watchdog: add support for Broadcom BCM63xx built-in watchdog

This patch adds support for the Broadcom BCM63xx SoC built-in watchdog, it
uses one of the BCM63xx hardware timer id.

Signed-off-by: Miguel Gaio <miguel.gaio@efixo.com>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 350 insertions, 0 deletions

diff --git a/drivers/watchdog/bcm63xx_wdt.c b/drivers/watchdog/bcm63xx_wdt.c
new file mode 100644
index 000000000000..a1debc89356b
--- /dev/null
+++ b/drivers/watchdog/bcm63xx_wdt.c
@@ -0,0 +1,350 @@
+/*
+ *  Broadcom BCM63xx SoC watchdog driver
+ *
+ *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
+ *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
+ *
+ *  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/bitops.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/reboot.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/interrupt.h>
+#include <linux/ptrace.h>
+#include <linux/resource.h>
+#include <linux/platform_device.h>
+
+#include <bcm63xx_cpu.h>
+#include <bcm63xx_io.h>
+#include <bcm63xx_regs.h>
+#include <bcm63xx_timer.h>
+
+#define PFX KBUILD_MODNAME
+
+#define WDT_HZ          50000000 /* Fclk */
+#define WDT_DEFAULT_TIME        30      /* seconds */
+#define WDT_MAX_TIME            256     /* seconds */
+
+static struct {
+        void __iomem *regs;
+        struct timer_list timer;
+        int default_ticks;
+        unsigned long inuse;
+        atomic_t ticks;
+} bcm63xx_wdt_device;
+
+static int expect_close;
+
+static int wdt_time = WDT_DEFAULT_TIME;
+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) ")");
+
+/* HW functions */
+static void bcm63xx_wdt_hw_start(void)
+{
+        bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
+        bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+        bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+}
+
+static void bcm63xx_wdt_hw_stop(void)
+{
+        bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+        bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+}
+
+static void bcm63xx_wdt_isr(void *data)
+{
+        struct pt_regs *regs = get_irq_regs();
+
+        die(PFX " fire", regs);
+}
+
+static void bcm63xx_timer_tick(unsigned long unused)
+{
+        if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
+                bcm63xx_wdt_hw_start();
+                mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
+        } else
+                printk(KERN_CRIT PFX ": watchdog will restart system\n");
+}
+
+static void bcm63xx_wdt_pet(void)
+{
+        atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
+}
+
+static void bcm63xx_wdt_start(void)
+{
+        bcm63xx_wdt_pet();
+        bcm63xx_timer_tick(0);
+}
+
+static void bcm63xx_wdt_pause(void)
+{
+        del_timer_sync(&bcm63xx_wdt_device.timer);
+        bcm63xx_wdt_hw_stop();
+}
+
+static int bcm63xx_wdt_settimeout(int new_time)
+{
+        if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
+                return -EINVAL;
+
+        wdt_time = new_time;
+
+        return 0;
+}
+
+static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
+{
+        if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
+                return -EBUSY;
+
+        bcm63xx_wdt_start();
+        return nonseekable_open(inode, file);
+}
+
+static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
+{
+        if (expect_close == 42)
+                bcm63xx_wdt_pause();
+        else {
+                printk(KERN_CRIT PFX
+                        ": Unexpected close, not stopping watchdog!\n");
+                bcm63xx_wdt_start();
+        }
+        clear_bit(0, &bcm63xx_wdt_device.inuse);
+        expect_close = 0;
+        return 0;
+}
+
+static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
+                                size_t len, loff_t *ppos)
+{
+        if (len) {
+                if (!nowayout) {
+                        size_t i;
+
+                        /* In case it was set long ago */
+                        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;
+                        }
+                }
+                bcm63xx_wdt_pet();
+        }
+        return len;
+}
+
+static struct watchdog_info bcm63xx_wdt_info = {
+        .identity       = PFX,
+        .options        = WDIOF_SETTIMEOUT |
+                                WDIOF_KEEPALIVEPING |
+                                WDIOF_MAGICCLOSE,
+};
+
+
+static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
+                                unsigned long arg)
+{
+        void __user *argp = (void __user *)arg;
+        int __user *p = argp;
+        int new_value, retval = -EINVAL;
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                return copy_to_user(argp, &bcm63xx_wdt_info,
+                        sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
+
+        case WDIOC_GETSTATUS:
+        case WDIOC_GETBOOTSTATUS:
+                return put_user(0, p);
+
+        case WDIOC_SETOPTIONS:
+                if (get_user(new_value, p))
+                        return -EFAULT;
+
+                if (new_value & WDIOS_DISABLECARD) {
+                        bcm63xx_wdt_pause();
+                        retval = 0;
+                }
+                if (new_value & WDIOS_ENABLECARD) {
+                        bcm63xx_wdt_start();
+                        retval = 0;
+                }
+
+                return retval;
+
+        case WDIOC_KEEPALIVE:
+                bcm63xx_wdt_pet();
+                return 0;
+
+        case WDIOC_SETTIMEOUT:
+                if (get_user(new_value, p))
+                        return -EFAULT;
+
+                if (bcm63xx_wdt_settimeout(new_value))
+                        return -EINVAL;
+
+                bcm63xx_wdt_pet();
+
+        case WDIOC_GETTIMEOUT:
+                return put_user(wdt_time, p);
+
+        default:
+                return -ENOTTY;
+
+        }
+}
+
+static int bcm63xx_wdt_notify_sys(struct notifier_block *this,
+                                unsigned long code, void *unused)
+{
+        if (code == SYS_DOWN || code == SYS_HALT)
+                bcm63xx_wdt_pause();
+        return NOTIFY_DONE;
+}
+
+static const struct file_operations bcm63xx_wdt_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .write          = bcm63xx_wdt_write,
+        .unlocked_ioctl = bcm63xx_wdt_ioctl,
+        .open           = bcm63xx_wdt_open,
+        .release        = bcm63xx_wdt_release,
+};
+
+static struct miscdevice bcm63xx_wdt_miscdev = {
+        .minor  = WATCHDOG_MINOR,
+        .name   = "watchdog",
+        .fops   = &bcm63xx_wdt_fops,
+};
+
+static struct notifier_block bcm63xx_wdt_notifier = {
+        .notifier_call = bcm63xx_wdt_notify_sys,
+};
+
+
+static int bcm63xx_wdt_probe(struct platform_device *pdev)
+{
+        int ret;
+        struct resource *r;
+
+        setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!r) {
+                dev_err(&pdev->dev, "failed to get resources\n");
+                return -ENODEV;
+        }
+
+        bcm63xx_wdt_device.regs = ioremap_nocache(r->start, r->end - r->start);
+        if (!bcm63xx_wdt_device.regs) {
+                dev_err(&pdev->dev, "failed to remap I/O resources\n");
+                return -ENXIO;
+        }
+
+        ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "failed to register wdt timer isr\n");
+                goto unmap;
+        }
+
+        if (bcm63xx_wdt_settimeout(wdt_time)) {
+                bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
+                dev_info(&pdev->dev,
+                        ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
+                        wdt_time);
+        }
+
+        ret = register_reboot_notifier(&bcm63xx_wdt_notifier);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to register reboot_notifier\n");
+                goto unregister_timer;
+        }
+
+        ret = misc_register(&bcm63xx_wdt_miscdev);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "failed to register watchdog device\n");
+                goto unregister_reboot_notifier;
+        }
+
+        dev_info(&pdev->dev, " started, timer margin: %d sec\n",
+                                                WDT_DEFAULT_TIME);
+
+        return 0;
+
+unregister_reboot_notifier:
+        unregister_reboot_notifier(&bcm63xx_wdt_notifier);
+unregister_timer:
+        bcm63xx_timer_unregister(TIMER_WDT_ID);
+unmap:
+        iounmap(bcm63xx_wdt_device.regs);
+        return ret;
+}
+
+static int bcm63xx_wdt_remove(struct platform_device *pdev)
+{
+        if (!nowayout)
+                bcm63xx_wdt_pause();
+
+        misc_deregister(&bcm63xx_wdt_miscdev);
+
+        iounmap(bcm63xx_wdt_device.regs);
+
+        unregister_reboot_notifier(&bcm63xx_wdt_notifier);
+        bcm63xx_timer_unregister(TIMER_WDT_ID);
+
+        return 0;
+}
+
+static struct platform_driver bcm63xx_wdt = {
+        .probe  = bcm63xx_wdt_probe,
+        .remove = bcm63xx_wdt_remove,
+        .driver = {
+                .name = "bcm63xx-wdt",
+        }
+};
+
+static int __init bcm63xx_wdt_init(void)
+{
+        return platform_driver_register(&bcm63xx_wdt);
+}
+
+static void __exit bcm63xx_wdt_exit(void)
+{
+        platform_driver_unregister(&bcm63xx_wdt);
+}
+
+module_init(bcm63xx_wdt_init);
+module_exit(bcm63xx_wdt_exit);
+
+MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
+MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
+MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:bcm63xx-wdt");