+++ /dev/null
-/*
- * Watchdog driver for the mpcore watchdog timer
- *
- * (c) Copyright 2004 ARM Limited
- *
- * Based on the SoftDog driver:
- * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
- * All Rights Reserved.
- *
- * 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>
- *
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/module.h>
-#include <linux/moduleparam.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/platform_device.h>
-#include <linux/uaccess.h>
-#include <linux/slab.h>
-#include <linux/io.h>
-
-#include <asm/smp_twd.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_pdev;
-static DEFINE_SPINLOCK(wdt_lock);
-
-#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 bool nowayout = WATCHDOG_NOWAYOUT;
-module_param(nowayout, bool, 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 mpcore_wdt *wdt = arg;
-
- /* Check it really was our interrupt */
- if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
- dev_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 long count;
-
- spin_lock(&wdt_lock);
- /* Assume prescale is set to 256 */
- count = __raw_readl(wdt->base + TWD_WDOG_COUNTER);
- count = (0xFFFFFFFFU - count) * (HZ / 5);
- count = (count / 256) * mpcore_margin;
-
- /* Reload the counter */
- writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
- wdt->perturb = wdt->perturb ? 0 : 1;
- spin_unlock(&wdt_lock);
-}
-
-static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
-{
- spin_lock(&wdt_lock);
- writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
- writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
- writel(0x0, wdt->base + TWD_WDOG_CONTROL);
- spin_unlock(&wdt_lock);
-}
-
-static void mpcore_wdt_start(struct mpcore_wdt *wdt)
-{
- dev_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 = platform_get_drvdata(mpcore_wdt_pdev);
-
- 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_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;
-
- /*
- * 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 const struct watchdog_info ident = {
- .options = WDIOF_SETTIMEOUT |
- WDIOF_KEEPALIVEPING |
- WDIOF_MAGICCLOSE,
- .identity = "MPcore Watchdog",
-};
-
-static long mpcore_wdt_ioctl(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 -ENOTTY;
-
- 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_GETSTATUS:
- case WDIOC_GETBOOTSTATUS:
- uarg.i = 0;
- 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_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 -ENOTTY;
- }
-
- 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 platform_device *pdev)
-{
- struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
-
- if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
- mpcore_wdt_stop(wdt);
-}
-
-/*
- * Kernel Interfaces
- */
-static const struct file_operations mpcore_wdt_fops = {
- .owner = THIS_MODULE,
- .llseek = no_llseek,
- .write = mpcore_wdt_write,
- .unlocked_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 mpcore_wdt_probe(struct platform_device *pdev)
-{
- struct mpcore_wdt *wdt;
- struct resource *res;
- int ret;
-
- /* We only accept one device, and it must have an id of -1 */
- if (pdev->id != -1)
- return -ENODEV;
-
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!res)
- return -ENODEV;
-
- wdt = devm_kzalloc(&pdev->dev, sizeof(struct mpcore_wdt), GFP_KERNEL);
- if (!wdt)
- return -ENOMEM;
-
- wdt->dev = &pdev->dev;
- wdt->irq = platform_get_irq(pdev, 0);
- if (wdt->irq >= 0) {
- ret = devm_request_irq(wdt->dev, wdt->irq, mpcore_wdt_fire, 0,
- "mpcore_wdt", wdt);
- if (ret) {
- dev_err(wdt->dev,
- "cannot register IRQ%d for watchdog\n",
- wdt->irq);
- return ret;
- }
- }
-
- wdt->base = devm_ioremap(wdt->dev, res->start, resource_size(res));
- if (!wdt->base)
- return -ENOMEM;
-
- mpcore_wdt_miscdev.parent = &pdev->dev;
- ret = misc_register(&mpcore_wdt_miscdev);
- if (ret) {
- dev_err(wdt->dev,
- "cannot register miscdev on minor=%d (err=%d)\n",
- WATCHDOG_MINOR, ret);
- return ret;
- }
-
- mpcore_wdt_stop(wdt);
- platform_set_drvdata(pdev, wdt);
- mpcore_wdt_pdev = pdev;
-
- return 0;
-}
-
-static int mpcore_wdt_remove(struct platform_device *pdev)
-{
- misc_deregister(&mpcore_wdt_miscdev);
-
- mpcore_wdt_pdev = NULL;
-
- return 0;
-}
-
-#ifdef CONFIG_PM
-static int mpcore_wdt_suspend(struct platform_device *pdev, pm_message_t msg)
-{
- struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
- mpcore_wdt_stop(wdt); /* Turn the WDT off */
- return 0;
-}
-
-static int mpcore_wdt_resume(struct platform_device *pdev)
-{
- struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
- /* re-activate timer */
- if (test_bit(0, &wdt->timer_alive))
- mpcore_wdt_start(wdt);
- return 0;
-}
-#else
-#define mpcore_wdt_suspend NULL
-#define mpcore_wdt_resume NULL
-#endif
-
-/* work with hotplug and coldplug */
-MODULE_ALIAS("platform:mpcore_wdt");
-
-static struct platform_driver mpcore_wdt_driver = {
- .probe = mpcore_wdt_probe,
- .remove = mpcore_wdt_remove,
- .suspend = mpcore_wdt_suspend,
- .resume = mpcore_wdt_resume,
- .shutdown = mpcore_wdt_shutdown,
- .driver = {
- .owner = THIS_MODULE,
- .name = "mpcore_wdt",
- },
-};
-
-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);
- pr_info("mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
- TIMER_MARGIN);
- }
-
- pr_info("MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n",
- mpcore_noboot, mpcore_margin, nowayout);
-
- return platform_driver_register(&mpcore_wdt_driver);
-}
-
-static void __exit mpcore_wdt_exit(void)
-{
- platform_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);
projects / linux-2.6-microblaze.git / commitdiff