[deliverable/linux.git] / drivers / watchdog / max63xx_wdt.c

/*
 * drivers/char/watchdog/max63xx_wdt.c
 *
 * Driver for max63{69,70,71,72,73,74} watchdog timers
 *
 * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * This driver assumes the watchdog pins are memory mapped (as it is
 * the case for the Arcom Zeus). Should it be connected over GPIOs or
 * another interface, some abstraction will have to be introduced.
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/slab.h>

#define DEFAULT_HEARTBEAT 60
#define MAX_HEARTBEAT     60

static unsigned int heartbeat = DEFAULT_HEARTBEAT;
static bool nowayout  = WATCHDOG_NOWAYOUT;

/*
 * Memory mapping: a single byte, 3 first lower bits to select bit 3
 * to ping the watchdog.
 */
#define MAX6369_WDSET	(7 << 0)
#define MAX6369_WDI	(1 << 3)

static DEFINE_SPINLOCK(io_lock);

static int nodelay;
static void __iomem	*wdt_base;

/*
 * The timeout values used are actually the absolute minimum the chip
 * offers. Typical values on my board are slightly over twice as long
 * (10s setting ends up with a 25s timeout), and can be up to 3 times
 * the nominal setting (according to the datasheet). So please take
 * these values with a grain of salt. Same goes for the initial delay
 * "feature". Only max6373/74 have a few settings without this initial
 * delay (selected with the "nodelay" parameter).
 *
 * I also decided to remove from the tables any timeout smaller than a
 * second, as it looked completly overkill...
 */

/* Timeouts in second */
struct max63xx_timeout {
	u8 wdset;
	u8 tdelay;
	u8 twd;
};

static struct max63xx_timeout max6369_table[] = {
	{ 5,  1,  1 },
	{ 6, 10, 10 },
	{ 7, 60, 60 },
	{ },
};

static struct max63xx_timeout max6371_table[] = {
	{ 6, 60,  3 },
	{ 7, 60, 60 },
	{ },
};

static struct max63xx_timeout max6373_table[] = {
	{ 2, 60,  1 },
	{ 5,  0,  1 },
	{ 1,  3,  3 },
	{ 7, 60, 10 },
	{ 6,  0, 10 },
	{ },
};

static struct max63xx_timeout *current_timeout;

static struct max63xx_timeout *
max63xx_select_timeout(struct max63xx_timeout *table, int value)
{
	while (table->twd) {
		if (value <= table->twd) {
			if (nodelay && table->tdelay == 0)
				return table;

			if (!nodelay)
				return table;
		}

		table++;
	}

	return NULL;
}

static int max63xx_wdt_ping(struct watchdog_device *wdd)
{
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);

	__raw_writeb(val | MAX6369_WDI, wdt_base);
	__raw_writeb(val & ~MAX6369_WDI, wdt_base);

	spin_unlock(&io_lock);
	return 0;
}

static int max63xx_wdt_start(struct watchdog_device *wdd)
{
	struct max63xx_timeout *entry = watchdog_get_drvdata(wdd);
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);
	val &= ~MAX6369_WDSET;
	val |= entry->wdset;
	__raw_writeb(val, wdt_base);

	spin_unlock(&io_lock);

	/* check for a edge triggered startup */
	if (entry->tdelay == 0)
		max63xx_wdt_ping(wdd);
	return 0;
}

static int max63xx_wdt_stop(struct watchdog_device *wdd)
{
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);
	val &= ~MAX6369_WDSET;
	val |= 3;
	__raw_writeb(val, wdt_base);

	spin_unlock(&io_lock);
	return 0;
}

static const struct watchdog_info max63xx_wdt_info = {
	.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "max63xx Watchdog",
};

static const struct watchdog_ops max63xx_wdt_ops = {
	.owner = THIS_MODULE,
	.start = max63xx_wdt_start,
	.stop = max63xx_wdt_stop,
	.ping = max63xx_wdt_ping,
};

static struct watchdog_device max63xx_wdt_dev = {
	.info = &max63xx_wdt_info,
	.ops = &max63xx_wdt_ops,
};

static int max63xx_wdt_probe(struct platform_device *pdev)
{
	struct resource	*wdt_mem;
	struct max63xx_timeout *table;

	table = (struct max63xx_timeout *)pdev->id_entry->driver_data;

	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
		heartbeat = DEFAULT_HEARTBEAT;

	dev_info(&pdev->dev, "requesting %ds heartbeat\n", heartbeat);
	current_timeout = max63xx_select_timeout(table, heartbeat);

	if (!current_timeout) {
		dev_err(&pdev->dev, "unable to satisfy heartbeat request\n");
		return -EINVAL;
	}

	dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay\n",
		 current_timeout->twd, current_timeout->tdelay);

	heartbeat = current_timeout->twd;

	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	wdt_base = devm_ioremap_resource(&pdev->dev, wdt_mem);
	if (IS_ERR(wdt_base))
		return PTR_ERR(wdt_base);

	max63xx_wdt_dev.timeout = heartbeat;
	watchdog_set_nowayout(&max63xx_wdt_dev, nowayout);
	watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout);

	return watchdog_register_device(&max63xx_wdt_dev);
}

static int max63xx_wdt_remove(struct platform_device *pdev)
{
	watchdog_unregister_device(&max63xx_wdt_dev);
	return 0;
}

static struct platform_device_id max63xx_id_table[] = {
	{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
	{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
	{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
	{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
	{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
	{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
	{ },
};
MODULE_DEVICE_TABLE(platform, max63xx_id_table);

static struct platform_driver max63xx_wdt_driver = {
	.probe		= max63xx_wdt_probe,
	.remove		= max63xx_wdt_remove,
	.id_table	= max63xx_id_table,
	.driver		= {
		.name	= "max63xx_wdt",
	},
};

module_platform_driver(max63xx_wdt_driver);

MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
MODULE_DESCRIPTION("max63xx Watchdog Driver");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
		 "Watchdog heartbeat period in seconds from 1 to "
		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
		 __MODULE_STRING(DEFAULT_HEARTBEAT));

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

module_param(nodelay, int, 0);
MODULE_PARM_DESC(nodelay,
		 "Force selection of a timeout setting without initial delay "
		 "(max6373/74 only, default=0)");

MODULE_LICENSE("GPL");
Commit	Line	Data
	1	/*
	2	* drivers/char/watchdog/max63xx_wdt.c
	3	*
	4	* Driver for max63{69,70,71,72,73,74} watchdog timers
	5	*
	6	* Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
	7	*
	8	* This file is licensed under the terms of the GNU General Public
	9	* License version 2. This program is licensed "as is" without any
	10	* warranty of any kind, whether express or implied.
	11	*
	12	* This driver assumes the watchdog pins are memory mapped (as it is
	13	* the case for the Arcom Zeus). Should it be connected over GPIOs or
	14	* another interface, some abstraction will have to be introduced.
	15	*/
	16
	17	#include <linux/err.h>
	18	#include <linux/module.h>
	19	#include <linux/moduleparam.h>
	20	#include <linux/types.h>
	21	#include <linux/kernel.h>
	22	#include <linux/watchdog.h>
	23	#include <linux/bitops.h>
	24	#include <linux/platform_device.h>
	25	#include <linux/spinlock.h>
	26	#include <linux/io.h>
	27	#include <linux/slab.h>
	28
	29	#define DEFAULT_HEARTBEAT 60
	30	#define MAX_HEARTBEAT 60
	31
	32	static unsigned int heartbeat = DEFAULT_HEARTBEAT;
	33	static bool nowayout = WATCHDOG_NOWAYOUT;
	34
	35	/*
	36	* Memory mapping: a single byte, 3 first lower bits to select bit 3
	37	* to ping the watchdog.
	38	*/
	39	#define MAX6369_WDSET (7 << 0)
	40	#define MAX6369_WDI (1 << 3)
	41
	42	static DEFINE_SPINLOCK(io_lock);
	43
	44	static int nodelay;
	45	static void __iomem *wdt_base;
	46
	47	/*
	48	* The timeout values used are actually the absolute minimum the chip
	49	* offers. Typical values on my board are slightly over twice as long
	50	* (10s setting ends up with a 25s timeout), and can be up to 3 times
	51	* the nominal setting (according to the datasheet). So please take
	52	* these values with a grain of salt. Same goes for the initial delay
	53	* "feature". Only max6373/74 have a few settings without this initial
	54	* delay (selected with the "nodelay" parameter).
	55	*
	56	* I also decided to remove from the tables any timeout smaller than a
	57	* second, as it looked completly overkill...
	58	*/
	59
	60	/* Timeouts in second */
	61	struct max63xx_timeout {
	62	u8 wdset;
	63	u8 tdelay;
	64	u8 twd;
	65	};
	66
	67	static struct max63xx_timeout max6369_table[] = {
	68	{ 5, 1, 1 },
	69	{ 6, 10, 10 },
	70	{ 7, 60, 60 },
	71	{ },
	72	};
	73
	74	static struct max63xx_timeout max6371_table[] = {
	75	{ 6, 60, 3 },
	76	{ 7, 60, 60 },
	77	{ },
	78	};
	79
	80	static struct max63xx_timeout max6373_table[] = {
	81	{ 2, 60, 1 },
	82	{ 5, 0, 1 },
	83	{ 1, 3, 3 },
	84	{ 7, 60, 10 },
	85	{ 6, 0, 10 },
	86	{ },
	87	};
	88
	89	static struct max63xx_timeout *current_timeout;
	90
	91	static struct max63xx_timeout *
	92	max63xx_select_timeout(struct max63xx_timeout *table, int value)
	93	{
	94	while (table->twd) {
	95	if (value <= table->twd) {
	96	if (nodelay && table->tdelay == 0)
	97	return table;
	98
	99	if (!nodelay)
	100	return table;
	101	}
	102
	103	table++;
	104	}
	105
	106	return NULL;
	107	}
	108
	109	static int max63xx_wdt_ping(struct watchdog_device *wdd)
	110	{
	111	u8 val;
	112
	113	spin_lock(&io_lock);
	114
	115	val = __raw_readb(wdt_base);
	116
	117	__raw_writeb(val \| MAX6369_WDI, wdt_base);
	118	__raw_writeb(val & ~MAX6369_WDI, wdt_base);
	119
	120	spin_unlock(&io_lock);
	121	return 0;
	122	}
	123
	124	static int max63xx_wdt_start(struct watchdog_device *wdd)
	125	{
	126	struct max63xx_timeout *entry = watchdog_get_drvdata(wdd);
	127	u8 val;
	128
	129	spin_lock(&io_lock);
	130
	131	val = __raw_readb(wdt_base);
	132	val &= ~MAX6369_WDSET;
	133	val \|= entry->wdset;
	134	__raw_writeb(val, wdt_base);
	135
	136	spin_unlock(&io_lock);
	137
	138	/* check for a edge triggered startup */
	139	if (entry->tdelay == 0)
	140	max63xx_wdt_ping(wdd);
	141	return 0;
	142	}
	143
	144	static int max63xx_wdt_stop(struct watchdog_device *wdd)
	145	{
	146	u8 val;
	147
	148	spin_lock(&io_lock);
	149
	150	val = __raw_readb(wdt_base);
	151	val &= ~MAX6369_WDSET;
	152	val \|= 3;
	153	__raw_writeb(val, wdt_base);
	154
	155	spin_unlock(&io_lock);
	156	return 0;
	157	}
	158
	159	static const struct watchdog_info max63xx_wdt_info = {
	160	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	161	.identity = "max63xx Watchdog",
	162	};
	163
	164	static const struct watchdog_ops max63xx_wdt_ops = {
	165	.owner = THIS_MODULE,
	166	.start = max63xx_wdt_start,
	167	.stop = max63xx_wdt_stop,
	168	.ping = max63xx_wdt_ping,
	169	};
	170
	171	static struct watchdog_device max63xx_wdt_dev = {
	172	.info = &max63xx_wdt_info,
	173	.ops = &max63xx_wdt_ops,
	174	};
	175
	176	static int max63xx_wdt_probe(struct platform_device *pdev)
	177	{
	178	struct resource *wdt_mem;
	179	struct max63xx_timeout *table;
	180
	181	table = (struct max63xx_timeout *)pdev->id_entry->driver_data;
	182
	183	if (heartbeat < 1 \|\| heartbeat > MAX_HEARTBEAT)
	184	heartbeat = DEFAULT_HEARTBEAT;
	185
	186	dev_info(&pdev->dev, "requesting %ds heartbeat\n", heartbeat);
	187	current_timeout = max63xx_select_timeout(table, heartbeat);
	188
	189	if (!current_timeout) {
	190	dev_err(&pdev->dev, "unable to satisfy heartbeat request\n");
	191	return -EINVAL;
	192	}
	193
	194	dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay\n",
	195	current_timeout->twd, current_timeout->tdelay);
	196
	197	heartbeat = current_timeout->twd;
	198
	199	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	200	wdt_base = devm_ioremap_resource(&pdev->dev, wdt_mem);
	201	if (IS_ERR(wdt_base))
	202	return PTR_ERR(wdt_base);
	203
	204	max63xx_wdt_dev.timeout = heartbeat;
	205	watchdog_set_nowayout(&max63xx_wdt_dev, nowayout);
	206	watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout);
	207
	208	return watchdog_register_device(&max63xx_wdt_dev);
	209	}
	210
	211	static int max63xx_wdt_remove(struct platform_device *pdev)
	212	{
	213	watchdog_unregister_device(&max63xx_wdt_dev);
	214	return 0;
	215	}
	216
	217	static struct platform_device_id max63xx_id_table[] = {
	218	{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
	219	{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
	220	{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
	221	{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
	222	{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
	223	{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
	224	{ },
	225	};
	226	MODULE_DEVICE_TABLE(platform, max63xx_id_table);
	227
	228	static struct platform_driver max63xx_wdt_driver = {
	229	.probe = max63xx_wdt_probe,
	230	.remove = max63xx_wdt_remove,
	231	.id_table = max63xx_id_table,
	232	.driver = {
	233	.name = "max63xx_wdt",
	234	},
	235	};
	236
	237	module_platform_driver(max63xx_wdt_driver);
	238
	239	MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
	240	MODULE_DESCRIPTION("max63xx Watchdog Driver");
	241
	242	module_param(heartbeat, int, 0);
	243	MODULE_PARM_DESC(heartbeat,
	244	"Watchdog heartbeat period in seconds from 1 to "
	245	__MODULE_STRING(MAX_HEARTBEAT) ", default "
	246	__MODULE_STRING(DEFAULT_HEARTBEAT));
	247
	248	module_param(nowayout, bool, 0);
	249	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	250	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	251
	252	module_param(nodelay, int, 0);
	253	MODULE_PARM_DESC(nodelay,
	254	"Force selection of a timeout setting without initial delay "
	255	"(max6373/74 only, default=0)");
	256
	257	MODULE_LICENSE("GPL");