[linux-block.git] / drivers / watchdog / coh901327_wdt.c

/*
 * coh901327_wdt.c
 *
 * Copyright (C) 2008-2009 ST-Ericsson AB
 * License terms: GNU General Public License (GPL) version 2
 * Watchdog driver for the ST-Ericsson AB COH 901 327 IP core
 * Author: Linus Walleij <linus.walleij@stericsson.com>
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>

#define DRV_NAME "WDOG COH 901 327"

/*
 * COH 901 327 register definitions
 */

/* WDOG_FEED Register 32bit (-/W) */
#define U300_WDOG_FR							0x00
#define U300_WDOG_FR_FEED_RESTART_TIMER					0xFEEDU
/* WDOG_TIMEOUT Register 32bit (R/W) */
#define U300_WDOG_TR							0x04
#define U300_WDOG_TR_TIMEOUT_MASK					0x7FFFU
/* WDOG_DISABLE1 Register 32bit (-/W) */
#define U300_WDOG_D1R							0x08
#define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER				0x2BADU
/* WDOG_DISABLE2 Register 32bit (R/W) */
#define U300_WDOG_D2R							0x0C
#define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER				0xCAFEU
#define U300_WDOG_D2R_DISABLE_STATUS_DISABLED				0xDABEU
#define U300_WDOG_D2R_DISABLE_STATUS_ENABLED				0x0000U
/* WDOG_STATUS Register 32bit (R/W) */
#define U300_WDOG_SR							0x10
#define U300_WDOG_SR_STATUS_TIMED_OUT					0xCFE8U
#define U300_WDOG_SR_STATUS_NORMAL					0x0000U
#define U300_WDOG_SR_RESET_STATUS_RESET					0xE8B4U
/* WDOG_COUNT Register 32bit (R/-) */
#define U300_WDOG_CR							0x14
#define U300_WDOG_CR_VALID_IND						0x8000U
#define U300_WDOG_CR_VALID_STABLE					0x0000U
#define U300_WDOG_CR_COUNT_VALUE_MASK					0x7FFFU
/* WDOG_JTAGOVR Register 32bit (R/W) */
#define U300_WDOG_JOR							0x18
#define U300_WDOG_JOR_JTAG_MODE_IND					0x0002U
#define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE				0x0001U
/* WDOG_RESTART Register 32bit (-/W) */
#define U300_WDOG_RR							0x1C
#define U300_WDOG_RR_RESTART_VALUE_RESUME				0xACEDU
/* WDOG_IRQ_EVENT Register 32bit (R/W) */
#define U300_WDOG_IER							0x20
#define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND				0x0001U
#define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE				0x0001U
/* WDOG_IRQ_MASK Register 32bit (R/W) */
#define U300_WDOG_IMR							0x24
#define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE				0x0001U
/* WDOG_IRQ_FORCE Register 32bit (R/W) */
#define U300_WDOG_IFR							0x28
#define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE			0x0001U

/* Default timeout in seconds = 1 minute */
static int margin = 60;
static resource_size_t phybase;
static resource_size_t physize;
static int irq;
static void __iomem *virtbase;
static struct device *parent;

/*
 * The watchdog block is of course always clocked, the
 * clk_enable()/clk_disable() calls are mainly for performing reference
 * counting higher up in the clock hierarchy.
 */
static struct clk *clk;

/*
 * Enabling and disabling functions.
 */
static void coh901327_enable(u16 timeout)
{
	u16 val;
	unsigned long freq;
	unsigned long delay_ns;

	clk_enable(clk);
	/* Restart timer if it is disabled */
	val = readw(virtbase + U300_WDOG_D2R);
	if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
		writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
		       virtbase + U300_WDOG_RR);
	/* Acknowledge any pending interrupt so it doesn't just fire off */
	writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
	       virtbase + U300_WDOG_IER);
	/*
	 * The interrupt is cleared in the 32 kHz clock domain.
	 * Wait 3 32 kHz cycles for it to take effect
	 */
	freq = clk_get_rate(clk);
	delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */
	delay_ns = 3 * delay_ns; /* Wait 3 cycles */
	ndelay(delay_ns);
	/* Enable the watchdog interrupt */
	writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
	/* Activate the watchdog timer */
	writew(timeout, virtbase + U300_WDOG_TR);
	/* Start the watchdog timer */
	writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
	/*
	 * Extra read so that this change propagate in the watchdog.
	 */
	(void) readw(virtbase + U300_WDOG_CR);
	val = readw(virtbase + U300_WDOG_D2R);
	clk_disable(clk);
	if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
		dev_err(parent,
			"%s(): watchdog not enabled! D2R value %04x\n",
			__func__, val);
}

static void coh901327_disable(void)
{
	u16 val;

	clk_enable(clk);
	/* Disable the watchdog interrupt if it is active */
	writew(0x0000U, virtbase + U300_WDOG_IMR);
	/* If the watchdog is currently enabled, attempt to disable it */
	val = readw(virtbase + U300_WDOG_D2R);
	if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
		writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
		       virtbase + U300_WDOG_D1R);
		writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
		       virtbase + U300_WDOG_D2R);
		/* Write this twice (else problems occur) */
		writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
		       virtbase + U300_WDOG_D2R);
	}
	val = readw(virtbase + U300_WDOG_D2R);
	clk_disable(clk);
	if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
		dev_err(parent,
			"%s(): watchdog not disabled! D2R value %04x\n",
			__func__, val);
}

static int coh901327_start(struct watchdog_device *wdt_dev)
{
	coh901327_enable(margin * 100);
	return 0;
}

static int coh901327_stop(struct watchdog_device *wdt_dev)
{
	coh901327_disable();
	return 0;
}

static int coh901327_ping(struct watchdog_device *wdd)
{
	clk_enable(clk);
	/* Feed the watchdog */
	writew(U300_WDOG_FR_FEED_RESTART_TIMER,
	       virtbase + U300_WDOG_FR);
	clk_disable(clk);
	return 0;
}

static int coh901327_settimeout(struct watchdog_device *wdt_dev,
				unsigned int time)
{
	margin = time;
	clk_enable(clk);
	/* Set new timeout value */
	writew(margin * 100, virtbase + U300_WDOG_TR);
	/* Feed the dog */
	writew(U300_WDOG_FR_FEED_RESTART_TIMER,
	       virtbase + U300_WDOG_FR);
	clk_disable(clk);
	return 0;
}

static unsigned int coh901327_gettimeleft(struct watchdog_device *wdt_dev)
{
	u16 val;

	clk_enable(clk);
	/* Read repeatedly until the value is stable! */
	val = readw(virtbase + U300_WDOG_CR);
	while (val & U300_WDOG_CR_VALID_IND)
		val = readw(virtbase + U300_WDOG_CR);
	val &= U300_WDOG_CR_COUNT_VALUE_MASK;
	clk_disable(clk);
	if (val != 0)
		val /= 100;

	return val;
}

/*
 * This interrupt occurs 10 ms before the watchdog WILL bark.
 */
static irqreturn_t coh901327_interrupt(int irq, void *data)
{
	u16 val;

	/*
	 * Ack IRQ? If this occurs we're FUBAR anyway, so
	 * just acknowledge, disable the interrupt and await the imminent end.
	 * If you at some point need a host of callbacks to be called
	 * when the system is about to watchdog-reset, add them here!
	 *
	 * NOTE: on future versions of this IP-block, it will be possible
	 * to prevent a watchdog reset by feeding the watchdog at this
	 * point.
	 */
	clk_enable(clk);
	val = readw(virtbase + U300_WDOG_IER);
	if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
		writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
		       virtbase + U300_WDOG_IER);
	writew(0x0000U, virtbase + U300_WDOG_IMR);
	clk_disable(clk);
	dev_crit(parent, "watchdog is barking!\n");
	return IRQ_HANDLED;
}

static const struct watchdog_info coh901327_ident = {
	.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
	.identity = DRV_NAME,
};

static struct watchdog_ops coh901327_ops = {
	.owner = THIS_MODULE,
	.start = coh901327_start,
	.stop = coh901327_stop,
	.ping = coh901327_ping,
	.set_timeout = coh901327_settimeout,
	.get_timeleft = coh901327_gettimeleft,
};

static struct watchdog_device coh901327_wdt = {
	.info = &coh901327_ident,
	.ops = &coh901327_ops,
	/*
	 * Max margin is 327 since the 10ms
	 * timeout register is max
	 * 0x7FFF = 327670ms ~= 327s.
	 */
	.min_timeout = 0,
	.max_timeout = 327,
};

static int __exit coh901327_remove(struct platform_device *pdev)
{
	watchdog_unregister_device(&coh901327_wdt);
	coh901327_disable();
	free_irq(irq, pdev);
	clk_put(clk);
	iounmap(virtbase);
	release_mem_region(phybase, physize);
	return 0;
}

static int __init coh901327_probe(struct platform_device *pdev)
{
	int ret;
	u16 val;
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENOENT;

	parent = &pdev->dev;
	physize = resource_size(res);
	phybase = res->start;

	if (request_mem_region(phybase, physize, DRV_NAME) == NULL) {
		ret = -EBUSY;
		goto out;
	}

	virtbase = ioremap(phybase, physize);
	if (!virtbase) {
		ret = -ENOMEM;
		goto out_no_remap;
	}

	clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		ret = PTR_ERR(clk);
		dev_err(&pdev->dev, "could not get clock\n");
		goto out_no_clk;
	}
	ret = clk_enable(clk);
	if (ret) {
		dev_err(&pdev->dev, "could not enable clock\n");
		goto out_no_clk_enable;
	}

	val = readw(virtbase + U300_WDOG_SR);
	switch (val) {
	case U300_WDOG_SR_STATUS_TIMED_OUT:
		dev_info(&pdev->dev,
			"watchdog timed out since last chip reset!\n");
		coh901327_wdt.bootstatus |= WDIOF_CARDRESET;
		/* Status will be cleared below */
		break;
	case U300_WDOG_SR_STATUS_NORMAL:
		dev_info(&pdev->dev,
			"in normal status, no timeouts have occurred.\n");
		break;
	default:
		dev_info(&pdev->dev,
			"contains an illegal status code (%08x)\n", val);
		break;
	}

	val = readw(virtbase + U300_WDOG_D2R);
	switch (val) {
	case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
		dev_info(&pdev->dev, "currently disabled.\n");
		break;
	case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
		dev_info(&pdev->dev,
			 "currently enabled! (disabling it now)\n");
		coh901327_disable();
		break;
	default:
		dev_err(&pdev->dev,
			"contains an illegal enable/disable code (%08x)\n",
			val);
		break;
	}

	/* Reset the watchdog */
	writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);

	irq = platform_get_irq(pdev, 0);
	if (request_irq(irq, coh901327_interrupt, 0,
			DRV_NAME " Bark", pdev)) {
		ret = -EIO;
		goto out_no_irq;
	}

	clk_disable(clk);

	ret = watchdog_register_device(&coh901327_wdt);
	if (ret == 0)
		dev_info(&pdev->dev,
			 "initialized. timer margin=%d sec\n", margin);
	else
		goto out_no_wdog;

	return 0;

out_no_wdog:
	free_irq(irq, pdev);
out_no_irq:
	clk_disable(clk);
out_no_clk_enable:
	clk_put(clk);
out_no_clk:
	iounmap(virtbase);
out_no_remap:
	release_mem_region(phybase, SZ_4K);
out:
	return ret;
}

#ifdef CONFIG_PM

static u16 wdogenablestore;
static u16 irqmaskstore;

static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
{
	irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
	wdogenablestore = readw(virtbase + U300_WDOG_D2R);
	/* If watchdog is on, disable it here and now */
	if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
		coh901327_disable();
	return 0;
}

static int coh901327_resume(struct platform_device *pdev)
{
	/* Restore the watchdog interrupt */
	writew(irqmaskstore, virtbase + U300_WDOG_IMR);
	if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
		/* Restart the watchdog timer */
		writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
		       virtbase + U300_WDOG_RR);
		writew(U300_WDOG_FR_FEED_RESTART_TIMER,
		       virtbase + U300_WDOG_FR);
	}
	return 0;
}
#else
#define coh901327_suspend NULL
#define coh901327_resume  NULL
#endif

/*
 * Mistreating the watchdog is the only way to perform a software reset of the
 * system on EMP platforms. So we implement this and export a symbol for it.
 */
void coh901327_watchdog_reset(void)
{
	/* Enable even if on JTAG too */
	writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
	       virtbase + U300_WDOG_JOR);
	/*
	 * Timeout = 5s, we have to wait for the watchdog reset to
	 * actually take place: the watchdog will be reloaded with the
	 * default value immediately, so we HAVE to reboot and get back
	 * into the kernel in 30s, or the device will reboot again!
	 * The boot loader will typically deactivate the watchdog, so we
	 * need time enough for the boot loader to get to the point of
	 * deactivating the watchdog before it is shut down by it.
	 *
	 * NOTE: on future versions of the watchdog, this restriction is
	 * gone: the watchdog will be reloaded with a default value (1 min)
	 * instead of last value, and you can conveniently set the watchdog
	 * timeout to 10ms (value = 1) without any problems.
	 */
	coh901327_enable(500);
	/* Return and await doom */
}

static struct platform_driver coh901327_driver = {
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "coh901327_wdog",
	},
	.remove		= __exit_p(coh901327_remove),
	.suspend	= coh901327_suspend,
	.resume		= coh901327_resume,
};

static int __init coh901327_init(void)
{
	return platform_driver_probe(&coh901327_driver, coh901327_probe);
}
module_init(coh901327_init);

static void __exit coh901327_exit(void)
{
	platform_driver_unregister(&coh901327_driver);
}
module_exit(coh901327_exit);

MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
MODULE_DESCRIPTION("COH 901 327 Watchdog");

module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");

MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:coh901327-watchdog");
Commit	Line	Data
01480701 LW	1	/*
	2	* coh901327_wdt.c
	3	*
	4	* Copyright (C) 2008-2009 ST-Ericsson AB
	5	* License terms: GNU General Public License (GPL) version 2
	6	* Watchdog driver for the ST-Ericsson AB COH 901 327 IP core
	7	* Author: Linus Walleij <linus.walleij@stericsson.com>
	8	*/
	9	#include <linux/module.h>
	10	#include <linux/types.h>
01480701 LW	11	#include <linux/watchdog.h>
	12	#include <linux/interrupt.h>
	13	#include <linux/pm.h>
	14	#include <linux/platform_device.h>
	15	#include <linux/io.h>
	16	#include <linux/bitops.h>
01480701	17	#include <linux/clk.h>
5973bee4	18	#include <linux/delay.h>
15b25701	19	#include <linux/err.h>
01480701 LW	20
	21	#define DRV_NAME "WDOG COH 901 327"
	22
	23	/*
	24	* COH 901 327 register definitions
	25	*/
	26
	27	/* WDOG_FEED Register 32bit (-/W) */
	28	#define U300_WDOG_FR 0x00
	29	#define U300_WDOG_FR_FEED_RESTART_TIMER 0xFEEDU
	30	/* WDOG_TIMEOUT Register 32bit (R/W) */
	31	#define U300_WDOG_TR 0x04
	32	#define U300_WDOG_TR_TIMEOUT_MASK 0x7FFFU
	33	/* WDOG_DISABLE1 Register 32bit (-/W) */
	34	#define U300_WDOG_D1R 0x08
	35	#define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER 0x2BADU
	36	/* WDOG_DISABLE2 Register 32bit (R/W) */
	37	#define U300_WDOG_D2R 0x0C
	38	#define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER 0xCAFEU
	39	#define U300_WDOG_D2R_DISABLE_STATUS_DISABLED 0xDABEU
	40	#define U300_WDOG_D2R_DISABLE_STATUS_ENABLED 0x0000U
	41	/* WDOG_STATUS Register 32bit (R/W) */
	42	#define U300_WDOG_SR 0x10
	43	#define U300_WDOG_SR_STATUS_TIMED_OUT 0xCFE8U
	44	#define U300_WDOG_SR_STATUS_NORMAL 0x0000U
	45	#define U300_WDOG_SR_RESET_STATUS_RESET 0xE8B4U
	46	/* WDOG_COUNT Register 32bit (R/-) */
	47	#define U300_WDOG_CR 0x14
	48	#define U300_WDOG_CR_VALID_IND 0x8000U
	49	#define U300_WDOG_CR_VALID_STABLE 0x0000U
	50	#define U300_WDOG_CR_COUNT_VALUE_MASK 0x7FFFU
	51	/* WDOG_JTAGOVR Register 32bit (R/W) */
	52	#define U300_WDOG_JOR 0x18
	53	#define U300_WDOG_JOR_JTAG_MODE_IND 0x0002U
	54	#define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE 0x0001U
	55	/* WDOG_RESTART Register 32bit (-/W) */
	56	#define U300_WDOG_RR 0x1C
	57	#define U300_WDOG_RR_RESTART_VALUE_RESUME 0xACEDU
	58	/* WDOG_IRQ_EVENT Register 32bit (R/W) */
	59	#define U300_WDOG_IER 0x20
	60	#define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND 0x0001U
	61	#define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE 0x0001U
	62	/* WDOG_IRQ_MASK Register 32bit (R/W) */
	63	#define U300_WDOG_IMR 0x24
	64	#define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE 0x0001U
	65	/* WDOG_IRQ_FORCE Register 32bit (R/W) */
	66	#define U300_WDOG_IFR 0x28
	67	#define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE 0x0001U
	68
	69	/* Default timeout in seconds = 1 minute */
	70	static int margin = 60;
	71	static resource_size_t phybase;
	72	static resource_size_t physize;
	73	static int irq;
	74	static void __iomem *virtbase;
01480701 LW	75	static struct device *parent;
	76
	77	/*
	78	* The watchdog block is of course always clocked, the
	79	* clk_enable()/clk_disable() calls are mainly for performing reference
	80	* counting higher up in the clock hierarchy.
	81	*/
	82	static struct clk *clk;
	83
	84	/*
	85	* Enabling and disabling functions.
	86	*/
	87	static void coh901327_enable(u16 timeout)
	88	{
	89	u16 val;
5973bee4 LW	90	unsigned long freq;
5973bee4 LW	91	unsigned long delay_ns;
01480701 LW	92
	93	clk_enable(clk);
	94	/* Restart timer if it is disabled */
	95	val = readw(virtbase + U300_WDOG_D2R);
	96	if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
	97	writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
	98	virtbase + U300_WDOG_RR);
	99	/* Acknowledge any pending interrupt so it doesn't just fire off */
	100	writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
	101	virtbase + U300_WDOG_IER);
5973bee4 LW	102	/*
	103	* The interrupt is cleared in the 32 kHz clock domain.
	104	* Wait 3 32 kHz cycles for it to take effect
	105	*/
	106	freq = clk_get_rate(clk);
0ecc3bf4	107	delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */
5973bee4 LW	108	delay_ns = 3 * delay_ns; /* Wait 3 cycles */
5973bee4 LW	109	ndelay(delay_ns);
01480701 LW	110	/* Enable the watchdog interrupt */
	111	writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
	112	/* Activate the watchdog timer */
	113	writew(timeout, virtbase + U300_WDOG_TR);
	114	/* Start the watchdog timer */
	115	writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
	116	/*
	117	* Extra read so that this change propagate in the watchdog.
	118	*/
	119	(void) readw(virtbase + U300_WDOG_CR);
	120	val = readw(virtbase + U300_WDOG_D2R);
	121	clk_disable(clk);
	122	if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
	123	dev_err(parent,
	124	"%s(): watchdog not enabled! D2R value %04x\n",
	125	__func__, val);
	126	}
	127
	128	static void coh901327_disable(void)
	129	{
	130	u16 val;
	131
	132	clk_enable(clk);
	133	/* Disable the watchdog interrupt if it is active */
	134	writew(0x0000U, virtbase + U300_WDOG_IMR);
	135	/* If the watchdog is currently enabled, attempt to disable it */
	136	val = readw(virtbase + U300_WDOG_D2R);
	137	if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
	138	writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
	139	virtbase + U300_WDOG_D1R);
	140	writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
	141	virtbase + U300_WDOG_D2R);
	142	/* Write this twice (else problems occur) */
	143	writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
	144	virtbase + U300_WDOG_D2R);
	145	}
	146	val = readw(virtbase + U300_WDOG_D2R);
	147	clk_disable(clk);
	148	if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
	149	dev_err(parent,
	150	"%s(): watchdog not disabled! D2R value %04x\n",
	151	__func__, val);
	152	}
	153
15b25701	154	static int coh901327_start(struct watchdog_device *wdt_dev)
01480701 LW	155	{
01480701 LW	156	coh901327_enable(margin * 100);
15b25701 LW	157	return 0;
	158	}
	159
	160	static int coh901327_stop(struct watchdog_device *wdt_dev)
	161	{
	162	coh901327_disable();
	163	return 0;
01480701 LW	164	}
01480701 LW	165
15b25701	166	static int coh901327_ping(struct watchdog_device *wdd)
01480701 LW	167	{
	168	clk_enable(clk);
	169	/* Feed the watchdog */
	170	writew(U300_WDOG_FR_FEED_RESTART_TIMER,
	171	virtbase + U300_WDOG_FR);
	172	clk_disable(clk);
15b25701	173	return 0;
01480701 LW	174	}
01480701 LW	175
15b25701 LW	176	static int coh901327_settimeout(struct watchdog_device *wdt_dev,
15b25701 LW	177	unsigned int time)
01480701	178	{
01480701 LW	179	margin = time;
	180	clk_enable(clk);
	181	/* Set new timeout value */
	182	writew(margin * 100, virtbase + U300_WDOG_TR);
	183	/* Feed the dog */
	184	writew(U300_WDOG_FR_FEED_RESTART_TIMER,
	185	virtbase + U300_WDOG_FR);
	186	clk_disable(clk);
	187	return 0;
	188	}
	189
15b25701 LW	190	static unsigned int coh901327_gettimeleft(struct watchdog_device *wdt_dev)
	191	{
	192	u16 val;
	193
	194	clk_enable(clk);
	195	/* Read repeatedly until the value is stable! */
	196	val = readw(virtbase + U300_WDOG_CR);
	197	while (val & U300_WDOG_CR_VALID_IND)
	198	val = readw(virtbase + U300_WDOG_CR);
	199	val &= U300_WDOG_CR_COUNT_VALUE_MASK;
	200	clk_disable(clk);
	201	if (val != 0)
	202	val /= 100;
	203
	204	return val;
	205	}
	206
01480701 LW	207	/*
	208	* This interrupt occurs 10 ms before the watchdog WILL bark.
	209	*/
	210	static irqreturn_t coh901327_interrupt(int irq, void *data)
	211	{
	212	u16 val;
	213
	214	/*
	215	* Ack IRQ? If this occurs we're FUBAR anyway, so
	216	* just acknowledge, disable the interrupt and await the imminent end.
	217	* If you at some point need a host of callbacks to be called
	218	* when the system is about to watchdog-reset, add them here!
	219	*
	220	* NOTE: on future versions of this IP-block, it will be possible
	221	* to prevent a watchdog reset by feeding the watchdog at this
	222	* point.
	223	*/
	224	clk_enable(clk);
	225	val = readw(virtbase + U300_WDOG_IER);
	226	if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
	227	writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
	228	virtbase + U300_WDOG_IER);
	229	writew(0x0000U, virtbase + U300_WDOG_IMR);
	230	clk_disable(clk);
	231	dev_crit(parent, "watchdog is barking!\n");
	232	return IRQ_HANDLED;
	233	}
	234
15b25701 LW	235	static const struct watchdog_info coh901327_ident = {
	236	.options = WDIOF_CARDRESET \| WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	237	.identity = DRV_NAME,
	238	};
01480701	239
15b25701 LW	240	static struct watchdog_ops coh901327_ops = {
	241	.owner = THIS_MODULE,
	242	.start = coh901327_start,
	243	.stop = coh901327_stop,
	244	.ping = coh901327_ping,
	245	.set_timeout = coh901327_settimeout,
	246	.get_timeleft = coh901327_gettimeleft,
01480701 LW	247	};
01480701 LW	248
15b25701 LW	249	static struct watchdog_device coh901327_wdt = {
	250	.info = &coh901327_ident,
	251	.ops = &coh901327_ops,
	252	/*
	253	* Max margin is 327 since the 10ms
	254	* timeout register is max
	255	* 0x7FFF = 327670ms ~= 327s.
	256	*/
	257	.min_timeout = 0,
	258	.max_timeout = 327,
01480701 LW	259	};
	260
	261	static int __exit coh901327_remove(struct platform_device *pdev)
	262	{
15b25701	263	watchdog_unregister_device(&coh901327_wdt);
01480701 LW	264	coh901327_disable();
	265	free_irq(irq, pdev);
	266	clk_put(clk);
	267	iounmap(virtbase);
	268	release_mem_region(phybase, physize);
	269	return 0;
	270	}
	271
01480701 LW	272	static int __init coh901327_probe(struct platform_device *pdev)
	273	{
	274	int ret;
	275	u16 val;
	276	struct resource *res;
	277
	278	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	279	if (!res)
	280	return -ENOENT;
	281
	282	parent = &pdev->dev;
	283	physize = resource_size(res);
	284	phybase = res->start;
	285
	286	if (request_mem_region(phybase, physize, DRV_NAME) == NULL) {
	287	ret = -EBUSY;
	288	goto out;
	289	}
	290
	291	virtbase = ioremap(phybase, physize);
	292	if (!virtbase) {
	293	ret = -ENOMEM;
	294	goto out_no_remap;
	295	}
	296
	297	clk = clk_get(&pdev->dev, NULL);
	298	if (IS_ERR(clk)) {
	299	ret = PTR_ERR(clk);
	300	dev_err(&pdev->dev, "could not get clock\n");
	301	goto out_no_clk;
	302	}
	303	ret = clk_enable(clk);
	304	if (ret) {
	305	dev_err(&pdev->dev, "could not enable clock\n");
	306	goto out_no_clk_enable;
	307	}
	308
	309	val = readw(virtbase + U300_WDOG_SR);
	310	switch (val) {
	311	case U300_WDOG_SR_STATUS_TIMED_OUT:
	312	dev_info(&pdev->dev,
	313	"watchdog timed out since last chip reset!\n");
15b25701	314	coh901327_wdt.bootstatus \|= WDIOF_CARDRESET;
01480701 LW	315	/* Status will be cleared below */
	316	break;
	317	case U300_WDOG_SR_STATUS_NORMAL:
	318	dev_info(&pdev->dev,
	319	"in normal status, no timeouts have occurred.\n");
	320	break;
	321	default:
	322	dev_info(&pdev->dev,
	323	"contains an illegal status code (%08x)\n", val);
	324	break;
	325	}
	326
	327	val = readw(virtbase + U300_WDOG_D2R);
	328	switch (val) {
	329	case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
	330	dev_info(&pdev->dev, "currently disabled.\n");
	331	break;
	332	case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
	333	dev_info(&pdev->dev,
	334	"currently enabled! (disabling it now)\n");
	335	coh901327_disable();
	336	break;
	337	default:
	338	dev_err(&pdev->dev,
	339	"contains an illegal enable/disable code (%08x)\n",
	340	val);
	341	break;
	342	}
	343
	344	/* Reset the watchdog */
	345	writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);
	346
	347	irq = platform_get_irq(pdev, 0);
86b59128	348	if (request_irq(irq, coh901327_interrupt, 0,
01480701 LW	349	DRV_NAME " Bark", pdev)) {
	350	ret = -EIO;
	351	goto out_no_irq;
	352	}
	353
	354	clk_disable(clk);
	355
15b25701	356	ret = watchdog_register_device(&coh901327_wdt);
01480701 LW	357	if (ret == 0)
	358	dev_info(&pdev->dev,
	359	"initialized. timer margin=%d sec\n", margin);
	360	else
	361	goto out_no_wdog;
	362
	363	return 0;
	364
	365	out_no_wdog:
	366	free_irq(irq, pdev);
	367	out_no_irq:
	368	clk_disable(clk);
	369	out_no_clk_enable:
	370	clk_put(clk);
	371	out_no_clk:
	372	iounmap(virtbase);
	373	out_no_remap:
	374	release_mem_region(phybase, SZ_4K);
	375	out:
	376	return ret;
	377	}
	378
	379	#ifdef CONFIG_PM
452190cb LW	380
	381	static u16 wdogenablestore;
	382	static u16 irqmaskstore;
	383
01480701 LW	384	static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
	385	{
	386	irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
	387	wdogenablestore = readw(virtbase + U300_WDOG_D2R);
	388	/* If watchdog is on, disable it here and now */
	389	if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
	390	coh901327_disable();
	391	return 0;
	392	}
	393
	394	static int coh901327_resume(struct platform_device *pdev)
	395	{
	396	/* Restore the watchdog interrupt */
	397	writew(irqmaskstore, virtbase + U300_WDOG_IMR);
	398	if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
	399	/* Restart the watchdog timer */
	400	writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
	401	virtbase + U300_WDOG_RR);
	402	writew(U300_WDOG_FR_FEED_RESTART_TIMER,
	403	virtbase + U300_WDOG_FR);
	404	}
	405	return 0;
	406	}
	407	#else
	408	#define coh901327_suspend NULL
	409	#define coh901327_resume NULL
	410	#endif
	411
	412	/*
	413	* Mistreating the watchdog is the only way to perform a software reset of the
	414	* system on EMP platforms. So we implement this and export a symbol for it.
	415	*/
	416	void coh901327_watchdog_reset(void)
	417	{
	418	/* Enable even if on JTAG too */
	419	writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
	420	virtbase + U300_WDOG_JOR);
	421	/*
	422	* Timeout = 5s, we have to wait for the watchdog reset to
	423	* actually take place: the watchdog will be reloaded with the
	424	* default value immediately, so we HAVE to reboot and get back
	425	* into the kernel in 30s, or the device will reboot again!
	426	* The boot loader will typically deactivate the watchdog, so we
	427	* need time enough for the boot loader to get to the point of
	428	* deactivating the watchdog before it is shut down by it.
	429	*
	430	* NOTE: on future versions of the watchdog, this restriction is
af901ca1	431	* gone: the watchdog will be reloaded with a default value (1 min)
01480701 LW	432	* instead of last value, and you can conveniently set the watchdog
	433	* timeout to 10ms (value = 1) without any problems.
	434	*/
	435	coh901327_enable(500);
	436	/* Return and await doom */
	437	}
	438
	439	static struct platform_driver coh901327_driver = {
	440	.driver = {
	441	.owner = THIS_MODULE,
	442	.name = "coh901327_wdog",
	443	},
	444	.remove = __exit_p(coh901327_remove),
	445	.suspend = coh901327_suspend,
	446	.resume = coh901327_resume,
	447	};
	448
	449	static int __init coh901327_init(void)
	450	{
	451	return platform_driver_probe(&coh901327_driver, coh901327_probe);
	452	}
	453	module_init(coh901327_init);
	454
	455	static void __exit coh901327_exit(void)
	456	{
	457	platform_driver_unregister(&coh901327_driver);
	458	}
	459	module_exit(coh901327_exit);
	460
	461	MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
	462	MODULE_DESCRIPTION("COH 901 327 Watchdog");
	463
	464	module_param(margin, int, 0);
	465	MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
	466
	467	MODULE_LICENSE("GPL");
15b25701	468	MODULE_ALIAS("platform:coh901327-watchdog");