[WATCHDOG] TXx9 watchdog driver

This is a driver for watchdog timer built into TXx9 MIPS SoCs.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 276 insertions, 0 deletions

diff --git a/drivers/watchdog/txx9wdt.c b/drivers/watchdog/txx9wdt.c
new file mode 100644
index 000000000000..328b3c7211ef
--- /dev/null
+++ b/drivers/watchdog/txx9wdt.c
@@ -0,0 +1,276 @@
+/*
+ * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
+ *
+ * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <asm/txx9tmr.h>
+
+#define TIMER_MARGIN    60              /* Default is 60 seconds */
+
+static int timeout = TIMER_MARGIN;      /* in seconds */
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+        "Watchdog timeout in seconds. "
+        "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
+        "default=" __MODULE_STRING(TIMER_MARGIN) ")");
+
+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) ")");
+
+#define WD_TIMER_CCD    7       /* 1/256 */
+#define WD_TIMER_CLK    (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
+#define WD_MAX_TIMEOUT  ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
+
+static unsigned long txx9wdt_alive;
+static int expect_close;
+static struct txx9_tmr_reg __iomem *txx9wdt_reg;
+static struct clk *txx9_imclk;
+
+static void txx9wdt_ping(void)
+{
+        __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
+}
+
+static void txx9wdt_start(void)
+{
+        __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
+        __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
+        __raw_writel(0, &txx9wdt_reg->tisr);    /* clear pending interrupt */
+        __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
+                     &txx9wdt_reg->tcr);
+        __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
+}
+
+static void txx9wdt_stop(void)
+{
+        __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
+        __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
+                     &txx9wdt_reg->tcr);
+}
+
+static int txx9wdt_open(struct inode *inode, struct file *file)
+{
+        if (test_and_set_bit(0, &txx9wdt_alive))
+                return -EBUSY;
+
+        if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
+                clear_bit(0, &txx9wdt_alive);
+                return -EBUSY;
+        }
+
+        if (nowayout)
+                __module_get(THIS_MODULE);
+
+        txx9wdt_start();
+        return nonseekable_open(inode, file);
+}
+
+static int txx9wdt_release(struct inode *inode, struct file *file)
+{
+        if (expect_close)
+                txx9wdt_stop();
+        else {
+                printk(KERN_CRIT "txx9wdt: "
+                       "Unexpected close, not stopping watchdog!\n");
+                txx9wdt_ping();
+        }
+        clear_bit(0, &txx9wdt_alive);
+        expect_close = 0;
+        return 0;
+}
+
+static ssize_t txx9wdt_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 = 1;
+                        }
+                }
+                txx9wdt_ping();
+        }
+        return len;
+}
+
+static int txx9wdt_ioctl(struct inode *inode, struct file *file,
+        unsigned int cmd, unsigned long arg)
+{
+        void __user *argp = (void __user *)arg;
+        int __user *p = argp;
+        int new_timeout;
+        static struct watchdog_info ident = {
+                .options =              WDIOF_SETTIMEOUT |
+                                        WDIOF_KEEPALIVEPING |
+                                        WDIOF_MAGICCLOSE,
+                .firmware_version =     0,
+                .identity =             "Hardware Watchdog for TXx9",
+        };
+
+        switch (cmd) {
+        default:
+                return -ENOTTY;
+        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:
+                txx9wdt_ping();
+                return 0;
+        case WDIOC_SETTIMEOUT:
+                if (get_user(new_timeout, p))
+                        return -EFAULT;
+                if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT)
+                        return -EINVAL;
+                timeout = new_timeout;
+                txx9wdt_stop();
+                txx9wdt_start();
+                /* Fall */
+        case WDIOC_GETTIMEOUT:
+                return put_user(timeout, p);
+        }
+}
+
+static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code,
+        void *unused)
+{
+        if (code == SYS_DOWN || code == SYS_HALT)
+                txx9wdt_stop();
+        return NOTIFY_DONE;
+}
+
+static const struct file_operations txx9wdt_fops = {
+        .owner =        THIS_MODULE,
+        .llseek =       no_llseek,
+        .write =        txx9wdt_write,
+        .ioctl =        txx9wdt_ioctl,
+        .open =         txx9wdt_open,
+        .release =      txx9wdt_release,
+};
+
+static struct miscdevice txx9wdt_miscdev = {
+        .minor =        WATCHDOG_MINOR,
+        .name =         "watchdog",
+        .fops =         &txx9wdt_fops,
+};
+
+static struct notifier_block txx9wdt_notifier = {
+        .notifier_call = txx9wdt_notify_sys
+};
+
+static int __init txx9wdt_probe(struct platform_device *dev)
+{
+        struct resource *res;
+        int ret;
+
+        txx9_imclk = clk_get(NULL, "imbus_clk");
+        if (IS_ERR(txx9_imclk)) {
+                ret = PTR_ERR(txx9_imclk);
+                txx9_imclk = NULL;
+                goto exit;
+        }
+        ret = clk_enable(txx9_imclk);
+        if (ret) {
+                clk_put(txx9_imclk);
+                txx9_imclk = NULL;
+                goto exit;
+        }
+
+        res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+        if (!res)
+                goto exit_busy;
+        if (!devm_request_mem_region(&dev->dev,
+                                     res->start, res->end - res->start + 1,
+                                     "txx9wdt"))
+                goto exit_busy;
+        txx9wdt_reg = devm_ioremap(&dev->dev,
+                                   res->start, res->end - res->start + 1);
+        if (!txx9wdt_reg)
+                goto exit_busy;
+
+        ret = register_reboot_notifier(&txx9wdt_notifier);
+        if (ret)
+                goto exit;
+
+        ret = misc_register(&txx9wdt_miscdev);
+        if (ret) {
+                unregister_reboot_notifier(&txx9wdt_notifier);
+                goto exit;
+        }
+
+        printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
+               "timeout=%d sec (max %ld) (nowayout= %d)\n",
+               timeout, WD_MAX_TIMEOUT, nowayout);
+
+        return 0;
+exit_busy:
+        ret = -EBUSY;
+exit:
+        if (txx9_imclk) {
+                clk_disable(txx9_imclk);
+                clk_put(txx9_imclk);
+        }
+        return ret;
+}
+
+static int __exit txx9wdt_remove(struct platform_device *dev)
+{
+        misc_deregister(&txx9wdt_miscdev);
+        unregister_reboot_notifier(&txx9wdt_notifier);
+        clk_disable(txx9_imclk);
+        clk_put(txx9_imclk);
+        return 0;
+}
+
+static struct platform_driver txx9wdt_driver = {
+        .remove = __exit_p(txx9wdt_remove),
+        .driver = {
+                .name = "txx9wdt",
+                .owner = THIS_MODULE,
+        },
+};
+
+static int __init watchdog_init(void)
+{
+        return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
+}
+
+static void __exit watchdog_exit(void)
+{
+        platform_driver_unregister(&txx9wdt_driver);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_DESCRIPTION("TXx9 Watchdog Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);