[linux-2.6-block.git] / drivers / misc / sram.c

/*
 * Generic on-chip SRAM allocation driver
 *
 * Copyright (C) 2012 Philipp Zabel, Pengutronix
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/list.h>
#include <linux/list_sort.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/genalloc.h>

#define SRAM_GRANULARITY	32

struct sram_dev {
	struct gen_pool *pool;
	struct clk *clk;
};

struct sram_reserve {
	struct list_head list;
	u32 start;
	u32 size;
};

static int sram_reserve_cmp(void *priv, struct list_head *a,
					struct list_head *b)
{
	struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
	struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);

	return ra->start - rb->start;
}

static int sram_probe(struct platform_device *pdev)
{
	void __iomem *virt_base;
	struct sram_dev *sram;
	struct resource *res;
	struct device_node *np = pdev->dev.of_node, *child;
	unsigned long size, cur_start, cur_size;
	struct sram_reserve *rblocks, *block;
	struct list_head reserve_list;
	unsigned int nblocks;
	int ret;

	INIT_LIST_HEAD(&reserve_list);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	virt_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(virt_base))
		return PTR_ERR(virt_base);

	size = resource_size(res);

	sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
	if (!sram)
		return -ENOMEM;

	sram->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(sram->clk))
		sram->clk = NULL;
	else
		clk_prepare_enable(sram->clk);

	sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1);
	if (!sram->pool)
		return -ENOMEM;

	/*
	 * We need an additional block to mark the end of the memory region
	 * after the reserved blocks from the dt are processed.
	 */
	nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
	rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
	if (!rblocks) {
		ret = -ENOMEM;
		goto err_alloc;
	}

	block = &rblocks[0];
	for_each_available_child_of_node(np, child) {
		struct resource child_res;

		ret = of_address_to_resource(child, 0, &child_res);
		if (ret < 0) {
			dev_err(&pdev->dev,
				"could not get address for node %s\n",
				child->full_name);
			goto err_chunks;
		}

		if (child_res.start < res->start || child_res.end > res->end) {
			dev_err(&pdev->dev,
				"reserved block %s outside the sram area\n",
				child->full_name);
			ret = -EINVAL;
			goto err_chunks;
		}

		block->start = child_res.start - res->start;
		block->size = resource_size(&child_res);
		list_add_tail(&block->list, &reserve_list);

		dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n",
			block->start,
			block->start + block->size);

		block++;
	}

	/* the last chunk marks the end of the region */
	rblocks[nblocks - 1].start = size;
	rblocks[nblocks - 1].size = 0;
	list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);

	list_sort(NULL, &reserve_list, sram_reserve_cmp);

	cur_start = 0;

	list_for_each_entry(block, &reserve_list, list) {
		/* can only happen if sections overlap */
		if (block->start < cur_start) {
			dev_err(&pdev->dev,
				"block at 0x%x starts after current offset 0x%lx\n",
				block->start, cur_start);
			ret = -EINVAL;
			goto err_chunks;
		}

		/* current start is in a reserved block, so continue after it */
		if (block->start == cur_start) {
			cur_start = block->start + block->size;
			continue;
		}

		/*
		 * allocate the space between the current starting
		 * address and the following reserved block, or the
		 * end of the region.
		 */
		cur_size = block->start - cur_start;

		dev_dbg(&pdev->dev, "adding chunk 0x%lx-0x%lx\n",
			cur_start, cur_start + cur_size);
		ret = gen_pool_add_virt(sram->pool,
				(unsigned long)virt_base + cur_start,
				res->start + cur_start, cur_size, -1);
		if (ret < 0)
			goto err_chunks;

		/* next allocation after this reserved block */
		cur_start = block->start + block->size;
	}

	kfree(rblocks);

	platform_set_drvdata(pdev, sram);

	dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);

	return 0;

err_chunks:
	kfree(rblocks);
err_alloc:
	if (sram->clk)
		clk_disable_unprepare(sram->clk);
	return ret;
}

static int sram_remove(struct platform_device *pdev)
{
	struct sram_dev *sram = platform_get_drvdata(pdev);

	if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
		dev_dbg(&pdev->dev, "removed while SRAM allocated\n");

	if (sram->clk)
		clk_disable_unprepare(sram->clk);

	return 0;
}

#ifdef CONFIG_OF
static struct of_device_id sram_dt_ids[] = {
	{ .compatible = "mmio-sram" },
	{}
};
#endif

static struct platform_driver sram_driver = {
	.driver = {
		.name = "sram",
		.of_match_table = of_match_ptr(sram_dt_ids),
	},
	.probe = sram_probe,
	.remove = sram_remove,
};

static int __init sram_init(void)
{
	return platform_driver_register(&sram_driver);
}

postcore_initcall(sram_init);
Commit	Line	Data
4984c6f5 PZ	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/kernel.h>
	22	#include <linux/init.h>
	23	#include <linux/clk.h>
	24	#include <linux/err.h>
	25	#include <linux/io.h>
	26	#include <linux/of.h>
2da19688 HS	27	#include <linux/of_address.h>
	28	#include <linux/list.h>
	29	#include <linux/list_sort.h>
4984c6f5 PZ	30	#include <linux/platform_device.h>
	31	#include <linux/slab.h>
	32	#include <linux/spinlock.h>
	33	#include <linux/genalloc.h>
	34
	35	#define SRAM_GRANULARITY 32
	36
	37	struct sram_dev {
	38	struct gen_pool *pool;
	39	struct clk *clk;
	40	};
	41
2da19688 HS	42	struct sram_reserve {
	43	struct list_head list;
	44	u32 start;
	45	u32 size;
	46	};
	47
	48	static int sram_reserve_cmp(void priv, struct list_head a,
	49	struct list_head *b)
	50	{
	51	struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
	52	struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
	53
	54	return ra->start - rb->start;
	55	}
	56
4984c6f5 PZ	57	static int sram_probe(struct platform_device *pdev)
	58	{
	59	void __iomem *virt_base;
	60	struct sram_dev *sram;
	61	struct resource *res;
2da19688 HS	62	struct device_node np = pdev->dev.of_node, child;
	63	unsigned long size, cur_start, cur_size;
	64	struct sram_reserve rblocks, block;
	65	struct list_head reserve_list;
	66	unsigned int nblocks;
4984c6f5 PZ	67	int ret;
4984c6f5 PZ	68
2da19688 HS	69	INIT_LIST_HEAD(&reserve_list);
2da19688 HS	70
4984c6f5	71	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
21b066f1 LN	72	virt_base = devm_ioremap_resource(&pdev->dev, res);
	73	if (IS_ERR(virt_base))
	74	return PTR_ERR(virt_base);
	75
f3cbfa5d	76	size = resource_size(res);
4984c6f5 PZ	77
	78	sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
	79	if (!sram)
	80	return -ENOMEM;
	81
	82	sram->clk = devm_clk_get(&pdev->dev, NULL);
	83	if (IS_ERR(sram->clk))
	84	sram->clk = NULL;
	85	else
	86	clk_prepare_enable(sram->clk);
	87
	88	sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1);
	89	if (!sram->pool)
	90	return -ENOMEM;
	91
2da19688 HS	92	/*
	93	* We need an additional block to mark the end of the memory region
	94	* after the reserved blocks from the dt are processed.
	95	*/
	96	nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
	97	rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
	98	if (!rblocks) {
	99	ret = -ENOMEM;
	100	goto err_alloc;
4984c6f5 PZ	101	}
4984c6f5 PZ	102
2da19688 HS	103	block = &rblocks[0];
	104	for_each_available_child_of_node(np, child) {
	105	struct resource child_res;
	106
	107	ret = of_address_to_resource(child, 0, &child_res);
	108	if (ret < 0) {
	109	dev_err(&pdev->dev,
	110	"could not get address for node %s\n",
	111	child->full_name);
	112	goto err_chunks;
	113	}
	114
	115	if (child_res.start < res->start \|\| child_res.end > res->end) {
	116	dev_err(&pdev->dev,
	117	"reserved block %s outside the sram area\n",
	118	child->full_name);
	119	ret = -EINVAL;
	120	goto err_chunks;
	121	}
	122
	123	block->start = child_res.start - res->start;
	124	block->size = resource_size(&child_res);
	125	list_add_tail(&block->list, &reserve_list);
	126
	127	dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n",
	128	block->start,
	129	block->start + block->size);
	130
	131	block++;
	132	}
	133
	134	/* the last chunk marks the end of the region */
	135	rblocks[nblocks - 1].start = size;
	136	rblocks[nblocks - 1].size = 0;
	137	list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
	138
	139	list_sort(NULL, &reserve_list, sram_reserve_cmp);
	140
	141	cur_start = 0;
	142
	143	list_for_each_entry(block, &reserve_list, list) {
	144	/* can only happen if sections overlap */
	145	if (block->start < cur_start) {
	146	dev_err(&pdev->dev,
	147	"block at 0x%x starts after current offset 0x%lx\n",
	148	block->start, cur_start);
	149	ret = -EINVAL;
	150	goto err_chunks;
	151	}
	152
	153	/* current start is in a reserved block, so continue after it */
	154	if (block->start == cur_start) {
	155	cur_start = block->start + block->size;
	156	continue;
	157	}
	158
	159	/*
	160	* allocate the space between the current starting
	161	* address and the following reserved block, or the
	162	* end of the region.
	163	*/
	164	cur_size = block->start - cur_start;
	165
	166	dev_dbg(&pdev->dev, "adding chunk 0x%lx-0x%lx\n",
167	cur_start, cur_start + cur_size);
168	ret = gen_pool_add_virt(sram->pool,
169	(unsigned long)virt_base + cur_start,
170	res->start + cur_start, cur_size, -1);
171	if (ret < 0)
172	goto err_chunks;
173
174	/* next allocation after this reserved block */
175	cur_start = block->start + block->size;
176	}
177
178	kfree(rblocks);
179
4984c6f5 PZ	180	platform_set_drvdata(pdev, sram);
	181
	182	dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);
	183
	184	return 0;
2da19688 HS	185
	186	err_chunks:
	187	kfree(rblocks);
	188	err_alloc:
	189	if (sram->clk)
	190	clk_disable_unprepare(sram->clk);
	191	return ret;
4984c6f5 PZ	192	}
	193
	194	static int sram_remove(struct platform_device *pdev)
	195	{
	196	struct sram_dev *sram = platform_get_drvdata(pdev);
	197
	198	if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
	199	dev_dbg(&pdev->dev, "removed while SRAM allocated\n");
	200
4984c6f5 PZ	201	if (sram->clk)
	202	clk_disable_unprepare(sram->clk);
	203
	204	return 0;
	205	}
	206
	207	#ifdef CONFIG_OF
	208	static struct of_device_id sram_dt_ids[] = {
	209	{ .compatible = "mmio-sram" },
	210	{}
	211	};
	212	#endif
	213
	214	static struct platform_driver sram_driver = {
	215	.driver = {
	216	.name = "sram",
	217	.of_match_table = of_match_ptr(sram_dt_ids),
	218	},
	219	.probe = sram_probe,
	220	.remove = sram_remove,
	221	};
	222
	223	static int __init sram_init(void)
	224	{
	225	return platform_driver_register(&sram_driver);
	226	}
	227
	228	postcore_initcall(sram_init);