GNU Linux-libre 4.9.328-gnu1
[releases.git] / drivers / watchdog / atlas7_wdt.c
1 /*
2  * Watchdog driver for CSR Atlas7
3  *
4  * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
5  *
6  * Licensed under GPLv2.
7  */
8
9 #include <linux/clk.h>
10 #include <linux/io.h>
11 #include <linux/module.h>
12 #include <linux/moduleparam.h>
13 #include <linux/of.h>
14 #include <linux/platform_device.h>
15 #include <linux/watchdog.h>
16
17 #define ATLAS7_TIMER_WDT_INDEX          5
18 #define ATLAS7_WDT_DEFAULT_TIMEOUT      20
19
20 #define ATLAS7_WDT_CNT_CTRL     (0 + 4 * ATLAS7_TIMER_WDT_INDEX)
21 #define ATLAS7_WDT_CNT_MATCH    (0x18 + 4 * ATLAS7_TIMER_WDT_INDEX)
22 #define ATLAS7_WDT_CNT          (0x48 +  4 * ATLAS7_TIMER_WDT_INDEX)
23 #define ATLAS7_WDT_CNT_EN       (BIT(0) | BIT(1))
24 #define ATLAS7_WDT_EN           0x64
25
26 static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT;
27 static bool nowayout = WATCHDOG_NOWAYOUT;
28
29 module_param(timeout, uint, 0);
30 module_param(nowayout, bool, 0);
31
32 MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
33 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
34                         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
35
36 struct atlas7_wdog {
37         struct device *dev;
38         void __iomem *base;
39         unsigned long tick_rate;
40         struct clk *clk;
41 };
42
43 static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd)
44 {
45         struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
46         u32 counter, match, delta;
47
48         counter = readl(wdt->base + ATLAS7_WDT_CNT);
49         match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH);
50         delta = match - counter;
51
52         return  delta / wdt->tick_rate;
53 }
54
55 static int atlas7_wdt_ping(struct watchdog_device *wdd)
56 {
57         struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
58         u32 counter, match, delta;
59
60         counter = readl(wdt->base + ATLAS7_WDT_CNT);
61         delta = wdd->timeout * wdt->tick_rate;
62         match = counter + delta;
63
64         writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH);
65
66         return 0;
67 }
68
69 static int atlas7_wdt_enable(struct watchdog_device *wdd)
70 {
71         struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
72
73         atlas7_wdt_ping(wdd);
74
75         writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) | ATLAS7_WDT_CNT_EN,
76               wdt->base + ATLAS7_WDT_CNT_CTRL);
77         writel(1, wdt->base + ATLAS7_WDT_EN);
78
79         return 0;
80 }
81
82 static int atlas7_wdt_disable(struct watchdog_device *wdd)
83 {
84         struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
85
86         writel(0, wdt->base + ATLAS7_WDT_EN);
87         writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) & ~ATLAS7_WDT_CNT_EN,
88               wdt->base + ATLAS7_WDT_CNT_CTRL);
89
90         return 0;
91 }
92
93 static int atlas7_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
94 {
95         wdd->timeout = to;
96
97         return 0;
98 }
99
100 #define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
101
102 static const struct watchdog_info atlas7_wdt_ident = {
103         .options = OPTIONS,
104         .firmware_version = 0,
105         .identity = "atlas7 Watchdog",
106 };
107
108 static struct watchdog_ops atlas7_wdt_ops = {
109         .owner = THIS_MODULE,
110         .start = atlas7_wdt_enable,
111         .stop = atlas7_wdt_disable,
112         .get_timeleft = atlas7_wdt_gettimeleft,
113         .ping = atlas7_wdt_ping,
114         .set_timeout = atlas7_wdt_settimeout,
115 };
116
117 static struct watchdog_device atlas7_wdd = {
118         .info = &atlas7_wdt_ident,
119         .ops = &atlas7_wdt_ops,
120         .timeout = ATLAS7_WDT_DEFAULT_TIMEOUT,
121 };
122
123 static const struct of_device_id atlas7_wdt_ids[] = {
124         { .compatible = "sirf,atlas7-tick"},
125         {}
126 };
127
128 static int atlas7_wdt_probe(struct platform_device *pdev)
129 {
130         struct device_node *np = pdev->dev.of_node;
131         struct atlas7_wdog *wdt;
132         struct resource *res;
133         struct clk *clk;
134         int ret;
135
136         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
137         if (!wdt)
138                 return -ENOMEM;
139         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
140         wdt->base = devm_ioremap_resource(&pdev->dev, res);
141         if (IS_ERR(wdt->base))
142                 return PTR_ERR(wdt->base);
143
144         clk = of_clk_get(np, 0);
145         if (IS_ERR(clk))
146                 return PTR_ERR(clk);
147         ret = clk_prepare_enable(clk);
148         if (ret) {
149                 dev_err(&pdev->dev, "clk enable failed\n");
150                 goto err;
151         }
152
153         /* disable watchdog hardware */
154         writel(0, wdt->base + ATLAS7_WDT_CNT_CTRL);
155
156         wdt->tick_rate = clk_get_rate(clk);
157         if (!wdt->tick_rate) {
158                 ret = -EINVAL;
159                 goto err1;
160         }
161
162         wdt->clk = clk;
163         atlas7_wdd.min_timeout = 1;
164         atlas7_wdd.max_timeout = UINT_MAX / wdt->tick_rate;
165
166         watchdog_init_timeout(&atlas7_wdd, 0, &pdev->dev);
167         watchdog_set_nowayout(&atlas7_wdd, nowayout);
168
169         watchdog_set_drvdata(&atlas7_wdd, wdt);
170         platform_set_drvdata(pdev, &atlas7_wdd);
171
172         ret = watchdog_register_device(&atlas7_wdd);
173         if (ret)
174                 goto err1;
175
176         return 0;
177
178 err1:
179         clk_disable_unprepare(clk);
180 err:
181         clk_put(clk);
182         return ret;
183 }
184
185 static void atlas7_wdt_shutdown(struct platform_device *pdev)
186 {
187         struct watchdog_device *wdd = platform_get_drvdata(pdev);
188         struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
189
190         atlas7_wdt_disable(wdd);
191         clk_disable_unprepare(wdt->clk);
192 }
193
194 static int atlas7_wdt_remove(struct platform_device *pdev)
195 {
196         struct watchdog_device *wdd = platform_get_drvdata(pdev);
197         struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
198
199         atlas7_wdt_shutdown(pdev);
200         clk_put(wdt->clk);
201         return 0;
202 }
203
204 static int __maybe_unused atlas7_wdt_suspend(struct device *dev)
205 {
206         /*
207          * NOTE:timer controller registers settings are saved
208          * and restored back by the timer-atlas7.c
209          */
210         return 0;
211 }
212
213 static int __maybe_unused atlas7_wdt_resume(struct device *dev)
214 {
215         struct watchdog_device *wdd = dev_get_drvdata(dev);
216
217         /*
218          * NOTE: Since timer controller registers settings are saved
219          * and restored back by the timer-atlas7.c, so we need not
220          * update WD settings except refreshing timeout.
221          */
222         atlas7_wdt_ping(wdd);
223
224         return 0;
225 }
226
227 static SIMPLE_DEV_PM_OPS(atlas7_wdt_pm_ops,
228                 atlas7_wdt_suspend, atlas7_wdt_resume);
229
230 MODULE_DEVICE_TABLE(of, atlas7_wdt_ids);
231
232 static struct platform_driver atlas7_wdt_driver = {
233         .driver = {
234                 .name = "atlas7-wdt",
235                 .pm = &atlas7_wdt_pm_ops,
236                 .of_match_table = atlas7_wdt_ids,
237         },
238         .probe = atlas7_wdt_probe,
239         .remove = atlas7_wdt_remove,
240         .shutdown = atlas7_wdt_shutdown,
241 };
242 module_platform_driver(atlas7_wdt_driver);
243
244 MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
245 MODULE_AUTHOR("Guo Zeng <Guo.Zeng@csr.com>");
246 MODULE_LICENSE("GPL v2");
247 MODULE_ALIAS("platform:atlas7-wdt");