1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Reset driver for NXP LPC18xx/43xx Reset Generation Unit (RGU).
*
* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/reset-controller.h>
#include <linux/spinlock.h>
/* LPC18xx RGU registers */
#define LPC18XX_RGU_CTRL0 0x100
#define LPC18XX_RGU_CTRL1 0x104
#define LPC18XX_RGU_ACTIVE_STATUS0 0x150
#define LPC18XX_RGU_ACTIVE_STATUS1 0x154
#define LPC18XX_RGU_RESETS_PER_REG 32
/* Internal reset outputs */
#define LPC18XX_RGU_CORE_RST 0
#define LPC43XX_RGU_M0SUB_RST 12
#define LPC43XX_RGU_M0APP_RST 56
struct lpc18xx_rgu_data {
struct reset_controller_dev rcdev;
struct notifier_block restart_nb;
struct clk *clk_delay;
struct clk *clk_reg;
void __iomem *base;
spinlock_t lock;
u32 delay_us;
};
#define to_rgu_data(p) container_of(p, struct lpc18xx_rgu_data, rcdev)
static int lpc18xx_rgu_restart(struct notifier_block *nb, unsigned long mode,
void *cmd)
{
struct lpc18xx_rgu_data *rc = container_of(nb, struct lpc18xx_rgu_data,
restart_nb);
writel(BIT(LPC18XX_RGU_CORE_RST), rc->base + LPC18XX_RGU_CTRL0);
mdelay(2000);
pr_emerg("%s: unable to restart system\n", __func__);
return NOTIFY_DONE;
}
/*
* The LPC18xx RGU has mostly self-deasserting resets except for the
* two reset lines going to the internal Cortex-M0 cores.
*
* To prevent the M0 core resets from accidentally getting deasserted
* status register must be check and bits in control register set to
* preserve the state.
*/
static int lpc18xx_rgu_setclear_reset(struct reset_controller_dev *rcdev,
unsigned long id, bool set)
{
struct lpc18xx_rgu_data *rc = to_rgu_data(rcdev);
u32 stat_offset = LPC18XX_RGU_ACTIVE_STATUS0;
u32 ctrl_offset = LPC18XX_RGU_CTRL0;
unsigned long flags;
u32 stat, rst_bit;
stat_offset += (id / LPC18XX_RGU_RESETS_PER_REG) * sizeof(u32);
ctrl_offset += (id / LPC18XX_RGU_RESETS_PER_REG) * sizeof(u32);
rst_bit = 1 << (id % LPC18XX_RGU_RESETS_PER_REG);
spin_lock_irqsave(&rc->lock, flags);
stat = ~readl(rc->base + stat_offset);
if (set)
writel(stat | rst_bit, rc->base + ctrl_offset);
else
writel(stat & ~rst_bit, rc->base + ctrl_offset);
spin_unlock_irqrestore(&rc->lock, flags);
return 0;
}
static int lpc18xx_rgu_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return lpc18xx_rgu_setclear_reset(rcdev, id, true);
}
static int lpc18xx_rgu_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return lpc18xx_rgu_setclear_reset(rcdev, id, false);
}
/* Only M0 cores require explicit reset deassert */
static int lpc18xx_rgu_reset(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct lpc18xx_rgu_data *rc = to_rgu_data(rcdev);
lpc18xx_rgu_assert(rcdev, id);
udelay(rc->delay_us);
switch (id) {
case LPC43XX_RGU_M0SUB_RST:
case LPC43XX_RGU_M0APP_RST:
lpc18xx_rgu_setclear_reset(rcdev, id, false);
}
return 0;
}
static int lpc18xx_rgu_status(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct lpc18xx_rgu_data *rc = to_rgu_data(rcdev);
u32 bit, offset = LPC18XX_RGU_ACTIVE_STATUS0;
offset += (id / LPC18XX_RGU_RESETS_PER_REG) * sizeof(u32);
bit = 1 << (id % LPC18XX_RGU_RESETS_PER_REG);
return !(readl(rc->base + offset) & bit);
}
static const struct reset_control_ops lpc18xx_rgu_ops = {
.reset = lpc18xx_rgu_reset,
.assert = lpc18xx_rgu_assert,
.deassert = lpc18xx_rgu_deassert,
.status = lpc18xx_rgu_status,
};
static int lpc18xx_rgu_probe(struct platform_device *pdev)
{
struct lpc18xx_rgu_data *rc;
u32 fcclk, firc;
int ret;
rc = devm_kzalloc(&pdev->dev, sizeof(*rc), GFP_KERNEL);
if (!rc)
return -ENOMEM;
rc->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(rc->base))
return PTR_ERR(rc->base);
rc->clk_reg = devm_clk_get(&pdev->dev, "reg");
if (IS_ERR(rc->clk_reg)) {
dev_err(&pdev->dev, "reg clock not found\n");
return PTR_ERR(rc->clk_reg);
}
rc->clk_delay = devm_clk_get(&pdev->dev, "delay");
if (IS_ERR(rc->clk_delay)) {
dev_err(&pdev->dev, "delay clock not found\n");
return PTR_ERR(rc->clk_delay);
}
ret = clk_prepare_enable(rc->clk_reg);
if (ret) {
dev_err(&pdev->dev, "unable to enable reg clock\n");
return ret;
}
ret = clk_prepare_enable(rc->clk_delay);
if (ret) {
dev_err(&pdev->dev, "unable to enable delay clock\n");
goto dis_clk_reg;
}
fcclk = clk_get_rate(rc->clk_reg) / USEC_PER_SEC;
firc = clk_get_rate(rc->clk_delay) / USEC_PER_SEC;
if (fcclk == 0 || firc == 0)
rc->delay_us = 2;
else
rc->delay_us = DIV_ROUND_UP(fcclk, firc * firc);
spin_lock_init(&rc->lock);
rc->rcdev.owner = THIS_MODULE;
rc->rcdev.nr_resets = 64;
rc->rcdev.ops = &lpc18xx_rgu_ops;
rc->rcdev.of_node = pdev->dev.of_node;
platform_set_drvdata(pdev, rc);
ret = reset_controller_register(&rc->rcdev);
if (ret) {
dev_err(&pdev->dev, "unable to register device\n");
goto dis_clks;
}
rc->restart_nb.priority = 192,
rc->restart_nb.notifier_call = lpc18xx_rgu_restart,
ret = register_restart_handler(&rc->restart_nb);
if (ret)
dev_warn(&pdev->dev, "failed to register restart handler\n");
return 0;
dis_clks:
clk_disable_unprepare(rc->clk_delay);
dis_clk_reg:
clk_disable_unprepare(rc->clk_reg);
return ret;
}
static const struct of_device_id lpc18xx_rgu_match[] = {
{ .compatible = "nxp,lpc1850-rgu" },
{ }
};
static struct platform_driver lpc18xx_rgu_driver = {
.probe = lpc18xx_rgu_probe,
.driver = {
.name = "lpc18xx-reset",
.of_match_table = lpc18xx_rgu_match,
.suppress_bind_attrs = true,
},
};
builtin_platform_driver(lpc18xx_rgu_driver);
|
