1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) STMicroelectronics 2022 - All Rights Reserved
4 * Author: Gabriel Fernandez <gabriel.fernandez@foss.st.com> for STMicroelectronics.
5 */
6
7#include <linux/of.h>
8#include <linux/platform_device.h>
9#include <linux/regmap.h>
10#include <linux/reset-controller.h>
11#include <linux/slab.h>
12#include <linux/spinlock.h>
13
14#include "reset-stm32.h"
15
16struct stm32_reset_data {
17	/* reset lock */
18	spinlock_t			lock;
19	struct reset_controller_dev	rcdev;
20	void __iomem			*membase;
21	u32				clear_offset;
22};
23
24static inline struct stm32_reset_data *
25to_stm32_reset_data(struct reset_controller_dev *rcdev)
26{
27	return container_of(rcdev, struct stm32_reset_data, rcdev);
28}
29
30static int stm32_reset_update(struct reset_controller_dev *rcdev,
31			      unsigned long id, bool assert)
32{
33	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
34	int reg_width = sizeof(u32);
35	int bank = id / (reg_width * BITS_PER_BYTE);
36	int offset = id % (reg_width * BITS_PER_BYTE);
37
38	if (data->clear_offset) {
39		void __iomem *addr;
40
41		addr = data->membase + (bank * reg_width);
42		if (!assert)
43			addr += data->clear_offset;
44
45		writel(BIT(offset), addr);
46
47	} else {
48		unsigned long flags;
49		u32 reg;
50
51		spin_lock_irqsave(&data->lock, flags);
52
53		reg = readl(data->membase + (bank * reg_width));
54
55		if (assert)
56			reg |= BIT(offset);
57		else
58			reg &= ~BIT(offset);
59
60		writel(reg, data->membase + (bank * reg_width));
61
62		spin_unlock_irqrestore(&data->lock, flags);
63	}
64
65	return 0;
66}
67
68static int stm32_reset_assert(struct reset_controller_dev *rcdev,
69			      unsigned long id)
70{
71	return stm32_reset_update(rcdev, id, true);
72}
73
74static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
75				unsigned long id)
76{
77	return stm32_reset_update(rcdev, id, false);
78}
79
80static int stm32_reset_status(struct reset_controller_dev *rcdev,
81			      unsigned long id)
82{
83	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
84	int reg_width = sizeof(u32);
85	int bank = id / (reg_width * BITS_PER_BYTE);
86	int offset = id % (reg_width * BITS_PER_BYTE);
87	u32 reg;
88
89	reg = readl(data->membase + (bank * reg_width));
90
91	return !!(reg & BIT(offset));
92}
93
94static const struct reset_control_ops stm32_reset_ops = {
95	.assert		= stm32_reset_assert,
96	.deassert	= stm32_reset_deassert,
97	.status		= stm32_reset_status,
98};
99
100int stm32_rcc_reset_init(struct device *dev, struct clk_stm32_reset_data *data,
101			 void __iomem *base)
102{
103	struct stm32_reset_data *reset_data;
104
105	reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
106	if (!reset_data)
107		return -ENOMEM;
108
109	spin_lock_init(&reset_data->lock);
110
111	reset_data->membase = base;
112	reset_data->rcdev.owner = THIS_MODULE;
113	reset_data->rcdev.ops = &stm32_reset_ops;
114	reset_data->rcdev.of_node = dev_of_node(dev);
115	reset_data->rcdev.nr_resets = data->nr_lines;
116	reset_data->clear_offset = data->clear_offset;
117
118	return reset_controller_register(&reset_data->rcdev);
119}
120