1 files changed, 330 insertions, 0 deletions

diff --git a/drivers/watchdog/gef_wdt.c b/drivers/watchdog/gef_wdt.c
new file mode 100644
index 000000000000..f0c2b7a1a175
--- /dev/null
+++ b/drivers/watchdog/gef_wdt.c
@@ -0,0 +1,330 @@
+/*
+ * GE Fanuc watchdog userspace interface
+ *
+ * Author:  Martyn Welch <martyn.welch@gefanuc.com>
+ *
+ * Copyright 2008 GE Fanuc Intelligent Platforms Embedded Systems, Inc.
+ *
+ * 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.
+ *
+ * Based on: mv64x60_wdt.c (MV64X60 watchdog userspace interface)
+ *   Author: James Chapman <jchapman@katalix.com>
+ */
+
+/* TODO:
+ * This driver does not provide support for the hardwares capability of sending
+ * an interrupt at a programmable threshold.
+ *
+ * This driver currently can only support 1 watchdog - there are 2 in the
+ * hardware that this driver supports. Thus one could be configured as a
+ * process-based watchdog (via /dev/watchdog), the second (using the interrupt
+ * capabilities) a kernel-based watchdog.
+ */
+
+#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+#include <sysdev/fsl_soc.h>
+
+/*
+ * 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 GEF_WDC_ENABLE_SHIFT    24
+#define GEF_WDC_SERVICE_SHIFT   26
+#define GEF_WDC_ENABLED_SHIFT   31
+
+#define GEF_WDC_ENABLED_TRUE    1
+#define GEF_WDC_ENABLED_FALSE   0
+
+/* Flags bits */
+#define GEF_WDOG_FLAG_OPENED    0
+
+static unsigned long wdt_flags;
+static int wdt_status;
+static void __iomem *gef_wdt_regs;
+static int gef_wdt_timeout;
+static int gef_wdt_count;
+static unsigned int bus_clk;
+static char expect_close;
+static DEFINE_SPINLOCK(gef_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 gef_wdt_toggle_wdc(int enabled_predicate, int field_shift)
+{
+        u32 data;
+        u32 enabled;
+        int ret = 0;
+
+        spin_lock(&gef_wdt_spinlock);
+        data = ioread32be(gef_wdt_regs);
+        enabled = (data >> GEF_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) | gef_wdt_count;
+                iowrite32be(data, gef_wdt_regs);
+
+                data = (2 << field_shift) | gef_wdt_count;
+                iowrite32be(data, gef_wdt_regs);
+                ret = 1;
+        }
+        spin_unlock(&gef_wdt_spinlock);
+
+        return ret;
+}
+
+static void gef_wdt_service(void)
+{
+        gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
+                GEF_WDC_SERVICE_SHIFT);
+}
+
+static void gef_wdt_handler_enable(void)
+{
+        if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_FALSE,
+                                   GEF_WDC_ENABLE_SHIFT)) {
+                gef_wdt_service();
+                printk(KERN_NOTICE "gef_wdt: watchdog activated\n");
+        }
+}
+
+static void gef_wdt_handler_disable(void)
+{
+        if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
+                                   GEF_WDC_ENABLE_SHIFT))
+                printk(KERN_NOTICE "gef_wdt: watchdog deactivated\n");
+}
+
+static void gef_wdt_set_timeout(unsigned int timeout)
+{
+        /* maximum bus cycle count is 0xFFFFFFFF */
+        if (timeout > 0xFFFFFFFF / bus_clk)
+                timeout = 0xFFFFFFFF / bus_clk;
+
+        /* Register only holds upper 24 bits, bit shifted into lower 24 */
+        gef_wdt_count = (timeout * bus_clk) >> 8;
+        gef_wdt_timeout = timeout;
+}
+
+
+static ssize_t gef_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;
+                        }
+                }
+                gef_wdt_service();
+        }
+
+        return len;
+}
+
+static long gef_wdt_ioctl(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 = "GE Fanuc 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_SETOPTIONS:
+                if (get_user(options, (int __user *)argp))
+                        return -EFAULT;
+
+                if (options & WDIOS_DISABLECARD)
+                        gef_wdt_handler_disable();
+
+                if (options & WDIOS_ENABLECARD)
+                        gef_wdt_handler_enable();
+                break;
+
+        case WDIOC_KEEPALIVE:
+                gef_wdt_service();
+                wdt_status |= WDIOF_KEEPALIVEPING;
+                break;
+
+        case WDIOC_SETTIMEOUT:
+                if (get_user(timeout, (int __user *)argp))
+                        return -EFAULT;
+                gef_wdt_set_timeout(timeout);
+                /* Fall through */
+
+        case WDIOC_GETTIMEOUT:
+                if (put_user(gef_wdt_timeout, (int __user *)argp))
+                        return -EFAULT;
+                break;
+
+        default:
+                return -ENOTTY;
+        }
+
+        return 0;
+}
+
+static int gef_wdt_open(struct inode *inode, struct file *file)
+{
+        if (test_and_set_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags))
+                return -EBUSY;
+
+        if (nowayout)
+                __module_get(THIS_MODULE);
+
+        gef_wdt_handler_enable();
+
+        return nonseekable_open(inode, file);
+}
+
+static int gef_wdt_release(struct inode *inode, struct file *file)
+{
+        if (expect_close == 42)
+                gef_wdt_handler_disable();
+        else {
+                printk(KERN_CRIT
+                       "gef_wdt: unexpected close, not stopping timer!\n");
+                gef_wdt_service();
+        }
+        expect_close = 0;
+
+        clear_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags);
+
+        return 0;
+}
+
+static const struct file_operations gef_wdt_fops = {
+        .owner = THIS_MODULE,
+        .llseek = no_llseek,
+        .write = gef_wdt_write,
+        .unlocked_ioctl = gef_wdt_ioctl,
+        .open = gef_wdt_open,
+        .release = gef_wdt_release,
+};
+
+static struct miscdevice gef_wdt_miscdev = {
+        .minor = WATCHDOG_MINOR,
+        .name = "watchdog",
+        .fops = &gef_wdt_fops,
+};
+
+
+static int __devinit gef_wdt_probe(struct of_device *dev,
+        const struct of_device_id *match)
+{
+        int timeout = 10;
+        u32 freq;
+
+        bus_clk = 133; /* in MHz */
+
+        freq = fsl_get_sys_freq();
+        if (freq > 0)
+                bus_clk = freq;
+
+        /* Map devices registers into memory */
+        gef_wdt_regs = of_iomap(dev->node, 0);
+        if (gef_wdt_regs == NULL)
+                return -ENOMEM;
+
+        gef_wdt_set_timeout(timeout);
+
+        gef_wdt_handler_disable();      /* in case timer was already running */
+
+        return misc_register(&gef_wdt_miscdev);
+}
+
+static int __devexit gef_wdt_remove(struct platform_device *dev)
+{
+        misc_deregister(&gef_wdt_miscdev);
+
+        gef_wdt_handler_disable();
+
+        iounmap(gef_wdt_regs);
+
+        return 0;
+}
+
+static const struct of_device_id gef_wdt_ids[] = {
+        {
+                .compatible = "gef,fpga-wdt",
+        },
+        {},
+};
+
+static struct of_platform_driver gef_wdt_driver = {
+        .owner          = THIS_MODULE,
+        .name           = "gef_wdt",
+        .match_table    = gef_wdt_ids,
+        .probe          = gef_wdt_probe,
+};
+
+static int __init gef_wdt_init(void)
+{
+        printk(KERN_INFO "GE Fanuc watchdog driver\n");
+        return of_register_platform_driver(&gef_wdt_driver);
+}
+
+static void __exit gef_wdt_exit(void)
+{
+        of_unregister_platform_driver(&gef_wdt_driver);
+}
+
+module_init(gef_wdt_init);
+module_exit(gef_wdt_exit);
+
+MODULE_AUTHOR("Martyn Welch <martyn.welch@gefanuc.com>");
+MODULE_DESCRIPTION("GE Fanuc watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform: gef_wdt");