xref: /openbmc/linux/drivers/clk/rockchip/softrst.c (revision b593bce5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2014 MundoReader S.L.
4  * Author: Heiko Stuebner <heiko@sntech.de>
5  */
6 
7 #include <linux/slab.h>
8 #include <linux/io.h>
9 #include <linux/reset-controller.h>
10 #include <linux/spinlock.h>
11 #include "clk.h"
12 
13 struct rockchip_softrst {
14 	struct reset_controller_dev	rcdev;
15 	void __iomem			*reg_base;
16 	int				num_regs;
17 	int				num_per_reg;
18 	u8				flags;
19 	spinlock_t			lock;
20 };
21 
22 static int rockchip_softrst_assert(struct reset_controller_dev *rcdev,
23 			      unsigned long id)
24 {
25 	struct rockchip_softrst *softrst = container_of(rcdev,
26 						     struct rockchip_softrst,
27 						     rcdev);
28 	int bank = id / softrst->num_per_reg;
29 	int offset = id % softrst->num_per_reg;
30 
31 	if (softrst->flags & ROCKCHIP_SOFTRST_HIWORD_MASK) {
32 		writel(BIT(offset) | (BIT(offset) << 16),
33 		       softrst->reg_base + (bank * 4));
34 	} else {
35 		unsigned long flags;
36 		u32 reg;
37 
38 		spin_lock_irqsave(&softrst->lock, flags);
39 
40 		reg = readl(softrst->reg_base + (bank * 4));
41 		writel(reg | BIT(offset), softrst->reg_base + (bank * 4));
42 
43 		spin_unlock_irqrestore(&softrst->lock, flags);
44 	}
45 
46 	return 0;
47 }
48 
49 static int rockchip_softrst_deassert(struct reset_controller_dev *rcdev,
50 				unsigned long id)
51 {
52 	struct rockchip_softrst *softrst = container_of(rcdev,
53 						     struct rockchip_softrst,
54 						     rcdev);
55 	int bank = id / softrst->num_per_reg;
56 	int offset = id % softrst->num_per_reg;
57 
58 	if (softrst->flags & ROCKCHIP_SOFTRST_HIWORD_MASK) {
59 		writel((BIT(offset) << 16), softrst->reg_base + (bank * 4));
60 	} else {
61 		unsigned long flags;
62 		u32 reg;
63 
64 		spin_lock_irqsave(&softrst->lock, flags);
65 
66 		reg = readl(softrst->reg_base + (bank * 4));
67 		writel(reg & ~BIT(offset), softrst->reg_base + (bank * 4));
68 
69 		spin_unlock_irqrestore(&softrst->lock, flags);
70 	}
71 
72 	return 0;
73 }
74 
75 static const struct reset_control_ops rockchip_softrst_ops = {
76 	.assert		= rockchip_softrst_assert,
77 	.deassert	= rockchip_softrst_deassert,
78 };
79 
80 void __init rockchip_register_softrst(struct device_node *np,
81 				      unsigned int num_regs,
82 				      void __iomem *base, u8 flags)
83 {
84 	struct rockchip_softrst *softrst;
85 	int ret;
86 
87 	softrst = kzalloc(sizeof(*softrst), GFP_KERNEL);
88 	if (!softrst)
89 		return;
90 
91 	spin_lock_init(&softrst->lock);
92 
93 	softrst->reg_base = base;
94 	softrst->flags = flags;
95 	softrst->num_regs = num_regs;
96 	softrst->num_per_reg = (flags & ROCKCHIP_SOFTRST_HIWORD_MASK) ? 16
97 								      : 32;
98 
99 	softrst->rcdev.owner = THIS_MODULE;
100 	softrst->rcdev.nr_resets =  num_regs * softrst->num_per_reg;
101 	softrst->rcdev.ops = &rockchip_softrst_ops;
102 	softrst->rcdev.of_node = np;
103 	ret = reset_controller_register(&softrst->rcdev);
104 	if (ret) {
105 		pr_err("%s: could not register reset controller, %d\n",
106 		       __func__, ret);
107 		kfree(softrst);
108 	}
109 };
110