1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2020 Sifive, Inc.
4  * Author: Sagar Kadam <sagar.kadam@sifive.com>
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <reset-uclass.h>
10 #include <asm/io.h>
11 #include <dm/device_compat.h>
12 #include <dm/device-internal.h>
13 #include <dm/lists.h>
14 #include <linux/bitops.h>
15 
16 #define PRCI_RESETREG_OFFSET 0x28
17 
18 struct sifive_reset_priv {
19 	void *base;
20 	/* number of reset signals */
21 	int nr_reset;
22 };
23 
sifive_rst_trigger(struct reset_ctl * rst,bool level)24 static int sifive_rst_trigger(struct reset_ctl *rst, bool level)
25 {
26 	struct sifive_reset_priv *priv = dev_get_priv(rst->dev);
27 	int id = rst->id;
28 	int regval = readl(priv->base + PRCI_RESETREG_OFFSET);
29 
30 	/* Derive bitposition from rst id */
31 	if (level)
32 		/* Reset deassert */
33 		regval |= BIT(id);
34 	else
35 		/* Reset assert */
36 		regval &= ~BIT(id);
37 
38 	writel(regval, priv->base + PRCI_RESETREG_OFFSET);
39 
40 	return 0;
41 }
42 
sifive_reset_assert(struct reset_ctl * rst)43 static int sifive_reset_assert(struct reset_ctl *rst)
44 {
45 	return sifive_rst_trigger(rst, false);
46 }
47 
sifive_reset_deassert(struct reset_ctl * rst)48 static int sifive_reset_deassert(struct reset_ctl *rst)
49 {
50 	return sifive_rst_trigger(rst, true);
51 }
52 
sifive_reset_request(struct reset_ctl * rst)53 static int sifive_reset_request(struct reset_ctl *rst)
54 {
55 	struct sifive_reset_priv *priv = dev_get_priv(rst->dev);
56 
57 	debug("%s(rst=%p) (dev=%p, id=%lu) (nr_reset=%d)\n", __func__,
58 	      rst, rst->dev, rst->id, priv->nr_reset);
59 
60 	if (rst->id > priv->nr_reset)
61 		return -EINVAL;
62 
63 	return 0;
64 }
65 
sifive_reset_probe(struct udevice * dev)66 static int sifive_reset_probe(struct udevice *dev)
67 {
68 	struct sifive_reset_priv *priv = dev_get_priv(dev);
69 
70 	priv->base = dev_remap_addr(dev);
71 	if (!priv->base)
72 		return -ENOMEM;
73 
74 	return 0;
75 }
76 
sifive_reset_bind(struct udevice * dev,ulong count)77 int sifive_reset_bind(struct udevice *dev, ulong count)
78 {
79 	struct udevice *rst_dev;
80 	struct sifive_reset_priv *priv;
81 	int ret;
82 
83 	ret = device_bind_driver_to_node(dev, "sifive-reset", "reset",
84 					 dev_ofnode(dev), &rst_dev);
85 	if (ret) {
86 		dev_err(dev, "failed to bind sifive_reset driver (ret=%d)\n", ret);
87 		return ret;
88 	}
89 	priv = malloc(sizeof(struct sifive_reset_priv));
90 	priv->nr_reset = count;
91 	dev_set_priv(rst_dev, priv);
92 
93 	return 0;
94 }
95 
96 const struct reset_ops sifive_reset_ops = {
97 	.request = sifive_reset_request,
98 	.rst_assert = sifive_reset_assert,
99 	.rst_deassert = sifive_reset_deassert,
100 };
101 
102 U_BOOT_DRIVER(sifive_reset) = {
103 	.name		= "sifive-reset",
104 	.id		= UCLASS_RESET,
105 	.ops		= &sifive_reset_ops,
106 	.probe		= sifive_reset_probe,
107 	.priv_auto	= sizeof(struct sifive_reset_priv),
108 };
109