--- /dev/null
+/*
+ * drivers/watchdog/ar7_wdt.c
+ *
+ * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
+ * Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
+ *
+ * Some code taken from:
+ * National Semiconductor SCx200 Watchdog support
+ * Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+#include <asm/addrspace.h>
+#include <asm/ar7/ar7.h>
+
+#define DRVNAME "ar7_wdt"
+#define LONGNAME "TI AR7 Watchdog Timer"
+
+MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
+MODULE_DESCRIPTION(LONGNAME);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
+static int margin = 60;
+module_param(margin, int, 0);
+MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
+
+#define READ_REG(x) readl((void __iomem *)&(x))
+#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
+
+struct ar7_wdt {
+ u32 kick_lock;
+ u32 kick;
+ u32 change_lock;
+ u32 change;
+ u32 disable_lock;
+ u32 disable;
+ u32 prescale_lock;
+ u32 prescale;
+};
+
+static struct semaphore open_semaphore;
+static unsigned expect_close;
+
+/* XXX currently fixed, allows max margin ~68.72 secs */
+#define prescale_value 0xffff
+
+/* Offset of the WDT registers */
+static unsigned long ar7_regs_wdt;
+/* Pointer to the remapped WDT IO space */
+static struct ar7_wdt *ar7_wdt;
+static void ar7_wdt_get_regs(void)
+{
+ u16 chip_id = ar7_chip_id();
+ switch (chip_id) {
+ case AR7_CHIP_7100:
+ case AR7_CHIP_7200:
+ ar7_regs_wdt = AR7_REGS_WDT;
+ break;
+ default:
+ ar7_regs_wdt = UR8_REGS_WDT;
+ break;
+ }
+}
+
+
+static void ar7_wdt_kick(u32 value)
+{
+ WRITE_REG(ar7_wdt->kick_lock, 0x5555);
+ if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
+ WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
+ if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
+ WRITE_REG(ar7_wdt->kick, value);
+ return;
+ }
+ }
+ printk(KERN_ERR DRVNAME ": failed to unlock WDT kick reg\n");
+}
+
+static void ar7_wdt_prescale(u32 value)
+{
+ WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
+ if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
+ WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
+ if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
+ WRITE_REG(ar7_wdt->prescale, value);
+ return;
+ }
+ }
+ printk(KERN_ERR DRVNAME ": failed to unlock WDT prescale reg\n");
+}
+
+static void ar7_wdt_change(u32 value)
+{
+ WRITE_REG(ar7_wdt->change_lock, 0x6666);
+ if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
+ WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
+ if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
+ WRITE_REG(ar7_wdt->change, value);
+ return;
+ }
+ }
+ printk(KERN_ERR DRVNAME ": failed to unlock WDT change reg\n");
+}
+
+static void ar7_wdt_disable(u32 value)
+{
+ WRITE_REG(ar7_wdt->disable_lock, 0x7777);
+ if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
+ WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
+ if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
+ WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
+ if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
+ WRITE_REG(ar7_wdt->disable, value);
+ return;
+ }
+ }
+ }
+ printk(KERN_ERR DRVNAME ": failed to unlock WDT disable reg\n");
+}
+
+static void ar7_wdt_update_margin(int new_margin)
+{
+ u32 change;
+
+ change = new_margin * (ar7_vbus_freq() / prescale_value);
+ if (change < 1) change = 1;
+ if (change > 0xffff) change = 0xffff;
+ ar7_wdt_change(change);
+ margin = change * prescale_value / ar7_vbus_freq();
+ printk(KERN_INFO DRVNAME
+ ": timer margin %d seconds (prescale %d, change %d, freq %d)\n",
+ margin, prescale_value, change, ar7_vbus_freq());
+}
+
+static void ar7_wdt_enable_wdt(void)
+{
+ printk(KERN_DEBUG DRVNAME ": enabling watchdog timer\n");
+ ar7_wdt_disable(1);
+ ar7_wdt_kick(1);
+}
+
+static void ar7_wdt_disable_wdt(void)
+{
+ printk(KERN_DEBUG DRVNAME ": disabling watchdog timer\n");
+ ar7_wdt_disable(0);
+}
+
+static int ar7_wdt_open(struct inode *inode, struct file *file)
+{
+ /* only allow one at a time */
+ if (down_trylock(&open_semaphore))
+ return -EBUSY;
+ ar7_wdt_enable_wdt();
+ expect_close = 0;
+
+ return nonseekable_open(inode, file);
+}
+
+static int ar7_wdt_release(struct inode *inode, struct file *file)
+{
+ if (!expect_close)
+ printk(KERN_WARNING DRVNAME
+ ": watchdog device closed unexpectedly,"
+ "will not disable the watchdog timer\n");
+ else if (!nowayout)
+ ar7_wdt_disable_wdt();
+
+ up(&open_semaphore);
+
+ return 0;
+}
+
+static int ar7_wdt_notify_sys(struct notifier_block *this,
+ unsigned long code, void *unused)
+{
+ if (code == SYS_HALT || code == SYS_POWER_OFF)
+ if (!nowayout)
+ ar7_wdt_disable_wdt();
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block ar7_wdt_notifier = {
+ .notifier_call = ar7_wdt_notify_sys
+};
+
+static ssize_t ar7_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ /* check for a magic close character */
+ if (len) {
+ size_t i;
+
+ ar7_wdt_kick(1);
+
+ 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;
+ }
+
+ }
+ return len;
+}
+
+static int ar7_wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ static struct watchdog_info ident = {
+ .identity = LONGNAME,
+ .firmware_version = 1,
+ .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING),
+ };
+ int new_margin;
+
+ switch (cmd) {
+ default:
+ return -ENOTTY;
+ case WDIOC_GETSUPPORT:
+ if (copy_to_user((struct watchdog_info *)arg, &ident,
+ sizeof(ident)))
+ return -EFAULT;
+ return 0;
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ if (put_user(0, (int *)arg))
+ return -EFAULT;
+ return 0;
+ case WDIOC_KEEPALIVE:
+ ar7_wdt_kick(1);
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_margin, (int *)arg))
+ return -EFAULT;
+ if (new_margin < 1)
+ return -EINVAL;
+
+ ar7_wdt_update_margin(new_margin);
+ ar7_wdt_kick(1);
+
+ case WDIOC_GETTIMEOUT:
+ if (put_user(margin, (int *)arg))
+ return -EFAULT;
+ return 0;
+ }
+}
+
+static struct file_operations ar7_wdt_fops = {
+ .owner = THIS_MODULE,
+ .write = ar7_wdt_write,
+ .ioctl = ar7_wdt_ioctl,
+ .open = ar7_wdt_open,
+ .release = ar7_wdt_release,
+};
+
+static struct miscdevice ar7_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &ar7_wdt_fops,
+};
+
+static int __init ar7_wdt_init(void)
+{
+ int rc;
+
+ ar7_wdt_get_regs();
+
+ if (!request_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt),
+ LONGNAME)) {
+ printk(KERN_WARNING DRVNAME ": watchdog I/O region busy\n");
+ return -EBUSY;
+ }
+
+ ar7_wdt = (struct ar7_wdt *)
+ ioremap(ar7_regs_wdt, sizeof(struct ar7_wdt));
+
+ ar7_wdt_disable_wdt();
+ ar7_wdt_prescale(prescale_value);
+ ar7_wdt_update_margin(margin);
+
+ sema_init(&open_semaphore, 1);
+
+ rc = register_reboot_notifier(&ar7_wdt_notifier);
+ if (rc) {
+ printk(KERN_ERR DRVNAME
+ ": unable to register reboot notifier\n");
+ goto out_alloc;
+ }
+
+ rc = misc_register(&ar7_wdt_miscdev);
+ if (rc) {
+ printk(KERN_ERR DRVNAME ": unable to register misc device\n");
+ goto out_register;
+ }
+ goto out;
+
+out_register:
+ unregister_reboot_notifier(&ar7_wdt_notifier);
+out_alloc:
+ iounmap(ar7_wdt);
+ release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
+out:
+ return rc;
+}
+
+static void __exit ar7_wdt_cleanup(void)
+{
+ misc_deregister(&ar7_wdt_miscdev);
+ unregister_reboot_notifier(&ar7_wdt_notifier);
+ iounmap(ar7_wdt);
+ release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
+}
+
+module_init(ar7_wdt_init);
+module_exit(ar7_wdt_cleanup);
projects / linux-2.6 / commitdiff