[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>

1 files changed, 354 insertions, 0 deletions

diff --git a/drivers/watchdog/adx_wdt.c b/drivers/watchdog/adx_wdt.c
new file mode 100644
index 000000000000..77afb0acc500
--- /dev/null
+++ b/drivers/watchdog/adx_wdt.c
@@ -0,0 +1,354 @@
+/*
+ * 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);