/* * Watchdog for the 7101 PMU version found in the ALi M1535 chipsets * * 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. */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/ioport.h> #include <linux/notifier.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/pci.h> #include <asm/uaccess.h> #include <asm/io.h> #define WATCHDOG_NAME "ALi_M1535" #define PFX WATCHDOG_NAME ": " #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ /* internal variables */ static unsigned long ali_is_open; static char ali_expect_release; static struct pci_dev *ali_pci; static u32 ali_timeout_bits; /* stores the computed timeout */ static spinlock_t ali_lock; /* Guards the hardware */ /* module parameters */ static int timeout = WATCHDOG_TIMEOUT; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (0<timeout<18000, 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=CONFIG_WATCHDOG_NOWAYOUT)"); /* * ali_start - start watchdog countdown * * Starts the timer running providing the timer has a counter * configuration set. */ static void ali_start(void) { u32 val; spin_lock(&ali_lock); pci_read_config_dword(ali_pci, 0xCC, &val); val &= ~0x3F; /* Mask count */ val |= (1<<25) | ali_timeout_bits; pci_write_config_dword(ali_pci, 0xCC, val); spin_unlock(&ali_lock); } /* * ali_stop - stop the timer countdown * * Stop the ALi watchdog countdown */ static void ali_stop(void) { u32 val; spin_lock(&ali_lock); pci_read_config_dword(ali_pci, 0xCC, &val); val &= ~0x3F; /* Mask count to zero (disabled) */ val &= ~(1<<25);/* and for safety mask the reset enable */ pci_write_config_dword(ali_pci, 0xCC, val); spin_unlock(&ali_lock); } /* * ali_keepalive - send a keepalive to the watchdog * * Send a keepalive to the timer (actually we restart the timer). */ static void ali_keepalive(void) { ali_start(); } /* * ali_settimer - compute the timer reload value * @t: time in seconds * * Computes the timeout values needed */ static int ali_settimer(int t) { if(t < 0) return -EINVAL; else if(t < 60) ali_timeout_bits = t|(1<<6); else if(t < 3600) ali_timeout_bits = (t/60)|(1<<7); else if(t < 18000) ali_timeout_bits = (t/300)|(1<<6)|(1<<7); else return -EINVAL; timeout = t; return 0; } /* * /dev/watchdog handling */ /* * ali_write - writes to ALi watchdog * @file: file from VFS * @data: user address of data * @len: length of data * @ppos: pointer to the file offset * * Handle a write to the ALi watchdog. Writing to the file pings * the watchdog and resets it. Writing the magic 'V' sequence allows * the next close to turn off the watchdog. */ static ssize_t ali_write(struct file *file, const char __user *data, size_t len, loff_t * ppos) { /* See if we got the magic character 'V' and reload the timer */ if (len) { if (!nowayout) { size_t i; /* note: just in case someone wrote the magic character * five months ago... */ ali_expect_release = 0; /* scan to see whether or not we got the magic character */ for (i = 0; i != len; i++) { char c; if(get_user(c, data+i)) return -EFAULT; if (c == 'V') ali_expect_release = 42; } } /* someone wrote to us, we should reload the timer */ ali_start(); } return len; } /* * ali_ioctl - handle watchdog ioctls * @inode: VFS inode * @file: VFS file pointer * @cmd: ioctl number * @arg: arguments to the ioctl * * Handle the watchdog ioctls supported by the ALi driver. Really * we want an extension to enable irq ack monitoring and the like */ static int ali_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 = 0, .identity = "ALi M1535 WatchDog Timer", }; switch (cmd) { 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: ali_keepalive(); return 0; case WDIOC_SETOPTIONS: { int new_options, retval = -EINVAL; if (get_user (new_options, p)) return -EFAULT; if (new_options & WDIOS_DISABLECARD) { ali_stop(); retval = 0; } if (new_options & WDIOS_ENABLECARD) { ali_start(); retval = 0; } return retval; } case WDIOC_SETTIMEOUT: { int new_timeout; if (get_user(new_timeout, p)) return -EFAULT; if (ali_settimer(new_timeout)) return -EINVAL; ali_keepalive(); /* Fall */ } case WDIOC_GETTIMEOUT: return put_user(timeout, p); default: return -ENOIOCTLCMD; } } /* * ali_open - handle open of ali watchdog * @inode: inode from VFS * @file: file from VFS * * Open the ALi watchdog device. Ensure only one person opens it * at a time. Also start the watchdog running. */ static int ali_open(struct inode *inode, struct file *file) { /* /dev/watchdog can only be opened once */ if (test_and_set_bit(0, &ali_is_open)) return -EBUSY; /* Activate */ ali_start(); return nonseekable_open(inode, file); } /* * ali_release - close an ALi watchdog * @inode: inode from VFS * @file: file from VFS * * Close the ALi watchdog device. Actual shutdown of the timer * only occurs if the magic sequence has been set. */ static int ali_release(struct inode *inode, struct file *file) { /* * Shut off the timer. */ if (ali_expect_release == 42) { ali_stop(); } else { printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); ali_keepalive(); } clear_bit(0, &ali_is_open); ali_expect_release = 0; return 0; } /* * ali_notify_sys - System down notifier * * Notifier for system down */ static int ali_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code==SYS_DOWN || code==SYS_HALT) { /* Turn the WDT off */ ali_stop(); } return NOTIFY_DONE; } /* * Data for PCI driver interface * * This data only exists for exporting the supported * PCI ids via MODULE_DEVICE_TABLE. We do not actually * register a pci_driver, because someone else might one day * want to register another driver on the same PCI id. */ static struct pci_device_id ali_pci_tbl[] = { { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,}, { 0, }, }; MODULE_DEVICE_TABLE(pci, ali_pci_tbl); /* * ali_find_watchdog - find a 1535 and 7101 * * Scans the PCI hardware for a 1535 series bridge and matching 7101 * watchdog device. This may be overtight but it is better to be safe */ static int __init ali_find_watchdog(void) { struct pci_dev *pdev; u32 wdog; /* Check for a 1535 series bridge */ pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x1535, NULL); if(pdev == NULL) return -ENODEV; /* Check for the a 7101 PMU */ pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x7101, NULL); if(pdev == NULL) return -ENODEV; if(pci_enable_device(pdev)) return -EIO; ali_pci = pdev; /* * Initialize the timer bits */ pci_read_config_dword(pdev, 0xCC, &wdog); wdog &= ~0x3F; /* Timer bits */ wdog &= ~((1<<27)|(1<<26)|(1<<25)|(1<<24)); /* Issued events */ wdog &= ~((1<<16)|(1<<13)|(1<<12)|(1<<11)|(1<<10)|(1<<9)); /* No monitor bits */ pci_write_config_dword(pdev, 0xCC, wdog); return 0; } /* * Kernel Interfaces */ static struct file_operations ali_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = ali_write, .ioctl = ali_ioctl, .open = ali_open, .release = ali_release, }; static struct miscdevice ali_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ali_fops, }; static struct notifier_block ali_notifier = { .notifier_call = ali_notify_sys, }; /* * watchdog_init - module initialiser * * Scan for a suitable watchdog and if so initialize it. Return an error * if we cannot, the error causes the module to unload */ static int __init watchdog_init(void) { int ret; spin_lock_init(&ali_lock); /* Check whether or not the hardware watchdog is there */ if (ali_find_watchdog() != 0) { return -ENODEV; } /* Check that the timeout value is within it's range ; if not reset to the default */ if (timeout < 1 || timeout >= 18000) { timeout = WATCHDOG_TIMEOUT; printk(KERN_INFO PFX "timeout value must be 0<timeout<18000, using %d\n", timeout); } /* Calculate the watchdog's timeout */ ali_settimer(timeout); ret = misc_register(&ali_miscdev); if (ret != 0) { printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto out; } ret = register_reboot_notifier(&ali_notifier); if (ret != 0) { printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret); goto unreg_miscdev; } printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", timeout, nowayout); out: return ret; unreg_miscdev: misc_deregister(&ali_miscdev); goto out; } /* * watchdog_exit - module de-initialiser * * Called while unloading a successfully installed watchdog module. */ static void __exit watchdog_exit(void) { /* Stop the timer before we leave */ ali_stop(); /* Deregister */ unregister_reboot_notifier(&ali_notifier); misc_deregister(&ali_miscdev); } module_init(watchdog_init); module_exit(watchdog_exit); MODULE_AUTHOR("Alan Cox"); MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);