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 */
20static 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
101struct sp_reset {
102 struct reset_controller_dev rcdev;
103 struct notifier_block notifier;
104 void __iomem *base;
105};
106
107static inline struct sp_reset *to_sp_reset(struct reset_controller_dev *rcdev)
108{
109 return container_of(rcdev, struct sp_reset, rcdev);
110}
111
112static 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, addr: reset->base + (index * 4));
122
123 return 0;
124}
125
126static int sp_reset_assert(struct reset_controller_dev *rcdev,
127 unsigned long id)
128{
129 return sp_reset_update(rcdev, id, assert: true);
130}
131
132static int sp_reset_deassert(struct reset_controller_dev *rcdev,
133 unsigned long id)
134{
135 return sp_reset_update(rcdev, id, assert: false);
136}
137
138static 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(addr: reset->base + (index * 4));
147
148 return !!(reg & BIT(shift));
149}
150
151static 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
157static 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(rcdev: &reset->rcdev, id: 0);
163 sp_reset_deassert(rcdev: &reset->rcdev, id: 0);
164
165 return NOTIFY_DONE;
166}
167
168static 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, size: sizeof(*reset), GFP_KERNEL);
176 if (!reset)
177 return -ENOMEM;
178
179 reset->base = devm_platform_get_and_ioremap_resource(pdev, index: 0, res: &res);
180 if (IS_ERR(ptr: reset->base))
181 return PTR_ERR(ptr: reset->base);
182
183 reset->rcdev.ops = &sp_reset_ops;
184 reset->rcdev.owner = THIS_MODULE;
185 reset->rcdev.of_node = dev->of_node;
186 reset->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_HWM_REG;
187
188 ret = devm_reset_controller_register(dev, rcdev: &reset->rcdev);
189 if (ret)
190 return ret;
191
192 reset->notifier.notifier_call = sp_restart;
193 reset->notifier.priority = 192;
194
195 return register_restart_handler(&reset->notifier);
196}
197
198static const struct of_device_id sp_reset_dt_ids[] = {
199 {.compatible = "sunplus,sp7021-reset",},
200 { /* sentinel */ },
201};
202
203static struct platform_driver sp_reset_driver = {
204 .probe = sp_reset_probe,
205 .driver = {
206 .name = "sunplus-reset",
207 .of_match_table = sp_reset_dt_ids,
208 .suppress_bind_attrs = true,
209 },
210};
211builtin_platform_driver(sp_reset_driver);
212

source code of linux/drivers/reset/reset-sunplus.c