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
 31struct sram_partition {
 32	void __iomem *base;
 33
 34	struct gen_pool *pool;
 35	struct bin_attribute battr;
 36	struct mutex lock;
 37};
 38
 39struct 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
 50struct 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
 59static 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
 74static 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
 89static 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
109static 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
127static 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
151static 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
169static 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
178static 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
337static 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 (IS_ERR(sram->virt_base))
368		return PTR_ERR(sram->virt_base);
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
393static 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
409static const struct of_device_id sram_dt_ids[] = {
410	{ .compatible = "mmio-sram" },
411	{}
412};
413#endif
414
415static 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
424static int __init sram_init(void)
425{
426	return platform_driver_register(&sram_driver);
427}
428
429postcore_initcall(sram_init);