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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
45static struct clk *rt288x_wdt_clk;
46static unsigned long rt288x_wdt_freq;
47static void __iomem *rt288x_wdt_base;
48static struct reset_control *rt288x_wdt_reset;
49
50static bool nowayout = WATCHDOG_NOWAYOUT;
51module_param(nowayout, bool, 0);
52MODULE_PARM_DESC(nowayout,
53 "Watchdog cannot be stopped once started (default="
54 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
55
56static inline void rt_wdt_w32(unsigned reg, u32 val)
57{
58 iowrite32(val, rt288x_wdt_base + reg);
59}
60
61static inline u32 rt_wdt_r32(unsigned reg)
62{
63 return ioread32(rt288x_wdt_base + reg);
64}
65
66static 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
73static 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
93static 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
106static 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
114static 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
122static struct watchdog_info rt288x_wdt_info = {
123 .identity = "Ralink Watchdog",
124 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
125};
126
127static 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
135static struct watchdog_device rt288x_wdt_dev = {
136 .info = &rt288x_wdt_info,
137 .ops = &rt288x_wdt_ops,
138 .min_timeout = 1,
139};
140
141static 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(&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
176static int rt288x_wdt_remove(struct platform_device *pdev)
177{
178 watchdog_unregister_device(&rt288x_wdt_dev);
179
180 return 0;
181}
182
183static void rt288x_wdt_shutdown(struct platform_device *pdev)
184{
185 rt288x_wdt_stop(&rt288x_wdt_dev);
186}
187
188static const struct of_device_id rt288x_wdt_match[] = {
189 { .compatible = "ralink,rt2880-wdt" },
190 {},
191};
192MODULE_DEVICE_TABLE(of, rt288x_wdt_match);
193
194static 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
204module_platform_driver(rt288x_wdt_driver);
205
206MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
207MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
208MODULE_LICENSE("GPL v2");
209
