diff options
Diffstat (limited to 'drivers/misc/sram.c')
-rw-r--r-- | drivers/misc/sram.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c new file mode 100644 index 000000000000..437192e43006 --- /dev/null +++ b/drivers/misc/sram.c | |||
@@ -0,0 +1,121 @@ | |||
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/platform_device.h> | ||
28 | #include <linux/slab.h> | ||
29 | #include <linux/spinlock.h> | ||
30 | #include <linux/genalloc.h> | ||
31 | |||
32 | #define SRAM_GRANULARITY 32 | ||
33 | |||
34 | struct sram_dev { | ||
35 | struct gen_pool *pool; | ||
36 | struct clk *clk; | ||
37 | }; | ||
38 | |||
39 | static int sram_probe(struct platform_device *pdev) | ||
40 | { | ||
41 | void __iomem *virt_base; | ||
42 | struct sram_dev *sram; | ||
43 | struct resource *res; | ||
44 | unsigned long size; | ||
45 | int ret; | ||
46 | |||
47 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
48 | if (!res) | ||
49 | return -EINVAL; | ||
50 | |||
51 | size = resource_size(res); | ||
52 | |||
53 | virt_base = devm_request_and_ioremap(&pdev->dev, res); | ||
54 | if (!virt_base) | ||
55 | return -EADDRNOTAVAIL; | ||
56 | |||
57 | sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL); | ||
58 | if (!sram) | ||
59 | return -ENOMEM; | ||
60 | |||
61 | sram->clk = devm_clk_get(&pdev->dev, NULL); | ||
62 | if (IS_ERR(sram->clk)) | ||
63 | sram->clk = NULL; | ||
64 | else | ||
65 | clk_prepare_enable(sram->clk); | ||
66 | |||
67 | sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1); | ||
68 | if (!sram->pool) | ||
69 | return -ENOMEM; | ||
70 | |||
71 | ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base, | ||
72 | res->start, size, -1); | ||
73 | if (ret < 0) { | ||
74 | gen_pool_destroy(sram->pool); | ||
75 | return ret; | ||
76 | } | ||
77 | |||
78 | platform_set_drvdata(pdev, sram); | ||
79 | |||
80 | dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base); | ||
81 | |||
82 | return 0; | ||
83 | } | ||
84 | |||
85 | static int sram_remove(struct platform_device *pdev) | ||
86 | { | ||
87 | struct sram_dev *sram = platform_get_drvdata(pdev); | ||
88 | |||
89 | if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool)) | ||
90 | dev_dbg(&pdev->dev, "removed while SRAM allocated\n"); | ||
91 | |||
92 | gen_pool_destroy(sram->pool); | ||
93 | |||
94 | if (sram->clk) | ||
95 | clk_disable_unprepare(sram->clk); | ||
96 | |||
97 | return 0; | ||
98 | } | ||
99 | |||
100 | #ifdef CONFIG_OF | ||
101 | static struct of_device_id sram_dt_ids[] = { | ||
102 | { .compatible = "mmio-sram" }, | ||
103 | {} | ||
104 | }; | ||
105 | #endif | ||
106 | |||
107 | static struct platform_driver sram_driver = { | ||
108 | .driver = { | ||
109 | .name = "sram", | ||
110 | .of_match_table = of_match_ptr(sram_dt_ids), | ||
111 | }, | ||
112 | .probe = sram_probe, | ||
113 | .remove = sram_remove, | ||
114 | }; | ||
115 | |||
116 | static int __init sram_init(void) | ||
117 | { | ||
118 | return platform_driver_register(&sram_driver); | ||
119 | } | ||
120 | |||
121 | postcore_initcall(sram_init); | ||