1 /*
2 * Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer
3 *
4 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2013 John Crispin <john@phrozen.org>
6 *
7 * This driver was based on: drivers/watchdog/softdog.c
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License version 2 as published
11 * by the Free Software Foundation.
12 */
13
14 #include <linux/clk.h>
15 #include <linux/reset.h>
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/watchdog.h>
19 #include <linux/moduleparam.h>
20 #include <linux/platform_device.h>
21
22 #include <asm/mach-ralink/ralink_regs.h>
23
24 #define SYSC_RSTSTAT 0x38
25 #define WDT_RST_CAUSE BIT(1)
26
27 #define RALINK_WDT_TIMEOUT 30
28 #define RALINK_WDT_PRESCALE 65536
29
30 #define TIMER_REG_TMR1LOAD 0x00
31 #define TIMER_REG_TMR1CTL 0x08
32
33 #define TMRSTAT_TMR1RST BIT(5)
34
35 #define TMR1CTL_ENABLE BIT(7)
36 #define TMR1CTL_MODE_SHIFT 4
37 #define TMR1CTL_MODE_MASK 0x3
38 #define TMR1CTL_MODE_FREE_RUNNING 0x0
39 #define TMR1CTL_MODE_PERIODIC 0x1
40 #define TMR1CTL_MODE_TIMEOUT 0x2
41 #define TMR1CTL_MODE_WDT 0x3
42 #define TMR1CTL_PRESCALE_MASK 0xf
43 #define TMR1CTL_PRESCALE_65536 0xf
44
45 static struct clk *rt288x_wdt_clk;
46 static unsigned long rt288x_wdt_freq;
47 static void __iomem *rt288x_wdt_base;
48 static struct reset_control *rt288x_wdt_reset;
49
50 static bool nowayout = WATCHDOG_NOWAYOUT;
51 module_param(nowayout, bool, 0);
52 MODULE_PARM_DESC(nowayout,
53 "Watchdog cannot be stopped once started (default="
54 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
55
rt_wdt_w32(unsigned reg,u32 val)56 static inline void rt_wdt_w32(unsigned reg, u32 val)
57 {
58 iowrite32(val, rt288x_wdt_base + reg);
59 }
60
rt_wdt_r32(unsigned reg)61 static inline u32 rt_wdt_r32(unsigned reg)
62 {
63 return ioread32(rt288x_wdt_base + reg);
64 }
65
rt288x_wdt_ping(struct watchdog_device * w)66 static int rt288x_wdt_ping(struct watchdog_device *w)
67 {
68 rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq);
69
70 return 0;
71 }
72
rt288x_wdt_start(struct watchdog_device * w)73 static int rt288x_wdt_start(struct watchdog_device *w)
74 {
75 u32 t;
76
77 t = rt_wdt_r32(TIMER_REG_TMR1CTL);
78 t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |
79 TMR1CTL_PRESCALE_MASK);
80 t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |
81 TMR1CTL_PRESCALE_65536);
82 rt_wdt_w32(TIMER_REG_TMR1CTL, t);
83
84 rt288x_wdt_ping(w);
85
86 t = rt_wdt_r32(TIMER_REG_TMR1CTL);
87 t |= TMR1CTL_ENABLE;
88 rt_wdt_w32(TIMER_REG_TMR1CTL, t);
89
90 return 0;
91 }
92
rt288x_wdt_stop(struct watchdog_device * w)93 static int rt288x_wdt_stop(struct watchdog_device *w)
94 {
95 u32 t;
96
97 rt288x_wdt_ping(w);
98
99 t = rt_wdt_r32(TIMER_REG_TMR1CTL);
100 t &= ~TMR1CTL_ENABLE;
101 rt_wdt_w32(TIMER_REG_TMR1CTL, t);
102
103 return 0;
104 }
105
rt288x_wdt_set_timeout(struct watchdog_device * w,unsigned int t)106 static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
107 {
108 w->timeout = t;
109 rt288x_wdt_ping(w);
110
111 return 0;
112 }
113
rt288x_wdt_bootcause(void)114 static int rt288x_wdt_bootcause(void)
115 {
116 if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
117 return WDIOF_CARDRESET;
118
119 return 0;
120 }
121
122 static const struct watchdog_info rt288x_wdt_info = {
123 .identity = "Ralink Watchdog",
124 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
125 };
126
127 static const struct watchdog_ops rt288x_wdt_ops = {
128 .owner = THIS_MODULE,
129 .start = rt288x_wdt_start,
130 .stop = rt288x_wdt_stop,
131 .ping = rt288x_wdt_ping,
132 .set_timeout = rt288x_wdt_set_timeout,
133 };
134
135 static struct watchdog_device rt288x_wdt_dev = {
136 .info = &rt288x_wdt_info,
137 .ops = &rt288x_wdt_ops,
138 .min_timeout = 1,
139 };
140
rt288x_wdt_probe(struct platform_device * pdev)141 static int rt288x_wdt_probe(struct platform_device *pdev)
142 {
143 struct resource *res;
144 int ret;
145
146 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
147 rt288x_wdt_base = devm_ioremap_resource(&pdev->dev, res);
148 if (IS_ERR(rt288x_wdt_base))
149 return PTR_ERR(rt288x_wdt_base);
150
151 rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL);
152 if (IS_ERR(rt288x_wdt_clk))
153 return PTR_ERR(rt288x_wdt_clk);
154
155 rt288x_wdt_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
156 if (!IS_ERR(rt288x_wdt_reset))
157 reset_control_deassert(rt288x_wdt_reset);
158
159 rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE;
160
161 rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();
162 rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
163 rt288x_wdt_dev.parent = &pdev->dev;
164
165 watchdog_init_timeout(&rt288x_wdt_dev, rt288x_wdt_dev.max_timeout,
166 &pdev->dev);
167 watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);
168
169 ret = watchdog_register_device(&rt288x_wdt_dev);
170 if (!ret)
171 dev_info(&pdev->dev, "Initialized\n");
172
173 return 0;
174 }
175
rt288x_wdt_remove(struct platform_device * pdev)176 static int rt288x_wdt_remove(struct platform_device *pdev)
177 {
178 watchdog_unregister_device(&rt288x_wdt_dev);
179
180 return 0;
181 }
182
rt288x_wdt_shutdown(struct platform_device * pdev)183 static void rt288x_wdt_shutdown(struct platform_device *pdev)
184 {
185 rt288x_wdt_stop(&rt288x_wdt_dev);
186 }
187
188 static const struct of_device_id rt288x_wdt_match[] = {
189 { .compatible = "ralink,rt2880-wdt" },
190 {},
191 };
192 MODULE_DEVICE_TABLE(of, rt288x_wdt_match);
193
194 static struct platform_driver rt288x_wdt_driver = {
195 .probe = rt288x_wdt_probe,
196 .remove = rt288x_wdt_remove,
197 .shutdown = rt288x_wdt_shutdown,
198 .driver = {
199 .name = KBUILD_MODNAME,
200 .of_match_table = rt288x_wdt_match,
201 },
202 };
203
204 module_platform_driver(rt288x_wdt_driver);
205
206 MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
207 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
208 MODULE_LICENSE("GPL v2");
209
