417 lines
10 KiB
C
417 lines
10 KiB
C
/*
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* ALi M7101 PMU Computer Watchdog Timer driver
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*
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* Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>
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* and the Cobalt kernel WDT timer driver by Tim Hockin
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* <thockin@cobaltnet.com>
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*
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* (c)2002 Steve Hill <steve@navaho.co.uk>
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*
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* This WDT driver is different from most other Linux WDT
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* drivers in that the driver will ping the watchdog by itself,
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* because this particular WDT has a very short timeout (1.6
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* seconds) and it would be insane to count on any userspace
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* daemon always getting scheduled within that time frame.
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*
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* Additions:
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* Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
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* found on very old cobalt hardware.
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* -- Mike Waychison <michael.waychison@sun.com>
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/timer.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/ioport.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/pci.h>
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#include <asm/io.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#define OUR_NAME "alim7101_wdt"
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#define PFX OUR_NAME ": "
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#define WDT_ENABLE 0x9C
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#define WDT_DISABLE 0x8C
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#define ALI_7101_WDT 0x92
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#define ALI_7101_GPIO 0x7D
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#define ALI_7101_GPIO_O 0x7E
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#define ALI_WDT_ARM 0x01
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/*
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* We're going to use a 1 second timeout.
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* If we reset the watchdog every ~250ms we should be safe. */
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#define WDT_INTERVAL (HZ/4+1)
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/*
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* We must not require too good response from the userspace daemon.
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* Here we require the userspace daemon to send us a heartbeat
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* char to /dev/watchdog every 30 seconds.
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*/
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#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
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static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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static int use_gpio = 0; /* Use the pic (for a1d revision alim7101) */
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module_param(use_gpio, int, 0);
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MODULE_PARM_DESC(use_gpio, "Use the gpio watchdog. (required by old cobalt boards)");
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static void wdt_timer_ping(unsigned long);
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static struct timer_list timer;
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static unsigned long next_heartbeat;
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static unsigned long wdt_is_open;
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static char wdt_expect_close;
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static struct pci_dev *alim7101_pmu;
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
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/*
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* Whack the dog
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*/
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static void wdt_timer_ping(unsigned long data)
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{
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/* If we got a heartbeat pulse within the WDT_US_INTERVAL
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* we agree to ping the WDT
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*/
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char tmp;
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if(time_before(jiffies, next_heartbeat))
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{
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/* Ping the WDT (this is actually a disarm/arm sequence) */
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pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
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pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
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pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
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if (use_gpio) {
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pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
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pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
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| 0x20);
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pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
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& ~0x20);
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}
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} else {
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printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
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}
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/* Re-set the timer interval */
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timer.expires = jiffies + WDT_INTERVAL;
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add_timer(&timer);
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}
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/*
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* Utility routines
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*/
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static void wdt_change(int writeval)
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{
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char tmp;
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pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
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if (writeval == WDT_ENABLE) {
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pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
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if (use_gpio) {
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pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
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pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp & ~0x20);
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}
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} else {
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pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
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if (use_gpio) {
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pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
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pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp | 0x20);
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}
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}
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}
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static void wdt_startup(void)
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{
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next_heartbeat = jiffies + (timeout * HZ);
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/* We must enable before we kick off the timer in case the timer
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occurs as we ping it */
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wdt_change(WDT_ENABLE);
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/* Start the timer */
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timer.expires = jiffies + WDT_INTERVAL;
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add_timer(&timer);
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printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
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}
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static void wdt_turnoff(void)
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{
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/* Stop the timer */
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del_timer_sync(&timer);
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wdt_change(WDT_DISABLE);
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printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
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}
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static void wdt_keepalive(void)
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{
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/* user land ping */
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next_heartbeat = jiffies + (timeout * HZ);
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}
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/*
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* /dev/watchdog handling
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*/
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static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
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{
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/* See if we got the magic character 'V' and reload the timer */
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if(count) {
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if (!nowayout) {
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size_t ofs;
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/* note: just in case someone wrote the magic character
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* five months ago... */
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wdt_expect_close = 0;
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/* now scan */
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for (ofs = 0; ofs != count; ofs++) {
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char c;
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if (get_user(c, buf+ofs))
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return -EFAULT;
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if (c == 'V')
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wdt_expect_close = 42;
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}
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}
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/* someone wrote to us, we should restart timer */
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wdt_keepalive();
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}
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return count;
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}
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static int fop_open(struct inode * inode, struct file * file)
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{
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/* Just in case we're already talking to someone... */
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if(test_and_set_bit(0, &wdt_is_open))
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return -EBUSY;
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/* Good, fire up the show */
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wdt_startup();
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return nonseekable_open(inode, file);
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}
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static int fop_close(struct inode * inode, struct file * file)
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{
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if(wdt_expect_close == 42)
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wdt_turnoff();
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else {
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/* wim: shouldn't there be a: del_timer(&timer); */
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printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
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}
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clear_bit(0, &wdt_is_open);
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wdt_expect_close = 0;
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return 0;
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}
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static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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static struct watchdog_info ident =
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{
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.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
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.firmware_version = 1,
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.identity = "ALiM7101",
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};
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switch(cmd)
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{
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_KEEPALIVE:
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wdt_keepalive();
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return 0;
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case WDIOC_SETOPTIONS:
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{
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int new_options, retval = -EINVAL;
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if(get_user(new_options, p))
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return -EFAULT;
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if(new_options & WDIOS_DISABLECARD) {
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wdt_turnoff();
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retval = 0;
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}
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if(new_options & WDIOS_ENABLECARD) {
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wdt_startup();
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retval = 0;
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}
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return retval;
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}
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case WDIOC_SETTIMEOUT:
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{
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int new_timeout;
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if(get_user(new_timeout, p))
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return -EFAULT;
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if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
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return -EINVAL;
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timeout = new_timeout;
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wdt_keepalive();
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/* Fall through */
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}
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, p);
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default:
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return -ENOIOCTLCMD;
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}
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}
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static struct file_operations wdt_fops = {
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.owner= THIS_MODULE,
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.llseek= no_llseek,
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.write= fop_write,
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.open= fop_open,
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.release= fop_close,
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.ioctl= fop_ioctl,
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};
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static struct miscdevice wdt_miscdev = {
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.minor=WATCHDOG_MINOR,
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.name="watchdog",
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.fops=&wdt_fops,
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};
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/*
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* Notifier for system down
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*/
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static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
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{
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if (code==SYS_DOWN || code==SYS_HALT)
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wdt_turnoff();
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if (code==SYS_RESTART) {
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/*
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* Cobalt devices have no way of rebooting themselves other than
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* getting the watchdog to pull reset, so we restart the watchdog on
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* reboot with no heartbeat
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*/
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wdt_change(WDT_ENABLE);
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printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");
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}
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return NOTIFY_DONE;
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}
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/*
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* The WDT needs to learn about soft shutdowns in order to
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* turn the timebomb registers off.
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*/
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static struct notifier_block wdt_notifier=
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{
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.notifier_call = wdt_notify_sys,
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};
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static void __exit alim7101_wdt_unload(void)
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{
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wdt_turnoff();
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/* Deregister */
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misc_deregister(&wdt_miscdev);
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unregister_reboot_notifier(&wdt_notifier);
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}
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static int __init alim7101_wdt_init(void)
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{
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int rc = -EBUSY;
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struct pci_dev *ali1543_south;
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char tmp;
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printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
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alim7101_pmu = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,NULL);
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if (!alim7101_pmu) {
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printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");
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return -EBUSY;
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}
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/* Set the WDT in the PMU to 1 second */
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pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
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ali1543_south = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, NULL);
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if (!ali1543_south) {
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printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n");
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return -EBUSY;
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}
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pci_read_config_byte(ali1543_south, 0x5e, &tmp);
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if ((tmp & 0x1e) == 0x00) {
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if (!use_gpio) {
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printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n");
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return -EBUSY;
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}
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nowayout = 1;
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} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
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printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
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return -EBUSY;
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}
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if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
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{
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timeout = WATCHDOG_TIMEOUT;
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printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
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timeout);
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}
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init_timer(&timer);
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timer.function = wdt_timer_ping;
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timer.data = 1;
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rc = misc_register(&wdt_miscdev);
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if (rc) {
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printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
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wdt_miscdev.minor, rc);
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goto err_out;
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}
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rc = register_reboot_notifier(&wdt_notifier);
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if (rc) {
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printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
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rc);
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goto err_out_miscdev;
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}
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if (nowayout) {
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__module_get(THIS_MODULE);
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}
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printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
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timeout, nowayout);
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return 0;
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err_out_miscdev:
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misc_deregister(&wdt_miscdev);
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err_out:
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return rc;
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}
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module_init(alim7101_wdt_init);
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module_exit(alim7101_wdt_unload);
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MODULE_AUTHOR("Steve Hill");
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MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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