[linux-2.6-block.git] / drivers / watchdog / davinci_wdt.c

/*
 * drivers/char/watchdog/davinci_wdt.c
 *
 * Watchdog driver for DaVinci DM644x/DM646x processors
 *
 * Copyright (C) 2006 Texas Instruments.
 *
 * 2007 (c) MontaVista Software, Inc. 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.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/err.h>

#define MODULE_NAME "DAVINCI-WDT: "

#define DEFAULT_HEARTBEAT 60
#define MAX_HEARTBEAT     600	/* really the max margin is 264/27MHz*/

/* Timer register set definition */
#define PID12	(0x0)
#define EMUMGT	(0x4)
#define TIM12	(0x10)
#define TIM34	(0x14)
#define PRD12	(0x18)
#define PRD34	(0x1C)
#define TCR	(0x20)
#define TGCR	(0x24)
#define WDTCR	(0x28)

/* TCR bit definitions */
#define ENAMODE12_DISABLED	(0 << 6)
#define ENAMODE12_ONESHOT	(1 << 6)
#define ENAMODE12_PERIODIC	(2 << 6)

/* TGCR bit definitions */
#define TIM12RS_UNRESET		(1 << 0)
#define TIM34RS_UNRESET		(1 << 1)
#define TIMMODE_64BIT_WDOG      (2 << 2)

/* WDTCR bit definitions */
#define WDEN			(1 << 14)
#define WDFLAG			(1 << 15)
#define WDKEY_SEQ0		(0xa5c6 << 16)
#define WDKEY_SEQ1		(0xda7e << 16)

static int heartbeat = DEFAULT_HEARTBEAT;

static DEFINE_SPINLOCK(io_lock);
static unsigned long wdt_status;
#define WDT_IN_USE        0
#define WDT_OK_TO_CLOSE   1
#define WDT_REGION_INITED 2
#define WDT_DEVICE_INITED 3

static void __iomem	*wdt_base;
struct clk		*wdt_clk;

static void wdt_service(void)
{
	spin_lock(&io_lock);

	/* put watchdog in service state */
	iowrite32(WDKEY_SEQ0, wdt_base + WDTCR);
	/* put watchdog in active state */
	iowrite32(WDKEY_SEQ1, wdt_base + WDTCR);

	spin_unlock(&io_lock);
}

static void wdt_enable(void)
{
	u32 tgcr;
	u32 timer_margin;
	unsigned long wdt_freq;

	wdt_freq = clk_get_rate(wdt_clk);

	spin_lock(&io_lock);

	/* disable, internal clock source */
	iowrite32(0, wdt_base + TCR);
	/* reset timer, set mode to 64-bit watchdog, and unreset */
	iowrite32(0, wdt_base + TGCR);
	tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
	iowrite32(tgcr, wdt_base + TGCR);
	/* clear counter regs */
	iowrite32(0, wdt_base + TIM12);
	iowrite32(0, wdt_base + TIM34);
	/* set timeout period */
	timer_margin = (((u64)heartbeat * wdt_freq) & 0xffffffff);
	iowrite32(timer_margin, wdt_base + PRD12);
	timer_margin = (((u64)heartbeat * wdt_freq) >> 32);
	iowrite32(timer_margin, wdt_base + PRD34);
	/* enable run continuously */
	iowrite32(ENAMODE12_PERIODIC, wdt_base + TCR);
	/* Once the WDT is in pre-active state write to
	 * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
	 * write protected (except for the WDKEY field)
	 */
	/* put watchdog in pre-active state */
	iowrite32(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
	/* put watchdog in active state */
	iowrite32(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR);

	spin_unlock(&io_lock);
}

static int davinci_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
		return -EBUSY;

	wdt_enable();

	return nonseekable_open(inode, file);
}

static ssize_t
davinci_wdt_write(struct file *file, const char *data, size_t len,
		  loff_t *ppos)
{
	if (len)
		wdt_service();

	return len;
}

static const struct watchdog_info ident = {
	.options = WDIOF_KEEPALIVEPING,
	.identity = "DaVinci Watchdog",
};

static long davinci_wdt_ioctl(struct file *file,
					unsigned int cmd, unsigned long arg)
{
	int ret = -ENOTTY;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info *)arg, &ident,
				   sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_KEEPALIVE:
		wdt_service();
		ret = 0;
		break;

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, (int *)arg);
		break;
	}
	return ret;
}

static int davinci_wdt_release(struct inode *inode, struct file *file)
{
	wdt_service();
	clear_bit(WDT_IN_USE, &wdt_status);

	return 0;
}

static const struct file_operations davinci_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = davinci_wdt_write,
	.unlocked_ioctl = davinci_wdt_ioctl,
	.open = davinci_wdt_open,
	.release = davinci_wdt_release,
};

static struct miscdevice davinci_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &davinci_wdt_fops,
};

static int davinci_wdt_probe(struct platform_device *pdev)
{
	int ret = 0;
	struct device *dev = &pdev->dev;
	struct resource  *wdt_mem;

	wdt_clk = devm_clk_get(dev, NULL);
	if (WARN_ON(IS_ERR(wdt_clk)))
		return PTR_ERR(wdt_clk);

	clk_prepare_enable(wdt_clk);

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

	dev_info(dev, "heartbeat %d sec\n", heartbeat);

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

	ret = misc_register(&davinci_wdt_miscdev);
	if (ret < 0) {
		dev_err(dev, "cannot register misc device\n");
	} else {
		set_bit(WDT_DEVICE_INITED, &wdt_status);
	}

	return ret;
}

static int davinci_wdt_remove(struct platform_device *pdev)
{
	misc_deregister(&davinci_wdt_miscdev);
	clk_disable_unprepare(wdt_clk);

	return 0;
}

static const struct of_device_id davinci_wdt_of_match[] = {
	{ .compatible = "ti,davinci-wdt", },
	{},
};
MODULE_DEVICE_TABLE(of, davinci_wdt_of_match);

static struct platform_driver platform_wdt_driver = {
	.driver = {
		.name = "watchdog",
		.owner	= THIS_MODULE,
		.of_match_table = davinci_wdt_of_match,
	},
	.probe = davinci_wdt_probe,
	.remove = davinci_wdt_remove,
};

module_platform_driver(platform_wdt_driver);

MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("DaVinci 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_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:watchdog");
Commit	Line	Data
7d831bf5 VB	1	/*
	2	* drivers/char/watchdog/davinci_wdt.c
	3	*
	4	* Watchdog driver for DaVinci DM644x/DM646x processors
	5	*
	6	* Copyright (C) 2006 Texas Instruments.
	7	*
	8	* 2007 (c) MontaVista Software, Inc. This file is licensed under
	9	* the terms of the GNU General Public License version 2. This program
	10	* is licensed "as is" without any warranty of any kind, whether express
	11	* or implied.
	12	*/
	13
	14	#include <linux/module.h>
	15	#include <linux/moduleparam.h>
	16	#include <linux/types.h>
	17	#include <linux/kernel.h>
	18	#include <linux/fs.h>
	19	#include <linux/miscdevice.h>
	20	#include <linux/watchdog.h>
	21	#include <linux/init.h>
	22	#include <linux/bitops.h>
	23	#include <linux/platform_device.h>
	24	#include <linux/spinlock.h>
f78b0a8f AC	25	#include <linux/uaccess.h>
f78b0a8f AC	26	#include <linux/io.h>
371d3525	27	#include <linux/device.h>
9fd868f4	28	#include <linux/clk.h>
5a0e3ad6	29	#include <linux/slab.h>
6330c707	30	#include <linux/err.h>
7d831bf5 VB	31
	32	#define MODULE_NAME "DAVINCI-WDT: "
	33
	34	#define DEFAULT_HEARTBEAT 60
	35	#define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/
	36
	37	/* Timer register set definition */
	38	#define PID12 (0x0)
	39	#define EMUMGT (0x4)
	40	#define TIM12 (0x10)
	41	#define TIM34 (0x14)
	42	#define PRD12 (0x18)
	43	#define PRD34 (0x1C)
	44	#define TCR (0x20)
	45	#define TGCR (0x24)
	46	#define WDTCR (0x28)
	47
	48	/* TCR bit definitions */
	49	#define ENAMODE12_DISABLED (0 << 6)
	50	#define ENAMODE12_ONESHOT (1 << 6)
	51	#define ENAMODE12_PERIODIC (2 << 6)
	52
	53	/* TGCR bit definitions */
	54	#define TIM12RS_UNRESET (1 << 0)
	55	#define TIM34RS_UNRESET (1 << 1)
	56	#define TIMMODE_64BIT_WDOG (2 << 2)
	57
	58	/* WDTCR bit definitions */
	59	#define WDEN (1 << 14)
	60	#define WDFLAG (1 << 15)
	61	#define WDKEY_SEQ0 (0xa5c6 << 16)
	62	#define WDKEY_SEQ1 (0xda7e << 16)
	63
	64	static int heartbeat = DEFAULT_HEARTBEAT;
	65
c7dfd0cc	66	static DEFINE_SPINLOCK(io_lock);
7d831bf5 VB	67	static unsigned long wdt_status;
	68	#define WDT_IN_USE 0
	69	#define WDT_OK_TO_CLOSE 1
	70	#define WDT_REGION_INITED 2
	71	#define WDT_DEVICE_INITED 3
	72
7d831bf5	73	static void __iomem *wdt_base;
9fd868f4	74	struct clk *wdt_clk;
7d831bf5 VB	75
	76	static void wdt_service(void)
	77	{
	78	spin_lock(&io_lock);
	79
	80	/* put watchdog in service state */
371d3525	81	iowrite32(WDKEY_SEQ0, wdt_base + WDTCR);
7d831bf5	82	/* put watchdog in active state */
371d3525	83	iowrite32(WDKEY_SEQ1, wdt_base + WDTCR);
7d831bf5 VB	84
	85	spin_unlock(&io_lock);
	86	}
	87
	88	static void wdt_enable(void)
	89	{
	90	u32 tgcr;
	91	u32 timer_margin;
9fd868f4 KH	92	unsigned long wdt_freq;
	93
	94	wdt_freq = clk_get_rate(wdt_clk);
7d831bf5 VB	95
	96	spin_lock(&io_lock);
	97
	98	/* disable, internal clock source */
371d3525	99	iowrite32(0, wdt_base + TCR);
7d831bf5	100	/* reset timer, set mode to 64-bit watchdog, and unreset */
371d3525	101	iowrite32(0, wdt_base + TGCR);
7d831bf5	102	tgcr = TIMMODE_64BIT_WDOG \| TIM12RS_UNRESET \| TIM34RS_UNRESET;
371d3525	103	iowrite32(tgcr, wdt_base + TGCR);
7d831bf5	104	/* clear counter regs */
371d3525 KH	105	iowrite32(0, wdt_base + TIM12);
371d3525 KH	106	iowrite32(0, wdt_base + TIM34);
7d831bf5	107	/* set timeout period */
9fd868f4	108	timer_margin = (((u64)heartbeat * wdt_freq) & 0xffffffff);
371d3525	109	iowrite32(timer_margin, wdt_base + PRD12);
9fd868f4	110	timer_margin = (((u64)heartbeat * wdt_freq) >> 32);
371d3525	111	iowrite32(timer_margin, wdt_base + PRD34);
7d831bf5	112	/* enable run continuously */
371d3525	113	iowrite32(ENAMODE12_PERIODIC, wdt_base + TCR);
7d831bf5 VB	114	/* Once the WDT is in pre-active state write to
	115	* TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
	116	* write protected (except for the WDKEY field)
	117	*/
	118	/* put watchdog in pre-active state */
371d3525	119	iowrite32(WDKEY_SEQ0 \| WDEN, wdt_base + WDTCR);
7d831bf5	120	/* put watchdog in active state */
371d3525	121	iowrite32(WDKEY_SEQ1 \| WDEN, wdt_base + WDTCR);
7d831bf5 VB	122
	123	spin_unlock(&io_lock);
	124	}
	125
	126	static int davinci_wdt_open(struct inode inode, struct file file)
	127	{
	128	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	129	return -EBUSY;
	130
	131	wdt_enable();
	132
	133	return nonseekable_open(inode, file);
	134	}
	135
	136	static ssize_t
	137	davinci_wdt_write(struct file file, const char data, size_t len,
	138	loff_t *ppos)
	139	{
7d831bf5 VB	140	if (len)
	141	wdt_service();
	142
	143	return len;
	144	}
	145
42747d71	146	static const struct watchdog_info ident = {
f1a08cc9	147	.options = WDIOF_KEEPALIVEPING,
7d831bf5 VB	148	.identity = "DaVinci Watchdog",
	149	};
	150
f78b0a8f AC	151	static long davinci_wdt_ioctl(struct file *file,
f78b0a8f AC	152	unsigned int cmd, unsigned long arg)
7d831bf5 VB	153	{
	154	int ret = -ENOTTY;
	155
	156	switch (cmd) {
	157	case WDIOC_GETSUPPORT:
	158	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	159	sizeof(ident)) ? -EFAULT : 0;
	160	break;
	161
	162	case WDIOC_GETSTATUS:
f1a08cc9	163	case WDIOC_GETBOOTSTATUS:
7d831bf5 VB	164	ret = put_user(0, (int *)arg);
	165	break;
	166
7d831bf5 VB	167	case WDIOC_KEEPALIVE:
	168	wdt_service();
	169	ret = 0;
	170	break;
0c06090c WVS	171
	172	case WDIOC_GETTIMEOUT:
	173	ret = put_user(heartbeat, (int *)arg);
	174	break;
7d831bf5 VB	175	}
	176	return ret;
	177	}
	178
	179	static int davinci_wdt_release(struct inode inode, struct file file)
	180	{
	181	wdt_service();
	182	clear_bit(WDT_IN_USE, &wdt_status);
	183
	184	return 0;
	185	}
	186
	187	static const struct file_operations davinci_wdt_fops = {
	188	.owner = THIS_MODULE,
	189	.llseek = no_llseek,
	190	.write = davinci_wdt_write,
f78b0a8f	191	.unlocked_ioctl = davinci_wdt_ioctl,
7d831bf5 VB	192	.open = davinci_wdt_open,
	193	.release = davinci_wdt_release,
	194	};
	195
	196	static struct miscdevice davinci_wdt_miscdev = {
	197	.minor = WATCHDOG_MINOR,
	198	.name = "watchdog",
	199	.fops = &davinci_wdt_fops,
	200	};
	201
2d991a16	202	static int davinci_wdt_probe(struct platform_device *pdev)
7d831bf5	203	{
e20880e6	204	int ret = 0;
371d3525	205	struct device *dev = &pdev->dev;
e20880e6	206	struct resource *wdt_mem;
7d831bf5	207
362ce5ae	208	wdt_clk = devm_clk_get(dev, NULL);
9fd868f4 KH	209	if (WARN_ON(IS_ERR(wdt_clk)))
	210	return PTR_ERR(wdt_clk);
	211
5235f57a	212	clk_prepare_enable(wdt_clk);
9fd868f4	213
7d831bf5 VB	214	if (heartbeat < 1 \|\| heartbeat > MAX_HEARTBEAT)
	215	heartbeat = DEFAULT_HEARTBEAT;
	216
371d3525	217	dev_info(dev, "heartbeat %d sec\n", heartbeat);
7d831bf5	218
f712eacf	219	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
6330c707 SK	220	wdt_base = devm_ioremap_resource(dev, wdt_mem);
	221	if (IS_ERR(wdt_base))
	222	return PTR_ERR(wdt_base);
7d831bf5 VB	223
	224	ret = misc_register(&davinci_wdt_miscdev);
	225	if (ret < 0) {
371d3525	226	dev_err(dev, "cannot register misc device\n");
7d831bf5 VB	227	} else {
	228	set_bit(WDT_DEVICE_INITED, &wdt_status);
	229	}
	230
	231	return ret;
	232	}
	233
4b12b896	234	static int davinci_wdt_remove(struct platform_device *pdev)
7d831bf5 VB	235	{
7d831bf5 VB	236	misc_deregister(&davinci_wdt_miscdev);
5235f57a	237	clk_disable_unprepare(wdt_clk);
9fd868f4	238
7d831bf5 VB	239	return 0;
	240	}
	241
902e2e7d MK	242	static const struct of_device_id davinci_wdt_of_match[] = {
	243	{ .compatible = "ti,davinci-wdt", },
	244	{},
	245	};
	246	MODULE_DEVICE_TABLE(of, davinci_wdt_of_match);
	247
7d831bf5 VB	248	static struct platform_driver platform_wdt_driver = {
	249	.driver = {
	250	.name = "watchdog",
f37d193c	251	.owner = THIS_MODULE,
902e2e7d	252	.of_match_table = davinci_wdt_of_match,
7d831bf5 VB	253	},
7d831bf5 VB	254	.probe = davinci_wdt_probe,
82268714	255	.remove = davinci_wdt_remove,
7d831bf5 VB	256	};
7d831bf5 VB	257
b8ec6118	258	module_platform_driver(platform_wdt_driver);
7d831bf5 VB	259
	260	MODULE_AUTHOR("Texas Instruments");
	261	MODULE_DESCRIPTION("DaVinci Watchdog Driver");
	262
	263	module_param(heartbeat, int, 0);
	264	MODULE_PARM_DESC(heartbeat,
	265	"Watchdog heartbeat period in seconds from 1 to "
	266	__MODULE_STRING(MAX_HEARTBEAT) ", default "
	267	__MODULE_STRING(DEFAULT_HEARTBEAT));
	268
	269	MODULE_LICENSE("GPL");
	270	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
f37d193c	271	MODULE_ALIAS("platform:watchdog");