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8#include <linux/clk.h>
9#include <linux/io.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/of.h>
13#include <linux/platform_device.h>
14#include <linux/watchdog.h>
15
16#define WDT_CNT 0x00
17#define WDT_MIN 0x04
18#define WDT_MAX 0x08
19#define WDT_CTL 0x0c
20#define WDT_CMD 0x10
21#define WDT_CMD_CLEAR 0x4352
22#define WDT_CMD_START_STOP 0x5354
23#define WDT_DIV 0x30
24
25#define VISCONTI_WDT_FREQ 2000000
26#define WDT_DEFAULT_TIMEOUT 10U
27
28static bool nowayout = WATCHDOG_NOWAYOUT;
29module_param(nowayout, bool, 0);
30MODULE_PARM_DESC(
31 nowayout,
32 "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT)")");
33
34struct visconti_wdt_priv {
35 struct watchdog_device wdev;
36 void __iomem *base;
37 u32 div;
38};
39
40static int visconti_wdt_start(struct watchdog_device *wdev)
41{
42 struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
43 u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ;
44
45 writel(priv->div, priv->base + WDT_DIV);
46 writel(0, priv->base + WDT_MIN);
47 writel(timeout, priv->base + WDT_MAX);
48 writel(0, priv->base + WDT_CTL);
49 writel(WDT_CMD_START_STOP, priv->base + WDT_CMD);
50
51 return 0;
52}
53
54static int visconti_wdt_stop(struct watchdog_device *wdev)
55{
56 struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
57
58 writel(1, priv->base + WDT_CTL);
59 writel(WDT_CMD_START_STOP, priv->base + WDT_CMD);
60
61 return 0;
62}
63
64static int visconti_wdt_ping(struct watchdog_device *wdd)
65{
66 struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdd);
67
68 writel(WDT_CMD_CLEAR, priv->base + WDT_CMD);
69
70 return 0;
71}
72
73static unsigned int visconti_wdt_get_timeleft(struct watchdog_device *wdev)
74{
75 struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
76 u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ;
77 u32 cnt = readl(priv->base + WDT_CNT);
78
79 if (timeout <= cnt)
80 return 0;
81 timeout -= cnt;
82
83 return timeout / VISCONTI_WDT_FREQ;
84}
85
86static int visconti_wdt_set_timeout(struct watchdog_device *wdev, unsigned int timeout)
87{
88 u32 val;
89 struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
90
91 wdev->timeout = timeout;
92 val = wdev->timeout * VISCONTI_WDT_FREQ;
93
94
95 writel(WDT_CMD_CLEAR, priv->base + WDT_CMD);
96 writel(val, priv->base + WDT_MAX);
97
98 return 0;
99}
100
101static const struct watchdog_info visconti_wdt_info = {
102 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
103 .identity = "Visconti Watchdog",
104};
105
106static const struct watchdog_ops visconti_wdt_ops = {
107 .owner = THIS_MODULE,
108 .start = visconti_wdt_start,
109 .stop = visconti_wdt_stop,
110 .ping = visconti_wdt_ping,
111 .get_timeleft = visconti_wdt_get_timeleft,
112 .set_timeout = visconti_wdt_set_timeout,
113};
114
115static void visconti_clk_disable_unprepare(void *data)
116{
117 clk_disable_unprepare(data);
118}
119
120static int visconti_wdt_probe(struct platform_device *pdev)
121{
122 struct watchdog_device *wdev;
123 struct visconti_wdt_priv *priv;
124 struct device *dev = &pdev->dev;
125 struct clk *clk;
126 int ret;
127 unsigned long clk_freq;
128
129 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
130 if (!priv)
131 return -ENOMEM;
132
133 priv->base = devm_platform_ioremap_resource(pdev, 0);
134 if (IS_ERR(priv->base))
135 return PTR_ERR(priv->base);
136
137 clk = devm_clk_get(dev, NULL);
138 if (IS_ERR(clk))
139 return dev_err_probe(dev, PTR_ERR(clk), "Could not get clock\n");
140
141 ret = clk_prepare_enable(clk);
142 if (ret) {
143 dev_err(dev, "Could not enable clock\n");
144 return ret;
145 }
146
147 ret = devm_add_action_or_reset(dev, visconti_clk_disable_unprepare, clk);
148 if (ret)
149 return ret;
150
151 clk_freq = clk_get_rate(clk);
152 if (!clk_freq)
153 return -EINVAL;
154
155 priv->div = clk_freq / VISCONTI_WDT_FREQ;
156
157
158 wdev = &priv->wdev;
159 wdev->info = &visconti_wdt_info;
160 wdev->ops = &visconti_wdt_ops;
161 wdev->parent = dev;
162 wdev->min_timeout = 1;
163 wdev->max_timeout = 0xffffffff / VISCONTI_WDT_FREQ;
164 wdev->timeout = min(wdev->max_timeout, WDT_DEFAULT_TIMEOUT);
165
166 watchdog_set_drvdata(wdev, priv);
167 watchdog_set_nowayout(wdev, nowayout);
168 watchdog_stop_on_unregister(wdev);
169
170
171 ret = watchdog_init_timeout(wdev, 0, dev);
172 if (ret)
173 dev_warn(dev, "Specified timeout value invalid, using default\n");
174
175 return devm_watchdog_register_device(dev, wdev);
176}
177
178static const struct of_device_id visconti_wdt_of_match[] = {
179 { .compatible = "toshiba,visconti-wdt", },
180 {}
181};
182MODULE_DEVICE_TABLE(of, visconti_wdt_of_match);
183
184static struct platform_driver visconti_wdt_driver = {
185 .driver = {
186 .name = "visconti_wdt",
187 .of_match_table = visconti_wdt_of_match,
188 },
189 .probe = visconti_wdt_probe,
190};
191module_platform_driver(visconti_wdt_driver);
192
193MODULE_DESCRIPTION("TOSHIBA Visconti Watchdog Driver");
194MODULE_AUTHOR("Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp");
195MODULE_LICENSE("GPL v2");
196
