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