1 files changed, 563 insertions, 0 deletions

diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
new file mode 100644
index 000000000000..5d1c15f83d23
--- /dev/null
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -0,0 +1,563 @@
+/* linux/drivers/char/watchdog/s3c2410_wdt.c
+ *
+ * Copyright (c) 2004 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2410 Watchdog Timer Support
+ *
+ * Based on, softdog.c by Alan Cox,
+ *     (c) Copyright 1996 Alan Cox <alan@redhat.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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Changelog:
+ *      05-Oct-2004     BJD     Added semaphore init to stop crashes on open
+ *                              Fixed tmr_count / wdt_count confusion
+ *                              Added configurable debug
+ *
+ *      11-Jan-2005     BJD     Fixed divide-by-2 in timeout code
+ *
+ *      25-Jan-2005     DA      Added suspend/resume support
+ *                              Replaced reboot notifier with .shutdown method
+ *
+ *      10-Mar-2005     LCVR    Changed S3C2410_VA to S3C24XX_VA
+*/
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#include <asm/arch/map.h>
+
+#undef S3C_VA_WATCHDOG
+#define S3C_VA_WATCHDOG (0)
+
+#include <asm/plat-s3c/regs-watchdog.h>
+
+#define PFX "s3c2410-wdt: "
+
+#define CONFIG_S3C2410_WATCHDOG_ATBOOT          (0)
+#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME    (15)
+
+static int nowayout     = WATCHDOG_NOWAYOUT;
+static int tmr_margin   = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
+static int tmr_atboot   = CONFIG_S3C2410_WATCHDOG_ATBOOT;
+static int soft_noboot  = 0;
+static int debug        = 0;
+
+module_param(tmr_margin,  int, 0);
+module_param(tmr_atboot,  int, 0);
+module_param(nowayout,    int, 0);
+module_param(soft_noboot, int, 0);
+module_param(debug,       int, 0);
+
+MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
+
+MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
+
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
+
+MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
+
+
+typedef enum close_state {
+        CLOSE_STATE_NOT,
+        CLOSE_STATE_ALLOW=0x4021
+} close_state_t;
+
+static DECLARE_MUTEX(open_lock);
+
+static struct device    *wdt_dev;       /* platform device attached to */
+static struct resource  *wdt_mem;
+static struct resource  *wdt_irq;
+static struct clk       *wdt_clock;
+static void __iomem     *wdt_base;
+static unsigned int      wdt_count;
+static close_state_t     allow_close;
+
+/* watchdog control routines */
+
+#define DBG(msg...) do { \
+        if (debug) \
+                printk(KERN_INFO msg); \
+        } while(0)
+
+/* functions */
+
+static int s3c2410wdt_keepalive(void)
+{
+        writel(wdt_count, wdt_base + S3C2410_WTCNT);
+        return 0;
+}
+
+static int s3c2410wdt_stop(void)
+{
+        unsigned long wtcon;
+
+        wtcon = readl(wdt_base + S3C2410_WTCON);
+        wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
+        writel(wtcon, wdt_base + S3C2410_WTCON);
+
+        return 0;
+}
+
+static int s3c2410wdt_start(void)
+{
+        unsigned long wtcon;
+
+        s3c2410wdt_stop();
+
+        wtcon = readl(wdt_base + S3C2410_WTCON);
+        wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
+
+        if (soft_noboot) {
+                wtcon |= S3C2410_WTCON_INTEN;
+                wtcon &= ~S3C2410_WTCON_RSTEN;
+        } else {
+                wtcon &= ~S3C2410_WTCON_INTEN;
+                wtcon |= S3C2410_WTCON_RSTEN;
+        }
+
+        DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
+            __FUNCTION__, wdt_count, wtcon);
+
+        writel(wdt_count, wdt_base + S3C2410_WTDAT);
+        writel(wdt_count, wdt_base + S3C2410_WTCNT);
+        writel(wtcon, wdt_base + S3C2410_WTCON);
+
+        return 0;
+}
+
+static int s3c2410wdt_set_heartbeat(int timeout)
+{
+        unsigned int freq = clk_get_rate(wdt_clock);
+        unsigned int count;
+        unsigned int divisor = 1;
+        unsigned long wtcon;
+
+        if (timeout < 1)
+                return -EINVAL;
+
+        freq /= 128;
+        count = timeout * freq;
+
+        DBG("%s: count=%d, timeout=%d, freq=%d\n",
+            __FUNCTION__, count, timeout, freq);
+
+        /* if the count is bigger than the watchdog register,
+           then work out what we need to do (and if) we can
+           actually make this value
+        */
+
+        if (count >= 0x10000) {
+                for (divisor = 1; divisor <= 0x100; divisor++) {
+                        if ((count / divisor) < 0x10000)
+                                break;
+                }
+
+                if ((count / divisor) >= 0x10000) {
+                        dev_err(wdt_dev, "timeout %d too big\n", timeout);
+                        return -EINVAL;
+                }
+        }
+
+        tmr_margin = timeout;
+
+        DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
+            __FUNCTION__, timeout, divisor, count, count/divisor);
+
+        count /= divisor;
+        wdt_count = count;
+
+        /* update the pre-scaler */
+        wtcon = readl(wdt_base + S3C2410_WTCON);
+        wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
+        wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
+
+        writel(count, wdt_base + S3C2410_WTDAT);
+        writel(wtcon, wdt_base + S3C2410_WTCON);
+
+        return 0;
+}
+
+/*
+ *      /dev/watchdog handling
+ */
+
+static int s3c2410wdt_open(struct inode *inode, struct file *file)
+{
+        if(down_trylock(&open_lock))
+                return -EBUSY;
+
+        if (nowayout)
+                __module_get(THIS_MODULE);
+
+        allow_close = CLOSE_STATE_NOT;
+
+        /* start the timer */
+        s3c2410wdt_start();
+        return nonseekable_open(inode, file);
+}
+
+static int s3c2410wdt_release(struct inode *inode, struct file *file)
+{
+        /*
+         *      Shut off the timer.
+         *      Lock it in if it's a module and we set nowayout
+         */
+
+        if (allow_close == CLOSE_STATE_ALLOW) {
+                s3c2410wdt_stop();
+        } else {
+                dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
+                s3c2410wdt_keepalive();
+        }
+
+        allow_close = CLOSE_STATE_NOT;
+        up(&open_lock);
+        return 0;
+}
+
+static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
+                                size_t len, loff_t *ppos)
+{
+        /*
+         *      Refresh the timer.
+         */
+        if(len) {
+                if (!nowayout) {
+                        size_t i;
+
+                        /* In case it was set long ago */
+                        allow_close = CLOSE_STATE_NOT;
+
+                        for (i = 0; i != len; i++) {
+                                char c;
+
+                                if (get_user(c, data + i))
+                                        return -EFAULT;
+                                if (c == 'V')
+                                        allow_close = CLOSE_STATE_ALLOW;
+                        }
+                }
+
+                s3c2410wdt_keepalive();
+        }
+        return len;
+}
+
+#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
+
+static struct watchdog_info s3c2410_wdt_ident = {
+        .options          =     OPTIONS,
+        .firmware_version =     0,
+        .identity         =     "S3C2410 Watchdog",
+};
+
+
+static int s3c2410wdt_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_margin;
+
+        switch (cmd) {
+                default:
+                        return -ENOTTY;
+
+                case WDIOC_GETSUPPORT:
+                        return copy_to_user(argp, &s3c2410_wdt_ident,
+                                sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
+
+                case WDIOC_GETSTATUS:
+                case WDIOC_GETBOOTSTATUS:
+                        return put_user(0, p);
+
+                case WDIOC_KEEPALIVE:
+                        s3c2410wdt_keepalive();
+                        return 0;
+
+                case WDIOC_SETTIMEOUT:
+                        if (get_user(new_margin, p))
+                                return -EFAULT;
+
+                        if (s3c2410wdt_set_heartbeat(new_margin))
+                                return -EINVAL;
+
+                        s3c2410wdt_keepalive();
+                        return put_user(tmr_margin, p);
+
+                case WDIOC_GETTIMEOUT:
+                        return put_user(tmr_margin, p);
+        }
+}
+
+/* kernel interface */
+
+static const struct file_operations s3c2410wdt_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .write          = s3c2410wdt_write,
+        .ioctl          = s3c2410wdt_ioctl,
+        .open           = s3c2410wdt_open,
+        .release        = s3c2410wdt_release,
+};
+
+static struct miscdevice s3c2410wdt_miscdev = {
+        .minor          = WATCHDOG_MINOR,
+        .name           = "watchdog",
+        .fops           = &s3c2410wdt_fops,
+};
+
+/* interrupt handler code */
+
+static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
+{
+        dev_info(wdt_dev, "watchdog timer expired (irq)\n");
+
+        s3c2410wdt_keepalive();
+        return IRQ_HANDLED;
+}
+/* device interface */
+
+static int s3c2410wdt_probe(struct platform_device *pdev)
+{
+        struct resource *res;
+        struct device *dev;
+        unsigned int wtcon;
+        int started = 0;
+        int ret;
+        int size;
+
+        DBG("%s: probe=%p\n", __FUNCTION__, pdev);
+
+        dev = &pdev->dev;
+        wdt_dev = &pdev->dev;
+
+        /* get the memory region for the watchdog timer */
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (res == NULL) {
+                dev_err(dev, "no memory resource specified\n");
+                return -ENOENT;
+        }
+
+        size = (res->end-res->start)+1;
+        wdt_mem = request_mem_region(res->start, size, pdev->name);
+        if (wdt_mem == NULL) {
+                dev_err(dev, "failed to get memory region\n");
+                ret = -ENOENT;
+                goto err_req;
+        }
+
+        wdt_base = ioremap(res->start, size);
+        if (wdt_base == 0) {
+                dev_err(dev, "failed to ioremap() region\n");
+                ret = -EINVAL;
+                goto err_req;
+        }
+
+        DBG("probe: mapped wdt_base=%p\n", wdt_base);
+
+        wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+        if (wdt_irq == NULL) {
+                dev_err(dev, "no irq resource specified\n");
+                ret = -ENOENT;
+                goto err_map;
+        }
+
+        ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
+        if (ret != 0) {
+                dev_err(dev, "failed to install irq (%d)\n", ret);
+                goto err_map;
+        }
+
+        wdt_clock = clk_get(&pdev->dev, "watchdog");
+        if (IS_ERR(wdt_clock)) {
+                dev_err(dev, "failed to find watchdog clock source\n");
+                ret = PTR_ERR(wdt_clock);
+                goto err_irq;
+        }
+
+        clk_enable(wdt_clock);
+
+        /* see if we can actually set the requested timer margin, and if
+         * not, try the default value */
+
+        if (s3c2410wdt_set_heartbeat(tmr_margin)) {
+                started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
+
+                if (started == 0) {
+                        dev_info(dev,"tmr_margin value out of range, default %d used\n",
+                               CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
+                } else {
+                        dev_info(dev, "default timer value is out of range, cannot start\n");
+                }
+        }
+
+        ret = misc_register(&s3c2410wdt_miscdev);
+        if (ret) {
+                dev_err(dev, "cannot register miscdev on minor=%d (%d)\n",
+                        WATCHDOG_MINOR, ret);
+                goto err_clk;
+        }
+
+        if (tmr_atboot && started == 0) {
+                dev_info(dev, "starting watchdog timer\n");
+                s3c2410wdt_start();
+        } else if (!tmr_atboot) {
+                /* if we're not enabling the watchdog, then ensure it is
+                 * disabled if it has been left running from the bootloader
+                 * or other source */
+
+                s3c2410wdt_stop();
+        }
+
+        /* print out a statement of readiness */
+
+        wtcon = readl(wdt_base + S3C2410_WTCON);
+
+        dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
+                 (wtcon & S3C2410_WTCON_ENABLE) ?  "" : "in",
+                 (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
+                 (wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
+        
+        return 0;
+
+ err_clk:
+        clk_disable(wdt_clock);
+        clk_put(wdt_clock);
+
+ err_irq:
+        free_irq(wdt_irq->start, pdev);
+
+ err_map:
+        iounmap(wdt_base);
+
+ err_req:
+        release_resource(wdt_mem);
+        kfree(wdt_mem);
+
+        return ret;
+}
+
+static int s3c2410wdt_remove(struct platform_device *dev)
+{
+        release_resource(wdt_mem);
+        kfree(wdt_mem);
+        wdt_mem = NULL;
+
+        free_irq(wdt_irq->start, dev);
+        wdt_irq = NULL;
+
+        clk_disable(wdt_clock);
+        clk_put(wdt_clock);
+        wdt_clock = NULL;
+
+        iounmap(wdt_base);
+        misc_deregister(&s3c2410wdt_miscdev);
+        return 0;
+}
+
+static void s3c2410wdt_shutdown(struct platform_device *dev)
+{
+        s3c2410wdt_stop();      
+}
+
+#ifdef CONFIG_PM
+
+static unsigned long wtcon_save;
+static unsigned long wtdat_save;
+
+static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
+{
+        /* Save watchdog state, and turn it off. */
+        wtcon_save = readl(wdt_base + S3C2410_WTCON);
+        wtdat_save = readl(wdt_base + S3C2410_WTDAT);
+
+        /* Note that WTCNT doesn't need to be saved. */
+        s3c2410wdt_stop();
+
+        return 0;
+}
+
+static int s3c2410wdt_resume(struct platform_device *dev)
+{
+        /* Restore watchdog state. */
+
+        writel(wtdat_save, wdt_base + S3C2410_WTDAT);
+        writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
+        writel(wtcon_save, wdt_base + S3C2410_WTCON);
+
+        printk(KERN_INFO PFX "watchdog %sabled\n",
+               (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
+
+        return 0;
+}
+
+#else
+#define s3c2410wdt_suspend NULL
+#define s3c2410wdt_resume  NULL
+#endif /* CONFIG_PM */
+
+
+static struct platform_driver s3c2410wdt_driver = {
+        .probe          = s3c2410wdt_probe,
+        .remove         = s3c2410wdt_remove,
+        .shutdown       = s3c2410wdt_shutdown,
+        .suspend        = s3c2410wdt_suspend,
+        .resume         = s3c2410wdt_resume,
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = "s3c2410-wdt",
+        },
+};
+
+
+static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
+
+static int __init watchdog_init(void)
+{
+        printk(banner);
+        return platform_driver_register(&s3c2410wdt_driver);
+}
+
+static void __exit watchdog_exit(void)
+{
+        platform_driver_unregister(&s3c2410wdt_driver);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
+              "Dimitry Andric <dimitry.andric@tomtom.com>");
+MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);