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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 { | |
665d82fb VZ |
38 | struct device *dev; |
39 | void __iomem *virt_base; | |
40 | ||
4984c6f5 PZ |
41 | struct gen_pool *pool; |
42 | struct clk *clk; | |
43 | }; | |
44 | ||
2da19688 HS |
45 | struct sram_reserve { |
46 | struct list_head list; | |
47 | u32 start; | |
48 | u32 size; | |
49 | }; | |
50 | ||
51 | static int sram_reserve_cmp(void *priv, struct list_head *a, | |
52 | struct list_head *b) | |
53 | { | |
54 | struct sram_reserve *ra = list_entry(a, struct sram_reserve, list); | |
55 | struct sram_reserve *rb = list_entry(b, struct sram_reserve, list); | |
56 | ||
57 | return ra->start - rb->start; | |
58 | } | |
59 | ||
4984c6f5 PZ |
60 | static int sram_probe(struct platform_device *pdev) |
61 | { | |
4984c6f5 PZ |
62 | struct sram_dev *sram; |
63 | struct resource *res; | |
2da19688 HS |
64 | struct device_node *np = pdev->dev.of_node, *child; |
65 | unsigned long size, cur_start, cur_size; | |
66 | struct sram_reserve *rblocks, *block; | |
67 | struct list_head reserve_list; | |
68 | unsigned int nblocks; | |
4984c6f5 PZ |
69 | int ret; |
70 | ||
2da19688 HS |
71 | INIT_LIST_HEAD(&reserve_list); |
72 | ||
665d82fb VZ |
73 | sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL); |
74 | if (!sram) | |
75 | return -ENOMEM; | |
76 | ||
77 | sram->dev = &pdev->dev; | |
78 | ||
4984c6f5 | 79 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
0ab163ad | 80 | if (!res) { |
665d82fb | 81 | dev_err(sram->dev, "found no memory resource\n"); |
0ab163ad AK |
82 | return -EINVAL; |
83 | } | |
21b066f1 | 84 | |
f3cbfa5d | 85 | size = resource_size(res); |
4984c6f5 | 86 | |
665d82fb VZ |
87 | if (!devm_request_mem_region(sram->dev, res->start, size, pdev->name)) { |
88 | dev_err(sram->dev, "could not request region for resource\n"); | |
0ab163ad AK |
89 | return -EBUSY; |
90 | } | |
91 | ||
665d82fb VZ |
92 | sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size); |
93 | if (IS_ERR(sram->virt_base)) | |
94 | return PTR_ERR(sram->virt_base); | |
4984c6f5 | 95 | |
665d82fb VZ |
96 | sram->pool = devm_gen_pool_create(sram->dev, |
97 | ilog2(SRAM_GRANULARITY), -1); | |
4984c6f5 PZ |
98 | if (!sram->pool) |
99 | return -ENOMEM; | |
100 | ||
2da19688 HS |
101 | /* |
102 | * We need an additional block to mark the end of the memory region | |
103 | * after the reserved blocks from the dt are processed. | |
104 | */ | |
105 | nblocks = (np) ? of_get_available_child_count(np) + 1 : 1; | |
106 | rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL); | |
ee895ccd VZ |
107 | if (!rblocks) |
108 | return -ENOMEM; | |
4984c6f5 | 109 | |
2da19688 HS |
110 | block = &rblocks[0]; |
111 | for_each_available_child_of_node(np, child) { | |
112 | struct resource child_res; | |
113 | ||
114 | ret = of_address_to_resource(child, 0, &child_res); | |
115 | if (ret < 0) { | |
665d82fb | 116 | dev_err(sram->dev, |
2da19688 HS |
117 | "could not get address for node %s\n", |
118 | child->full_name); | |
b13365bb | 119 | of_node_put(child); |
2da19688 HS |
120 | goto err_chunks; |
121 | } | |
122 | ||
123 | if (child_res.start < res->start || child_res.end > res->end) { | |
665d82fb | 124 | dev_err(sram->dev, |
2da19688 HS |
125 | "reserved block %s outside the sram area\n", |
126 | child->full_name); | |
127 | ret = -EINVAL; | |
b13365bb | 128 | of_node_put(child); |
2da19688 HS |
129 | goto err_chunks; |
130 | } | |
131 | ||
132 | block->start = child_res.start - res->start; | |
133 | block->size = resource_size(&child_res); | |
134 | list_add_tail(&block->list, &reserve_list); | |
135 | ||
665d82fb VZ |
136 | dev_dbg(sram->dev, "found reserved block 0x%x-0x%x\n", |
137 | block->start, block->start + block->size); | |
2da19688 HS |
138 | |
139 | block++; | |
140 | } | |
141 | ||
142 | /* the last chunk marks the end of the region */ | |
143 | rblocks[nblocks - 1].start = size; | |
144 | rblocks[nblocks - 1].size = 0; | |
145 | list_add_tail(&rblocks[nblocks - 1].list, &reserve_list); | |
146 | ||
147 | list_sort(NULL, &reserve_list, sram_reserve_cmp); | |
148 | ||
149 | cur_start = 0; | |
150 | ||
151 | list_for_each_entry(block, &reserve_list, list) { | |
152 | /* can only happen if sections overlap */ | |
153 | if (block->start < cur_start) { | |
665d82fb | 154 | dev_err(sram->dev, |
2da19688 HS |
155 | "block at 0x%x starts after current offset 0x%lx\n", |
156 | block->start, cur_start); | |
157 | ret = -EINVAL; | |
158 | goto err_chunks; | |
159 | } | |
160 | ||
161 | /* current start is in a reserved block, so continue after it */ | |
162 | if (block->start == cur_start) { | |
163 | cur_start = block->start + block->size; | |
164 | continue; | |
165 | } | |
166 | ||
167 | /* | |
168 | * allocate the space between the current starting | |
169 | * address and the following reserved block, or the | |
170 | * end of the region. | |
171 | */ | |
172 | cur_size = block->start - cur_start; | |
173 | ||
665d82fb | 174 | dev_dbg(sram->dev, "adding chunk 0x%lx-0x%lx\n", |
2da19688 | 175 | cur_start, cur_start + cur_size); |
665d82fb | 176 | |
2da19688 | 177 | ret = gen_pool_add_virt(sram->pool, |
665d82fb | 178 | (unsigned long)sram->virt_base + cur_start, |
2da19688 HS |
179 | res->start + cur_start, cur_size, -1); |
180 | if (ret < 0) | |
181 | goto err_chunks; | |
182 | ||
183 | /* next allocation after this reserved block */ | |
184 | cur_start = block->start + block->size; | |
185 | } | |
186 | ||
187 | kfree(rblocks); | |
188 | ||
665d82fb | 189 | sram->clk = devm_clk_get(sram->dev, NULL); |
ee895ccd VZ |
190 | if (IS_ERR(sram->clk)) |
191 | sram->clk = NULL; | |
192 | else | |
193 | clk_prepare_enable(sram->clk); | |
194 | ||
4984c6f5 PZ |
195 | platform_set_drvdata(pdev, sram); |
196 | ||
665d82fb VZ |
197 | dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n", |
198 | gen_pool_size(sram->pool) / 1024, sram->virt_base); | |
4984c6f5 PZ |
199 | |
200 | return 0; | |
2da19688 HS |
201 | |
202 | err_chunks: | |
203 | kfree(rblocks); | |
ee895ccd | 204 | |
2da19688 | 205 | return ret; |
4984c6f5 PZ |
206 | } |
207 | ||
208 | static int sram_remove(struct platform_device *pdev) | |
209 | { | |
210 | struct sram_dev *sram = platform_get_drvdata(pdev); | |
211 | ||
212 | if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool)) | |
665d82fb | 213 | dev_err(sram->dev, "removed while SRAM allocated\n"); |
4984c6f5 | 214 | |
4984c6f5 PZ |
215 | if (sram->clk) |
216 | clk_disable_unprepare(sram->clk); | |
217 | ||
218 | return 0; | |
219 | } | |
220 | ||
221 | #ifdef CONFIG_OF | |
6893d9b5 | 222 | static const struct of_device_id sram_dt_ids[] = { |
4984c6f5 PZ |
223 | { .compatible = "mmio-sram" }, |
224 | {} | |
225 | }; | |
226 | #endif | |
227 | ||
228 | static struct platform_driver sram_driver = { | |
229 | .driver = { | |
230 | .name = "sram", | |
231 | .of_match_table = of_match_ptr(sram_dt_ids), | |
232 | }, | |
233 | .probe = sram_probe, | |
234 | .remove = sram_remove, | |
235 | }; | |
236 | ||
237 | static int __init sram_init(void) | |
238 | { | |
239 | return platform_driver_register(&sram_driver); | |
240 | } | |
241 | ||
242 | postcore_initcall(sram_init); |