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