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
16 struct 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
24 static inline struct stm32_reset_data *
to_stm32_reset_data(struct reset_controller_dev * rcdev)25 to_stm32_reset_data(struct reset_controller_dev *rcdev)
26 {
27 return container_of(rcdev, struct stm32_reset_data, rcdev);
28 }
29
stm32_reset_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)30 static 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
stm32_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)68 static int stm32_reset_assert(struct reset_controller_dev *rcdev,
69 unsigned long id)
70 {
71 return stm32_reset_update(rcdev, id, true);
72 }
73
stm32_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)74 static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
75 unsigned long id)
76 {
77 return stm32_reset_update(rcdev, id, false);
78 }
79
stm32_reset_status(struct reset_controller_dev * rcdev,unsigned long id)80 static 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
94 static 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
stm32_rcc_reset_init(struct device * dev,struct clk_stm32_reset_data * data,void __iomem * base)100 int 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