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