1 files changed, 316 insertions, 0 deletions

diff --git a/drivers/watchdog/mpc8xxx_wdt.c b/drivers/watchdog/mpc8xxx_wdt.c
new file mode 100644
index 000000000000..f2094960e662
--- /dev/null
+++ b/drivers/watchdog/mpc8xxx_wdt.c
@@ -0,0 +1,316 @@
+/*
+ * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
+ *
+ * Authors: Dave Updegraff <dave@cray.org>
+ *          Kumar Gala <galak@kernel.crashing.org>
+ *              Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
+ *                              ..and from sc520_wdt
+ * Copyright (c) 2008  MontaVista Software, Inc.
+ *                     Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * Note: it appears that you can only actually ENABLE or DISABLE the thing
+ * once after POR. Once enabled, you cannot disable, and vice versa.
+ *
+ * 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/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/miscdevice.h>
+#include <linux/of_platform.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <sysdev/fsl_soc.h>
+
+struct mpc8xxx_wdt {
+        __be32 res0;
+        __be32 swcrr; /* System watchdog control register */
+#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
+#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
+#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
+#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
+        __be32 swcnr; /* System watchdog count register */
+        u8 res1[2];
+        __be16 swsrr; /* System watchdog service register */
+        u8 res2[0xF0];
+};
+
+struct mpc8xxx_wdt_type {
+        int prescaler;
+        bool hw_enabled;
+};
+
+static struct mpc8xxx_wdt __iomem *wd_base;
+
+static u16 timeout = 0xffff;
+module_param(timeout, ushort, 0);
+MODULE_PARM_DESC(timeout,
+        "Watchdog timeout in ticks. (0<timeout<65536, default=65535");
+
+static int reset = 1;
+module_param(reset, bool, 0);
+MODULE_PARM_DESC(reset,
+        "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
+
+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) ")");
+
+/*
+ * We always prescale, but if someone really doesn't want to they can set this
+ * to 0
+ */
+static int prescale = 1;
+static unsigned int timeout_sec;
+
+static unsigned long wdt_is_open;
+static DEFINE_SPINLOCK(wdt_spinlock);
+
+static void mpc8xxx_wdt_keepalive(void)
+{
+        /* Ping the WDT */
+        spin_lock(&wdt_spinlock);
+        out_be16(&wd_base->swsrr, 0x556c);
+        out_be16(&wd_base->swsrr, 0xaa39);
+        spin_unlock(&wdt_spinlock);
+}
+
+static void mpc8xxx_wdt_timer_ping(unsigned long arg);
+static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0);
+
+static void mpc8xxx_wdt_timer_ping(unsigned long arg)
+{
+        mpc8xxx_wdt_keepalive();
+        /* We're pinging it twice faster than needed, just to be sure. */
+        mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2);
+}
+
+static void mpc8xxx_wdt_pr_warn(const char *msg)
+{
+        pr_crit("mpc8xxx_wdt: %s, expect the %s soon!\n", msg,
+                reset ? "reset" : "machine check exception");
+}
+
+static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf,
+                                 size_t count, loff_t *ppos)
+{
+        if (count)
+                mpc8xxx_wdt_keepalive();
+        return count;
+}
+
+static int mpc8xxx_wdt_open(struct inode *inode, struct file *file)
+{
+        u32 tmp = SWCRR_SWEN;
+        if (test_and_set_bit(0, &wdt_is_open))
+                return -EBUSY;
+
+        /* Once we start the watchdog we can't stop it */
+        if (nowayout)
+                __module_get(THIS_MODULE);
+
+        /* Good, fire up the show */
+        if (prescale)
+                tmp |= SWCRR_SWPR;
+        if (reset)
+                tmp |= SWCRR_SWRI;
+
+        tmp |= timeout << 16;
+
+        out_be32(&wd_base->swcrr, tmp);
+
+        del_timer_sync(&wdt_timer);
+
+        return nonseekable_open(inode, file);
+}
+
+static int mpc8xxx_wdt_release(struct inode *inode, struct file *file)
+{
+        if (!nowayout)
+                mpc8xxx_wdt_timer_ping(0);
+        else
+                mpc8xxx_wdt_pr_warn("watchdog closed");
+        clear_bit(0, &wdt_is_open);
+        return 0;
+}
+
+static long mpc8xxx_wdt_ioctl(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,
+                .firmware_version = 1,
+                .identity = "MPC8xxx",
+        };
+
+        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:
+                mpc8xxx_wdt_keepalive();
+                return 0;
+        case WDIOC_GETTIMEOUT:
+                return put_user(timeout_sec, p);
+        default:
+                return -ENOTTY;
+        }
+}
+
+static const struct file_operations mpc8xxx_wdt_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .write          = mpc8xxx_wdt_write,
+        .unlocked_ioctl = mpc8xxx_wdt_ioctl,
+        .open           = mpc8xxx_wdt_open,
+        .release        = mpc8xxx_wdt_release,
+};
+
+static struct miscdevice mpc8xxx_wdt_miscdev = {
+        .minor  = WATCHDOG_MINOR,
+        .name   = "watchdog",
+        .fops   = &mpc8xxx_wdt_fops,
+};
+
+static int __devinit mpc8xxx_wdt_probe(struct of_device *ofdev,
+                                       const struct of_device_id *match)
+{
+        int ret;
+        struct device_node *np = ofdev->node;
+        struct mpc8xxx_wdt_type *wdt_type = match->data;
+        u32 freq = fsl_get_sys_freq();
+        bool enabled;
+
+        if (!freq || freq == -1)
+                return -EINVAL;
+
+        wd_base = of_iomap(np, 0);
+        if (!wd_base)
+                return -ENOMEM;
+
+        enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
+        if (!enabled && wdt_type->hw_enabled) {
+                pr_info("mpc8xxx_wdt: could not be enabled in software\n");
+                ret = -ENOSYS;
+                goto err_unmap;
+        }
+
+        /* Calculate the timeout in seconds */
+        if (prescale)
+                timeout_sec = (timeout * wdt_type->prescaler) / freq;
+        else
+                timeout_sec = timeout / freq;
+
+        pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d "
+                "(%d seconds)\n", reset ? "reset" : "interrupt", timeout,
+                timeout_sec);
+
+        /*
+         * If the watchdog was previously enabled or we're running on
+         * MPC8xxx, we should ping the wdt from the kernel until the
+         * userspace handles it.
+         */
+        if (enabled)
+                mpc8xxx_wdt_timer_ping(0);
+        return 0;
+err_unmap:
+        iounmap(wd_base);
+        wd_base = NULL;
+        return ret;
+}
+
+static int __devexit mpc8xxx_wdt_remove(struct of_device *ofdev)
+{
+        mpc8xxx_wdt_pr_warn("watchdog removed");
+        del_timer_sync(&wdt_timer);
+        misc_deregister(&mpc8xxx_wdt_miscdev);
+        iounmap(wd_base);
+
+        return 0;
+}
+
+static const struct of_device_id mpc8xxx_wdt_match[] = {
+        {
+                .compatible = "mpc83xx_wdt",
+                .data = &(struct mpc8xxx_wdt_type) {
+                        .prescaler = 0x10000,
+                },
+        },
+        {
+                .compatible = "fsl,mpc8610-wdt",
+                .data = &(struct mpc8xxx_wdt_type) {
+                        .prescaler = 0x10000,
+                        .hw_enabled = true,
+                },
+        },
+        {
+                .compatible = "fsl,mpc823-wdt",
+                .data = &(struct mpc8xxx_wdt_type) {
+                        .prescaler = 0x800,
+                },
+        },
+        {},
+};
+MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
+
+static struct of_platform_driver mpc8xxx_wdt_driver = {
+        .match_table    = mpc8xxx_wdt_match,
+        .probe          = mpc8xxx_wdt_probe,
+        .remove         = __devexit_p(mpc8xxx_wdt_remove),
+        .driver         = {
+                .name   = "mpc8xxx_wdt",
+                .owner  = THIS_MODULE,
+        },
+};
+
+/*
+ * We do wdt initialization in two steps: arch_initcall probes the wdt
+ * very early to start pinging the watchdog (misc devices are not yet
+ * available), and later module_init() just registers the misc device.
+ */
+static int __init mpc8xxx_wdt_init_late(void)
+{
+        int ret;
+
+        if (!wd_base)
+                return -ENODEV;
+
+        ret = misc_register(&mpc8xxx_wdt_miscdev);
+        if (ret) {
+                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+                        WATCHDOG_MINOR, ret);
+                return ret;
+        }
+        return 0;
+}
+module_init(mpc8xxx_wdt_init_late);
+
+static int __init mpc8xxx_wdt_init(void)
+{
+        return of_register_platform_driver(&mpc8xxx_wdt_driver);
+}
+arch_initcall(mpc8xxx_wdt_init);
+
+static void __exit mpc8xxx_wdt_exit(void)
+{
+        of_unregister_platform_driver(&mpc8xxx_wdt_driver);
+}
+module_exit(mpc8xxx_wdt_exit);
+
+MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
+MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
+                   "uProcessors");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);