1 files changed, 326 insertions, 0 deletions

diff --git a/drivers/watchdog/mv64x60_wdt.c b/drivers/watchdog/mv64x60_wdt.c
new file mode 100644
index 000000000000..0365c317f7e1
--- /dev/null
+++ b/drivers/watchdog/mv64x60_wdt.c
@@ -0,0 +1,326 @@
+/*
+ * mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
+ *
+ * Author: James Chapman <jchapman@katalix.com>
+ *
+ * Platform-specific setup code should configure the dog to generate
+ * interrupt or reset as required.  This code only enables/disables
+ * and services the watchdog.
+ *
+ * Derived from mpc8xx_wdt.c, with the following copyright.
+ * 
+ * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+
+#include <linux/mv643xx.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#define MV64x60_WDT_WDC_OFFSET  0
+
+/*
+ * The watchdog configuration register contains a pair of 2-bit fields,
+ *   1.  a reload field, bits 27-26, which triggers a reload of
+ *       the countdown register, and
+ *   2.  an enable field, bits 25-24, which toggles between
+ *       enabling and disabling the watchdog timer.
+ * Bit 31 is a read-only field which indicates whether the
+ * watchdog timer is currently enabled.
+ *
+ * The low 24 bits contain the timer reload value.
+ */
+#define MV64x60_WDC_ENABLE_SHIFT        24
+#define MV64x60_WDC_SERVICE_SHIFT       26
+#define MV64x60_WDC_ENABLED_SHIFT       31
+
+#define MV64x60_WDC_ENABLED_TRUE        1
+#define MV64x60_WDC_ENABLED_FALSE       0
+
+/* Flags bits */
+#define MV64x60_WDOG_FLAG_OPENED        0
+
+static unsigned long wdt_flags;
+static int wdt_status;
+static void __iomem *mv64x60_wdt_regs;
+static int mv64x60_wdt_timeout;
+static int mv64x60_wdt_count;
+static unsigned int bus_clk;
+static char expect_close;
+static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);
+
+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) ")");
+
+static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
+{
+        u32 data;
+        u32 enabled;
+        int ret = 0;
+
+        spin_lock(&mv64x60_wdt_spinlock);
+        data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+        enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;
+
+        /* only toggle the requested field if enabled state matches predicate */
+        if ((enabled ^ enabled_predicate) == 0) {
+                /* We write a 1, then a 2 -- to the appropriate field */
+                data = (1 << field_shift) | mv64x60_wdt_count;
+                writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+
+                data = (2 << field_shift) | mv64x60_wdt_count;
+                writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+                ret = 1;
+        }
+        spin_unlock(&mv64x60_wdt_spinlock);
+
+        return ret;
+}
+
+static void mv64x60_wdt_service(void)
+{
+        mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
+                               MV64x60_WDC_SERVICE_SHIFT);
+}
+
+static void mv64x60_wdt_handler_enable(void)
+{
+        if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
+                                   MV64x60_WDC_ENABLE_SHIFT)) {
+                mv64x60_wdt_service();
+                printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
+        }
+}
+
+static void mv64x60_wdt_handler_disable(void)
+{
+        if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
+                                   MV64x60_WDC_ENABLE_SHIFT))
+                printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
+}
+
+static void mv64x60_wdt_set_timeout(unsigned int timeout)
+{
+        /* maximum bus cycle count is 0xFFFFFFFF */
+        if (timeout > 0xFFFFFFFF / bus_clk)
+                timeout = 0xFFFFFFFF / bus_clk;
+
+        mv64x60_wdt_count = timeout * bus_clk >> 8;
+        mv64x60_wdt_timeout = timeout;
+}
+
+static int mv64x60_wdt_open(struct inode *inode, struct file *file)
+{
+        if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
+                return -EBUSY;
+
+        if (nowayout)
+                __module_get(THIS_MODULE);
+
+        mv64x60_wdt_handler_enable();
+
+        return nonseekable_open(inode, file);
+}
+
+static int mv64x60_wdt_release(struct inode *inode, struct file *file)
+{
+        if (expect_close == 42)
+                mv64x60_wdt_handler_disable();
+        else {
+                printk(KERN_CRIT
+                       "mv64x60_wdt: unexpected close, not stopping timer!\n");
+                mv64x60_wdt_service();
+        }
+        expect_close = 0;
+
+        clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
+
+        return 0;
+}
+
+static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
+                                 size_t len, loff_t * ppos)
+{
+        if (len) {
+                if (!nowayout) {
+                        size_t i;
+
+                        expect_close = 0;
+
+                        for (i = 0; i != len; i++) {
+                                char c;
+                                if(get_user(c, data + i))
+                                        return -EFAULT;
+                                if (c == 'V')
+                                        expect_close = 42;
+                        }
+                }
+                mv64x60_wdt_service();
+        }
+
+        return len;
+}
+
+static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
+                             unsigned int cmd, unsigned long arg)
+{
+        int timeout;
+        int options;
+        void __user *argp = (void __user *)arg;
+        static struct watchdog_info info = {
+                .options =      WDIOF_SETTIMEOUT        |
+                                WDIOF_MAGICCLOSE        |
+                                WDIOF_KEEPALIVEPING,
+                .firmware_version = 0,
+                .identity = "MV64x60 watchdog",
+        };
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                if (copy_to_user(argp, &info, sizeof(info)))
+                        return -EFAULT;
+                break;
+
+        case WDIOC_GETSTATUS:
+        case WDIOC_GETBOOTSTATUS:
+                if (put_user(wdt_status, (int __user *)argp))
+                        return -EFAULT;
+                wdt_status &= ~WDIOF_KEEPALIVEPING;
+                break;
+
+        case WDIOC_GETTEMP:
+                return -EOPNOTSUPP;
+
+        case WDIOC_SETOPTIONS:
+                if (get_user(options, (int __user *)argp))
+                        return -EFAULT;
+
+                if (options & WDIOS_DISABLECARD)
+                        mv64x60_wdt_handler_disable();
+
+                if (options & WDIOS_ENABLECARD)
+                        mv64x60_wdt_handler_enable();
+                break;
+
+        case WDIOC_KEEPALIVE:
+                mv64x60_wdt_service();
+                wdt_status |= WDIOF_KEEPALIVEPING;
+                break;
+
+        case WDIOC_SETTIMEOUT:
+                if (get_user(timeout, (int __user *)argp))
+                        return -EFAULT;
+                mv64x60_wdt_set_timeout(timeout);
+                /* Fall through */
+
+        case WDIOC_GETTIMEOUT:
+                if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
+                        return -EFAULT;
+                break;
+
+        default:
+                return -ENOTTY;
+        }
+
+        return 0;
+}
+
+static const struct file_operations mv64x60_wdt_fops = {
+        .owner = THIS_MODULE,
+        .llseek = no_llseek,
+        .write = mv64x60_wdt_write,
+        .ioctl = mv64x60_wdt_ioctl,
+        .open = mv64x60_wdt_open,
+        .release = mv64x60_wdt_release,
+};
+
+static struct miscdevice mv64x60_wdt_miscdev = {
+        .minor = WATCHDOG_MINOR,
+        .name = "watchdog",
+        .fops = &mv64x60_wdt_fops,
+};
+
+static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
+{
+        struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
+        struct resource *r;
+        int timeout = 10;
+
+        bus_clk = 133;                  /* in MHz */
+        if (pdata) {
+                timeout = pdata->timeout;
+                bus_clk = pdata->bus_clk;
+        }
+
+        /* Since bus_clk is truncated MHz, actual frequency could be
+         * up to 1MHz higher.  Round up, since it's better to time out
+         * too late than too soon.
+         */
+        bus_clk++;
+        bus_clk *= 1000000;             /* convert to Hz */
+
+        r = platform_get_resource(dev, IORESOURCE_MEM, 0);
+        if (!r)
+                return -ENODEV;
+
+        mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
+        if (mv64x60_wdt_regs == NULL)
+                return -ENOMEM;
+
+        mv64x60_wdt_set_timeout(timeout);
+
+        mv64x60_wdt_handler_disable();  /* in case timer was already running */
+
+        return misc_register(&mv64x60_wdt_miscdev);
+}
+
+static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
+{
+        misc_deregister(&mv64x60_wdt_miscdev);
+
+        mv64x60_wdt_handler_disable();
+
+        iounmap(mv64x60_wdt_regs);
+
+        return 0;
+}
+
+static struct platform_driver mv64x60_wdt_driver = {
+        .probe = mv64x60_wdt_probe,
+        .remove = __devexit_p(mv64x60_wdt_remove),
+        .driver = {
+                .owner = THIS_MODULE,
+                .name = MV64x60_WDT_NAME,
+        },
+};
+
+static int __init mv64x60_wdt_init(void)
+{
+        printk(KERN_INFO "MV64x60 watchdog driver\n");
+
+        return platform_driver_register(&mv64x60_wdt_driver);
+}
+
+static void __exit mv64x60_wdt_exit(void)
+{
+        platform_driver_unregister(&mv64x60_wdt_driver);
+}
+
+module_init(mv64x60_wdt_init);
+module_exit(mv64x60_wdt_exit);
+
+MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
+MODULE_DESCRIPTION("MV64x60 watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);