ap/os/linux/linux-3.4.x/drivers/watchdog/zx29_wdt.c

/*
 * drivers/watchdog/zx29_wdt.c
 *
 *  Copyright (C) 2015 ZTE-TSP
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/miscdevice.h> 
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/err.h>

#include <mach/board.h>
#include "zx29_wdt.h"

/*****************************************************************************
 **   |            -->              |        -->      |    
 **  15s(value load)          5s(feed in irq)    0s(reset if no feed)
 *****************************************************************************
 **/

#define CONFIG_ZX29_WATCHDOG_ATBOOT			(0)
#define CONFIG_ZX29_WATCHDOG_DEFAULT_TIME	(15)
#define CONFIG_ZX29_WATCHDOG_DEADLINE_TIME	(5)

static bool nowayout	= WATCHDOG_NOWAYOUT;	/* 1-disagree to close wdt  0-agree to close wdt */
static int tmr_margin	= CONFIG_ZX29_WATCHDOG_DEFAULT_TIME;  /* max during to feed dog, unit is second */
static int tmr_atboot	= CONFIG_ZX29_WATCHDOG_ATBOOT;	/* 0 - no enable wdt when boot */
static int debug;

module_param(tmr_margin,  int, 0);
module_param(tmr_atboot,  int, 0);
module_param(nowayout,   bool, 0);
module_param(debug,	  int, 0);

MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. (default="
		__MODULE_STRING(CONFIG_ZX29_WATCHDOG_DEFAULT_TIME) ")");
MODULE_PARM_DESC(tmr_atboot,
		"Watchdog is started at boot time if set to 1, default="
			__MODULE_STRING(CONFIG_ZX29_WATCHDOG_ATBOOT));
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug (default 0)");

static struct device    *wdt_dev;	/* platform device attached to */
static struct clk	*wdt_clock;
static struct clk	*wdt_apb_clock;
static void __iomem	*wdt_base;
static unsigned int	 wdt_count;
static DEFINE_SPINLOCK(wdt_lock);
static struct resource	*wdt_irq;

/* watchdog control routines */

#define DBG(fmt, ...)					\
do {							\
	if (debug)					\
		pr_info(fmt, ##__VA_ARGS__);		\
} while (0)

/* functions */
static unsigned int feed_count = 0;
static int zx29_wdt_keepalive(struct watchdog_device *wdd)
{
	spin_lock(&wdt_lock);
	__wdt_set_load(wdt_base, wdt_count);
	feed_count ++;
	spin_unlock(&wdt_lock);

	return 0;
}

static int zx29_wdt_stop(struct watchdog_device *wdd)
{
	spin_lock(&wdt_lock);
	__wdt_stop(wdt_base);
	spin_unlock(&wdt_lock);

	return 0;
}

static int zx29_wdt_start(struct watchdog_device *wdd)
{
	spin_lock(&wdt_lock);
	__wdt_start(wdt_base);
	spin_unlock(&wdt_lock);

	return 0;
}

/*
 * timeout  -- unit(s)
 * 
 */
static int zx29_wdt_set_heartbeat(struct watchdog_device *wdd, unsigned timeout)
{
	wdt_count = timeout*WDT_TIME_1S;
	zx29_wdt_keepalive(wdd);

	spin_lock(&wdt_lock);
	__wdt_set_int_value(wdt_base, CONFIG_ZX29_WATCHDOG_DEADLINE_TIME*WDT_TIME_1S);
	spin_unlock(&wdt_lock);	

	return 0;
}

#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)

static const struct watchdog_info zx29_wdt_ident = {
	.options          = OPTIONS,
	.firmware_version =	0,
	.identity         =	"ZX29 Watchdog",
};

static struct watchdog_ops zx29_wdt_ops = {
	.owner = THIS_MODULE,
	.start = zx29_wdt_start,
	.stop  = zx29_wdt_stop,
	.ping  = zx29_wdt_keepalive,
	.set_timeout = zx29_wdt_set_heartbeat,
};

static struct watchdog_device zx29_wdd = {
	.info = &zx29_wdt_ident,
	.ops  = &zx29_wdt_ops,
};

/* interrupt handler code */
static irqreturn_t zx29_wdt_irq(int irqno, void *param)
{
	dev_info(wdt_dev, "watchdog timer expired (irq)\n");

	zx29_wdt_keepalive(&zx29_wdd);
	return IRQ_HANDLED;
}

static int __devinit wdt_init_clk(struct platform_device *pdev)
{
	int ret;

	wdt_apb_clock = clk_get(&pdev->dev, "apb_clk");
	if (IS_ERR(wdt_apb_clock)) {
		dev_err(&pdev->dev, "failed to find watchdog apb clock source\n");
		ret = PTR_ERR(wdt_apb_clock);
		return ret;
	}
	clk_enable(wdt_apb_clock);
	
	wdt_clock = clk_get(&pdev->dev, "work_clk");
	if (IS_ERR(wdt_clock)) {
		dev_err(&pdev->dev, "failed to find watchdog clock source\n");
		ret = PTR_ERR(wdt_clock);
		goto err;
	}
	clk_enable(wdt_clock);
	clk_set_rate(wdt_clock, WDT_SOURCE_CLOCK_RATE);

	/* 32768/32 = 1kHz */
	__wdt_set_prescale(wdt_base, 31);
	
	return 0;

err:
	clk_disable(wdt_apb_clock);
	clk_put(wdt_apb_clock);
	wdt_apb_clock = NULL;

	return ret;
}

static int __devinit zx29_wdt_probe(struct platform_device *pdev)
{
	struct device *dev;
	int started = 0;
	int ret;
	struct resource	*wdt_mem;
	
	DBG("[WDT]%s: probe=%p\n", __func__, pdev);

	dev = &pdev->dev;
	wdt_dev = &pdev->dev;

	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (wdt_mem == NULL) {
		dev_err(dev, "no memory resource specified\n");
		return -ENOENT;
	}
	wdt_base = (void __iomem *)wdt_mem->start;
	DBG("[WDT]probe: wdt_base=%p\n", wdt_base);

	wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (wdt_irq == NULL) {
		dev_err(dev, "no irq resource specified\n");
		return -ENOENT;
	}

	ret = wdt_init_clk(pdev);
	if(ret)
		return ret;

	started = zx29_wdt_set_heartbeat(&zx29_wdd, tmr_margin);
	if (started) {
			dev_info(dev,
			   "tmr_margin value out of range, ( %d ) used\n",
			       tmr_margin);
	}

	ret = request_irq(wdt_irq->start, zx29_wdt_irq, 0, pdev->name, pdev);
	if (ret != 0) {
		dev_err(dev, "failed to install irq (%d)\n", ret);
		goto err_clk;
	}

	watchdog_set_nowayout(&zx29_wdd, nowayout);

	ret = watchdog_register_device(&zx29_wdd);
	if (ret) {
		dev_err(dev, "cannot register watchdog (%d)\n", ret);
		goto err_irq;
	}

	if (tmr_atboot && started == 0) {
		dev_info(dev, "starting watchdog timer\n");
		zx29_wdt_start(&zx29_wdd);
		__wdt_enable_reset();
	} else if (!tmr_atboot) {
		zx29_wdt_stop(&zx29_wdd);
	}

	pr_info("[WDT]Watchdog Timer init OK.\n");

	return 0;

 err_irq:
	free_irq(wdt_irq->start, pdev);

 err_clk:
	clk_disable(wdt_clock);
	clk_put(wdt_clock);
	wdt_clock = NULL;

	return ret;
}

static int __devexit zx29_wdt_remove(struct platform_device *dev)
{
	watchdog_unregister_device(&zx29_wdd);

	free_irq(wdt_irq->start, dev);

	clk_disable(wdt_clock);
	clk_put(wdt_clock);
	wdt_clock = NULL;

	clk_disable(wdt_apb_clock);
	clk_put(wdt_apb_clock);
	wdt_apb_clock = NULL;	

	return 0;
}

static void zx29_wdt_shutdown(struct platform_device *dev)
{
	zx29_wdt_stop(&zx29_wdd);
	__wdt_disable_reset();
}

#ifdef CONFIG_PM
static zx29_wdt_context wdt_context;
static int zx29_wdt_suspend(struct platform_device *dev, pm_message_t state)
{
	spin_lock(&wdt_lock);
	__wdt_save_context(wdt_base, (u32 *)&wdt_context);
	spin_unlock(&wdt_lock);

	return 0;
}

static int zx29_wdt_resume(struct platform_device *dev)
{
	spin_lock(&wdt_lock);
	__wdt_restore_context(wdt_base, (u32 *)&wdt_context);
	spin_unlock(&wdt_lock);
	
	return 0;
}

#else
#define zx29_wdt_suspend NULL
#define zx29_wdt_resume  NULL
#endif /* CONFIG_PM */

#ifdef CONFIG_OF
static const struct of_device_id zx29_wdt_match[] = {
	{ .compatible = "zte, zx29_ap_wdt" },
	{},
};
MODULE_DEVICE_TABLE(of, zx29_wdt_match);
#else
#define zx29_wdt_match NULL
#endif

static struct platform_driver zx29_wdt_driver = {
	.probe		= zx29_wdt_probe,
	.remove		= __devexit_p(zx29_wdt_remove),
	.shutdown	= zx29_wdt_shutdown,
	.suspend	= zx29_wdt_suspend,
	.resume		= zx29_wdt_resume,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "zx29_ap_wdt",
		.of_match_table	= zx29_wdt_match,
	},
};


static int __init watchdog_init(void)
{
	return platform_driver_register(&zx29_wdt_driver);
}

static void __exit watchdog_exit(void)
{
	platform_driver_unregister(&zx29_wdt_driver);
}

module_init(watchdog_init);
module_exit(watchdog_exit);