[mirror_ubuntu-bionic-kernel.git] / drivers / watchdog / rt2880_wdt.c

/*
 * Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer
 *
 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
 * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
 *
 * This driver was based on: drivers/watchdog/softdog.c
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/reset.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/miscdevice.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>

#include <asm/mach-ralink/ralink_regs.h>

#define SYSC_RSTSTAT			0x38
#define WDT_RST_CAUSE			BIT(1)

#define RALINK_WDT_TIMEOUT		30
#define RALINK_WDT_PRESCALE		65536

#define TIMER_REG_TMR1LOAD		0x00
#define TIMER_REG_TMR1CTL		0x08

#define TMRSTAT_TMR1RST			BIT(5)

#define TMR1CTL_ENABLE			BIT(7)
#define TMR1CTL_MODE_SHIFT		4
#define TMR1CTL_MODE_MASK		0x3
#define TMR1CTL_MODE_FREE_RUNNING	0x0
#define TMR1CTL_MODE_PERIODIC		0x1
#define TMR1CTL_MODE_TIMEOUT		0x2
#define TMR1CTL_MODE_WDT		0x3
#define TMR1CTL_PRESCALE_MASK		0xf
#define TMR1CTL_PRESCALE_65536		0xf

static struct clk *rt288x_wdt_clk;
static unsigned long rt288x_wdt_freq;
static void __iomem *rt288x_wdt_base;

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
		"Watchdog cannot be stopped once started (default="
		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static inline void rt_wdt_w32(unsigned reg, u32 val)
{
	iowrite32(val, rt288x_wdt_base + reg);
}

static inline u32 rt_wdt_r32(unsigned reg)
{
	return ioread32(rt288x_wdt_base + reg);
}

static int rt288x_wdt_ping(struct watchdog_device *w)
{
	rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq);

	return 0;
}

static int rt288x_wdt_start(struct watchdog_device *w)
{
	u32 t;

	t = rt_wdt_r32(TIMER_REG_TMR1CTL);
	t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |
		TMR1CTL_PRESCALE_MASK);
	t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |
		TMR1CTL_PRESCALE_65536);
	rt_wdt_w32(TIMER_REG_TMR1CTL, t);

	rt288x_wdt_ping(w);

	t = rt_wdt_r32(TIMER_REG_TMR1CTL);
	t |= TMR1CTL_ENABLE;
	rt_wdt_w32(TIMER_REG_TMR1CTL, t);

	return 0;
}

static int rt288x_wdt_stop(struct watchdog_device *w)
{
	u32 t;

	rt288x_wdt_ping(w);

	t = rt_wdt_r32(TIMER_REG_TMR1CTL);
	t &= ~TMR1CTL_ENABLE;
	rt_wdt_w32(TIMER_REG_TMR1CTL, t);

	return 0;
}

static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
{
	w->timeout = t;
	rt288x_wdt_ping(w);

	return 0;
}

static int rt288x_wdt_bootcause(void)
{
	if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
		return WDIOF_CARDRESET;

	return 0;
}

static struct watchdog_info rt288x_wdt_info = {
	.identity = "Ralink Watchdog",
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};

static struct watchdog_ops rt288x_wdt_ops = {
	.owner = THIS_MODULE,
	.start = rt288x_wdt_start,
	.stop = rt288x_wdt_stop,
	.ping = rt288x_wdt_ping,
	.set_timeout = rt288x_wdt_set_timeout,
};

static struct watchdog_device rt288x_wdt_dev = {
	.info = &rt288x_wdt_info,
	.ops = &rt288x_wdt_ops,
	.min_timeout = 1,
};

static int rt288x_wdt_probe(struct platform_device *pdev)
{
	struct resource *res;
	int ret;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	rt288x_wdt_base = devm_request_and_ioremap(&pdev->dev, res);
	if (IS_ERR(rt288x_wdt_base))
		return PTR_ERR(rt288x_wdt_base);

	rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(rt288x_wdt_clk))
		return PTR_ERR(rt288x_wdt_clk);

	device_reset(&pdev->dev);

	rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE;

	rt288x_wdt_dev.dev = &pdev->dev;
	rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();

	rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
	rt288x_wdt_dev.timeout = rt288x_wdt_dev.max_timeout;

	watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);

	ret = watchdog_register_device(&rt288x_wdt_dev);
	if (!ret)
		dev_info(&pdev->dev, "Initialized\n");

	return 0;
}

static int rt288x_wdt_remove(struct platform_device *pdev)
{
	watchdog_unregister_device(&rt288x_wdt_dev);

	return 0;
}

static void rt288x_wdt_shutdown(struct platform_device *pdev)
{
	rt288x_wdt_stop(&rt288x_wdt_dev);
}

static const struct of_device_id rt288x_wdt_match[] = {
	{ .compatible = "ralink,rt2880-wdt" },
	{},
};
MODULE_DEVICE_TABLE(of, rt288x_wdt_match);

static struct platform_driver rt288x_wdt_driver = {
	.probe		= rt288x_wdt_probe,
	.remove		= rt288x_wdt_remove,
	.shutdown	= rt288x_wdt_shutdown,
	.driver		= {
		.name		= KBUILD_MODNAME,
		.owner		= THIS_MODULE,
		.of_match_table	= rt288x_wdt_match,
	},
};

module_platform_driver(rt288x_wdt_driver);

MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
473cf939 JC	1	/*
	2	* Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer
	3	*
	4	* Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
	5	* Copyright (C) 2013 John Crispin <blogic@openwrt.org>
	6	*
	7	* This driver was based on: drivers/watchdog/softdog.c
	8	*
	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.
	12	*/
	13
	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/miscdevice.h>
	20	#include <linux/moduleparam.h>
	21	#include <linux/platform_device.h>
	22
	23	#include <asm/mach-ralink/ralink_regs.h>
	24
	25	#define SYSC_RSTSTAT 0x38
	26	#define WDT_RST_CAUSE BIT(1)
	27
	28	#define RALINK_WDT_TIMEOUT 30
	29	#define RALINK_WDT_PRESCALE 65536
	30
	31	#define TIMER_REG_TMR1LOAD 0x00
	32	#define TIMER_REG_TMR1CTL 0x08
	33
	34	#define TMRSTAT_TMR1RST BIT(5)
	35
	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
	45
	46	static struct clk *rt288x_wdt_clk;
	47	static unsigned long rt288x_wdt_freq;
	48	static void __iomem *rt288x_wdt_base;
	49
	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) ")");
	55
	56	static inline void rt_wdt_w32(unsigned reg, u32 val)
	57	{
	58	iowrite32(val, rt288x_wdt_base + reg);
	59	}
	60
	61	static inline u32 rt_wdt_r32(unsigned reg)
	62	{
	63	return ioread32(rt288x_wdt_base + reg);
	64	}
65
66	static 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
73	static 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
93	static 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
106	static 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
114	static 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
122	static struct watchdog_info rt288x_wdt_info = {
123	.identity = "Ralink Watchdog",
124	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
125	};
126
127	static 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
135	static struct watchdog_device rt288x_wdt_dev = {
136	.info = &rt288x_wdt_info,
137	.ops = &rt288x_wdt_ops,
138	.min_timeout = 1,
139	};
140
141	static 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_request_and_ioremap(&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	device_reset(&pdev->dev);
156
157	rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE;
158
159	rt288x_wdt_dev.dev = &pdev->dev;
160	rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();
161
162	rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
163	rt288x_wdt_dev.timeout = rt288x_wdt_dev.max_timeout;
164
165	watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);
166
167	ret = watchdog_register_device(&rt288x_wdt_dev);
168	if (!ret)
169	dev_info(&pdev->dev, "Initialized\n");
170
171	return 0;
172	}
173
174	static int rt288x_wdt_remove(struct platform_device *pdev)
175	{
176	watchdog_unregister_device(&rt288x_wdt_dev);
177
178	return 0;
179	}
180
181	static void rt288x_wdt_shutdown(struct platform_device *pdev)
182	{
183	rt288x_wdt_stop(&rt288x_wdt_dev);
184	}
185
186	static const struct of_device_id rt288x_wdt_match[] = {
187	{ .compatible = "ralink,rt2880-wdt" },
188	{},
189	};
190	MODULE_DEVICE_TABLE(of, rt288x_wdt_match);
191
192	static struct platform_driver rt288x_wdt_driver = {
193	.probe = rt288x_wdt_probe,
194	.remove = rt288x_wdt_remove,
195	.shutdown = rt288x_wdt_shutdown,
196	.driver = {
197	.name = KBUILD_MODNAME,
198	.owner = THIS_MODULE,
199	.of_match_table = rt288x_wdt_match,
200	},
201	};
202
203	module_platform_driver(rt288x_wdt_driver);
204
205	MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
206	MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
207	MODULE_LICENSE("GPL v2");