diff options
Diffstat (limited to 'drivers/watchdog/mtx-1_wdt.c')
| -rw-r--r-- | drivers/watchdog/mtx-1_wdt.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/drivers/watchdog/mtx-1_wdt.c b/drivers/watchdog/mtx-1_wdt.c new file mode 100644 index 0000000000..152e41ecbb --- /dev/null +++ b/drivers/watchdog/mtx-1_wdt.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Driver for the MTX-1 Watchdog. + * + * (C) Copyright 2005 4G Systems <info@4g-systems.biz>, + * All Rights Reserved. + * http://www.4g-systems.biz + * + * (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org> + * (c) Copyright 2005 4G Systems <info@4g-systems.biz> + * + * Release 0.01. + * Author: Michael Stickel michael.stickel@4g-systems.biz + * + * Release 0.02. + * Author: Florian Fainelli florian@openwrt.org + * use the Linux watchdog/timer APIs + * + * The Watchdog is configured to reset the MTX-1 + * if it is not triggered for 100 seconds. + * It should not be triggered more often than 1.6 seconds. + * + * A timer triggers the watchdog every 5 seconds, until + * it is opened for the first time. After the first open + * it MUST be triggered every 2..95 seconds. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/miscdevice.h> +#include <linux/fs.h> +#include <linux/ioport.h> +#include <linux/timer.h> +#include <linux/completion.h> +#include <linux/jiffies.h> +#include <linux/watchdog.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/uaccess.h> +#include <linux/gpio/consumer.h> + +#define MTX1_WDT_INTERVAL (5 * HZ) + +static int ticks = 100 * HZ; + +static struct { + struct completion stop; + spinlock_t lock; + int running; + struct timer_list timer; + int queue; + int default_ticks; + unsigned long inuse; + struct gpio_desc *gpiod; + unsigned int gstate; +} mtx1_wdt_device; + +static void mtx1_wdt_trigger(struct timer_list *unused) +{ + spin_lock(&mtx1_wdt_device.lock); + if (mtx1_wdt_device.running) + ticks--; + + /* toggle wdt gpio */ + mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate; + gpiod_set_value(mtx1_wdt_device.gpiod, mtx1_wdt_device.gstate); + + if (mtx1_wdt_device.queue && ticks) + mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); + else + complete(&mtx1_wdt_device.stop); + spin_unlock(&mtx1_wdt_device.lock); +} + +static void mtx1_wdt_reset(void) +{ + ticks = mtx1_wdt_device.default_ticks; +} + + +static void mtx1_wdt_start(void) +{ + unsigned long flags; + + spin_lock_irqsave(&mtx1_wdt_device.lock, flags); + if (!mtx1_wdt_device.queue) { + mtx1_wdt_device.queue = 1; + mtx1_wdt_device.gstate = 1; + gpiod_set_value(mtx1_wdt_device.gpiod, 1); + mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); + } + mtx1_wdt_device.running++; + spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); +} + +static int mtx1_wdt_stop(void) +{ + unsigned long flags; + + spin_lock_irqsave(&mtx1_wdt_device.lock, flags); + if (mtx1_wdt_device.queue) { + mtx1_wdt_device.queue = 0; + mtx1_wdt_device.gstate = 0; + gpiod_set_value(mtx1_wdt_device.gpiod, 0); + } + ticks = mtx1_wdt_device.default_ticks; + spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); + return 0; +} + +/* Filesystem functions */ + +static int mtx1_wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(0, &mtx1_wdt_device.inuse)) + return -EBUSY; + return stream_open(inode, file); +} + + +static int mtx1_wdt_release(struct inode *inode, struct file *file) +{ + clear_bit(0, &mtx1_wdt_device.inuse); + return 0; +} + +static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = (int __user *)argp; + unsigned int value; + static const struct watchdog_info ident = { + .options = WDIOF_CARDRESET, + .identity = "MTX-1 WDT", + }; + + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user(argp, &ident, sizeof(ident))) + return -EFAULT; + break; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + put_user(0, p); + break; + case WDIOC_SETOPTIONS: + if (get_user(value, p)) + return -EFAULT; + if (value & WDIOS_ENABLECARD) + mtx1_wdt_start(); + else if (value & WDIOS_DISABLECARD) + mtx1_wdt_stop(); + else + return -EINVAL; + return 0; + case WDIOC_KEEPALIVE: + mtx1_wdt_reset(); + break; + default: + return -ENOTTY; + } + return 0; +} + + +static ssize_t mtx1_wdt_write(struct file *file, const char *buf, + size_t count, loff_t *ppos) +{ + if (!count) + return -EIO; + mtx1_wdt_reset(); + return count; +} + +static const struct file_operations mtx1_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .unlocked_ioctl = mtx1_wdt_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = mtx1_wdt_open, + .write = mtx1_wdt_write, + .release = mtx1_wdt_release, +}; + + +static struct miscdevice mtx1_wdt_misc = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &mtx1_wdt_fops, +}; + + +static int mtx1_wdt_probe(struct platform_device *pdev) +{ + int ret; + + mtx1_wdt_device.gpiod = devm_gpiod_get(&pdev->dev, + NULL, GPIOD_OUT_HIGH); + if (IS_ERR(mtx1_wdt_device.gpiod)) { + dev_err(&pdev->dev, "failed to request gpio"); + return PTR_ERR(mtx1_wdt_device.gpiod); + } + + spin_lock_init(&mtx1_wdt_device.lock); + init_completion(&mtx1_wdt_device.stop); + mtx1_wdt_device.queue = 0; + clear_bit(0, &mtx1_wdt_device.inuse); + timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0); + mtx1_wdt_device.default_ticks = ticks; + + ret = misc_register(&mtx1_wdt_misc); + if (ret < 0) { + dev_err(&pdev->dev, "failed to register\n"); + return ret; + } + mtx1_wdt_start(); + dev_info(&pdev->dev, "MTX-1 Watchdog driver\n"); + return 0; +} + +static void mtx1_wdt_remove(struct platform_device *pdev) +{ + /* FIXME: do we need to lock this test ? */ + if (mtx1_wdt_device.queue) { + mtx1_wdt_device.queue = 0; + wait_for_completion(&mtx1_wdt_device.stop); + } + + misc_deregister(&mtx1_wdt_misc); +} + +static struct platform_driver mtx1_wdt_driver = { + .probe = mtx1_wdt_probe, + .remove_new = mtx1_wdt_remove, + .driver.name = "mtx1-wdt", + .driver.owner = THIS_MODULE, +}; + +module_platform_driver(mtx1_wdt_driver); + +MODULE_AUTHOR("Michael Stickel, Florian Fainelli"); +MODULE_DESCRIPTION("Driver for the MTX-1 watchdog"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:mtx1-wdt"); |