block->export || block->pool || block->protect_exec) &&
 289                     block->size) {
 290                         ret = sram_add_partition(sram, block,
 291                                                  res->start + block->start);
 292                         if (ret) {
 293                                 sram_free_partitions(sram);
 294                                 goto err_chunks;
 295                         }
 296                 }
 297
 298                 /* current start is in a reserved block, so continue after it */
 299                 if (block->start == cur_start) {
 300                         cur_start = block->start + block->size;
 301                         continue;
 302                 }
 303
 304                 /*
 305                  * allocate the space between the current starting
 306                  * address and the following reserved block, or the
 307                  * end of the region.
 308                  */
 309                 cur_size = block->start - cur_start;
 310
 311                 dev_dbg(sram->dev, "adding chunk 0x%lx-0x%lx\n",
 312                         cur_start, cur_start + cur_size);
 313
 314                 ret = gen_pool_add_virt(sram->pool,
 315                                 (unsigned long)sram->virt_base + cur_start,
 316                                 res->start + cur_start, cur_size, -1);
 317                 if (ret < 0) {
 318                         sram_free_partitions(sram);
 319                         goto err_chunks;
 320                 }
 321
 322                 /* next allocation after this reserved block */
 323                 cur_start = block->start + block->size;
 324         }
 325
 326 err_chunks:
 327         of_node_put(child);
 328         kfree(rblocks);
 329
 330         return ret;
 331 }
 332
 333 static int atmel_securam_wait(void)
 334 {
 335         struct regmap *regmap;
 336         u32 val;
 337
 338         regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-secumod");
 339         if (IS_ERR(regmap))
 340                 return -ENODEV;
 341
 342         return regmap_read_poll_timeout(regmap, AT91_SECUMOD_RAMRDY, val,
 343                                         val & AT91_SECUMOD_RAMRDY_READY,
 344                                         10000, 500000);
 345 }
 346
 347 static const struct of_device_id sram_dt_ids[] = {
 348         { .compatible = "mmio-sram" },
 349         { .compatible = "atmel,sama5d2-securam", .data = atmel_securam_wait },
 350         {}
 351 };
 352
 353 static int sram_probe(struct platform_device *pdev)
 354 {
 355         struct sram_dev *sram;
 356         struct resource *res;
 357         size_t size;
 358         int ret;
 359         int (*init_func)(void);
 360
 361         sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
 362         if (!sram)
 363                 return -ENOMEM;
 364
 365         sram->dev = &pdev->dev;
 366
 367         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 368         if (!res) {
 369                 dev_err(sram->dev, "found no memory resource\n");
 370                 return -EINVAL;
 371         }
 372
 373         size = resource_size(res);
 374
 375         if (!devm_request_mem_region(sram->dev, res->start, size, pdev->name)) {
 376                 dev_err(sram->dev, "could not request region for resource\n");
 377                 return -EBUSY;
 378         }
 379
 380         if (of_property_read_bool(pdev->dev.of_node, "no-memory-wc"))
 381                 sram->virt_base = devm_ioremap(sram->dev, res->start, size);
 382         else
 383                 sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size);
 384         if (!sram->virt_base)
 385                 return -ENOMEM;
 386
 387         sram->pool = devm_gen_pool_create(sram->dev, ilog2(SRAM_GRANULARITY),
 388                                           NUMA_NO_NODE, NULL);
 389         if (IS_ERR(sram->pool))
 390                 return PTR_ERR(sram->pool);
 391
 392         sram->clk = devm_clk_get(sram->dev, NULL);
 393         if (IS_ERR(sram->clk))
 394                 sram->clk = NULL;
 395         else
 396                 clk_prepare_enable(sram->clk);
 397
 398         ret = sram_reserve_regions(sram, res);
 399         if (ret)
 400                 goto err_disable_clk;
 401
 402         platform_set_drvdata(pdev, sram);
 403
 404         init_func = of_device_get_match_data(&pdev->dev);
 405         if (init_func) {
 406                 ret = init_func();
 407                 if (ret)
 408                         goto err_free_partitions;
 409         }
 410
 411         dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n",
 412                 gen_pool_size(sram->pool) / 1024, sram->virt_base);
 413
 414         return 0;
 415
 416 err_free_partitions:
 417         sram_free_partitions(sram);
 418 err_disable_clk:
 419         if (sram->clk)
 420                 clk_disable_unprepare(sram->clk);
 421
 422         return ret;
 423 }
 424
 425 static int sram_remove(struct platform_device *pdev)
 426 {
 427         struct sram_dev *sram = platform_get_drvdata(pdev);
 428
 429         sram_free_partitions(sram);
 430
 431         if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
 432                 dev_err(sram->dev, "removed while SRAM allocated\n");
 433
 434         if (sram->clk)
 435                 clk_disable_unprepare(sram->clk);
 436
 437         return 0;
 438 }
 439
 440 static struct platform_driver sram_driver = {
 441         .driver = {
 442                 .name = "sram",
 443                 .of_match_table = sram_dt_ids,
 444         },
 445         .probe = sram_probe,
 446         .remove = sram_remove,
 447 };
 448
 449 static int __init sram_init(void)
 450 {
 451         return platform_driver_register(&sram_driver);
 452 }
 453
 454 postcore_initcall(sram_init);