Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

Linux/drivers/misc/sram.c

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

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us