1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /*
3 * SP7021 reset driver
4 *
5 * Copyright (C) Sunplus Technology Co., Ltd.
6 * All rights reserved.
7 */
8
9 #include <linux/io.h>
10 #include <linux/init.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/platform_device.h>
13 #include <linux/reset-controller.h>
14 #include <linux/reboot.h>
15
16 /* HIWORD_MASK_REG BITS */
17 #define BITS_PER_HWM_REG 16
18
19 /* resets HW info: reg_index_shift */
20 static const u32 sp_resets[] = {
21 /* SP7021: mo_reset0 ~ mo_reset9 */
22 0x00,
23 0x02,
24 0x03,
25 0x04,
26 0x05,
27 0x06,
28 0x07,
29 0x08,
30 0x09,
31 0x0a,
32 0x0b,
33 0x0d,
34 0x0e,
35 0x0f,
36 0x10,
37 0x12,
38 0x14,
39 0x15,
40 0x16,
41 0x17,
42 0x18,
43 0x19,
44 0x1a,
45 0x1b,
46 0x1c,
47 0x1d,
48 0x1e,
49 0x1f,
50 0x20,
51 0x21,
52 0x22,
53 0x23,
54 0x24,
55 0x25,
56 0x26,
57 0x2a,
58 0x2b,
59 0x2d,
60 0x2e,
61 0x30,
62 0x31,
63 0x32,
64 0x33,
65 0x3d,
66 0x3e,
67 0x3f,
68 0x42,
69 0x44,
70 0x4b,
71 0x4c,
72 0x4d,
73 0x4e,
74 0x4f,
75 0x50,
76 0x55,
77 0x60,
78 0x61,
79 0x6a,
80 0x6f,
81 0x70,
82 0x73,
83 0x74,
84 0x86,
85 0x8a,
86 0x8b,
87 0x8d,
88 0x8e,
89 0x8f,
90 0x90,
91 0x92,
92 0x93,
93 0x94,
94 0x95,
95 0x96,
96 0x97,
97 0x98,
98 0x99,
99 };
100
101 struct sp_reset {
102 struct reset_controller_dev rcdev;
103 struct notifier_block notifier;
104 void __iomem *base;
105 };
106
to_sp_reset(struct reset_controller_dev * rcdev)107 static inline struct sp_reset *to_sp_reset(struct reset_controller_dev *rcdev)
108 {
109 return container_of(rcdev, struct sp_reset, rcdev);
110 }
111
sp_reset_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)112 static int sp_reset_update(struct reset_controller_dev *rcdev,
113 unsigned long id, bool assert)
114 {
115 struct sp_reset *reset = to_sp_reset(rcdev);
116 int index = sp_resets[id] / BITS_PER_HWM_REG;
117 int shift = sp_resets[id] % BITS_PER_HWM_REG;
118 u32 val;
119
120 val = (1 << (16 + shift)) | (assert << shift);
121 writel(val, reset->base + (index * 4));
122
123 return 0;
124 }
125
sp_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)126 static int sp_reset_assert(struct reset_controller_dev *rcdev,
127 unsigned long id)
128 {
129 return sp_reset_update(rcdev, id, true);
130 }
131
sp_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)132 static int sp_reset_deassert(struct reset_controller_dev *rcdev,
133 unsigned long id)
134 {
135 return sp_reset_update(rcdev, id, false);
136 }
137
sp_reset_status(struct reset_controller_dev * rcdev,unsigned long id)138 static int sp_reset_status(struct reset_controller_dev *rcdev,
139 unsigned long id)
140 {
141 struct sp_reset *reset = to_sp_reset(rcdev);
142 int index = sp_resets[id] / BITS_PER_HWM_REG;
143 int shift = sp_resets[id] % BITS_PER_HWM_REG;
144 u32 reg;
145
146 reg = readl(reset->base + (index * 4));
147
148 return !!(reg & BIT(shift));
149 }
150
151 static const struct reset_control_ops sp_reset_ops = {
152 .assert = sp_reset_assert,
153 .deassert = sp_reset_deassert,
154 .status = sp_reset_status,
155 };
156
sp_restart(struct notifier_block * nb,unsigned long mode,void * cmd)157 static int sp_restart(struct notifier_block *nb, unsigned long mode,
158 void *cmd)
159 {
160 struct sp_reset *reset = container_of(nb, struct sp_reset, notifier);
161
162 sp_reset_assert(&reset->rcdev, 0);
163 sp_reset_deassert(&reset->rcdev, 0);
164
165 return NOTIFY_DONE;
166 }
167
sp_reset_probe(struct platform_device * pdev)168 static int sp_reset_probe(struct platform_device *pdev)
169 {
170 struct device *dev = &pdev->dev;
171 struct sp_reset *reset;
172 struct resource *res;
173 int ret;
174
175 reset = devm_kzalloc(dev, sizeof(*reset), GFP_KERNEL);
176 if (!reset)
177 return -ENOMEM;
178
179 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
180 reset->base = devm_ioremap_resource(dev, res);
181 if (IS_ERR(reset->base))
182 return PTR_ERR(reset->base);
183
184 reset->rcdev.ops = &sp_reset_ops;
185 reset->rcdev.owner = THIS_MODULE;
186 reset->rcdev.of_node = dev->of_node;
187 reset->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_HWM_REG;
188
189 ret = devm_reset_controller_register(dev, &reset->rcdev);
190 if (ret)
191 return ret;
192
193 reset->notifier.notifier_call = sp_restart;
194 reset->notifier.priority = 192;
195
196 return register_restart_handler(&reset->notifier);
197 }
198
199 static const struct of_device_id sp_reset_dt_ids[] = {
200 {.compatible = "sunplus,sp7021-reset",},
201 { /* sentinel */ },
202 };
203
204 static struct platform_driver sp_reset_driver = {
205 .probe = sp_reset_probe,
206 .driver = {
207 .name = "sunplus-reset",
208 .of_match_table = sp_reset_dt_ids,
209 .suppress_bind_attrs = true,
210 },
211 };
212 builtin_platform_driver(sp_reset_driver);
213
