drivers/watchdog/davinci_wdt.c - third_party/linux - Git at Google

 /*
  * 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 <asm/hardware.h>
 #include <asm/uaccess.h>
 #include <asm/io.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 struct resource	*wdt_mem;
 static void __iomem	*wdt_base;

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

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

 	spin_unlock(&io_lock);
 }

 static void wdt_enable(void)
 {
 	u32 tgcr;
 	u32 timer_margin;

 	spin_lock(&io_lock);

 	/* disable, internal clock source */
 	davinci_writel(0, wdt_base + TCR);
 	/* reset timer, set mode to 64-bit watchdog, and unreset */
 	davinci_writel(0, wdt_base + TGCR);
 	tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
 	davinci_writel(tgcr, wdt_base + TGCR);
 	/* clear counter regs */
 	davinci_writel(0, wdt_base + TIM12);
 	davinci_writel(0, wdt_base + TIM34);
 	/* set timeout period */
 	timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff);
 	davinci_writel(timer_margin, wdt_base + PRD12);
 	timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32);
 	davinci_writel(timer_margin, wdt_base + PRD34);
 	/* enable run continuously */
 	davinci_writel(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 */
 	davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
 	/* put watchdog in active state */
 	davinci_writel(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 struct watchdog_info ident = {
 	.options = WDIOF_KEEPALIVEPING,
 	.identity = "DaVinci Watchdog",
 };

 static int
 davinci_wdt_ioctl(struct inode *inode, 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_GETTIMEOUT:
 		ret = put_user(heartbeat, (int *)arg);
 		break;

 	case WDIOC_KEEPALIVE:
 		wdt_service();
 		ret = 0;
 		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,
 	.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, size;
 	struct resource *res;

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

 	printk(KERN_INFO MODULE_NAME
 		"DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (res == NULL) {
 		printk(KERN_INFO MODULE_NAME
 			"failed to get memory region resource\n");
 		return -ENOENT;
 	}

 	size = res->end - res->start + 1;
 	wdt_mem = request_mem_region(res->start, size, pdev->name);

 	if (wdt_mem == NULL) {
 		printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
 		return -ENOENT;
 	}
 	wdt_base = (void __iomem *)(res->start);

 	ret = misc_register(&davinci_wdt_miscdev);
 	if (ret < 0) {
 		printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
 		release_resource(wdt_mem);
 		kfree(wdt_mem);
 	} else {
 		set_bit(WDT_DEVICE_INITED, &wdt_status);
 	}

 	return ret;
 }

 static int davinci_wdt_remove(struct platform_device *pdev)
 {
 	misc_deregister(&davinci_wdt_miscdev);
 	if (wdt_mem) {
 		release_resource(wdt_mem);
 		kfree(wdt_mem);
 		wdt_mem = NULL;
 	}
 	return 0;
 }

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

 static int __init davinci_wdt_init(void)
 {
 	return platform_driver_register(&platform_wdt_driver);
 }

 static void __exit davinci_wdt_exit(void)
 {
 	platform_driver_unregister(&platform_wdt_driver);
 }

 module_init(davinci_wdt_init);
 module_exit(davinci_wdt_exit);

 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);
	/*
	* 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 <asm/hardware.h>
	#include <asm/uaccess.h>
	#include <asm/io.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 struct resource *wdt_mem;
	static void __iomem *wdt_base;

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

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

	spin_unlock(&io_lock);
	}

	static void wdt_enable(void)
	{
	u32 tgcr;
	u32 timer_margin;

	spin_lock(&io_lock);

	/* disable, internal clock source */
	davinci_writel(0, wdt_base + TCR);
	/* reset timer, set mode to 64-bit watchdog, and unreset */
	davinci_writel(0, wdt_base + TGCR);
	tgcr = TIMMODE_64BIT_WDOG \| TIM12RS_UNRESET \| TIM34RS_UNRESET;
	davinci_writel(tgcr, wdt_base + TGCR);
	/* clear counter regs */
	davinci_writel(0, wdt_base + TIM12);
	davinci_writel(0, wdt_base + TIM34);
	/* set timeout period */
	timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff);
	davinci_writel(timer_margin, wdt_base + PRD12);
	timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32);
	davinci_writel(timer_margin, wdt_base + PRD34);
	/* enable run continuously */
	davinci_writel(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 */
	davinci_writel(WDKEY_SEQ0 \| WDEN, wdt_base + WDTCR);
	/* put watchdog in active state */
	davinci_writel(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 struct watchdog_info ident = {
	.options = WDIOF_KEEPALIVEPING,
	.identity = "DaVinci Watchdog",
	};

	static int
	davinci_wdt_ioctl(struct inode inode, 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_GETTIMEOUT:
	ret = put_user(heartbeat, (int *)arg);
	break;

	case WDIOC_KEEPALIVE:
	wdt_service();
	ret = 0;
	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,
	.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, size;
	struct resource *res;

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

	printk(KERN_INFO MODULE_NAME
	"DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
	printk(KERN_INFO MODULE_NAME
	"failed to get memory region resource\n");
	return -ENOENT;
	}

	size = res->end - res->start + 1;
	wdt_mem = request_mem_region(res->start, size, pdev->name);

	if (wdt_mem == NULL) {
	printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
	return -ENOENT;
	}
	wdt_base = (void __iomem *)(res->start);

	ret = misc_register(&davinci_wdt_miscdev);
	if (ret < 0) {
	printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
	release_resource(wdt_mem);
	kfree(wdt_mem);
	} else {
	set_bit(WDT_DEVICE_INITED, &wdt_status);
	}

	return ret;
	}

	static int davinci_wdt_remove(struct platform_device *pdev)
	{
	misc_deregister(&davinci_wdt_miscdev);
	if (wdt_mem) {
	release_resource(wdt_mem);
	kfree(wdt_mem);
	wdt_mem = NULL;
	}
	return 0;
	}

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

	static int __init davinci_wdt_init(void)
	{
	return platform_driver_register(&platform_wdt_driver);
	}

	static void __exit davinci_wdt_exit(void)
	{
	platform_driver_unregister(&platform_wdt_driver);
	}

	module_init(davinci_wdt_init);
	module_exit(davinci_wdt_exit);

	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);