1 /*
2 * Amlogic Meson Reset Controller driver
3 *
4 * This file is provided under a dual BSD/GPLv2 license. When using or
5 * redistributing this file, you may do so under either license.
6 *
7 * GPL LICENSE SUMMARY
8 *
9 * Copyright (c) 2016 BayLibre, SAS.
10 * Author: Neil Armstrong <narmstrong@baylibre.com>
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of version 2 of the GNU General Public License as
14 * published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, see <http://www.gnu.org/licenses/>.
23 * The full GNU General Public License is included in this distribution
24 * in the file called COPYING.
25 *
26 * BSD LICENSE
27 *
28 * Copyright (c) 2016 BayLibre, SAS.
29 * Author: Neil Armstrong <narmstrong@baylibre.com>
30 *
31 * Redistribution and use in source and binary forms, with or without
32 * modification, are permitted provided that the following conditions
33 * are met:
34 *
35 * * Redistributions of source code must retain the above copyright
36 * notice, this list of conditions and the following disclaimer.
37 * * Redistributions in binary form must reproduce the above copyright
38 * notice, this list of conditions and the following disclaimer in
39 * the documentation and/or other materials provided with the
40 * distribution.
41 * * Neither the name of Intel Corporation nor the names of its
42 * contributors may be used to endorse or promote products derived
43 * from this software without specific prior written permission.
44 *
45 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
46 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
47 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
48 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
49 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
50 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
51 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
52 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
53 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
54 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
55 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56 */
57 #include <linux/err.h>
58 #include <linux/init.h>
59 #include <linux/io.h>
60 #include <linux/of.h>
61 #include <linux/platform_device.h>
62 #include <linux/reset-controller.h>
63 #include <linux/slab.h>
64 #include <linux/types.h>
65 #include <linux/of_device.h>
66
67 #define REG_COUNT 8
68 #define BITS_PER_REG 32
69 #define LEVEL_OFFSET 0x7c
70
71 struct meson_reset {
72 void __iomem *reg_base;
73 struct reset_controller_dev rcdev;
74 spinlock_t lock;
75 };
76
meson_reset_reset(struct reset_controller_dev * rcdev,unsigned long id)77 static int meson_reset_reset(struct reset_controller_dev *rcdev,
78 unsigned long id)
79 {
80 struct meson_reset *data =
81 container_of(rcdev, struct meson_reset, rcdev);
82 unsigned int bank = id / BITS_PER_REG;
83 unsigned int offset = id % BITS_PER_REG;
84 void __iomem *reg_addr = data->reg_base + (bank << 2);
85
86 writel(BIT(offset), reg_addr);
87
88 return 0;
89 }
90
meson_reset_level(struct reset_controller_dev * rcdev,unsigned long id,bool assert)91 static int meson_reset_level(struct reset_controller_dev *rcdev,
92 unsigned long id, bool assert)
93 {
94 struct meson_reset *data =
95 container_of(rcdev, struct meson_reset, rcdev);
96 unsigned int bank = id / BITS_PER_REG;
97 unsigned int offset = id % BITS_PER_REG;
98 void __iomem *reg_addr = data->reg_base + LEVEL_OFFSET + (bank << 2);
99 unsigned long flags;
100 u32 reg;
101
102 spin_lock_irqsave(&data->lock, flags);
103
104 reg = readl(reg_addr);
105 if (assert)
106 writel(reg & ~BIT(offset), reg_addr);
107 else
108 writel(reg | BIT(offset), reg_addr);
109
110 spin_unlock_irqrestore(&data->lock, flags);
111
112 return 0;
113 }
114
meson_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)115 static int meson_reset_assert(struct reset_controller_dev *rcdev,
116 unsigned long id)
117 {
118 return meson_reset_level(rcdev, id, true);
119 }
120
meson_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)121 static int meson_reset_deassert(struct reset_controller_dev *rcdev,
122 unsigned long id)
123 {
124 return meson_reset_level(rcdev, id, false);
125 }
126
127 static const struct reset_control_ops meson_reset_ops = {
128 .reset = meson_reset_reset,
129 .assert = meson_reset_assert,
130 .deassert = meson_reset_deassert,
131 };
132
133 static const struct of_device_id meson_reset_dt_ids[] = {
134 { .compatible = "amlogic,meson8b-reset" },
135 { .compatible = "amlogic,meson-gxbb-reset" },
136 { .compatible = "amlogic,meson-axg-reset" },
137 { /* sentinel */ },
138 };
139
meson_reset_probe(struct platform_device * pdev)140 static int meson_reset_probe(struct platform_device *pdev)
141 {
142 struct meson_reset *data;
143 struct resource *res;
144
145 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
146 if (!data)
147 return -ENOMEM;
148
149 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
150 data->reg_base = devm_ioremap_resource(&pdev->dev, res);
151 if (IS_ERR(data->reg_base))
152 return PTR_ERR(data->reg_base);
153
154 platform_set_drvdata(pdev, data);
155
156 spin_lock_init(&data->lock);
157
158 data->rcdev.owner = THIS_MODULE;
159 data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG;
160 data->rcdev.ops = &meson_reset_ops;
161 data->rcdev.of_node = pdev->dev.of_node;
162
163 return devm_reset_controller_register(&pdev->dev, &data->rcdev);
164 }
165
166 static struct platform_driver meson_reset_driver = {
167 .probe = meson_reset_probe,
168 .driver = {
169 .name = "meson_reset",
170 .of_match_table = meson_reset_dt_ids,
171 },
172 };
173 builtin_platform_driver(meson_reset_driver);
174