diff options
Diffstat (limited to 'drivers/char/watchdog/alim1535_wdt.c')
| -rw-r--r-- | drivers/char/watchdog/alim1535_wdt.c | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/drivers/char/watchdog/alim1535_wdt.c b/drivers/char/watchdog/alim1535_wdt.c new file mode 100644 index 000000000000..35dcbf8be7d1 --- /dev/null +++ b/drivers/char/watchdog/alim1535_wdt.c @@ -0,0 +1,463 @@ +/* + * 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) ")"); + +#ifdef CONFIG_WATCHDOG_NOWAYOUT +static int nowayout = 1; +#else +static int nowayout = 0; +#endif + +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, 1535, 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); |