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	reset->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
180	if (IS_ERR(reset->base))
181		return PTR_ERR(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, &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);