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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 | ||
4984c6f5 | 21 | #include <linux/clk.h> |
98ce2d27 | 22 | #include <linux/genalloc.h> |
4984c6f5 | 23 | #include <linux/io.h> |
2da19688 | 24 | #include <linux/list_sort.h> |
98ce2d27 | 25 | #include <linux/of_address.h> |
4984c6f5 PZ |
26 | #include <linux/platform_device.h> |
27 | #include <linux/slab.h> | |
4984c6f5 PZ |
28 | |
29 | #define SRAM_GRANULARITY 32 | |
30 | ||
31 | struct sram_dev { | |
665d82fb VZ |
32 | struct device *dev; |
33 | void __iomem *virt_base; | |
34 | ||
4984c6f5 PZ |
35 | struct gen_pool *pool; |
36 | struct clk *clk; | |
37 | }; | |
38 | ||
2da19688 HS |
39 | struct sram_reserve { |
40 | struct list_head list; | |
41 | u32 start; | |
42 | u32 size; | |
43 | }; | |
44 | ||
45 | static int sram_reserve_cmp(void *priv, struct list_head *a, | |
46 | struct list_head *b) | |
47 | { | |
48 | struct sram_reserve *ra = list_entry(a, struct sram_reserve, list); | |
49 | struct sram_reserve *rb = list_entry(b, struct sram_reserve, list); | |
50 | ||
51 | return ra->start - rb->start; | |
52 | } | |
53 | ||
a0a5be0b | 54 | static int sram_reserve_regions(struct sram_dev *sram, struct resource *res) |
4984c6f5 | 55 | { |
a0a5be0b | 56 | struct device_node *np = sram->dev->of_node, *child; |
2da19688 HS |
57 | unsigned long size, cur_start, cur_size; |
58 | struct sram_reserve *rblocks, *block; | |
59 | struct list_head reserve_list; | |
60 | unsigned int nblocks; | |
a0a5be0b | 61 | int ret = 0; |
4984c6f5 | 62 | |
2da19688 HS |
63 | INIT_LIST_HEAD(&reserve_list); |
64 | ||
f3cbfa5d | 65 | size = resource_size(res); |
4984c6f5 | 66 | |
2da19688 HS |
67 | /* |
68 | * We need an additional block to mark the end of the memory region | |
69 | * after the reserved blocks from the dt are processed. | |
70 | */ | |
71 | nblocks = (np) ? of_get_available_child_count(np) + 1 : 1; | |
72 | rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL); | |
ee895ccd VZ |
73 | if (!rblocks) |
74 | return -ENOMEM; | |
4984c6f5 | 75 | |
2da19688 HS |
76 | block = &rblocks[0]; |
77 | for_each_available_child_of_node(np, child) { | |
78 | struct resource child_res; | |
79 | ||
80 | ret = of_address_to_resource(child, 0, &child_res); | |
81 | if (ret < 0) { | |
665d82fb | 82 | dev_err(sram->dev, |
2da19688 HS |
83 | "could not get address for node %s\n", |
84 | child->full_name); | |
b13365bb | 85 | of_node_put(child); |
2da19688 HS |
86 | goto err_chunks; |
87 | } | |
88 | ||
89 | if (child_res.start < res->start || child_res.end > res->end) { | |
665d82fb | 90 | dev_err(sram->dev, |
2da19688 HS |
91 | "reserved block %s outside the sram area\n", |
92 | child->full_name); | |
93 | ret = -EINVAL; | |
b13365bb | 94 | of_node_put(child); |
2da19688 HS |
95 | goto err_chunks; |
96 | } | |
97 | ||
98 | block->start = child_res.start - res->start; | |
99 | block->size = resource_size(&child_res); | |
100 | list_add_tail(&block->list, &reserve_list); | |
101 | ||
665d82fb VZ |
102 | dev_dbg(sram->dev, "found reserved block 0x%x-0x%x\n", |
103 | block->start, block->start + block->size); | |
2da19688 HS |
104 | |
105 | block++; | |
106 | } | |
107 | ||
108 | /* the last chunk marks the end of the region */ | |
109 | rblocks[nblocks - 1].start = size; | |
110 | rblocks[nblocks - 1].size = 0; | |
111 | list_add_tail(&rblocks[nblocks - 1].list, &reserve_list); | |
112 | ||
113 | list_sort(NULL, &reserve_list, sram_reserve_cmp); | |
114 | ||
115 | cur_start = 0; | |
116 | ||
117 | list_for_each_entry(block, &reserve_list, list) { | |
118 | /* can only happen if sections overlap */ | |
119 | if (block->start < cur_start) { | |
665d82fb | 120 | dev_err(sram->dev, |
2da19688 HS |
121 | "block at 0x%x starts after current offset 0x%lx\n", |
122 | block->start, cur_start); | |
123 | ret = -EINVAL; | |
124 | goto err_chunks; | |
125 | } | |
126 | ||
127 | /* current start is in a reserved block, so continue after it */ | |
128 | if (block->start == cur_start) { | |
129 | cur_start = block->start + block->size; | |
130 | continue; | |
131 | } | |
132 | ||
133 | /* | |
134 | * allocate the space between the current starting | |
135 | * address and the following reserved block, or the | |
136 | * end of the region. | |
137 | */ | |
138 | cur_size = block->start - cur_start; | |
139 | ||
665d82fb | 140 | dev_dbg(sram->dev, "adding chunk 0x%lx-0x%lx\n", |
2da19688 | 141 | cur_start, cur_start + cur_size); |
665d82fb | 142 | |
2da19688 | 143 | ret = gen_pool_add_virt(sram->pool, |
665d82fb | 144 | (unsigned long)sram->virt_base + cur_start, |
2da19688 HS |
145 | res->start + cur_start, cur_size, -1); |
146 | if (ret < 0) | |
147 | goto err_chunks; | |
148 | ||
149 | /* next allocation after this reserved block */ | |
150 | cur_start = block->start + block->size; | |
151 | } | |
152 | ||
a0a5be0b | 153 | err_chunks: |
2da19688 HS |
154 | kfree(rblocks); |
155 | ||
a0a5be0b VZ |
156 | return ret; |
157 | } | |
158 | ||
159 | static int sram_probe(struct platform_device *pdev) | |
160 | { | |
161 | struct sram_dev *sram; | |
162 | struct resource *res; | |
163 | size_t size; | |
164 | int ret; | |
165 | ||
166 | sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL); | |
167 | if (!sram) | |
168 | return -ENOMEM; | |
169 | ||
170 | sram->dev = &pdev->dev; | |
171 | ||
172 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
173 | if (!res) { | |
174 | dev_err(sram->dev, "found no memory resource\n"); | |
175 | return -EINVAL; | |
176 | } | |
177 | ||
178 | size = resource_size(res); | |
179 | ||
180 | if (!devm_request_mem_region(sram->dev, res->start, size, pdev->name)) { | |
181 | dev_err(sram->dev, "could not request region for resource\n"); | |
182 | return -EBUSY; | |
183 | } | |
184 | ||
185 | sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size); | |
186 | if (IS_ERR(sram->virt_base)) | |
187 | return PTR_ERR(sram->virt_base); | |
188 | ||
189 | sram->pool = devm_gen_pool_create(sram->dev, | |
190 | ilog2(SRAM_GRANULARITY), -1); | |
191 | if (!sram->pool) | |
192 | return -ENOMEM; | |
193 | ||
194 | ret = sram_reserve_regions(sram, res); | |
195 | if (ret) | |
196 | return ret; | |
197 | ||
665d82fb | 198 | sram->clk = devm_clk_get(sram->dev, NULL); |
ee895ccd VZ |
199 | if (IS_ERR(sram->clk)) |
200 | sram->clk = NULL; | |
201 | else | |
202 | clk_prepare_enable(sram->clk); | |
203 | ||
4984c6f5 PZ |
204 | platform_set_drvdata(pdev, sram); |
205 | ||
665d82fb VZ |
206 | dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n", |
207 | gen_pool_size(sram->pool) / 1024, sram->virt_base); | |
4984c6f5 PZ |
208 | |
209 | return 0; | |
210 | } | |
211 | ||
212 | static int sram_remove(struct platform_device *pdev) | |
213 | { | |
214 | struct sram_dev *sram = platform_get_drvdata(pdev); | |
215 | ||
216 | if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool)) | |
665d82fb | 217 | dev_err(sram->dev, "removed while SRAM allocated\n"); |
4984c6f5 | 218 | |
4984c6f5 PZ |
219 | if (sram->clk) |
220 | clk_disable_unprepare(sram->clk); | |
221 | ||
222 | return 0; | |
223 | } | |
224 | ||
225 | #ifdef CONFIG_OF | |
6893d9b5 | 226 | static const struct of_device_id sram_dt_ids[] = { |
4984c6f5 PZ |
227 | { .compatible = "mmio-sram" }, |
228 | {} | |
229 | }; | |
230 | #endif | |
231 | ||
232 | static struct platform_driver sram_driver = { | |
233 | .driver = { | |
234 | .name = "sram", | |
235 | .of_match_table = of_match_ptr(sram_dt_ids), | |
236 | }, | |
237 | .probe = sram_probe, | |
238 | .remove = sram_remove, | |
239 | }; | |
240 | ||
241 | static int __init sram_init(void) | |
242 | { | |
243 | return platform_driver_register(&sram_driver); | |
244 | } | |
245 | ||
246 | postcore_initcall(sram_init); |