diff options
Diffstat (limited to 'drivers/watchdog/stmp3xxx_wdt.c')
| -rw-r--r-- | drivers/watchdog/stmp3xxx_wdt.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/drivers/watchdog/stmp3xxx_wdt.c b/drivers/watchdog/stmp3xxx_wdt.c new file mode 100644 index 00000000..21d96b92 --- /dev/null +++ b/drivers/watchdog/stmp3xxx_wdt.c @@ -0,0 +1,288 @@ +/* + * Watchdog driver for Freescale STMP37XX/STMP378X + * + * Author: Vitaly Wool <vital@embeddedalley.com> + * + * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved. + * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> +#include <linux/uaccess.h> +#include <linux/module.h> + +#include <mach/platform.h> +#include <mach/regs-rtc.h> + +#define DEFAULT_HEARTBEAT 19 +#define MAX_HEARTBEAT (0x10000000 >> 6) + +/* missing bitmask in headers */ +#define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER 0x80000000 + +#define WDT_IN_USE 0 +#define WDT_OK_TO_CLOSE 1 + +#define WDOG_COUNTER_RATE 1000 /* 1 kHz clock */ + +static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock); +static unsigned long wdt_status; +static const bool nowayout = WATCHDOG_NOWAYOUT; +static int heartbeat = DEFAULT_HEARTBEAT; +static unsigned long boot_status; + +static void wdt_enable(u32 value) +{ + spin_lock(&stmp3xxx_wdt_io_lock); + __raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG); + stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL); + stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, + REGS_RTC_BASE + HW_RTC_PERSISTENT1); + spin_unlock(&stmp3xxx_wdt_io_lock); +} + +static void wdt_disable(void) +{ + spin_lock(&stmp3xxx_wdt_io_lock); + stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, + REGS_RTC_BASE + HW_RTC_PERSISTENT1); + stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL); + spin_unlock(&stmp3xxx_wdt_io_lock); +} + +static void wdt_ping(void) +{ + wdt_enable(heartbeat * WDOG_COUNTER_RATE); +} + +static int stmp3xxx_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_ping(); + + return nonseekable_open(inode, file); +} + +static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *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_ping(); + } + + return len; +} + +static const struct watchdog_info ident = { + .options = WDIOF_CARDRESET | + WDIOF_MAGICCLOSE | + WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING, + .identity = "STMP3XXX Watchdog", +}; + +static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + int new_heartbeat, opts; + int ret = -ENOTTY; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + ret = put_user(0, p); + break; + + case WDIOC_GETBOOTSTATUS: + ret = put_user(boot_status, p); + break; + + case WDIOC_SETOPTIONS: + if (get_user(opts, p)) { + ret = -EFAULT; + break; + } + if (opts & WDIOS_DISABLECARD) + wdt_disable(); + else if (opts & WDIOS_ENABLECARD) + wdt_ping(); + else { + pr_debug("%s: unknown option 0x%x\n", __func__, opts); + ret = -EINVAL; + break; + } + ret = 0; + break; + + case WDIOC_KEEPALIVE: + wdt_ping(); + ret = 0; + break; + + case WDIOC_SETTIMEOUT: + if (get_user(new_heartbeat, p)) { + ret = -EFAULT; + break; + } + if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) { + ret = -EINVAL; + break; + } + + heartbeat = new_heartbeat; + wdt_ping(); + /* Fall through */ + + case WDIOC_GETTIMEOUT: + ret = put_user(heartbeat, p); + break; + } + return ret; +} + +static int stmp3xxx_wdt_release(struct inode *inode, struct file *file) +{ + int ret = 0; + + if (!nowayout) { + if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { + wdt_ping(); + pr_debug("%s: Device closed unexpectedly\n", __func__); + ret = -EINVAL; + } else { + wdt_disable(); + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + } + } + clear_bit(WDT_IN_USE, &wdt_status); + + return ret; +} + +static const struct file_operations stmp3xxx_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = stmp3xxx_wdt_write, + .unlocked_ioctl = stmp3xxx_wdt_ioctl, + .open = stmp3xxx_wdt_open, + .release = stmp3xxx_wdt_release, +}; + +static struct miscdevice stmp3xxx_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &stmp3xxx_wdt_fops, +}; + +static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev) +{ + int ret = 0; + + if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) + heartbeat = DEFAULT_HEARTBEAT; + + boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) & + BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER; + boot_status = !!boot_status; + stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, + REGS_RTC_BASE + HW_RTC_PERSISTENT1); + wdt_disable(); /* disable for now */ + + ret = misc_register(&stmp3xxx_wdt_miscdev); + if (ret < 0) { + dev_err(&pdev->dev, "cannot register misc device\n"); + return ret; + } + + pr_info("initialized, heartbeat %d sec\n", heartbeat); + + return ret; +} + +static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev) +{ + misc_deregister(&stmp3xxx_wdt_miscdev); + return 0; +} + +#ifdef CONFIG_PM +static int wdt_suspended; +static u32 wdt_saved_time; + +static int stmp3xxx_wdt_suspend(struct platform_device *pdev, + pm_message_t state) +{ + if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) & + BM_RTC_CTRL_WATCHDOGEN) { + wdt_suspended = 1; + wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG); + wdt_disable(); + } + return 0; +} + +static int stmp3xxx_wdt_resume(struct platform_device *pdev) +{ + if (wdt_suspended) { + wdt_enable(wdt_saved_time); + wdt_suspended = 0; + } + return 0; +} +#else +#define stmp3xxx_wdt_suspend NULL +#define stmp3xxx_wdt_resume NULL +#endif + +static struct platform_driver platform_wdt_driver = { + .driver = { + .name = "stmp3xxx_wdt", + }, + .probe = stmp3xxx_wdt_probe, + .remove = __devexit_p(stmp3xxx_wdt_remove), + .suspend = stmp3xxx_wdt_suspend, + .resume = stmp3xxx_wdt_resume, +}; + +module_platform_driver(platform_wdt_driver); + +MODULE_DESCRIPTION("STMP3XXX Watchdog Driver"); +MODULE_LICENSE("GPL"); + +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, + "Watchdog heartbeat period in seconds from 1 to " + __MODULE_STRING(MAX_HEARTBEAT) ", default " + __MODULE_STRING(DEFAULT_HEARTBEAT)); + +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |