[WATCHDOG] Add watchdog driver for NUC900
Wan ZongShun [Mon, 17 Aug 2009 10:00:01 +0000 (18:00 +0800)]
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>

drivers/watchdog/Kconfig
drivers/watchdog/Makefile
drivers/watchdog/nuc900_wdt.c [new file with mode: 0644]

index 1940a08..3229889 100644 (file)
@@ -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
index 6c58e7c..e1784a6 100644 (file)
@@ -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 (file)
index 0000000..adefe3a
--- /dev/null
@@ -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");