diff options
Diffstat (limited to 'drivers/char/watchdog/shwdt.c')
| -rw-r--r-- | drivers/char/watchdog/shwdt.c | 485 |
1 files changed, 0 insertions, 485 deletions
diff --git a/drivers/char/watchdog/shwdt.c b/drivers/char/watchdog/shwdt.c deleted file mode 100644 index cecbedd473a..00000000000 --- a/drivers/char/watchdog/shwdt.c +++ /dev/null @@ -1,485 +0,0 @@ -/* - * drivers/char/watchdog/shwdt.c - * - * Watchdog driver for integrated watchdog in the SuperH processors. - * - * Copyright (C) 2001, 2002, 2003 Paul Mundt <lethal@linux-sh.org> - * - * 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. - * - * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> - * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT - * - * 19-Apr-2002 Rob Radez <rob@osinvestor.com> - * Added expect close support, made emulated timeout runtime changeable - * general cleanups, add some ioctls - */ -#include <linux/module.h> -#include <linux/moduleparam.h> -#include <linux/init.h> -#include <linux/types.h> -#include <linux/miscdevice.h> -#include <linux/watchdog.h> -#include <linux/reboot.h> -#include <linux/notifier.h> -#include <linux/ioport.h> -#include <linux/fs.h> -#include <linux/mm.h> -#include <asm/io.h> -#include <asm/uaccess.h> -#include <asm/watchdog.h> - -#define PFX "shwdt: " - -/* - * Default clock division ratio is 5.25 msecs. For an additional table of - * values, consult the asm-sh/watchdog.h. Overload this at module load - * time. - * - * In order for this to work reliably we need to have HZ set to 1000 or - * something quite higher than 100 (or we need a proper high-res timer - * implementation that will deal with this properly), otherwise the 10ms - * resolution of a jiffy is enough to trigger the overflow. For things like - * the SH-4 and SH-5, this isn't necessarily that big of a problem, though - * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely - * necssary. - * - * As a result of this timing problem, the only modes that are particularly - * feasible are the 4096 and the 2048 divisors, which yeild 5.25 and 2.62ms - * overflow periods respectively. - * - * Also, since we can't really expect userspace to be responsive enough - * before the overflow happens, we maintain two seperate timers .. One in - * the kernel for clearing out WOVF every 2ms or so (again, this depends on - * HZ == 1000), and another for monitoring userspace writes to the WDT device. - * - * As such, we currently use a configurable heartbeat interval which defaults - * to 30s. In this case, the userspace daemon is only responsible for periodic - * writes to the device before the next heartbeat is scheduled. If the daemon - * misses its deadline, the kernel timer will allow the WDT to overflow. - */ -static int clock_division_ratio = WTCSR_CKS_4096; - -#define next_ping_period(cks) msecs_to_jiffies(cks - 4) - -static void sh_wdt_ping(unsigned long data); - -static unsigned long shwdt_is_open; -static struct watchdog_info sh_wdt_info; -static char shwdt_expect_close; -static DEFINE_TIMER(timer, sh_wdt_ping, 0, 0); -static unsigned long next_heartbeat; - -#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */ -static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */ - -static int nowayout = WATCHDOG_NOWAYOUT; - -/** - * sh_wdt_start - Start the Watchdog - * - * Starts the watchdog. - */ -static void sh_wdt_start(void) -{ - __u8 csr; - - next_heartbeat = jiffies + (heartbeat * HZ); - mod_timer(&timer, next_ping_period(clock_division_ratio)); - - csr = sh_wdt_read_csr(); - csr |= WTCSR_WT | clock_division_ratio; - sh_wdt_write_csr(csr); - - sh_wdt_write_cnt(0); - - /* - * These processors have a bit of an inconsistent initialization - * process.. starting with SH-3, RSTS was moved to WTCSR, and the - * RSTCSR register was removed. - * - * On the SH-2 however, in addition with bits being in different - * locations, we must deal with RSTCSR outright.. - */ - csr = sh_wdt_read_csr(); - csr |= WTCSR_TME; - csr &= ~WTCSR_RSTS; - sh_wdt_write_csr(csr); - -#ifdef CONFIG_CPU_SH2 - /* - * Whoever came up with the RSTCSR semantics must've been smoking - * some of the good stuff, since in addition to the WTCSR/WTCNT write - * brain-damage, it's managed to fuck things up one step further.. - * - * If we need to clear the WOVF bit, the upper byte has to be 0xa5.. - * but if we want to touch RSTE or RSTS, the upper byte has to be - * 0x5a.. - */ - csr = sh_wdt_read_rstcsr(); - csr &= ~RSTCSR_RSTS; - sh_wdt_write_rstcsr(csr); -#endif -} - -/** - * sh_wdt_stop - Stop the Watchdog - * Stops the watchdog. - */ -static void sh_wdt_stop(void) -{ - __u8 csr; - - del_timer(&timer); - - csr = sh_wdt_read_csr(); - csr &= ~WTCSR_TME; - sh_wdt_write_csr(csr); -} - -/** - * sh_wdt_keepalive - Keep the Userspace Watchdog Alive - * The Userspace watchdog got a KeepAlive: schedule the next heartbeat. - */ -static inline void sh_wdt_keepalive(void) -{ - next_heartbeat = jiffies + (heartbeat * HZ); -} - -/** - * sh_wdt_set_heartbeat - Set the Userspace Watchdog heartbeat - * Set the Userspace Watchdog heartbeat - */ -static int sh_wdt_set_heartbeat(int t) -{ - if (unlikely((t < 1) || (t > 3600))) /* arbitrary upper limit */ - return -EINVAL; - - heartbeat = t; - return 0; -} - -/** - * sh_wdt_ping - Ping the Watchdog - * @data: Unused - * - * Clears overflow bit, resets timer counter. - */ -static void sh_wdt_ping(unsigned long data) -{ - if (time_before(jiffies, next_heartbeat)) { - __u8 csr; - - csr = sh_wdt_read_csr(); - csr &= ~WTCSR_IOVF; - sh_wdt_write_csr(csr); - - sh_wdt_write_cnt(0); - - mod_timer(&timer, next_ping_period(clock_division_ratio)); - } else - printk(KERN_WARNING PFX "Heartbeat lost! Will not ping " - "the watchdog\n"); -} - -/** - * sh_wdt_open - Open the Device - * @inode: inode of device - * @file: file handle of device - * - * Watchdog device is opened and started. - */ -static int sh_wdt_open(struct inode *inode, struct file *file) -{ - if (test_and_set_bit(0, &shwdt_is_open)) - return -EBUSY; - if (nowayout) - __module_get(THIS_MODULE); - - sh_wdt_start(); - - return nonseekable_open(inode, file); -} - -/** - * sh_wdt_close - Close the Device - * @inode: inode of device - * @file: file handle of device - * - * Watchdog device is closed and stopped. - */ -static int sh_wdt_close(struct inode *inode, struct file *file) -{ - if (shwdt_expect_close == 42) { - sh_wdt_stop(); - } else { - printk(KERN_CRIT PFX "Unexpected close, not " - "stopping watchdog!\n"); - sh_wdt_keepalive(); - } - - clear_bit(0, &shwdt_is_open); - shwdt_expect_close = 0; - - return 0; -} - -/** - * sh_wdt_write - Write to Device - * @file: file handle of device - * @buf: buffer to write - * @count: length of buffer - * @ppos: offset - * - * Pings the watchdog on write. - */ -static ssize_t sh_wdt_write(struct file *file, const char *buf, - size_t count, loff_t *ppos) -{ - if (count) { - if (!nowayout) { - size_t i; - - shwdt_expect_close = 0; - - for (i = 0; i != count; i++) { - char c; - if (get_user(c, buf + i)) - return -EFAULT; - if (c == 'V') - shwdt_expect_close = 42; - } - } - sh_wdt_keepalive(); - } - - return count; -} - -/** - * sh_wdt_mmap - map WDT/CPG registers into userspace - * @file: file structure for the device - * @vma: VMA to map the registers into - * - * A simple mmap() implementation for the corner cases where the counter - * needs to be mapped in userspace directly. Due to the relatively small - * size of the area, neighbouring registers not necessarily tied to the - * CPG will also be accessible through the register page, so this remains - * configurable for users that really know what they're doing. - * - * Additionaly, the register page maps in the CPG register base relative - * to the nearest page-aligned boundary, which requires that userspace do - * the appropriate CPU subtype math for calculating the page offset for - * the counter value. - */ -static int sh_wdt_mmap(struct file *file, struct vm_area_struct *vma) -{ - int ret = -ENOSYS; - -#ifdef CONFIG_SH_WDT_MMAP - unsigned long addr; - - /* Only support the simple cases where we map in a register page. */ - if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff) - return -EINVAL; - - /* - * Pick WTCNT as the start, it's usually the first register after the - * FRQCR, and neither one are generally page-aligned out of the box. - */ - addr = WTCNT & ~(PAGE_SIZE - 1); - - vma->vm_flags |= VM_IO; - vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); - - if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT, - PAGE_SIZE, vma->vm_page_prot)) { - printk(KERN_ERR PFX "%s: io_remap_pfn_range failed\n", - __FUNCTION__); - return -EAGAIN; - } - - ret = 0; -#endif - - return ret; -} - -/** - * sh_wdt_ioctl - Query Device - * @inode: inode of device - * @file: file handle of device - * @cmd: watchdog command - * @arg: argument - * - * Query basic information from the device or ping it, as outlined by the - * watchdog API. - */ -static int sh_wdt_ioctl(struct inode *inode, struct file *file, - unsigned int cmd, unsigned long arg) -{ - int new_heartbeat; - int options, retval = -EINVAL; - - switch (cmd) { - case WDIOC_GETSUPPORT: - return copy_to_user((struct watchdog_info *)arg, - &sh_wdt_info, - sizeof(sh_wdt_info)) ? -EFAULT : 0; - case WDIOC_GETSTATUS: - case WDIOC_GETBOOTSTATUS: - return put_user(0, (int *)arg); - case WDIOC_KEEPALIVE: - sh_wdt_keepalive(); - return 0; - case WDIOC_SETTIMEOUT: - if (get_user(new_heartbeat, (int *)arg)) - return -EFAULT; - - if (sh_wdt_set_heartbeat(new_heartbeat)) - return -EINVAL; - - sh_wdt_keepalive(); - /* Fall */ - case WDIOC_GETTIMEOUT: - return put_user(heartbeat, (int *)arg); - case WDIOC_SETOPTIONS: - if (get_user(options, (int *)arg)) - return -EFAULT; - - if (options & WDIOS_DISABLECARD) { - sh_wdt_stop(); - retval = 0; - } - - if (options & WDIOS_ENABLECARD) { - sh_wdt_start(); - retval = 0; - } - - return retval; - default: - return -ENOTTY; - } - - return 0; -} - -/** - * sh_wdt_notify_sys - Notifier Handler - * @this: notifier block - * @code: notifier event - * @unused: unused - * - * Handles specific events, such as turning off the watchdog during a - * shutdown event. - */ -static int sh_wdt_notify_sys(struct notifier_block *this, - unsigned long code, void *unused) -{ - if (code == SYS_DOWN || code == SYS_HALT) - sh_wdt_stop(); - - return NOTIFY_DONE; -} - -static const struct file_operations sh_wdt_fops = { - .owner = THIS_MODULE, - .llseek = no_llseek, - .write = sh_wdt_write, - .ioctl = sh_wdt_ioctl, - .open = sh_wdt_open, - .release = sh_wdt_close, - .mmap = sh_wdt_mmap, -}; - -static struct watchdog_info sh_wdt_info = { - .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | - WDIOF_MAGICCLOSE, - .firmware_version = 1, - .identity = "SH WDT", -}; - -static struct notifier_block sh_wdt_notifier = { - .notifier_call = sh_wdt_notify_sys, -}; - -static struct miscdevice sh_wdt_miscdev = { - .minor = WATCHDOG_MINOR, - .name = "watchdog", - .fops = &sh_wdt_fops, -}; - -/** - * sh_wdt_init - Initialize module - * Registers the device and notifier handler. Actual device - * initialization is handled by sh_wdt_open(). - */ -static int __init sh_wdt_init(void) -{ - int rc; - - if ((clock_division_ratio < 0x5) || (clock_division_ratio > 0x7)) { - clock_division_ratio = WTCSR_CKS_4096; - printk(KERN_INFO PFX "clock_division_ratio value must " - "be 0x5<=x<=0x7, using %d\n", clock_division_ratio); - } - - rc = sh_wdt_set_heartbeat(heartbeat); - if (unlikely(rc)) { - heartbeat = WATCHDOG_HEARTBEAT; - printk(KERN_INFO PFX "heartbeat value must " - "be 1<=x<=3600, using %d\n", heartbeat); - } - - rc = register_reboot_notifier(&sh_wdt_notifier); - if (unlikely(rc)) { - printk(KERN_ERR PFX "Can't register reboot notifier (err=%d)\n", - rc); - return rc; - } - - rc = misc_register(&sh_wdt_miscdev); - if (unlikely(rc)) { - printk(KERN_ERR PFX "Can't register miscdev on " - "minor=%d (err=%d)\n", sh_wdt_miscdev.minor, rc); - unregister_reboot_notifier(&sh_wdt_notifier); - return rc; - } - - printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n", - heartbeat, nowayout); - - return 0; -} - -/** - * sh_wdt_exit - Deinitialize module - * Unregisters the device and notifier handler. Actual device - * deinitialization is handled by sh_wdt_close(). - */ -static void __exit sh_wdt_exit(void) -{ - misc_deregister(&sh_wdt_miscdev); - unregister_reboot_notifier(&sh_wdt_notifier); -} - -MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); -MODULE_DESCRIPTION("SuperH watchdog driver"); -MODULE_LICENSE("GPL"); -MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); - -module_param(clock_division_ratio, int, 0); -MODULE_PARM_DESC(clock_division_ratio, "Clock division ratio. Valid ranges are from 0x5 (1.31ms) to 0x7 (5.25ms). (default=" __MODULE_STRING(clock_division_ratio) ")"); - -module_param(heartbeat, int, 0); -MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<=heartbeat<=3600, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")"); - -module_param(nowayout, int, 0); -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); - -module_init(sh_wdt_init); -module_exit(sh_wdt_exit); |