1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2015 Broadcom Corporation
4 *
5 */
6
7 #include <linux/clk.h>
8 #include <linux/init.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/platform_data/bcm7038_wdt.h>
14 #include <linux/pm.h>
15 #include <linux/watchdog.h>
16
17 #define WDT_START_1 0xff00
18 #define WDT_START_2 0x00ff
19 #define WDT_STOP_1 0xee00
20 #define WDT_STOP_2 0x00ee
21
22 #define WDT_TIMEOUT_REG 0x0
23 #define WDT_CMD_REG 0x4
24
25 #define WDT_MIN_TIMEOUT 1 /* seconds */
26 #define WDT_DEFAULT_TIMEOUT 30 /* seconds */
27 #define WDT_DEFAULT_RATE 27000000
28
29 struct bcm7038_watchdog {
30 void __iomem *base;
31 struct watchdog_device wdd;
32 u32 rate;
33 struct clk *clk;
34 };
35
36 static bool nowayout = WATCHDOG_NOWAYOUT;
37
bcm7038_wdt_write(u32 value,void __iomem * addr)38 static inline void bcm7038_wdt_write(u32 value, void __iomem *addr)
39 {
40 /* MIPS chips strapped for BE will automagically configure the
41 * peripheral registers for CPU-native byte order.
42 */
43 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
44 __raw_writel(value, addr);
45 else
46 writel_relaxed(value, addr);
47 }
48
bcm7038_wdt_read(void __iomem * addr)49 static inline u32 bcm7038_wdt_read(void __iomem *addr)
50 {
51 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
52 return __raw_readl(addr);
53 else
54 return readl_relaxed(addr);
55 }
56
bcm7038_wdt_set_timeout_reg(struct watchdog_device * wdog)57 static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
58 {
59 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
60 u32 timeout;
61
62 timeout = wdt->rate * wdog->timeout;
63
64 bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG);
65 }
66
bcm7038_wdt_ping(struct watchdog_device * wdog)67 static int bcm7038_wdt_ping(struct watchdog_device *wdog)
68 {
69 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
70
71 bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG);
72 bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG);
73
74 return 0;
75 }
76
bcm7038_wdt_start(struct watchdog_device * wdog)77 static int bcm7038_wdt_start(struct watchdog_device *wdog)
78 {
79 bcm7038_wdt_set_timeout_reg(wdog);
80 bcm7038_wdt_ping(wdog);
81
82 return 0;
83 }
84
bcm7038_wdt_stop(struct watchdog_device * wdog)85 static int bcm7038_wdt_stop(struct watchdog_device *wdog)
86 {
87 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
88
89 bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG);
90 bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG);
91
92 return 0;
93 }
94
bcm7038_wdt_set_timeout(struct watchdog_device * wdog,unsigned int t)95 static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,
96 unsigned int t)
97 {
98 /* Can't modify timeout value if watchdog timer is running */
99 bcm7038_wdt_stop(wdog);
100 wdog->timeout = t;
101 bcm7038_wdt_start(wdog);
102
103 return 0;
104 }
105
bcm7038_wdt_get_timeleft(struct watchdog_device * wdog)106 static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
107 {
108 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
109 u32 time_left;
110
111 time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG);
112
113 return time_left / wdt->rate;
114 }
115
116 static const struct watchdog_info bcm7038_wdt_info = {
117 .identity = "Broadcom BCM7038 Watchdog Timer",
118 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
119 WDIOF_MAGICCLOSE
120 };
121
122 static const struct watchdog_ops bcm7038_wdt_ops = {
123 .owner = THIS_MODULE,
124 .start = bcm7038_wdt_start,
125 .stop = bcm7038_wdt_stop,
126 .set_timeout = bcm7038_wdt_set_timeout,
127 .get_timeleft = bcm7038_wdt_get_timeleft,
128 };
129
bcm7038_wdt_probe(struct platform_device * pdev)130 static int bcm7038_wdt_probe(struct platform_device *pdev)
131 {
132 struct bcm7038_wdt_platform_data *pdata = pdev->dev.platform_data;
133 struct device *dev = &pdev->dev;
134 struct bcm7038_watchdog *wdt;
135 const char *clk_name = NULL;
136 int err;
137
138 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
139 if (!wdt)
140 return -ENOMEM;
141
142 platform_set_drvdata(pdev, wdt);
143
144 wdt->base = devm_platform_ioremap_resource(pdev, 0);
145 if (IS_ERR(wdt->base))
146 return PTR_ERR(wdt->base);
147
148 if (pdata && pdata->clk_name)
149 clk_name = pdata->clk_name;
150
151 wdt->clk = devm_clk_get_enabled(dev, clk_name);
152 /* If unable to get clock, use default frequency */
153 if (!IS_ERR(wdt->clk)) {
154 wdt->rate = clk_get_rate(wdt->clk);
155 /* Prevent divide-by-zero exception */
156 if (!wdt->rate)
157 wdt->rate = WDT_DEFAULT_RATE;
158 } else {
159 wdt->rate = WDT_DEFAULT_RATE;
160 wdt->clk = NULL;
161 }
162
163 wdt->wdd.info = &bcm7038_wdt_info;
164 wdt->wdd.ops = &bcm7038_wdt_ops;
165 wdt->wdd.min_timeout = WDT_MIN_TIMEOUT;
166 wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
167 wdt->wdd.max_timeout = 0xffffffff / wdt->rate;
168 wdt->wdd.parent = dev;
169 watchdog_set_drvdata(&wdt->wdd, wdt);
170
171 watchdog_stop_on_reboot(&wdt->wdd);
172 watchdog_stop_on_unregister(&wdt->wdd);
173 err = devm_watchdog_register_device(dev, &wdt->wdd);
174 if (err)
175 return err;
176
177 dev_info(dev, "Registered BCM7038 Watchdog\n");
178
179 return 0;
180 }
181
bcm7038_wdt_suspend(struct device * dev)182 static int bcm7038_wdt_suspend(struct device *dev)
183 {
184 struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
185
186 if (watchdog_active(&wdt->wdd))
187 return bcm7038_wdt_stop(&wdt->wdd);
188
189 return 0;
190 }
191
bcm7038_wdt_resume(struct device * dev)192 static int bcm7038_wdt_resume(struct device *dev)
193 {
194 struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
195
196 if (watchdog_active(&wdt->wdd))
197 return bcm7038_wdt_start(&wdt->wdd);
198
199 return 0;
200 }
201
202 static DEFINE_SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops,
203 bcm7038_wdt_suspend, bcm7038_wdt_resume);
204
205 static const struct of_device_id bcm7038_wdt_match[] = {
206 { .compatible = "brcm,bcm6345-wdt" },
207 { .compatible = "brcm,bcm7038-wdt" },
208 {},
209 };
210 MODULE_DEVICE_TABLE(of, bcm7038_wdt_match);
211
212 static const struct platform_device_id bcm7038_wdt_devtype[] = {
213 { .name = "bcm63xx-wdt" },
214 { /* sentinel */ },
215 };
216 MODULE_DEVICE_TABLE(platform, bcm7038_wdt_devtype);
217
218 static struct platform_driver bcm7038_wdt_driver = {
219 .probe = bcm7038_wdt_probe,
220 .id_table = bcm7038_wdt_devtype,
221 .driver = {
222 .name = "bcm7038-wdt",
223 .of_match_table = bcm7038_wdt_match,
224 .pm = pm_sleep_ptr(&bcm7038_wdt_pm_ops),
225 }
226 };
227 module_platform_driver(bcm7038_wdt_driver);
228
229 module_param(nowayout, bool, 0);
230 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
231 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
232 MODULE_LICENSE("GPL");
233 MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
234 MODULE_AUTHOR("Justin Chen");
235