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>
22 #include <asm/mach-ralink/ralink_regs.h>
24 #define SYSC_RSTSTAT 0x38
25 #define WDT_RST_CAUSE BIT(1)
27 #define RALINK_WDT_TIMEOUT 30
28 #define RALINK_WDT_PRESCALE 65536
30 #define TIMER_REG_TMR1LOAD 0x00
31 #define TIMER_REG_TMR1CTL 0x08
33 #define TMRSTAT_TMR1RST BIT(5)
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
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
;
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
) ")");
56 static inline void rt_wdt_w32(unsigned reg
, u32 val
)
58 iowrite32(val
, rt288x_wdt_base
+ reg
);
61 static inline u32
rt_wdt_r32(unsigned reg
)
63 return ioread32(rt288x_wdt_base
+ reg
);
66 static int rt288x_wdt_ping(struct watchdog_device
*w
)
68 rt_wdt_w32(TIMER_REG_TMR1LOAD
, w
->timeout
* rt288x_wdt_freq
);
73 static int rt288x_wdt_start(struct watchdog_device
*w
)
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
);
86 t
= rt_wdt_r32(TIMER_REG_TMR1CTL
);
88 rt_wdt_w32(TIMER_REG_TMR1CTL
, t
);
93 static int rt288x_wdt_stop(struct watchdog_device
*w
)
99 t
= rt_wdt_r32(TIMER_REG_TMR1CTL
);
100 t
&= ~TMR1CTL_ENABLE
;
101 rt_wdt_w32(TIMER_REG_TMR1CTL
, t
);
106 static int rt288x_wdt_set_timeout(struct watchdog_device
*w
, unsigned int t
)
114 static int rt288x_wdt_bootcause(void)
116 if (rt_sysc_r32(SYSC_RSTSTAT
) & WDT_RST_CAUSE
)
117 return WDIOF_CARDRESET
;
122 static const struct watchdog_info rt288x_wdt_info
= {
123 .identity
= "Ralink Watchdog",
124 .options
= WDIOF_SETTIMEOUT
| WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
,
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
,
135 static struct watchdog_device rt288x_wdt_dev
= {
136 .info
= &rt288x_wdt_info
,
137 .ops
= &rt288x_wdt_ops
,
141 static int rt288x_wdt_probe(struct platform_device
*pdev
)
143 struct resource
*res
;
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
);
151 rt288x_wdt_clk
= devm_clk_get(&pdev
->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(&pdev
->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
= &pdev
->dev
;
165 watchdog_init_timeout(&rt288x_wdt_dev
, rt288x_wdt_dev
.max_timeout
,
167 watchdog_set_nowayout(&rt288x_wdt_dev
, nowayout
);
169 ret
= watchdog_register_device(&rt288x_wdt_dev
);
171 dev_info(&pdev
->dev
, "Initialized\n");
176 static int rt288x_wdt_remove(struct platform_device
*pdev
)
178 watchdog_unregister_device(&rt288x_wdt_dev
);
183 static void rt288x_wdt_shutdown(struct platform_device
*pdev
)
185 rt288x_wdt_stop(&rt288x_wdt_dev
);
188 static const struct of_device_id rt288x_wdt_match
[] = {
189 { .compatible
= "ralink,rt2880-wdt" },
192 MODULE_DEVICE_TABLE(of
, rt288x_wdt_match
);
194 static struct platform_driver rt288x_wdt_driver
= {
195 .probe
= rt288x_wdt_probe
,
196 .remove
= rt288x_wdt_remove
,
197 .shutdown
= rt288x_wdt_shutdown
,
199 .name
= KBUILD_MODNAME
,
200 .of_match_table
= rt288x_wdt_match
,
204 module_platform_driver(rt288x_wdt_driver
);
206 MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
207 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
208 MODULE_LICENSE("GPL v2");