1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * AR71xx Reset Controller Driver
4 * Author: Alban Bedel
5 *
6 * Copyright (C) 2015 Alban Bedel <albeu@free.fr>
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 struct ath79_reset {
17 struct reset_controller_dev rcdev;
18 struct notifier_block restart_nb;
19 void __iomem *base;
20 spinlock_t lock;
21 };
22
23 #define FULL_CHIP_RESET 24
24
ath79_reset_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)25 static int ath79_reset_update(struct reset_controller_dev *rcdev,
26 unsigned long id, bool assert)
27 {
28 struct ath79_reset *ath79_reset =
29 container_of(rcdev, struct ath79_reset, rcdev);
30 unsigned long flags;
31 u32 val;
32
33 spin_lock_irqsave(&ath79_reset->lock, flags);
34 val = readl(ath79_reset->base);
35 if (assert)
36 val |= BIT(id);
37 else
38 val &= ~BIT(id);
39 writel(val, ath79_reset->base);
40 spin_unlock_irqrestore(&ath79_reset->lock, flags);
41
42 return 0;
43 }
44
ath79_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)45 static int ath79_reset_assert(struct reset_controller_dev *rcdev,
46 unsigned long id)
47 {
48 return ath79_reset_update(rcdev, id, true);
49 }
50
ath79_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)51 static int ath79_reset_deassert(struct reset_controller_dev *rcdev,
52 unsigned long id)
53 {
54 return ath79_reset_update(rcdev, id, false);
55 }
56
ath79_reset_status(struct reset_controller_dev * rcdev,unsigned long id)57 static int ath79_reset_status(struct reset_controller_dev *rcdev,
58 unsigned long id)
59 {
60 struct ath79_reset *ath79_reset =
61 container_of(rcdev, struct ath79_reset, rcdev);
62 u32 val;
63
64 val = readl(ath79_reset->base);
65
66 return !!(val & BIT(id));
67 }
68
69 static const struct reset_control_ops ath79_reset_ops = {
70 .assert = ath79_reset_assert,
71 .deassert = ath79_reset_deassert,
72 .status = ath79_reset_status,
73 };
74
ath79_reset_restart_handler(struct notifier_block * nb,unsigned long action,void * data)75 static int ath79_reset_restart_handler(struct notifier_block *nb,
76 unsigned long action, void *data)
77 {
78 struct ath79_reset *ath79_reset =
79 container_of(nb, struct ath79_reset, restart_nb);
80
81 ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);
82
83 return NOTIFY_DONE;
84 }
85
ath79_reset_probe(struct platform_device * pdev)86 static int ath79_reset_probe(struct platform_device *pdev)
87 {
88 struct ath79_reset *ath79_reset;
89 int err;
90
91 ath79_reset = devm_kzalloc(&pdev->dev,
92 sizeof(*ath79_reset), GFP_KERNEL);
93 if (!ath79_reset)
94 return -ENOMEM;
95
96 ath79_reset->base = devm_platform_ioremap_resource(pdev, 0);
97 if (IS_ERR(ath79_reset->base))
98 return PTR_ERR(ath79_reset->base);
99
100 spin_lock_init(&ath79_reset->lock);
101 ath79_reset->rcdev.ops = &ath79_reset_ops;
102 ath79_reset->rcdev.owner = THIS_MODULE;
103 ath79_reset->rcdev.of_node = pdev->dev.of_node;
104 ath79_reset->rcdev.of_reset_n_cells = 1;
105 ath79_reset->rcdev.nr_resets = 32;
106
107 err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev);
108 if (err)
109 return err;
110
111 ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler;
112 ath79_reset->restart_nb.priority = 128;
113
114 err = register_restart_handler(&ath79_reset->restart_nb);
115 if (err)
116 dev_warn(&pdev->dev, "Failed to register restart handler\n");
117
118 return 0;
119 }
120
121 static const struct of_device_id ath79_reset_dt_ids[] = {
122 { .compatible = "qca,ar7100-reset", },
123 { },
124 };
125
126 static struct platform_driver ath79_reset_driver = {
127 .probe = ath79_reset_probe,
128 .driver = {
129 .name = "ath79-reset",
130 .of_match_table = ath79_reset_dt_ids,
131 .suppress_bind_attrs = true,
132 },
133 };
134 builtin_platform_driver(ath79_reset_driver);
135