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John Crispinab3f09f2016-01-04 20:36:38 +01001/*
2 * Ralink MT7621/MT7628 built-in hardware watchdog timer
3 *
John Crispinf3519a62016-12-20 19:56:59 +01004 * Copyright (C) 2014 John Crispin <john@phrozen.org>
John Crispinab3f09f2016-01-04 20:36:38 +01005 *
6 * This driver was based on: drivers/watchdog/rt2880_wdt.c
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
11 */
12
13#include <linux/clk.h>
14#include <linux/reset.h>
15#include <linux/module.h>
16#include <linux/kernel.h>
17#include <linux/watchdog.h>
18#include <linux/moduleparam.h>
19#include <linux/platform_device.h>
20
21#include <asm/mach-ralink/ralink_regs.h>
22
23#define SYSC_RSTSTAT 0x38
24#define WDT_RST_CAUSE BIT(1)
25
26#define RALINK_WDT_TIMEOUT 30
27
28#define TIMER_REG_TMRSTAT 0x00
29#define TIMER_REG_TMR1LOAD 0x24
30#define TIMER_REG_TMR1CTL 0x20
31
32#define TMR1CTL_ENABLE BIT(7)
33#define TMR1CTL_RESTART BIT(9)
34#define TMR1CTL_PRESCALE_SHIFT 16
35
36static void __iomem *mt7621_wdt_base;
37static struct reset_control *mt7621_wdt_reset;
38
39static bool nowayout = WATCHDOG_NOWAYOUT;
40module_param(nowayout, bool, 0);
41MODULE_PARM_DESC(nowayout,
42 "Watchdog cannot be stopped once started (default="
43 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
44
45static inline void rt_wdt_w32(unsigned reg, u32 val)
46{
47 iowrite32(val, mt7621_wdt_base + reg);
48}
49
50static inline u32 rt_wdt_r32(unsigned reg)
51{
52 return ioread32(mt7621_wdt_base + reg);
53}
54
55static int mt7621_wdt_ping(struct watchdog_device *w)
56{
57 rt_wdt_w32(TIMER_REG_TMRSTAT, TMR1CTL_RESTART);
58
59 return 0;
60}
61
62static int mt7621_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
63{
64 w->timeout = t;
65 rt_wdt_w32(TIMER_REG_TMR1LOAD, t * 1000);
66 mt7621_wdt_ping(w);
67
68 return 0;
69}
70
71static int mt7621_wdt_start(struct watchdog_device *w)
72{
73 u32 t;
74
75 /* set the prescaler to 1ms == 1000us */
76 rt_wdt_w32(TIMER_REG_TMR1CTL, 1000 << TMR1CTL_PRESCALE_SHIFT);
77
78 mt7621_wdt_set_timeout(w, w->timeout);
79
80 t = rt_wdt_r32(TIMER_REG_TMR1CTL);
81 t |= TMR1CTL_ENABLE;
82 rt_wdt_w32(TIMER_REG_TMR1CTL, t);
83
84 return 0;
85}
86
87static int mt7621_wdt_stop(struct watchdog_device *w)
88{
89 u32 t;
90
91 mt7621_wdt_ping(w);
92
93 t = rt_wdt_r32(TIMER_REG_TMR1CTL);
94 t &= ~TMR1CTL_ENABLE;
95 rt_wdt_w32(TIMER_REG_TMR1CTL, t);
96
97 return 0;
98}
99
100static int mt7621_wdt_bootcause(void)
101{
102 if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
103 return WDIOF_CARDRESET;
104
105 return 0;
106}
107
Julia Lawall323edb22017-08-03 23:21:31 +0200108static const struct watchdog_info mt7621_wdt_info = {
John Crispinab3f09f2016-01-04 20:36:38 +0100109 .identity = "Mediatek Watchdog",
110 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
111};
112
Bhumika Goyalb893e342017-01-28 13:11:17 +0530113static const struct watchdog_ops mt7621_wdt_ops = {
John Crispinab3f09f2016-01-04 20:36:38 +0100114 .owner = THIS_MODULE,
115 .start = mt7621_wdt_start,
116 .stop = mt7621_wdt_stop,
117 .ping = mt7621_wdt_ping,
118 .set_timeout = mt7621_wdt_set_timeout,
119};
120
121static struct watchdog_device mt7621_wdt_dev = {
122 .info = &mt7621_wdt_info,
123 .ops = &mt7621_wdt_ops,
124 .min_timeout = 1,
125 .max_timeout = 0xfffful / 1000,
126};
127
128static int mt7621_wdt_probe(struct platform_device *pdev)
129{
130 struct resource *res;
131 int ret;
132
133 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
134 mt7621_wdt_base = devm_ioremap_resource(&pdev->dev, res);
135 if (IS_ERR(mt7621_wdt_base))
136 return PTR_ERR(mt7621_wdt_base);
137
Philipp Zabel0bade022017-07-19 17:26:38 +0200138 mt7621_wdt_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
John Crispinab3f09f2016-01-04 20:36:38 +0100139 if (!IS_ERR(mt7621_wdt_reset))
140 reset_control_deassert(mt7621_wdt_reset);
141
John Crispinab3f09f2016-01-04 20:36:38 +0100142 mt7621_wdt_dev.bootstatus = mt7621_wdt_bootcause();
143
144 watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
145 &pdev->dev);
146 watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
147
148 ret = watchdog_register_device(&mt7621_wdt_dev);
149
150 return 0;
151}
152
153static int mt7621_wdt_remove(struct platform_device *pdev)
154{
155 watchdog_unregister_device(&mt7621_wdt_dev);
156
157 return 0;
158}
159
160static void mt7621_wdt_shutdown(struct platform_device *pdev)
161{
162 mt7621_wdt_stop(&mt7621_wdt_dev);
163}
164
165static const struct of_device_id mt7621_wdt_match[] = {
166 { .compatible = "mediatek,mt7621-wdt" },
167 {},
168};
169MODULE_DEVICE_TABLE(of, mt7621_wdt_match);
170
171static struct platform_driver mt7621_wdt_driver = {
172 .probe = mt7621_wdt_probe,
173 .remove = mt7621_wdt_remove,
174 .shutdown = mt7621_wdt_shutdown,
175 .driver = {
176 .name = KBUILD_MODNAME,
177 .of_match_table = mt7621_wdt_match,
178 },
179};
180
181module_platform_driver(mt7621_wdt_driver);
182
183MODULE_DESCRIPTION("MediaTek MT762x hardware watchdog driver");
John Crispinf3519a62016-12-20 19:56:59 +0100184MODULE_AUTHOR("John Crispin <john@phrozen.org");
John Crispinab3f09f2016-01-04 20:36:38 +0100185MODULE_LICENSE("GPL v2");