diff options
Diffstat (limited to 'drivers/char/watchdog/sc520_wdt.c')
| -rw-r--r-- | drivers/char/watchdog/sc520_wdt.c | 435 |
1 files changed, 0 insertions, 435 deletions
diff --git a/drivers/char/watchdog/sc520_wdt.c b/drivers/char/watchdog/sc520_wdt.c deleted file mode 100644 index e8594c64d1e6..000000000000 --- a/drivers/char/watchdog/sc520_wdt.c +++ /dev/null @@ -1,435 +0,0 @@ -/* - * AMD Elan SC520 processor Watchdog Timer driver - * - * Based on acquirewdt.c by Alan Cox, - * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net> - * - * 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. - * - * The authors do NOT admit liability nor provide warranty for - * any of this software. This material is provided "AS-IS" in - * the hope that it may be useful for others. - * - * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net> - * 9/27 - 2001 [Initial release] - * - * Additional fixes Alan Cox - * - Fixed formatting - * - Removed debug printks - * - Fixed SMP built kernel deadlock - * - Switched to private locks not lock_kernel - * - Used ioremap/writew/readw - * - Added NOWAYOUT support - * 4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com> - * - Change comments - * - Eliminate fop_llseek - * - Change CONFIG_WATCHDOG_NOWAYOUT semantics - * - Add KERN_* tags to printks - * - fix possible wdt_is_open race - * - Report proper capabilities in watchdog_info - * - Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT, - * GETTIMEOUT, SETOPTIONS} ioctls - * 09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be> - * - cleanup of trailing spaces - * - added extra printk's for startup problems - * - use module_param - * - made timeout (the emulated heartbeat) a module_param - * - made the keepalive ping an internal subroutine - * 3/27 - 2004 Changes by Sean Young <sean@mess.org> - * - set MMCR_BASE to 0xfffef000 - * - CBAR does not need to be read - * - removed debugging printks - * - * This WDT driver is different from most other Linux WDT - * drivers in that the driver will ping the watchdog by itself, - * because this particular WDT has a very short timeout (1.6 - * seconds) and it would be insane to count on any userspace - * daemon always getting scheduled within that time frame. - * - * This driver uses memory mapped IO, and spinlock. - */ - -#include <linux/module.h> -#include <linux/moduleparam.h> -#include <linux/types.h> -#include <linux/timer.h> -#include <linux/miscdevice.h> -#include <linux/watchdog.h> -#include <linux/fs.h> -#include <linux/ioport.h> -#include <linux/notifier.h> -#include <linux/reboot.h> -#include <linux/init.h> -#include <linux/jiffies.h> - -#include <asm/io.h> -#include <asm/uaccess.h> -#include <asm/system.h> - -#define OUR_NAME "sc520_wdt" -#define PFX OUR_NAME ": " - -/* - * The AMD Elan SC520 timeout value is 492us times a power of 2 (0-7) - * - * 0: 492us 2: 1.01s 4: 4.03s 6: 16.22s - * 1: 503ms 3: 2.01s 5: 8.05s 7: 32.21s - * - * We will program the SC520 watchdog for a timeout of 2.01s. - * If we reset the watchdog every ~250ms we should be safe. - */ - -#define WDT_INTERVAL (HZ/4+1) - -/* - * We must not require too good response from the userspace daemon. - * Here we require the userspace daemon to send us a heartbeat - * char to /dev/watchdog every 30 seconds. - */ - -#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ -static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ -module_param(timeout, int, 0); -MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); - -static int nowayout = WATCHDOG_NOWAYOUT; -module_param(nowayout, int, 0); -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); - -/* - * AMD Elan SC520 - Watchdog Timer Registers - */ -#define MMCR_BASE 0xfffef000 /* The default base address */ -#define OFFS_WDTMRCTL 0xCB0 /* Watchdog Timer Control Register */ - -/* WDT Control Register bit definitions */ -#define WDT_EXP_SEL_01 0x0001 /* [01] Time-out = 496 us (with 33 Mhz clk). */ -#define WDT_EXP_SEL_02 0x0002 /* [02] Time-out = 508 ms (with 33 Mhz clk). */ -#define WDT_EXP_SEL_03 0x0004 /* [03] Time-out = 1.02 s (with 33 Mhz clk). */ -#define WDT_EXP_SEL_04 0x0008 /* [04] Time-out = 2.03 s (with 33 Mhz clk). */ -#define WDT_EXP_SEL_05 0x0010 /* [05] Time-out = 4.07 s (with 33 Mhz clk). */ -#define WDT_EXP_SEL_06 0x0020 /* [06] Time-out = 8.13 s (with 33 Mhz clk). */ -#define WDT_EXP_SEL_07 0x0040 /* [07] Time-out = 16.27s (with 33 Mhz clk). */ -#define WDT_EXP_SEL_08 0x0080 /* [08] Time-out = 32.54s (with 33 Mhz clk). */ -#define WDT_IRQ_FLG 0x1000 /* [12] Interrupt Request Flag */ -#define WDT_WRST_ENB 0x4000 /* [14] Watchdog Timer Reset Enable */ -#define WDT_ENB 0x8000 /* [15] Watchdog Timer Enable */ - -static __u16 __iomem *wdtmrctl; - -static void wdt_timer_ping(unsigned long); -static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); -static unsigned long next_heartbeat; -static unsigned long wdt_is_open; -static char wdt_expect_close; -static spinlock_t wdt_spinlock; - -/* - * Whack the dog - */ - -static void wdt_timer_ping(unsigned long data) -{ - /* If we got a heartbeat pulse within the WDT_US_INTERVAL - * we agree to ping the WDT - */ - if(time_before(jiffies, next_heartbeat)) - { - /* Ping the WDT */ - spin_lock(&wdt_spinlock); - writew(0xAAAA, wdtmrctl); - writew(0x5555, wdtmrctl); - spin_unlock(&wdt_spinlock); - - /* Re-set the timer interval */ - mod_timer(&timer, jiffies + WDT_INTERVAL); - } else { - printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); - } -} - -/* - * Utility routines - */ - -static void wdt_config(int writeval) -{ - __u16 dummy; - unsigned long flags; - - /* buy some time (ping) */ - spin_lock_irqsave(&wdt_spinlock, flags); - dummy=readw(wdtmrctl); /* ensure write synchronization */ - writew(0xAAAA, wdtmrctl); - writew(0x5555, wdtmrctl); - /* unlock WDT = make WDT configuration register writable one time */ - writew(0x3333, wdtmrctl); - writew(0xCCCC, wdtmrctl); - /* write WDT configuration register */ - writew(writeval, wdtmrctl); - spin_unlock_irqrestore(&wdt_spinlock, flags); -} - -static int wdt_startup(void) -{ - next_heartbeat = jiffies + (timeout * HZ); - - /* Start the timer */ - mod_timer(&timer, jiffies + WDT_INTERVAL); - - /* Start the watchdog */ - wdt_config(WDT_ENB | WDT_WRST_ENB | WDT_EXP_SEL_04); - - printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); - return 0; -} - -static int wdt_turnoff(void) -{ - /* Stop the timer */ - del_timer(&timer); - - /* Stop the watchdog */ - wdt_config(0); - - printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); - return 0; -} - -static int wdt_keepalive(void) -{ - /* user land ping */ - next_heartbeat = jiffies + (timeout * HZ); - return 0; -} - -static int wdt_set_heartbeat(int t) -{ - if ((t < 1) || (t > 3600)) /* arbitrary upper limit */ - return -EINVAL; - - timeout = t; - return 0; -} - -/* - * /dev/watchdog handling - */ - -static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) -{ - /* See if we got the magic character 'V' and reload the timer */ - if(count) { - if (!nowayout) { - size_t ofs; - - /* note: just in case someone wrote the magic character - * five months ago... */ - wdt_expect_close = 0; - - /* now scan */ - for(ofs = 0; ofs != count; ofs++) { - char c; - if (get_user(c, buf + ofs)) - return -EFAULT; - if(c == 'V') - wdt_expect_close = 42; - } - } - - /* Well, anyhow someone wrote to us, we should return that favour */ - wdt_keepalive(); - } - return count; -} - -static int fop_open(struct inode * inode, struct file * file) -{ - /* Just in case we're already talking to someone... */ - if(test_and_set_bit(0, &wdt_is_open)) - return -EBUSY; - if (nowayout) - __module_get(THIS_MODULE); - - /* Good, fire up the show */ - wdt_startup(); - return nonseekable_open(inode, file); -} - -static int fop_close(struct inode * inode, struct file * file) -{ - if(wdt_expect_close == 42) { - wdt_turnoff(); - } else { - printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); - wdt_keepalive(); - } - clear_bit(0, &wdt_is_open); - wdt_expect_close = 0; - return 0; -} - -static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, - unsigned long arg) -{ - void __user *argp = (void __user *)arg; - int __user *p = argp; - static struct watchdog_info ident = { - .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, - .firmware_version = 1, - .identity = "SC520", - }; - - switch(cmd) - { - default: - return -ENOTTY; - case WDIOC_GETSUPPORT: - return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; - case WDIOC_GETSTATUS: - case WDIOC_GETBOOTSTATUS: - return put_user(0, p); - case WDIOC_KEEPALIVE: - wdt_keepalive(); - return 0; - case WDIOC_SETOPTIONS: - { - int new_options, retval = -EINVAL; - - if(get_user(new_options, p)) - return -EFAULT; - - if(new_options & WDIOS_DISABLECARD) { - wdt_turnoff(); - retval = 0; - } - - if(new_options & WDIOS_ENABLECARD) { - wdt_startup(); - retval = 0; - } - - return retval; - } - case WDIOC_SETTIMEOUT: - { - int new_timeout; - - if(get_user(new_timeout, p)) - return -EFAULT; - - if(wdt_set_heartbeat(new_timeout)) - return -EINVAL; - - wdt_keepalive(); - /* Fall through */ - } - case WDIOC_GETTIMEOUT: - return put_user(timeout, p); - } -} - -static const struct file_operations wdt_fops = { - .owner = THIS_MODULE, - .llseek = no_llseek, - .write = fop_write, - .open = fop_open, - .release = fop_close, - .ioctl = fop_ioctl, -}; - -static struct miscdevice wdt_miscdev = { - .minor = WATCHDOG_MINOR, - .name = "watchdog", - .fops = &wdt_fops, -}; - -/* - * Notifier for system down - */ - -static int wdt_notify_sys(struct notifier_block *this, unsigned long code, - void *unused) -{ - if(code==SYS_DOWN || code==SYS_HALT) - wdt_turnoff(); - return NOTIFY_DONE; -} - -/* - * The WDT needs to learn about soft shutdowns in order to - * turn the timebomb registers off. - */ - -static struct notifier_block wdt_notifier = { - .notifier_call = wdt_notify_sys, -}; - -static void __exit sc520_wdt_unload(void) -{ - if (!nowayout) - wdt_turnoff(); - - /* Deregister */ - misc_deregister(&wdt_miscdev); - unregister_reboot_notifier(&wdt_notifier); - iounmap(wdtmrctl); -} - -static int __init sc520_wdt_init(void) -{ - int rc = -EBUSY; - - spin_lock_init(&wdt_spinlock); - - /* Check that the timeout value is within it's range ; if not reset to the default */ - if (wdt_set_heartbeat(timeout)) { - wdt_set_heartbeat(WATCHDOG_TIMEOUT); - printk(KERN_INFO PFX "timeout value must be 1<=timeout<=3600, using %d\n", - WATCHDOG_TIMEOUT); - } - - wdtmrctl = ioremap((unsigned long)(MMCR_BASE + OFFS_WDTMRCTL), 2); - if (!wdtmrctl) { - printk(KERN_ERR PFX "Unable to remap memory\n"); - rc = -ENOMEM; - goto err_out_region2; - } - - rc = register_reboot_notifier(&wdt_notifier); - if (rc) { - printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", - rc); - goto err_out_ioremap; - } - - rc = misc_register(&wdt_miscdev); - if (rc) { - printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", - WATCHDOG_MINOR, rc); - goto err_out_notifier; - } - - printk(KERN_INFO PFX "WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n", - timeout,nowayout); - - return 0; - -err_out_notifier: - unregister_reboot_notifier(&wdt_notifier); -err_out_ioremap: - iounmap(wdtmrctl); -err_out_region2: - return rc; -} - -module_init(sc520_wdt_init); -module_exit(sc520_wdt_unload); - -MODULE_AUTHOR("Scott and Bill Jennings"); -MODULE_DESCRIPTION("Driver for watchdog timer in AMD \"Elan\" SC520 uProcessor"); -MODULE_LICENSE("GPL"); -MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |