[ARM SMP] Add MPCore watchdog driver
Add platform independent parts of the ARM MPCore watchdog driver.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/char/watchdog/mpcore_wdt.c b/drivers/char/watchdog/mpcore_wdt.c
new file mode 100644
index 0000000..c694eee
--- /dev/null
+++ b/drivers/char/watchdog/mpcore_wdt.c
@@ -0,0 +1,434 @@
+/*
+ * Watchdog driver for the mpcore watchdog timer
+ *
+ * (c) Copyright 2004 ARM Limited
+ *
+ * Based on the SoftDog driver:
+ * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
+ * http://www.redhat.com
+ *
+ * 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.
+ *
+ * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
+ * warranty for any of this software. This material is provided
+ * "AS-IS" and at no charge.
+ *
+ * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
+ *
+ */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <asm/uaccess.h>
+
+struct mpcore_wdt {
+ unsigned long timer_alive;
+ struct device *dev;
+ void __iomem *base;
+ int irq;
+ unsigned int perturb;
+ char expect_close;
+};
+
+static struct platform_device *mpcore_wdt_dev;
+
+extern unsigned int mpcore_timer_rate;
+
+#define TIMER_MARGIN 60
+static int mpcore_margin = TIMER_MARGIN;
+module_param(mpcore_margin, int, 0);
+MODULE_PARM_DESC(mpcore_margin, "MPcore timer margin in seconds. (0<mpcore_margin<65536, default=" __MODULE_STRING(TIMER_MARGIN) ")");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+#define ONLY_TESTING 0
+static int mpcore_noboot = ONLY_TESTING;
+module_param(mpcore_noboot, int, 0);
+MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, set to 1 to ignore reboots, 0 to reboot (default=" __MODULE_STRING(ONLY_TESTING) ")");
+
+/*
+ * This is the interrupt handler. Note that we only use this
+ * in testing mode, so don't actually do a reboot here.
+ */
+static irqreturn_t mpcore_wdt_fire(int irq, void *arg, struct pt_regs *regs)
+{
+ struct mpcore_wdt *wdt = arg;
+
+ /* Check it really was our interrupt */
+ if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
+ dev_printk(KERN_CRIT, wdt->dev, "Triggered - Reboot ignored.\n");
+
+ /* Clear the interrupt on the watchdog */
+ writel(1, wdt->base + TWD_WDOG_INTSTAT);
+
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+/*
+ * mpcore_wdt_keepalive - reload the timer
+ *
+ * Note that the spec says a DIFFERENT value must be written to the reload
+ * register each time. The "perturb" variable deals with this by adding 1
+ * to the count every other time the function is called.
+ */
+static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
+{
+ unsigned int count;
+
+ /* Assume prescale is set to 256 */
+ count = (mpcore_timer_rate / 256) * mpcore_margin;
+
+ /* Reload the counter */
+ writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
+
+ wdt->perturb = wdt->perturb ? 0 : 1;
+}
+
+static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
+{
+ writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
+ writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
+ writel(0x0, wdt->base + TWD_WDOG_CONTROL);
+}
+
+static void mpcore_wdt_start(struct mpcore_wdt *wdt)
+{
+ dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
+
+ /* This loads the count register but does NOT start the count yet */
+ mpcore_wdt_keepalive(wdt);
+
+ if (mpcore_noboot) {
+ /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
+ writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
+ } else {
+ /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
+ writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
+ }
+}
+
+static int mpcore_wdt_set_heartbeat(int t)
+{
+ if (t < 0x0001 || t > 0xFFFF)
+ return -EINVAL;
+
+ mpcore_margin = t;
+ return 0;
+}
+
+/*
+ * /dev/watchdog handling
+ */
+static int mpcore_wdt_open(struct inode *inode, struct file *file)
+{
+ struct mpcore_wdt *wdt = dev_get_drvdata(&mpcore_wdt_dev->dev);
+
+ if (test_and_set_bit(0, &wdt->timer_alive))
+ return -EBUSY;
+
+ if (nowayout)
+ __module_get(THIS_MODULE);
+
+ file->private_data = wdt;
+
+ /*
+ * Activate timer
+ */
+ mpcore_wdt_start(wdt);
+
+ return nonseekable_open(inode, file);
+}
+
+static int mpcore_wdt_release(struct inode *inode, struct file *file)
+{
+ struct mpcore_wdt *wdt = file->private_data;
+
+ /*
+ * Shut off the timer.
+ * Lock it in if it's a module and we set nowayout
+ */
+ if (wdt->expect_close == 42) {
+ mpcore_wdt_stop(wdt);
+ } else {
+ dev_printk(KERN_CRIT, wdt->dev, "unexpected close, not stopping watchdog!\n");
+ mpcore_wdt_keepalive(wdt);
+ }
+ clear_bit(0, &wdt->timer_alive);
+ wdt->expect_close = 0;
+ return 0;
+}
+
+static ssize_t mpcore_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
+{
+ struct mpcore_wdt *wdt = file->private_data;
+
+ /* Can't seek (pwrite) on this device */
+ if (ppos != &file->f_pos)
+ return -ESPIPE;
+
+ /*
+ * Refresh the timer.
+ */
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ /* In case it was set long ago */
+ wdt->expect_close = 0;
+
+ for (i = 0; i != len; i++) {
+ char c;
+
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ wdt->expect_close = 42;
+ }
+ }
+ mpcore_wdt_keepalive(wdt);
+ }
+ return len;
+}
+
+static struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+ .identity = "MPcore Watchdog",
+};
+
+static int mpcore_wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ struct mpcore_wdt *wdt = file->private_data;
+ int ret;
+ union {
+ struct watchdog_info ident;
+ int i;
+ } uarg;
+
+ if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
+ return -ENOIOCTLCMD;
+
+ if (_IOC_DIR(cmd) & _IOC_WRITE) {
+ ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
+ if (ret)
+ return -EFAULT;
+ }
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ uarg.ident = ident;
+ ret = 0;
+ break;
+
+ case WDIOC_SETOPTIONS:
+ ret = -EINVAL;
+ if (uarg.i & WDIOS_DISABLECARD) {
+ mpcore_wdt_stop(wdt);
+ ret = 0;
+ }
+ if (uarg.i & WDIOS_ENABLECARD) {
+ mpcore_wdt_start(wdt);
+ ret = 0;
+ }
+ break;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ uarg.i = 0;
+ ret = 0;
+ break;
+
+ case WDIOC_KEEPALIVE:
+ mpcore_wdt_keepalive(wdt);
+ ret = 0;
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ ret = mpcore_wdt_set_heartbeat(uarg.i);
+ if (ret)
+ break;
+
+ mpcore_wdt_keepalive(wdt);
+ /* Fall */
+ case WDIOC_GETTIMEOUT:
+ uarg.i = mpcore_margin;
+ ret = 0;
+ break;
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+
+ if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
+ ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
+ if (ret)
+ ret = -EFAULT;
+ }
+ return ret;
+}
+
+/*
+ * System shutdown handler. Turn off the watchdog if we're
+ * restarting or halting the system.
+ */
+static void mpcore_wdt_shutdown(struct device *_dev)
+{
+ struct mpcore_wdt *wdt = dev_get_drvdata(_dev);
+
+ if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
+ mpcore_wdt_stop(wdt);
+}
+
+/*
+ * Kernel Interfaces
+ */
+static struct file_operations mpcore_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = mpcore_wdt_write,
+ .ioctl = mpcore_wdt_ioctl,
+ .open = mpcore_wdt_open,
+ .release = mpcore_wdt_release,
+};
+
+static struct miscdevice mpcore_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &mpcore_wdt_fops,
+};
+
+static int __devinit mpcore_wdt_probe(struct device *_dev)
+{
+ struct platform_device *dev = to_platform_device(_dev);
+ struct mpcore_wdt *wdt;
+ struct resource *res;
+ int ret;
+
+ /* We only accept one device, and it must have an id of -1 */
+ if (dev->id != -1)
+ return -ENODEV;
+
+ res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+ if (!res) {
+ ret = -ENODEV;
+ goto err_out;
+ }
+
+ wdt = kmalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
+ if (!wdt) {
+ ret = -ENOMEM;
+ goto err_out;
+ }
+ memset(wdt, 0, sizeof(struct mpcore_wdt));
+
+ wdt->dev = &dev->dev;
+ wdt->irq = platform_get_irq(dev, 0);
+ wdt->base = ioremap(res->start, res->end - res->start + 1);
+ if (!wdt->base) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
+
+ mpcore_wdt_miscdev.dev = &dev->dev;
+ ret = misc_register(&mpcore_wdt_miscdev);
+ if (ret) {
+ dev_printk(KERN_ERR, _dev, "cannot register miscdev on minor=%d (err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ goto err_misc;
+ }
+
+ ret = request_irq(wdt->irq, mpcore_wdt_fire, SA_INTERRUPT, "mpcore_wdt", wdt);
+ if (ret) {
+ dev_printk(KERN_ERR, _dev, "cannot register IRQ%d for watchdog\n", wdt->irq);
+ goto err_irq;
+ }
+
+ mpcore_wdt_stop(wdt);
+ dev_set_drvdata(&dev->dev, wdt);
+ mpcore_wdt_dev = dev;
+
+ return 0;
+
+ err_irq:
+ misc_deregister(&mpcore_wdt_miscdev);
+ err_misc:
+ iounmap(wdt->base);
+ err_free:
+ kfree(wdt);
+ err_out:
+ return ret;
+}
+
+static int __devexit mpcore_wdt_remove(struct device *dev)
+{
+ struct mpcore_wdt *wdt = dev_get_drvdata(dev);
+
+ dev_set_drvdata(dev, NULL);
+
+ misc_deregister(&mpcore_wdt_miscdev);
+
+ mpcore_wdt_dev = NULL;
+
+ free_irq(wdt->irq, wdt);
+ iounmap(wdt->base);
+ kfree(wdt);
+ return 0;
+}
+
+static struct device_driver mpcore_wdt_driver = {
+ .name = "mpcore_wdt",
+ .bus = &platform_bus_type,
+ .probe = mpcore_wdt_probe,
+ .remove = __devexit_p(mpcore_wdt_remove),
+ .shutdown = mpcore_wdt_shutdown,
+};
+
+static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
+
+static int __init mpcore_wdt_init(void)
+{
+ /*
+ * Check that the margin value is within it's range;
+ * if not reset to the default
+ */
+ if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
+ mpcore_wdt_set_heartbeat(TIMER_MARGIN);
+ printk(KERN_INFO "mpcore_margin value must be 0<mpcore_margin<65536, using %d\n",
+ TIMER_MARGIN);
+ }
+
+ printk(banner, mpcore_noboot, mpcore_margin, nowayout);
+
+ return driver_register(&mpcore_wdt_driver);
+}
+
+static void __exit mpcore_wdt_exit(void)
+{
+ driver_unregister(&mpcore_wdt_driver);
+}
+
+module_init(mpcore_wdt_init);
+module_exit(mpcore_wdt_exit);
+
+MODULE_AUTHOR("ARM Limited");
+MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);