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
|
/*
* Watchdog driver for Renesas WDT watchdog
*
* Copyright (C) 2015-16 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
* Copyright (C) 2015-16 Renesas Electronics Corporation
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/watchdog.h>
#define RWTCNT 0
#define RWTCSRA 4
#define RWTCSRA_WOVF BIT(4)
#define RWTCSRA_WRFLG BIT(5)
#define RWTCSRA_TME BIT(7)
#define RWDT_DEFAULT_TIMEOUT 60U
static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024 };
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
struct rwdt_priv {
void __iomem *base;
struct watchdog_device wdev;
struct clk *clk;
unsigned int clks_per_sec;
u8 cks;
};
static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg)
{
if (reg == RWTCNT)
val |= 0x5a5a0000;
else
val |= 0xa5a5a500;
writel_relaxed(val, priv->base + reg);
}
static int rwdt_init_timeout(struct watchdog_device *wdev)
{
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
rwdt_write(priv, 65536 - wdev->timeout * priv->clks_per_sec, RWTCNT);
return 0;
}
static int rwdt_start(struct watchdog_device *wdev)
{
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
clk_prepare_enable(priv->clk);
rwdt_write(priv, priv->cks, RWTCSRA);
rwdt_init_timeout(wdev);
while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)
cpu_relax();
rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA);
return 0;
}
static int rwdt_stop(struct watchdog_device *wdev)
{
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
rwdt_write(priv, priv->cks, RWTCSRA);
clk_disable_unprepare(priv->clk);
return 0;
}
static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev)
{
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
u16 val = readw_relaxed(priv->base + RWTCNT);
return DIV_ROUND_CLOSEST(65536 - val, priv->clks_per_sec);
}
static const struct watchdog_info rwdt_ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
.identity = "Renesas WDT Watchdog",
};
static const struct watchdog_ops rwdt_ops = {
.owner = THIS_MODULE,
.start = rwdt_start,
.stop = rwdt_stop,
.ping = rwdt_init_timeout,
.get_timeleft = rwdt_get_timeleft,
};
static int rwdt_probe(struct platform_device *pdev)
{
struct rwdt_priv *priv;
struct resource *res;
unsigned long rate;
unsigned int clks_per_sec;
int ret, i;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
priv->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(priv->clk))
return PTR_ERR(priv->clk);
rate = clk_get_rate(priv->clk);
if (!rate)
return -ENOENT;
for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) {
clks_per_sec = DIV_ROUND_UP(rate, clk_divs[i]);
if (clks_per_sec) {
priv->clks_per_sec = clks_per_sec;
priv->cks = i;
break;
}
}
if (!clks_per_sec) {
dev_err(&pdev->dev, "Can't find suitable clock divider\n");
return -ERANGE;
}
pm_runtime_enable(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
priv->wdev.info = &rwdt_ident,
priv->wdev.ops = &rwdt_ops,
priv->wdev.parent = &pdev->dev;
priv->wdev.min_timeout = 1;
priv->wdev.max_timeout = 65536 / clks_per_sec;
priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT);
platform_set_drvdata(pdev, priv);
watchdog_set_drvdata(&priv->wdev, priv);
watchdog_set_nowayout(&priv->wdev, nowayout);
/* This overrides the default timeout only if DT configuration was found */
ret = watchdog_init_timeout(&priv->wdev, 0, &pdev->dev);
if (ret)
dev_warn(&pdev->dev, "Specified timeout value invalid, using default\n");
ret = watchdog_register_device(&priv->wdev);
if (ret < 0) {
pm_runtime_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return ret;
}
return 0;
}
static int rwdt_remove(struct platform_device *pdev)
{
struct rwdt_priv *priv = platform_get_drvdata(pdev);
watchdog_unregister_device(&priv->wdev);
pm_runtime_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return 0;
}
/*
* This driver does also fit for R-Car Gen2 (r8a779[0-4]) WDT. However, for SMP
* to work there, one also needs a RESET (RST) driver which does not exist yet
* due to HW issues. This needs to be solved before adding compatibles here.
*/
static const struct of_device_id rwdt_ids[] = {
{ .compatible = "renesas,rcar-gen3-wdt", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rwdt_ids);
static struct platform_driver rwdt_driver = {
.driver = {
.name = "renesas_wdt",
.of_match_table = rwdt_ids,
},
.probe = rwdt_probe,
.remove = rwdt_remove,
};
module_platform_driver(rwdt_driver);
MODULE_DESCRIPTION("Renesas WDT Watchdog Driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
|
