2 * Generic on-chip SRAM allocation driver
4 * Copyright (C) 2012 Philipp Zabel, Pengutronix
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.
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,
21 #include <linux/clk.h>
22 #include <linux/genalloc.h>
24 #include <linux/list_sort.h>
25 #include <linux/of_address.h>
26 #include <linux/platform_device.h>
27 #include <linux/slab.h>
29 #define SRAM_GRANULARITY 32
31 struct sram_partition {
34 struct gen_pool *pool;
35 struct bin_attribute battr;
41 void __iomem *virt_base;
43 struct gen_pool *pool;
46 struct sram_partition *partition;
51 struct list_head list;
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)
63 struct sram_partition *part;
65 part = container_of(attr, struct sram_partition, battr);
67 mutex_lock(&part->lock);
68 memcpy_fromio(buf, part->base + pos, count);
69 mutex_unlock(&part->lock);
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)
78 struct sram_partition *part;
80 part = container_of(attr, struct sram_partition, battr);
82 mutex_lock(&part->lock);
83 memcpy_toio(part->base + pos, buf, count);
84 mutex_unlock(&part->lock);
89 static int sram_add_pool(struct sram_dev *sram, struct sram_reserve *block,
90 phys_addr_t start, struct sram_partition *part)
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);
99 ret = gen_pool_add_virt(part->pool, (unsigned long)part->base, start,
100 block->size, NUMA_NO_NODE);
102 dev_err(sram->dev, "failed to register subpool: %d\n", ret);
109 static int sram_add_export(struct sram_dev *sram, struct sram_reserve *block,
110 phys_addr_t start, struct sram_partition *part)
112 sysfs_bin_attr_init(&part->battr);
113 part->battr.attr.name = devm_kasprintf(sram->dev, GFP_KERNEL,
115 (unsigned long long)start);
116 if (!part->battr.attr.name)
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;
124 return device_create_bin_file(sram->dev, &part->battr);
127 static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block,
131 struct sram_partition *part = &sram->partition[sram->partitions];
133 mutex_init(&part->lock);
134 part->base = sram->virt_base + block->start;
137 ret = sram_add_pool(sram, block, start, part);
142 ret = sram_add_export(sram, block, start, part);
151 static void sram_free_partitions(struct sram_dev *sram)
153 struct sram_partition *part;
155 if (!sram->partitions)
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);
164 gen_pool_avail(part->pool) < gen_pool_size(part->pool))
165 dev_err(sram->dev, "removed pool while SRAM allocated\n");
169 static int sram_reserve_cmp(void *priv, struct list_head *a,
172 struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
173 struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
175 return ra->start - rb->start;
178 static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
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;
188 INIT_LIST_HEAD(&reserve_list);
190 size = resource_size(res);
193 * We need an additional block to mark the end of the memory region
194 * after the reserved blocks from the dt are processed.
196 nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
197 rblocks = kzalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
202 for_each_available_child_of_node(np, child) {
203 struct resource child_res;
205 ret = of_address_to_resource(child, 0, &child_res);
208 "could not get address for node %s\n",
213 if (child_res.start < res->start || child_res.end > res->end) {
215 "reserved block %s outside the sram area\n",
221 block->start = child_res.start - res->start;
222 block->size = resource_size(&child_res);
223 list_add_tail(&block->list, &reserve_list);
225 if (of_find_property(child, "export", NULL))
226 block->export = true;
228 if (of_find_property(child, "pool", NULL))
231 if ((block->export || block->pool) && block->size) {
235 ret = of_property_read_string(child, "label", &label);
236 if (ret && ret != -EINVAL) {
238 "%s has invalid label name\n",
245 block->label = devm_kstrdup(sram->dev,
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);
254 dev_dbg(sram->dev, "found reserved block 0x%x-0x%x\n",
255 block->start, block->start + block->size);
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);
267 list_sort(NULL, &reserve_list, sram_reserve_cmp);
270 sram->partition = devm_kzalloc(sram->dev,
271 exports * sizeof(*sram->partition),
273 if (!sram->partition) {
280 list_for_each_entry(block, &reserve_list, list) {
281 /* can only happen if sections overlap */
282 if (block->start < cur_start) {
284 "block at 0x%x starts after current offset 0x%lx\n",
285 block->start, cur_start);
287 sram_free_partitions(sram);
291 if ((block->export || block->pool) && block->size) {
292 ret = sram_add_partition(sram, block,
293 res->start + block->start);
295 sram_free_partitions(sram);
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;
307 * allocate the space between the current starting
308 * address and the following reserved block, or the
311 cur_size = block->start - cur_start;
313 dev_dbg(sram->dev, "adding chunk 0x%lx-0x%lx\n",
314 cur_start, cur_start + cur_size);
316 ret = gen_pool_add_virt(sram->pool,
317 (unsigned long)sram->virt_base + cur_start,
318 res->start + cur_start, cur_size, -1);
320 sram_free_partitions(sram);
324 /* next allocation after this reserved block */
325 cur_start = block->start + block->size;
337 static int sram_probe(struct platform_device *pdev)
339 struct sram_dev *sram;
340 struct resource *res;
344 sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
348 sram->dev = &pdev->dev;
350 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
352 dev_err(sram->dev, "found no memory resource\n");
356 size = resource_size(res);
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");
363 sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size);
364 if (IS_ERR(sram->virt_base))
365 return PTR_ERR(sram->virt_base);
367 sram->pool = devm_gen_pool_create(sram->dev, ilog2(SRAM_GRANULARITY),
369 if (IS_ERR(sram->pool))
370 return PTR_ERR(sram->pool);
372 ret = sram_reserve_regions(sram, res);
376 sram->clk = devm_clk_get(sram->dev, NULL);
377 if (IS_ERR(sram->clk))
380 clk_prepare_enable(sram->clk);
382 platform_set_drvdata(pdev, sram);
384 dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n",
385 gen_pool_size(sram->pool) / 1024, sram->virt_base);
390 static int sram_remove(struct platform_device *pdev)
392 struct sram_dev *sram = platform_get_drvdata(pdev);
394 sram_free_partitions(sram);
396 if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
397 dev_err(sram->dev, "removed while SRAM allocated\n");
400 clk_disable_unprepare(sram->clk);
406 static const struct of_device_id sram_dt_ids[] = {
407 { .compatible = "mmio-sram" },
412 static struct platform_driver sram_driver = {
415 .of_match_table = of_match_ptr(sram_dt_ids),
418 .remove = sram_remove,
421 static int __init sram_init(void)
423 return platform_driver_register(&sram_driver);
426 postcore_initcall(sram_init);