[WATCHDOG] Add watchdog driver for NUC900

Add watchdog device driver for the Nuvoton NUC900 series SoCs.

Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

3 files changed, 363 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1940a08d18de..3229889c3591 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -266,6 +266,15 @@ config STMP3XXX_WATCHDOG
           To compile this driver as a module, choose M here: the
           module will be called stmp3xxx_wdt.
 
+config NUC900_WATCHDOG
+        tristate "Nuvoton NUC900 watchdog"
+        depends on ARCH_W90X900
+        help
+          Say Y here if to include support for the watchdog timer
+          for the Nuvoton NUC900 series SoCs.
+          To compile this driver as a module, choose M here: the
+          module will be called nuc900_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 6c58e7ccee2c..e1784a6208a7 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
 obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
 obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
 obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
+obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/nuc900_wdt.c b/drivers/watchdog/nuc900_wdt.c
new file mode 100644
index 000000000000..adefe3a9d510
--- /dev/null
+++ b/drivers/watchdog/nuc900_wdt.c
@@ -0,0 +1,353 @@
+/*
+ * Copyright (c) 2009 Nuvoton technology corporation.
+ *
+ * Wan ZongShun <mcuos.com@gmail.com>
+ *
+ * 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;version 2 of the License.
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/uaccess.h>
+
+#define REG_WTCR                0x1c
+#define WTCLK                   (0x01 << 10)
+#define WTE                     (0x01 << 7)     /*wdt enable*/
+#define WTIS                    (0x03 << 4)
+#define WTIF                    (0x01 << 3)
+#define WTRF                    (0x01 << 2)
+#define WTRE                    (0x01 << 1)
+#define WTR                     (0x01 << 0)
+/*
+ * The watchdog time interval can be calculated via following formula:
+ * WTIS         real time interval (formula)
+ * 0x00         ((2^ 14 ) * ((external crystal freq) / 256))seconds
+ * 0x01         ((2^ 16 ) * ((external crystal freq) / 256))seconds
+ * 0x02         ((2^ 18 ) * ((external crystal freq) / 256))seconds
+ * 0x03         ((2^ 20 ) * ((external crystal freq) / 256))seconds
+ *
+ * The external crystal freq is 15Mhz in the nuc900 evaluation board.
+ * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds,
+ * 0x03 = +- 16.92 seconds..
+ */
+#define WDT_HW_TIMEOUT          0x02
+#define WDT_TIMEOUT             (HZ/2)
+#define WDT_HEARTBEAT           15
+
+static int heartbeat = WDT_HEARTBEAT;
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
+        "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
+
+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) ")");
+
+struct nuc900_wdt {
+        struct resource  *res;
+        struct clk       *wdt_clock;
+        struct platform_device *pdev;
+        void __iomem     *wdt_base;
+        char             expect_close;
+        struct timer_list timer;
+        spinlock_t       wdt_lock;
+        unsigned long next_heartbeat;
+};
+
+static unsigned long nuc900wdt_busy;
+struct nuc900_wdt *nuc900_wdt;
+
+static inline void nuc900_wdt_keepalive(void)
+{
+        unsigned int val;
+
+        spin_lock(&nuc900_wdt->wdt_lock);
+
+        val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
+        val |= (WTR | WTIF);
+        __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
+
+        spin_unlock(&nuc900_wdt->wdt_lock);
+}
+
+static inline void nuc900_wdt_start(void)
+{
+        unsigned int val;
+
+        spin_lock(&nuc900_wdt->wdt_lock);
+
+        val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
+        val |= (WTRE | WTE | WTR | WTCLK | WTIF);
+        val &= ~WTIS;
+        val |= (WDT_HW_TIMEOUT << 0x04);
+        __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
+
+        spin_unlock(&nuc900_wdt->wdt_lock);
+
+        nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
+        mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
+}
+
+static inline void nuc900_wdt_stop(void)
+{
+        unsigned int val;
+
+        del_timer(&nuc900_wdt->timer);
+
+        spin_lock(&nuc900_wdt->wdt_lock);
+
+        val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
+        val &= ~WTE;
+        __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
+
+        spin_unlock(&nuc900_wdt->wdt_lock);
+}
+
+static inline void nuc900_wdt_ping(void)
+{
+        nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
+}
+
+static int nuc900_wdt_open(struct inode *inode, struct file *file)
+{
+
+        if (test_and_set_bit(0, &nuc900wdt_busy))
+                return -EBUSY;
+
+        nuc900_wdt_start();
+
+        return nonseekable_open(inode, file);
+}
+
+static int nuc900_wdt_close(struct inode *inode, struct file *file)
+{
+        if (nuc900_wdt->expect_close == 42)
+                nuc900_wdt_stop();
+        else {
+                dev_crit(&nuc900_wdt->pdev->dev,
+                        "Unexpected close, not stopping watchdog!\n");
+                nuc900_wdt_ping();
+        }
+
+        nuc900_wdt->expect_close = 0;
+        clear_bit(0, &nuc900wdt_busy);
+        return 0;
+}
+
+static const struct watchdog_info nuc900_wdt_info = {
+        .identity       = "nuc900 watchdog",
+        .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+                                                WDIOF_MAGICCLOSE,
+};
+
+static long nuc900_wdt_ioctl(struct file *file,
+                                        unsigned int cmd, unsigned long arg)
+{
+        void __user *argp = (void __user *)arg;
+        int __user *p = argp;
+        int new_value;
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                return copy_to_user(argp, &nuc900_wdt_info,
+                                sizeof(nuc900_wdt_info)) ? -EFAULT : 0;
+        case WDIOC_GETSTATUS:
+        case WDIOC_GETBOOTSTATUS:
+                return put_user(0, p);
+
+        case WDIOC_KEEPALIVE:
+                nuc900_wdt_ping();
+                return 0;
+
+        case WDIOC_SETTIMEOUT:
+                if (get_user(new_value, p))
+                        return -EFAULT;
+
+                heartbeat = new_value;
+                nuc900_wdt_ping();
+
+                return put_user(new_value, p);
+        case WDIOC_GETTIMEOUT:
+                return put_user(heartbeat, p);
+        default:
+                return -ENOTTY;
+        }
+}
+
+static ssize_t nuc900_wdt_write(struct file *file, const char __user *data,
+                                                size_t len, loff_t *ppos)
+{
+        if (!len)
+                return 0;
+
+        /* Scan for magic character */
+        if (!nowayout) {
+                size_t i;
+
+                nuc900_wdt->expect_close = 0;
+
+                for (i = 0; i < len; i++) {
+                        char c;
+                        if (get_user(c, data + i))
+                                return -EFAULT;
+                        if (c == 'V') {
+                                nuc900_wdt->expect_close = 42;
+                                break;
+                        }
+                }
+        }
+
+        nuc900_wdt_ping();
+        return len;
+}
+
+static void nuc900_wdt_timer_ping(unsigned long data)
+{
+        if (time_before(jiffies, nuc900_wdt->next_heartbeat)) {
+                nuc900_wdt_keepalive();
+                mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
+        } else
+                dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n");
+}
+
+static const struct file_operations nuc900wdt_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .unlocked_ioctl = nuc900_wdt_ioctl,
+        .open           = nuc900_wdt_open,
+        .release        = nuc900_wdt_close,
+        .write          = nuc900_wdt_write,
+};
+
+static struct miscdevice nuc900wdt_miscdev = {
+        .minor          = WATCHDOG_MINOR,
+        .name           = "watchdog",
+        .fops           = &nuc900wdt_fops,
+};
+
+static int __devinit nuc900wdt_probe(struct platform_device *pdev)
+{
+        int ret = 0;
+
+        nuc900_wdt = kzalloc(sizeof(struct nuc900_wdt), GFP_KERNEL);
+        if (!nuc900_wdt)
+                return -ENOMEM;
+
+        nuc900_wdt->pdev = pdev;
+
+        spin_lock_init(&nuc900_wdt->wdt_lock);
+
+        nuc900_wdt->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (nuc900_wdt->res == NULL) {
+                dev_err(&pdev->dev, "no memory resource specified\n");
+                ret = -ENOENT;
+                goto err_get;
+        }
+
+        if (!request_mem_region(nuc900_wdt->res->start,
+                                resource_size(nuc900_wdt->res), pdev->name)) {
+                dev_err(&pdev->dev, "failed to get memory region\n");
+                ret = -ENOENT;
+                goto err_get;
+        }
+
+        nuc900_wdt->wdt_base = ioremap(nuc900_wdt->res->start,
+                                        resource_size(nuc900_wdt->res));
+        if (nuc900_wdt->wdt_base == NULL) {
+                dev_err(&pdev->dev, "failed to ioremap() region\n");
+                ret = -EINVAL;
+                goto err_req;
+        }
+
+        nuc900_wdt->wdt_clock = clk_get(&pdev->dev, NULL);
+        if (IS_ERR(nuc900_wdt->wdt_clock)) {
+                dev_err(&pdev->dev, "failed to find watchdog clock source\n");
+                ret = PTR_ERR(nuc900_wdt->wdt_clock);
+                goto err_map;
+        }
+
+        clk_enable(nuc900_wdt->wdt_clock);
+
+        setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0);
+
+        if (misc_register(&nuc900wdt_miscdev)) {
+                dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n",
+                        WATCHDOG_MINOR, ret);
+                goto err_clk;
+        }
+
+        return 0;
+
+err_clk:
+        clk_disable(nuc900_wdt->wdt_clock);
+        clk_put(nuc900_wdt->wdt_clock);
+err_map:
+        iounmap(nuc900_wdt->wdt_base);
+err_req:
+        release_mem_region(nuc900_wdt->res->start,
+                                        resource_size(nuc900_wdt->res));
+err_get:
+        kfree(nuc900_wdt);
+        return ret;
+}
+
+static int __devexit nuc900wdt_remove(struct platform_device *pdev)
+{
+        misc_deregister(&nuc900wdt_miscdev);
+
+        clk_disable(nuc900_wdt->wdt_clock);
+        clk_put(nuc900_wdt->wdt_clock);
+
+        iounmap(nuc900_wdt->wdt_base);
+
+        release_mem_region(nuc900_wdt->res->start,
+                                        resource_size(nuc900_wdt->res));
+
+        kfree(nuc900_wdt);
+
+        return 0;
+}
+
+static struct platform_driver nuc900wdt_driver = {
+        .probe          = nuc900wdt_probe,
+        .remove         = __devexit_p(nuc900wdt_remove),
+        .driver         = {
+                .name   = "nuc900-wdt",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static int __init nuc900_wdt_init(void)
+{
+        return platform_driver_register(&nuc900wdt_driver);
+}
+
+static void __exit nuc900_wdt_exit(void)
+{
+        platform_driver_unregister(&nuc900wdt_driver);
+}
+
+module_init(nuc900_wdt_init);
+module_exit(nuc900_wdt_exit);
+
+MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
+MODULE_DESCRIPTION("Watchdog driver for NUC900");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:nuc900-wdt");