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
atlas7_wdt_gettimeleft(struct watchdog_device * wdd)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
atlas7_wdt_ping(struct watchdog_device * wdd)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
atlas7_wdt_enable(struct watchdog_device * wdd)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
atlas7_wdt_disable(struct watchdog_device * wdd)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
atlas7_wdt_settimeout(struct watchdog_device * wdd,unsigned int to)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 const 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
atlas7_wdt_probe(struct platform_device * pdev)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
atlas7_wdt_shutdown(struct platform_device * pdev)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
atlas7_wdt_remove(struct platform_device * pdev)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
atlas7_wdt_suspend(struct device * dev)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
atlas7_wdt_resume(struct device * dev)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");
248
