--- /dev/null
+/* 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
+*/
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#include <asm/arch/map.h>
+#include <asm/hardware/clock.h>
+
+#undef S3C2410_VA_WATCHDOG
+#define S3C2410_VA_WATCHDOG (0)
+
+#include <asm/arch/regs-watchdog.h>
+
+#define PFX "s3c2410-wdt: "
+
+#define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
+#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+static int nowayout = 1;
+#else
+static int nowayout = 0;
+#endif
+
+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=CONFIG_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 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;
+
+ /* I think someone must have missed a divide-by-2 in the 2410,
+ * as a divisor of 128 gives half the calculated delay...
+ */
+
+ freq /= 128/2;
+ 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) {
+ printk(KERN_ERR PFX "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);
+ } else {
+ allow_close = CLOSE_STATE_ALLOW;
+ }
+
+ /* 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 {
+ printk(KERN_CRIT PFX "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 -ENOIOCTLCMD;
+
+ 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);
+ }
+}
+
+/*
+ * Notifier for system down
+ */
+
+static int s3c2410wdt_notify_sys(struct notifier_block *this, unsigned long code,
+ void *unused)
+{
+ if(code==SYS_DOWN || code==SYS_HALT) {
+ /* Turn the WDT off */
+ s3c2410wdt_stop();
+ }
+ return NOTIFY_DONE;
+}
+
+/* kernel interface */
+
+static 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,
+};
+
+static struct notifier_block s3c2410wdt_notifier = {
+ .notifier_call = s3c2410wdt_notify_sys,
+};
+
+/* interrupt handler code */
+
+static irqreturn_t s3c2410wdt_irq(int irqno, void *param,
+ struct pt_regs *regs)
+{
+ printk(KERN_INFO PFX "Watchdog timer expired!\n");
+
+ s3c2410wdt_keepalive();
+ return IRQ_HANDLED;
+}
+/* device interface */
+
+static int s3c2410wdt_probe(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct resource *res;
+ int started = 0;
+ int ret;
+ int size;
+
+ DBG("%s: probe=%p, device=%p\n", __FUNCTION__, pdev, dev);
+
+ /* get the memory region for the watchdog timer */
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (res == NULL) {
+ printk(KERN_INFO PFX "failed to get memory region resouce\n");
+ return -ENOENT;
+ }
+
+ size = (res->end-res->start)+1;
+ wdt_mem = request_mem_region(res->start, size, pdev->name);
+ if (wdt_mem == NULL) {
+ printk(KERN_INFO PFX "failed to get memory region\n");
+ return -ENOENT;
+ }
+
+ wdt_base = ioremap(res->start, size);
+ if (wdt_base == 0) {
+ printk(KERN_INFO PFX "failed to ioremap() region\n");
+ return -EINVAL;
+ }
+
+ DBG("probe: mapped wdt_base=%p\n", wdt_base);
+
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (res == NULL) {
+ printk(KERN_INFO PFX "failed to get irq resource\n");
+ return -ENOENT;
+ }
+
+ ret = request_irq(res->start, s3c2410wdt_irq, 0, pdev->name, dev);
+ if (ret != 0) {
+ printk(KERN_INFO PFX "failed to install irq (%d)\n", ret);
+ return ret;
+ }
+
+ wdt_clock = clk_get(dev, "watchdog");
+ if (wdt_clock == NULL) {
+ printk(KERN_INFO PFX "failed to find watchdog clock source\n");
+ return -ENOENT;
+ }
+
+ clk_use(wdt_clock);
+ 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) {
+ printk(KERN_INFO PFX "tmr_margin value out of range, default %d used\n",
+ CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
+ } else {
+ printk(KERN_INFO PFX "default timer value is out of range, cannot start\n");
+ }
+ }
+
+ ret = register_reboot_notifier(&s3c2410wdt_notifier);
+ if (ret) {
+ printk (KERN_ERR PFX "cannot register reboot notifier (%d)\n",
+ ret);
+ return ret;
+ }
+
+ ret = misc_register(&s3c2410wdt_miscdev);
+ if (ret) {
+ printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n",
+ WATCHDOG_MINOR, ret);
+ unregister_reboot_notifier(&s3c2410wdt_notifier);
+ return ret;
+ }
+
+ if (tmr_atboot && started == 0) {
+ printk(KERN_INFO PFX "Starting Watchdog Timer\n");
+ s3c2410wdt_start();
+ }
+
+ return 0;
+}
+
+static int s3c2410wdt_remove(struct device *dev)
+{
+ if (wdt_mem != NULL) {
+ release_resource(wdt_mem);
+ kfree(wdt_mem);
+ wdt_mem = NULL;
+ }
+
+ if (wdt_irq != NULL) {
+ free_irq(wdt_irq->start, dev);
+ wdt_irq = NULL;
+ }
+
+ if (wdt_clock != NULL) {
+ clk_disable(wdt_clock);
+ clk_unuse(wdt_clock);
+ clk_put(wdt_clock);
+ wdt_clock = NULL;
+ }
+
+ misc_deregister(&s3c2410wdt_miscdev);
+ return 0;
+}
+
+static struct device_driver s3c2410wdt_driver = {
+ .name = "s3c2410-wdt",
+ .bus = &platform_bus_type,
+ .probe = s3c2410wdt_probe,
+ .remove = s3c2410wdt_remove,
+};
+
+
+
+static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
+
+static int __init watchdog_init(void)
+{
+ printk(banner);
+ return driver_register(&s3c2410wdt_driver);
+}
+
+static void __exit watchdog_exit(void)
+{
+ driver_unregister(&s3c2410wdt_driver);
+ unregister_reboot_notifier(&s3c2410wdt_notifier);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
+MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
git://git.onelab.eu / linux-2.6.git / blobdiff