1 files changed, 447 insertions, 0 deletions

diff --git a/drivers/char/watchdog/sc520_wdt.c b/drivers/char/watchdog/sc520_wdt.c
new file mode 100644
index 000000000000..f6d143e1900d
--- /dev/null
+++ b/drivers/char/watchdog/sc520_wdt.c
@@ -0,0 +1,447 @@
+/*
+ *      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 <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) ")");
+
+#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)");
+
+/*
+ * 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 struct timer_list timer;
+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 */
+                timer.expires = jiffies + WDT_INTERVAL;
+                add_timer(&timer);
+        } 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 */
+        timer.expires = jiffies + WDT_INTERVAL;
+        add_timer(&timer);
+
+        /* 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)
+{
+        nonseekable_open(inode, 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 0;
+}
+
+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 -ENOIOCTLCMD;
+                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 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);
+
+        init_timer(&timer);
+        timer.function = wdt_timer_ping;
+        timer.data = 0;
+
+        /* 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);