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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 { | |
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; |
68 | ||
2da19688 HS |
69 | INIT_LIST_HEAD(&reserve_list); |
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 | } |
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); |