[WATCHDOG] Freescale STMP: watchdog driver

Add watchdog timer support for Freescale STMP3xxx boards

Signed-off-by: Vitaly Wool <vital@embeddedalley.com>
Signed-off-by: Dmitry Pervushin <dpervushin@embeddedalley.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -257,6 +257,15 @@ config TWL4030_WATCHDOG
 	  Support for TI TWL4030 watchdog.  Say 'Y' here to enable the
 	  watchdog timer support for TWL4030 chips.
 
+config STMP3XXX_WATCHDOG
+	tristate "Freescale STMP3XXX watchdog"
+	depends on ARCH_STMP3XXX
+	help
+	  Say Y here if to include support for the watchdog timer
+	  for the Sigmatel STMP37XX/378X SoC.
+	  To compile this driver as a module, choose M here: the
+	  module will be called stmp3xxx_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT

drivers/watchdog/Makefile

@@ -43,6 +43,7 @@ obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
 obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
 obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
 obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
+obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

drivers/watchdog/stmp3xxx_wdt.c

@@ -0,0 +1,296 @@
+/*
+ * Watchdog driver for Freescale STMP37XX/STMP378X
+ *
+ * Author: Vitaly Wool <vital@embeddedalley.com>
+ *
+ * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+
+#include <mach/platform.h>
+#include <mach/regs-rtc.h>
+
+#define DEFAULT_HEARTBEAT	19
+#define MAX_HEARTBEAT		(0x10000000 >> 6)
+
+/* missing bitmask in headers */
+#define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER     0x80000000
+
+#define WDT_IN_USE		0
+#define WDT_OK_TO_CLOSE		1
+
+#define WDOG_COUNTER_RATE	1000 /* 1 kHz clock */
+
+static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock);
+static unsigned long wdt_status;
+static const int nowayout = WATCHDOG_NOWAYOUT;
+static int heartbeat = DEFAULT_HEARTBEAT;
+static unsigned long boot_status;
+
+static void wdt_enable(u32 value)
+{
+	spin_lock(&stmp3xxx_wdt_io_lock);
+	__raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG);
+	stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
+	stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
+			REGS_RTC_BASE + HW_RTC_PERSISTENT1);
+	spin_unlock(&stmp3xxx_wdt_io_lock);
+}
+
+static void wdt_disable(void)
+{
+	spin_lock(&stmp3xxx_wdt_io_lock);
+	stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
+			REGS_RTC_BASE + HW_RTC_PERSISTENT1);
+	stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
+	spin_unlock(&stmp3xxx_wdt_io_lock);
+}
+
+static void wdt_ping(void)
+{
+	wdt_enable(heartbeat * WDOG_COUNTER_RATE);
+}
+
+static int stmp3xxx_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
+		return -EBUSY;
+
+	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+	wdt_ping();
+
+	return nonseekable_open(inode, file);
+}
+
+static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *data,
+	size_t len, loff_t *ppos)
+{
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+			for (i = 0; i != len; i++) {
+				char c;
+
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
+			}
+		}
+		wdt_ping();
+	}
+
+	return len;
+}
+
+static struct watchdog_info ident = {
+	.options	= WDIOF_CARDRESET |
+			  WDIOF_MAGICCLOSE |
+			  WDIOF_SETTIMEOUT |
+			  WDIOF_KEEPALIVEPING,
+	.identity	= "STMP3XXX Watchdog",
+};
+
+static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd,
+	unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	int new_heartbeat, opts;
+	int ret = -ENOTTY;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+		break;
+
+	case WDIOC_GETSTATUS:
+		ret = put_user(0, p);
+		break;
+
+	case WDIOC_GETBOOTSTATUS:
+		ret = put_user(boot_status, p);
+		break;
+
+	case WDIOC_SETOPTIONS:
+		if (get_user(opts, p)) {
+			ret = -EFAULT;
+			break;
+		}
+		if (opts & WDIOS_DISABLECARD)
+			wdt_disable();
+		else if (opts & WDIOS_ENABLECARD)
+			wdt_ping();
+		else {
+			pr_debug("%s: unknown option 0x%x\n", __func__, opts);
+			ret = -EINVAL;
+			break;
+		}
+		ret = 0;
+		break;
+
+	case WDIOC_KEEPALIVE:
+		wdt_ping();
+		ret = 0;
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_heartbeat, p)) {
+			ret = -EFAULT;
+			break;
+		}
+		if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) {
+			ret = -EINVAL;
+			break;
+		}
+
+		heartbeat = new_heartbeat;
+		wdt_ping();
+		/* Fall through */
+
+	case WDIOC_GETTIMEOUT:
+		ret = put_user(heartbeat, p);
+		break;
+	}
+	return ret;
+}
+
+static int stmp3xxx_wdt_release(struct inode *inode, struct file *file)
+{
+	int ret = 0;
+
+	if (!nowayout) {
+		if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
+			wdt_ping();
+			pr_debug("%s: Device closed unexpectdly\n", __func__);
+			ret = -EINVAL;
+		} else {
+			wdt_disable();
+			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+		}
+	}
+	clear_bit(WDT_IN_USE, &wdt_status);
+
+	return ret;
+}
+
+static const struct file_operations stmp3xxx_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = stmp3xxx_wdt_write,
+	.unlocked_ioctl = stmp3xxx_wdt_ioctl,
+	.open = stmp3xxx_wdt_open,
+	.release = stmp3xxx_wdt_release,
+};
+
+static struct miscdevice stmp3xxx_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &stmp3xxx_wdt_fops,
+};
+
+static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+
+	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
+		heartbeat = DEFAULT_HEARTBEAT;
+
+	boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) &
+			BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER;
+	boot_status = !!boot_status;
+	stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
+			REGS_RTC_BASE + HW_RTC_PERSISTENT1);
+	wdt_disable();		/* disable for now */
+
+	ret = misc_register(&stmp3xxx_wdt_miscdev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "cannot register misc device\n");
+		return ret;
+	}
+
+	printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n",
+		heartbeat);
+
+	return ret;
+}
+
+static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev)
+{
+	misc_deregister(&stmp3xxx_wdt_miscdev);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int wdt_suspended;
+static u32 wdt_saved_time;
+
+static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
+				pm_message_t state)
+{
+	if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
+		BM_RTC_CTRL_WATCHDOGEN) {
+		wdt_suspended = 1;
+		wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG);
+		wdt_disable();
+	}
+	return 0;
+}
+
+static int stmp3xxx_wdt_resume(struct platform_device *pdev)
+{
+	if (wdt_suspended) {
+		wdt_enable(wdt_saved_time);
+		wdt_suspended = 0;
+	}
+	return 0;
+}
+#else
+#define stmp3xxx_wdt_suspend	NULL
+#define stmp3xxx_wdt_resume	NULL
+#endif
+
+static struct platform_driver platform_wdt_driver = {
+	.driver = {
+		.name = "stmp3xxx_wdt",
+	},
+	.probe = stmp3xxx_wdt_probe,
+	.remove = __devexit_p(stmp3xxx_wdt_remove),
+	.suspend = stmp3xxx_wdt_suspend,
+	.resume = stmp3xxx_wdt_resume,
+};
+
+static int __init stmp3xxx_wdt_init(void)
+{
+	return platform_driver_register(&platform_wdt_driver);
+}
+
+static void __exit stmp3xxx_wdt_exit(void)
+{
+	return platform_driver_unregister(&platform_wdt_driver);
+}
+
+module_init(stmp3xxx_wdt_init);
+module_exit(stmp3xxx_wdt_exit);
+
+MODULE_DESCRIPTION("STMP3XXX Watchdog Driver");
+MODULE_LICENSE("GPL");
+
+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_ALIAS_MISCDEV(WATCHDOG_MINOR);