[WATCHDOG] Add support for the Avionic Design Xanthos watchdog timer.

This patch adds support for the watchdog timer on Avionic Design Xanthos
boards.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -282,6 +282,13 @@ config NUC900_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called nuc900_wdt.
 
+config ADX_WATCHDOG
+	tristate "Avionic Design Xanthos watchdog"
+	depends on ARCH_PXA_ADX
+	help
+	  Say Y here if you want support for the watchdog timer on Avionic
+	  Design Xanthos boards.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT

drivers/watchdog/Makefile

@@ -45,6 +45,7 @@ obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
 obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
 obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
 obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
+obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

drivers/watchdog/adx_wdt.c

+/*
+ * Copyright (C) 2008-2009 Avionic Design GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+
+#define WATCHDOG_NAME "adx-wdt"
+
+/* register offsets */
+#define	ADX_WDT_CONTROL		0x00
+#define	ADX_WDT_CONTROL_ENABLE	(1 << 0)
+#define	ADX_WDT_CONTROL_nRESET	(1 << 1)
+#define	ADX_WDT_TIMEOUT		0x08
+
+static struct platform_device *adx_wdt_dev;
+static unsigned long driver_open;
+
+#define	WDT_STATE_STOP	0
+#define	WDT_STATE_START	1
+
+struct adx_wdt {
+	void __iomem *base;
+	unsigned long timeout;
+	unsigned int state;
+	unsigned int wake;
+	spinlock_t lock;
+};
+
+static struct watchdog_info adx_wdt_info = {
+	.identity = "Avionic Design Xanthos Watchdog",
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+};
+
+static void adx_wdt_start_locked(struct adx_wdt *wdt)
+{
+	u32 ctrl;
+
+	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
+	ctrl |= ADX_WDT_CONTROL_ENABLE;
+	writel(ctrl, wdt->base + ADX_WDT_CONTROL);
+	wdt->state = WDT_STATE_START;
+}
+
+static void adx_wdt_start(struct adx_wdt *wdt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+	adx_wdt_start_locked(wdt);
+	spin_unlock_irqrestore(&wdt->lock, flags);
+}
+
+static void adx_wdt_stop_locked(struct adx_wdt *wdt)
+{
+	u32 ctrl;
+
+	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
+	ctrl &= ~ADX_WDT_CONTROL_ENABLE;
+	writel(ctrl, wdt->base + ADX_WDT_CONTROL);
+	wdt->state = WDT_STATE_STOP;
+}
+
+static void adx_wdt_stop(struct adx_wdt *wdt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+	adx_wdt_stop_locked(wdt);
+	spin_unlock_irqrestore(&wdt->lock, flags);
+}
+
+static void adx_wdt_set_timeout(struct adx_wdt *wdt, unsigned long seconds)
+{
+	unsigned long timeout = seconds * 1000;
+	unsigned long flags;
+	unsigned int state;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+	state = wdt->state;
+	adx_wdt_stop_locked(wdt);
+	writel(timeout, wdt->base + ADX_WDT_TIMEOUT);
+
+	if (state == WDT_STATE_START)
+		adx_wdt_start_locked(wdt);
+
+	wdt->timeout = timeout;
+	spin_unlock_irqrestore(&wdt->lock, flags);
+}
+
+static void adx_wdt_get_timeout(struct adx_wdt *wdt, unsigned long *seconds)
+{
+	*seconds = wdt->timeout / 1000;
+}
+
+static void adx_wdt_keepalive(struct adx_wdt *wdt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+	writel(wdt->timeout, wdt->base + ADX_WDT_TIMEOUT);
+	spin_unlock_irqrestore(&wdt->lock, flags);
+}
+
+static int adx_wdt_open(struct inode *inode, struct file *file)
+{
+	struct adx_wdt *wdt = platform_get_drvdata(adx_wdt_dev);
+
+	if (test_and_set_bit(0, &driver_open))
+		return -EBUSY;
+
+	file->private_data = wdt;
+	adx_wdt_set_timeout(wdt, 30);
+	adx_wdt_start(wdt);
+
+	return nonseekable_open(inode, file);
+}
+
+static int adx_wdt_release(struct inode *inode, struct file *file)
+{
+	struct adx_wdt *wdt = file->private_data;
+
+	adx_wdt_stop(wdt);
+	clear_bit(0, &driver_open);
+
+	return 0;
+}
+
+static long adx_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct adx_wdt *wdt = file->private_data;
+	void __user *argp = (void __user *)arg;
+	unsigned long __user *p = argp;
+	unsigned long seconds = 0;
+	unsigned int options;
+	long ret = -EINVAL;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user(argp, &adx_wdt_info, sizeof(adx_wdt_info)))
+			return -EFAULT;
+		else
+			return 0;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+
+	case WDIOC_KEEPALIVE:
+		adx_wdt_keepalive(wdt);
+		return 0;
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(seconds, p))
+			return -EFAULT;
+
+		adx_wdt_set_timeout(wdt, seconds);
+
+		/* fallthrough */
+	case WDIOC_GETTIMEOUT:
+		adx_wdt_get_timeout(wdt, &seconds);
+		return put_user(seconds, p);
+
+	case WDIOC_SETOPTIONS:
+		if (copy_from_user(&options, argp, sizeof(options)))
+			return -EFAULT;
+
+		if (options & WDIOS_DISABLECARD) {
+			adx_wdt_stop(wdt);
+			ret = 0;
+		}
+
+		if (options & WDIOS_ENABLECARD) {
+			adx_wdt_start(wdt);
+			ret = 0;
+		}
+
+		return ret;
+
+	default:
+		break;
+	}
+
+	return -ENOTTY;
+}
+
+static ssize_t adx_wdt_write(struct file *file, const char __user *data,
+		size_t len, loff_t *ppos)
+{
+	struct adx_wdt *wdt = file->private_data;
+
+	if (len)
+		adx_wdt_keepalive(wdt);
+
+	return len;
+}
+
+static const struct file_operations adx_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.open = adx_wdt_open,
+	.release = adx_wdt_release,
+	.unlocked_ioctl = adx_wdt_ioctl,
+	.write = adx_wdt_write,
+};
+
+static struct miscdevice adx_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &adx_wdt_fops,
+};
+
+static int __devinit adx_wdt_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct adx_wdt *wdt;
+	int ret = 0;
+	u32 ctrl;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt) {
+		dev_err(&pdev->dev, "cannot allocate WDT structure\n");
+		return -ENOMEM;
+	}
+
+	spin_lock_init(&wdt->lock);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "cannot obtain I/O memory region\n");
+		return -ENXIO;
+	}
+
+	res = devm_request_mem_region(&pdev->dev, res->start,
+			res->end - res->start + 1, res->name);
+	if (!res) {
+		dev_err(&pdev->dev, "cannot request I/O memory region\n");
+		return -ENXIO;
+	}
+
+	wdt->base = devm_ioremap_nocache(&pdev->dev, res->start,
+			res->end - res->start + 1);
+	if (!wdt->base) {
+		dev_err(&pdev->dev, "cannot remap I/O memory region\n");
+		return -ENXIO;
+	}
+
+	/* disable watchdog and reboot on timeout */
+	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
+	ctrl &= ~ADX_WDT_CONTROL_ENABLE;
+	ctrl &= ~ADX_WDT_CONTROL_nRESET;
+	writel(ctrl, wdt->base + ADX_WDT_CONTROL);
+
+	platform_set_drvdata(pdev, wdt);
+	adx_wdt_dev = pdev;
+
+	ret = misc_register(&adx_wdt_miscdev);
+	if (ret) {
+		dev_err(&pdev->dev, "cannot register miscdev on minor %d "
+				"(err=%d)\n", WATCHDOG_MINOR, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __devexit adx_wdt_remove(struct platform_device *pdev)
+{
+	struct adx_wdt *wdt = platform_get_drvdata(pdev);
+
+	misc_deregister(&adx_wdt_miscdev);
+	adx_wdt_stop(wdt);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static void adx_wdt_shutdown(struct platform_device *pdev)
+{
+	struct adx_wdt *wdt = platform_get_drvdata(pdev);
+	adx_wdt_stop(wdt);
+}
+
+#ifdef CONFIG_PM
+static int adx_wdt_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct adx_wdt *wdt = platform_get_drvdata(pdev);
+
+	wdt->wake = (wdt->state == WDT_STATE_START) ? 1 : 0;
+	adx_wdt_stop(wdt);
+
+	return 0;
+}
+
+static int adx_wdt_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct adx_wdt *wdt = platform_get_drvdata(pdev);
+
+	if (wdt->wake)
+		adx_wdt_start(wdt);
+
+	return 0;
+}
+
+static struct dev_pm_ops adx_wdt_pm_ops = {
+	.suspend = adx_wdt_suspend,
+	.resume = adx_wdt_resume,
+};
+
+#  define ADX_WDT_PM_OPS	(&adx_wdt_pm_ops)
+#else
+#  define ADX_WDT_PM_OPS	NULL
+#endif
+
+static struct platform_driver adx_wdt_driver = {
+	.probe = adx_wdt_probe,
+	.remove = __devexit_p(adx_wdt_remove),
+	.shutdown = adx_wdt_shutdown,
+	.driver = {
+		.name = WATCHDOG_NAME,
+		.owner = THIS_MODULE,
+		.pm = ADX_WDT_PM_OPS,
+	},
+};
+
+static int __init adx_wdt_init(void)
+{
+	return platform_driver_register(&adx_wdt_driver);
+}
+
+static void __exit adx_wdt_exit(void)
+{
+	platform_driver_unregister(&adx_wdt_driver);
+}
+
+module_init(adx_wdt_init);
+module_exit(adx_wdt_exit);
+
+MODULE_DESCRIPTION("Avionic Design Xanthos Watchdog Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);