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, 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, 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, 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(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(&reset->rcdev, 0);
163	sp_reset_deassert(&reset->rcdev, 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, 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
199static const struct of_device_id sp_reset_dt_ids[] = {
200	{.compatible = "sunplus,sp7021-reset",},
201	{ /* sentinel */ },
202};
203
204static 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};
212builtin_platform_driver(sp_reset_driver);
213