2 * Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer
4 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2013 John Crispin <john@phrozen.org>
7 * This driver was based on: drivers/watchdog/softdog.c
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.
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 #include <linux/mod_devicetable.h>
23 #include <asm/mach-ralink/ralink_regs.h>
25 #define SYSC_RSTSTAT 0x38
26 #define WDT_RST_CAUSE BIT(1)
28 #define RALINK_WDT_TIMEOUT 30
29 #define RALINK_WDT_PRESCALE 65536
31 #define TIMER_REG_TMR1LOAD 0x00
32 #define TIMER_REG_TMR1CTL 0x08
34 #define TMRSTAT_TMR1RST BIT(5)
36 #define TMR1CTL_ENABLE BIT(7)
37 #define TMR1CTL_MODE_SHIFT 4
38 #define TMR1CTL_MODE_MASK 0x3
39 #define TMR1CTL_MODE_FREE_RUNNING 0x0
40 #define TMR1CTL_MODE_PERIODIC 0x1
41 #define TMR1CTL_MODE_TIMEOUT 0x2
42 #define TMR1CTL_MODE_WDT 0x3
43 #define TMR1CTL_PRESCALE_MASK 0xf
44 #define TMR1CTL_PRESCALE_65536 0xf
46 static struct clk
*rt288x_wdt_clk
;
47 static unsigned long rt288x_wdt_freq
;
48 static void __iomem
*rt288x_wdt_base
;
49 static struct reset_control
*rt288x_wdt_reset
;
51 static bool nowayout
= WATCHDOG_NOWAYOUT
;
52 module_param(nowayout
, bool, 0);
53 MODULE_PARM_DESC(nowayout
,
54 "Watchdog cannot be stopped once started (default="
55 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
57 static inline void rt_wdt_w32(unsigned reg
, u32 val
)
59 iowrite32(val
, rt288x_wdt_base
+ reg
);
62 static inline u32
rt_wdt_r32(unsigned reg
)
64 return ioread32(rt288x_wdt_base
+ reg
);
67 static int rt288x_wdt_ping(struct watchdog_device
*w
)
69 rt_wdt_w32(TIMER_REG_TMR1LOAD
, w
->timeout
* rt288x_wdt_freq
);
74 static int rt288x_wdt_start(struct watchdog_device
*w
)
78 t
= rt_wdt_r32(TIMER_REG_TMR1CTL
);
79 t
&= ~(TMR1CTL_MODE_MASK
<< TMR1CTL_MODE_SHIFT
|
80 TMR1CTL_PRESCALE_MASK
);
81 t
|= (TMR1CTL_MODE_WDT
<< TMR1CTL_MODE_SHIFT
|
82 TMR1CTL_PRESCALE_65536
);
83 rt_wdt_w32(TIMER_REG_TMR1CTL
, t
);
87 t
= rt_wdt_r32(TIMER_REG_TMR1CTL
);
89 rt_wdt_w32(TIMER_REG_TMR1CTL
, t
);
94 static int rt288x_wdt_stop(struct watchdog_device
*w
)
100 t
= rt_wdt_r32(TIMER_REG_TMR1CTL
);
101 t
&= ~TMR1CTL_ENABLE
;
102 rt_wdt_w32(TIMER_REG_TMR1CTL
, t
);
107 static int rt288x_wdt_set_timeout(struct watchdog_device
*w
, unsigned int t
)
115 static int rt288x_wdt_bootcause(void)
117 if (rt_sysc_r32(SYSC_RSTSTAT
) & WDT_RST_CAUSE
)
118 return WDIOF_CARDRESET
;
123 static const struct watchdog_info rt288x_wdt_info
= {
124 .identity
= "Ralink Watchdog",
125 .options
= WDIOF_SETTIMEOUT
| WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
,
128 static const struct watchdog_ops rt288x_wdt_ops
= {
129 .owner
= THIS_MODULE
,
130 .start
= rt288x_wdt_start
,
131 .stop
= rt288x_wdt_stop
,
132 .ping
= rt288x_wdt_ping
,
133 .set_timeout
= rt288x_wdt_set_timeout
,
136 static struct watchdog_device rt288x_wdt_dev
= {
137 .info
= &rt288x_wdt_info
,
138 .ops
= &rt288x_wdt_ops
,
142 static int rt288x_wdt_probe(struct platform_device
*pdev
)
144 struct device
*dev
= &pdev
->dev
;
147 rt288x_wdt_base
= devm_platform_ioremap_resource(pdev
, 0);
148 if (IS_ERR(rt288x_wdt_base
))
149 return PTR_ERR(rt288x_wdt_base
);
151 rt288x_wdt_clk
= devm_clk_get(dev
, NULL
);
152 if (IS_ERR(rt288x_wdt_clk
))
153 return PTR_ERR(rt288x_wdt_clk
);
155 rt288x_wdt_reset
= devm_reset_control_get_exclusive(dev
, NULL
);
156 if (!IS_ERR(rt288x_wdt_reset
))
157 reset_control_deassert(rt288x_wdt_reset
);
159 rt288x_wdt_freq
= clk_get_rate(rt288x_wdt_clk
) / RALINK_WDT_PRESCALE
;
161 rt288x_wdt_dev
.bootstatus
= rt288x_wdt_bootcause();
162 rt288x_wdt_dev
.max_timeout
= (0xfffful
/ rt288x_wdt_freq
);
163 rt288x_wdt_dev
.parent
= dev
;
165 watchdog_init_timeout(&rt288x_wdt_dev
, rt288x_wdt_dev
.max_timeout
,
167 watchdog_set_nowayout(&rt288x_wdt_dev
, nowayout
);
169 watchdog_stop_on_reboot(&rt288x_wdt_dev
);
170 ret
= devm_watchdog_register_device(dev
, &rt288x_wdt_dev
);
172 dev_info(dev
, "Initialized\n");
177 static const struct of_device_id rt288x_wdt_match
[] = {
178 { .compatible
= "ralink,rt2880-wdt" },
181 MODULE_DEVICE_TABLE(of
, rt288x_wdt_match
);
183 static struct platform_driver rt288x_wdt_driver
= {
184 .probe
= rt288x_wdt_probe
,
186 .name
= KBUILD_MODNAME
,
187 .of_match_table
= rt288x_wdt_match
,
191 module_platform_driver(rt288x_wdt_driver
);
193 MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
194 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
195 MODULE_LICENSE("GPL v2");