diff options
Diffstat (limited to 'drivers/watchdog/orion5x_wdt.c')
| -rw-r--r-- | drivers/watchdog/orion5x_wdt.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/drivers/watchdog/orion5x_wdt.c b/drivers/watchdog/orion5x_wdt.c new file mode 100644 index 00000000000..14a339f58b6 --- /dev/null +++ b/drivers/watchdog/orion5x_wdt.c @@ -0,0 +1,245 @@ +/* + * drivers/watchdog/orion5x_wdt.c + * + * Watchdog driver for Orion5x processors + * + * Author: Sylver Bruneau <sylver.bruneau@googlemail.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/init.h> +#include <linux/uaccess.h> +#include <linux/io.h> +#include <linux/spinlock.h> + +/* + * Watchdog timer block registers. + */ +#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000) +#define WDT_EN 0x0010 +#define WDT_VAL (TIMER_VIRT_BASE + 0x0024) + +#define WDT_MAX_DURATION (0xffffffff / ORION5X_TCLK) +#define WDT_IN_USE 0 +#define WDT_OK_TO_CLOSE 1 + +static int nowayout = WATCHDOG_NOWAYOUT; +static int heartbeat = WDT_MAX_DURATION; /* (seconds) */ +static unsigned long wdt_status; +static spinlock_t wdt_lock; + +static void wdt_enable(void) +{ + u32 reg; + + spin_lock(&wdt_lock); + + /* Set watchdog duration */ + writel(ORION5X_TCLK * heartbeat, WDT_VAL); + + /* Clear watchdog timer interrupt */ + reg = readl(BRIDGE_CAUSE); + reg &= ~WDT_INT_REQ; + writel(reg, BRIDGE_CAUSE); + + /* Enable watchdog timer */ + reg = readl(TIMER_CTRL); + reg |= WDT_EN; + writel(reg, TIMER_CTRL); + + /* Enable reset on watchdog */ + reg = readl(CPU_RESET_MASK); + reg |= WDT_RESET; + writel(reg, CPU_RESET_MASK); + + spin_unlock(&wdt_lock); +} + +static void wdt_disable(void) +{ + u32 reg; + + spin_lock(&wdt_lock); + + /* Disable reset on watchdog */ + reg = readl(CPU_RESET_MASK); + reg &= ~WDT_RESET; + writel(reg, CPU_RESET_MASK); + + /* Disable watchdog timer */ + reg = readl(TIMER_CTRL); + reg &= ~WDT_EN; + writel(reg, TIMER_CTRL); + + spin_unlock(&wdt_lock); +} + +static int orion5x_wdt_get_timeleft(int *time_left) +{ + spin_lock(&wdt_lock); + *time_left = readl(WDT_VAL) / ORION5X_TCLK; + spin_unlock(&wdt_lock); + return 0; +} + +static int orion5x_wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(WDT_IN_USE, &wdt_status)) + return -EBUSY; + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + wdt_enable(); + return nonseekable_open(inode, file); +} + +static ssize_t orion5x_wdt_write(struct file *file, const char *data, + size_t len, loff_t *ppos) +{ + if (len) { + if (!nowayout) { + size_t i; + + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') + set_bit(WDT_OK_TO_CLOSE, &wdt_status); + } + } + wdt_enable(); + } + return len; +} + +static struct watchdog_info ident = { + .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING, + .identity = "Orion5x Watchdog", +}; + + +static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int ret = -ENOTTY; + int time; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user((struct watchdog_info *)arg, &ident, + sizeof(ident)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + ret = put_user(0, (int *)arg); + break; + + case WDIOC_KEEPALIVE: + wdt_enable(); + ret = 0; + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(time, (int *)arg); + if (ret) + break; + + if (time <= 0 || time > WDT_MAX_DURATION) { + ret = -EINVAL; + break; + } + heartbeat = time; + wdt_enable(); + /* Fall through */ + + case WDIOC_GETTIMEOUT: + ret = put_user(heartbeat, (int *)arg); + break; + + case WDIOC_GETTIMELEFT: + if (orion5x_wdt_get_timeleft(&time)) { + ret = -EINVAL; + break; + } + ret = put_user(time, (int *)arg); + break; + } + return ret; +} + +static int orion5x_wdt_release(struct inode *inode, struct file *file) +{ + if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) + wdt_disable(); + else + printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " + "timer will not stop\n"); + clear_bit(WDT_IN_USE, &wdt_status); + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + return 0; +} + + +static const struct file_operations orion5x_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = orion5x_wdt_write, + .unlocked_ioctl = orion5x_wdt_ioctl, + .open = orion5x_wdt_open, + .release = orion5x_wdt_release, +}; + +static struct miscdevice orion5x_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &orion5x_wdt_fops, +}; + +static int __init orion5x_wdt_init(void) +{ + int ret; + + spin_lock_init(&wdt_lock); + + ret = misc_register(&orion5x_wdt_miscdev); + if (ret == 0) + printk("Orion5x Watchdog Timer: heartbeat %d sec\n", + heartbeat); + + return ret; +} + +static void __exit orion5x_wdt_exit(void) +{ + misc_deregister(&orion5x_wdt_miscdev); +} + +module_init(orion5x_wdt_init); +module_exit(orion5x_wdt_exit); + +MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>"); +MODULE_DESCRIPTION("Orion5x Processor Watchdog"); + +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is " + __MODULE_STRING(WDT_MAX_DURATION) ")"); + +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |