[linux-2.6-block.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/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_ioremap_resource(&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,
		.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>
473cf939 JC	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
	45	static struct clk *rt288x_wdt_clk;
	46	static unsigned long rt288x_wdt_freq;
	47	static void __iomem *rt288x_wdt_base;
	48
	49	static bool nowayout = WATCHDOG_NOWAYOUT;
	50	module_param(nowayout, bool, 0);
	51	MODULE_PARM_DESC(nowayout,
	52	"Watchdog cannot be stopped once started (default="
	53	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	54
	55	static inline void rt_wdt_w32(unsigned reg, u32 val)
	56	{
	57	iowrite32(val, rt288x_wdt_base + reg);
	58	}
	59
	60	static inline u32 rt_wdt_r32(unsigned reg)
	61	{
	62	return ioread32(rt288x_wdt_base + reg);
	63	}
	64
	65	static int rt288x_wdt_ping(struct watchdog_device *w)
	66	{
	67	rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq);
	68
	69	return 0;
	70	}
	71
	72	static int rt288x_wdt_start(struct watchdog_device *w)
	73	{
	74	u32 t;
	75
	76	t = rt_wdt_r32(TIMER_REG_TMR1CTL);
	77	t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT \|
	78	TMR1CTL_PRESCALE_MASK);
	79	t \|= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT \|
	80	TMR1CTL_PRESCALE_65536);
	81	rt_wdt_w32(TIMER_REG_TMR1CTL, t);
	82
83	rt288x_wdt_ping(w);
84
85	t = rt_wdt_r32(TIMER_REG_TMR1CTL);
86	t \|= TMR1CTL_ENABLE;
87	rt_wdt_w32(TIMER_REG_TMR1CTL, t);
88
89	return 0;
90	}
91
92	static int rt288x_wdt_stop(struct watchdog_device *w)
93	{
94	u32 t;
95
96	rt288x_wdt_ping(w);
97
98	t = rt_wdt_r32(TIMER_REG_TMR1CTL);
99	t &= ~TMR1CTL_ENABLE;
100	rt_wdt_w32(TIMER_REG_TMR1CTL, t);
101
102	return 0;
103	}
104
105	static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
106	{
107	w->timeout = t;
108	rt288x_wdt_ping(w);
109
110	return 0;
111	}
112
113	static int rt288x_wdt_bootcause(void)
114	{
115	if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
116	return WDIOF_CARDRESET;
117
118	return 0;
119	}
120
121	static struct watchdog_info rt288x_wdt_info = {
122	.identity = "Ralink Watchdog",
123	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
124	};
125
126	static struct watchdog_ops rt288x_wdt_ops = {
127	.owner = THIS_MODULE,
128	.start = rt288x_wdt_start,
129	.stop = rt288x_wdt_stop,
130	.ping = rt288x_wdt_ping,
131	.set_timeout = rt288x_wdt_set_timeout,
132	};
133
134	static struct watchdog_device rt288x_wdt_dev = {
135	.info = &rt288x_wdt_info,
136	.ops = &rt288x_wdt_ops,
137	.min_timeout = 1,
138	};
139
140	static int rt288x_wdt_probe(struct platform_device *pdev)
141	{
142	struct resource *res;
143	int ret;
144
145	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
0859ffc3	146	rt288x_wdt_base = devm_ioremap_resource(&pdev->dev, res);
473cf939 JC	147	if (IS_ERR(rt288x_wdt_base))
	148	return PTR_ERR(rt288x_wdt_base);
	149
	150	rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL);
	151	if (IS_ERR(rt288x_wdt_clk))
	152	return PTR_ERR(rt288x_wdt_clk);
	153
	154	device_reset(&pdev->dev);
	155
	156	rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE;
	157
	158	rt288x_wdt_dev.dev = &pdev->dev;
	159	rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();
	160
	161	rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
	162	rt288x_wdt_dev.timeout = rt288x_wdt_dev.max_timeout;
	163
	164	watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);
	165
	166	ret = watchdog_register_device(&rt288x_wdt_dev);
	167	if (!ret)
	168	dev_info(&pdev->dev, "Initialized\n");
	169
	170	return 0;
	171	}
	172
	173	static int rt288x_wdt_remove(struct platform_device *pdev)
	174	{
	175	watchdog_unregister_device(&rt288x_wdt_dev);
	176
	177	return 0;
	178	}
	179
	180	static void rt288x_wdt_shutdown(struct platform_device *pdev)
	181	{
	182	rt288x_wdt_stop(&rt288x_wdt_dev);
	183	}
	184
	185	static const struct of_device_id rt288x_wdt_match[] = {
	186	{ .compatible = "ralink,rt2880-wdt" },
	187	{},
	188	};
	189	MODULE_DEVICE_TABLE(of, rt288x_wdt_match);
	190
	191	static struct platform_driver rt288x_wdt_driver = {
	192	.probe = rt288x_wdt_probe,
	193	.remove = rt288x_wdt_remove,
	194	.shutdown = rt288x_wdt_shutdown,
	195	.driver = {
	196	.name = KBUILD_MODNAME,
473cf939 JC	197	.of_match_table = rt288x_wdt_match,
	198	},
	199	};
	200
	201	module_platform_driver(rt288x_wdt_driver);
	202
	203	MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
	204	MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
	205	MODULE_LICENSE("GPL v2");