diff options
Diffstat (limited to 'drivers/watchdog/mpcore_wdt.c')
| -rw-r--r-- | drivers/watchdog/mpcore_wdt.c | 457 |
1 files changed, 457 insertions, 0 deletions
diff --git a/drivers/watchdog/mpcore_wdt.c b/drivers/watchdog/mpcore_wdt.c new file mode 100644 index 00000000..7c741dc9 --- /dev/null +++ b/drivers/watchdog/mpcore_wdt.c @@ -0,0 +1,457 @@ +/* + * 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_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 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_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 = 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_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; + + /* + * 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 __devinit 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_printk(KERN_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_printk(KERN_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 __devexit mpcore_wdt_remove(struct platform_device *pdev) +{ + platform_set_drvdata(pdev, NULL); + + 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 = __devexit_p(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); |