tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Hisilicon Reset Controller Driver
4 *
5 * Copyright (c) 2015-2016 HiSilicon Technologies Co., Ltd.
6 */
7
8#include <linux/io.h>
9#include <linux/of_address.h>
10#include <linux/platform_device.h>
11#include <linux/reset-controller.h>
12#include <linux/slab.h>
13#include <linux/spinlock.h>
14#include "reset.h"
15
16#define HISI_RESET_BIT_MASK 0x1f
17#define HISI_RESET_OFFSET_SHIFT 8
18#define HISI_RESET_OFFSET_MASK 0xffff00
19
20struct hisi_reset_controller {
21 spinlock_t lock;
22 void __iomem *membase;
23 struct reset_controller_dev rcdev;
24};
25
26
27#define to_hisi_reset_controller(rcdev) \
28 container_of(rcdev, struct hisi_reset_controller, rcdev)
29
30static int hisi_reset_of_xlate(struct reset_controller_dev *rcdev,
31 const struct of_phandle_args *reset_spec)
32{
33 u32 offset;
34 u8 bit;
35
36 offset = (reset_spec->args[0] << HISI_RESET_OFFSET_SHIFT)
37 & HISI_RESET_OFFSET_MASK;
38 bit = reset_spec->args[1] & HISI_RESET_BIT_MASK;
39
40 return (offset | bit);
41}
42
43static int hisi_reset_assert(struct reset_controller_dev *rcdev,
44 unsigned long id)
45{
46 struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
47 unsigned long flags;
48 u32 offset, reg;
49 u8 bit;
50
51 offset = (id & HISI_RESET_OFFSET_MASK) >> HISI_RESET_OFFSET_SHIFT;
52 bit = id & HISI_RESET_BIT_MASK;
53
54 spin_lock_irqsave(&rstc->lock, flags);
55
56 reg = readl(rstc->membase + offset);
57 writel(reg | BIT(bit), rstc->membase + offset);
58
59 spin_unlock_irqrestore(&rstc->lock, flags);
60
61 return 0;
62}
63
64static int hisi_reset_deassert(struct reset_controller_dev *rcdev,
65 unsigned long id)
66{
67 struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
68 unsigned long flags;
69 u32 offset, reg;
70 u8 bit;
71
72 offset = (id & HISI_RESET_OFFSET_MASK) >> HISI_RESET_OFFSET_SHIFT;
73 bit = id & HISI_RESET_BIT_MASK;
74
75 spin_lock_irqsave(&rstc->lock, flags);
76
77 reg = readl(rstc->membase + offset);
78 writel(reg & ~BIT(bit), rstc->membase + offset);
79
80 spin_unlock_irqrestore(&rstc->lock, flags);
81
82 return 0;
83}
84
85static const struct reset_control_ops hisi_reset_ops = {
86 .assert = hisi_reset_assert,
87 .deassert = hisi_reset_deassert,
88};
89
90struct hisi_reset_controller *hisi_reset_init(struct platform_device *pdev)
91{
92 struct hisi_reset_controller *rstc;
93 struct resource *res;
94
95 rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL);
96 if (!rstc)
97 return NULL;
98
99 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
100 rstc->membase = devm_ioremap_resource(&pdev->dev, res);
101 if (IS_ERR(rstc->membase))
102 return NULL;
103
104 spin_lock_init(&rstc->lock);
105 rstc->rcdev.owner = THIS_MODULE;
106 rstc->rcdev.ops = &hisi_reset_ops;
107 rstc->rcdev.of_node = pdev->dev.of_node;
108 rstc->rcdev.of_reset_n_cells = 2;
109 rstc->rcdev.of_xlate = hisi_reset_of_xlate;
110 reset_controller_register(&rstc->rcdev);
111
112 return rstc;
113}
114EXPORT_SYMBOL_GPL(hisi_reset_init);
115
116void hisi_reset_exit(struct hisi_reset_controller *rstc)
117{
118 reset_controller_unregister(&rstc->rcdev);
119}
120EXPORT_SYMBOL_GPL(hisi_reset_exit);