diff options
Diffstat (limited to 'drivers/char/watchdog/sa1100_wdt.c')
| -rw-r--r-- | drivers/char/watchdog/sa1100_wdt.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/char/watchdog/sa1100_wdt.c b/drivers/char/watchdog/sa1100_wdt.c new file mode 100644 index 00000000000..34e8f7b15e3 --- /dev/null +++ b/drivers/char/watchdog/sa1100_wdt.c @@ -0,0 +1,223 @@ +/* + * Watchdog driver for the SA11x0/PXA2xx + * + * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> + * Based on SoftDog driver by Alan Cox <alan@redhat.com> + * + * 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 Oleg Drokin nor iXcelerator.com admit liability nor provide + * warranty for any of this software. This material is provided + * "AS-IS" and at no charge. + * + * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> + * + * 27/11/2000 Initial release + */ +#include <linux/config.h> +#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> + +#ifdef CONFIG_ARCH_PXA +#include <asm/arch/pxa-regs.h> +#endif + +#include <asm/hardware.h> +#include <asm/bitops.h> +#include <asm/uaccess.h> + +#define OSCR_FREQ CLOCK_TICK_RATE +#define SA1100_CLOSE_MAGIC (0x5afc4453) + +static unsigned long sa1100wdt_users; +static int expect_close; +static int pre_margin; +static int boot_status; +#ifdef CONFIG_WATCHDOG_NOWAYOUT +static int nowayout = 1; +#else +static int nowayout = 0; +#endif + +/* + * Allow only one person to hold it open + */ +static int sa1100dog_open(struct inode *inode, struct file *file) +{ + nonseekable_open(inode, file); + if (test_and_set_bit(1,&sa1100wdt_users)) + return -EBUSY; + + /* Activate SA1100 Watchdog timer */ + OSMR3 = OSCR + pre_margin; + OSSR = OSSR_M3; + OWER = OWER_WME; + OIER |= OIER_E3; + return 0; +} + +/* + * Shut off the timer. + * Lock it in if it's a module and we defined ...NOWAYOUT + * Oddly, the watchdog can only be enabled, but we can turn off + * the interrupt, which appears to prevent the watchdog timing out. + */ +static int sa1100dog_release(struct inode *inode, struct file *file) +{ + OSMR3 = OSCR + pre_margin; + + if (expect_close == SA1100_CLOSE_MAGIC) { + OIER &= ~OIER_E3; + } else { + printk(KERN_CRIT "WATCHDOG: WDT device closed unexpectedly. WDT will not stop!\n"); + } + + clear_bit(1, &sa1100wdt_users); + expect_close = 0; + + return 0; +} + +static ssize_t sa1100dog_write(struct file *file, const char *data, size_t len, loff_t *ppos) +{ + if (len) { + if (!nowayout) { + size_t i; + + expect_close = 0; + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') + expect_close = SA1100_CLOSE_MAGIC; + } + } + /* Refresh OSMR3 timer. */ + OSMR3 = OSCR + pre_margin; + } + + return len; +} + +static struct watchdog_info ident = { + .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | + WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = "SA1100 Watchdog", +}; + +static int sa1100dog_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + int ret = -ENOIOCTLCMD; + int time; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user((struct watchdog_info *)arg, &ident, + sizeof(ident)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + ret = put_user(0, (int *)arg); + break; + + case WDIOC_GETBOOTSTATUS: + ret = put_user(boot_status, (int *)arg); + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(time, (int *)arg); + if (ret) + break; + + if (time <= 0 || time > 255) { + ret = -EINVAL; + break; + } + + pre_margin = OSCR_FREQ * time; + OSMR3 = OSCR + pre_margin; + /*fall through*/ + + case WDIOC_GETTIMEOUT: + ret = put_user(pre_margin / OSCR_FREQ, (int *)arg); + break; + + case WDIOC_KEEPALIVE: + OSMR3 = OSCR + pre_margin; + ret = 0; + break; + } + return ret; +} + +static struct file_operations sa1100dog_fops = +{ + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = sa1100dog_write, + .ioctl = sa1100dog_ioctl, + .open = sa1100dog_open, + .release = sa1100dog_release, +}; + +static struct miscdevice sa1100dog_miscdev = +{ + .minor = WATCHDOG_MINOR, + .name = "SA1100/PXA2xx watchdog", + .fops = &sa1100dog_fops, +}; + +static int margin __initdata = 60; /* (secs) Default is 1 minute */ + +static int __init sa1100dog_init(void) +{ + int ret; + + /* + * Read the reset status, and save it for later. If + * we suspend, RCSR will be cleared, and the watchdog + * reset reason will be lost. + */ + boot_status = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0; + pre_margin = OSCR_FREQ * margin; + + ret = misc_register(&sa1100dog_miscdev); + if (ret == 0) + printk("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n", + margin); + + return ret; +} + +static void __exit sa1100dog_exit(void) +{ + misc_deregister(&sa1100dog_miscdev); +} + +module_init(sa1100dog_init); +module_exit(sa1100dog_exit); + +MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>"); +MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog"); + +module_param(margin, int, 0); +MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); + +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |