--- /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
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/clk.h>
+
+#include <asm/addrspace.h>
+#include <asm/mach-ar7/ar7.h>
+
+#define LONGNAME "TI AR7 Watchdog Timer"
+
+MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
+MODULE_DESCRIPTION(LONGNAME);
+MODULE_LICENSE("GPL");
+
+static int margin = 60;
+module_param(margin, int, 0);
+MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 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 unsigned long wdt_is_open;
+static unsigned expect_close;
+static DEFINE_SPINLOCK(wdt_lock);
+
+/* XXX currently fixed, allows max margin ~68.72 secs */
+#define prescale_value 0xffff
+
+/* Resource of the WDT registers */
+static struct resource *ar7_regs_wdt;
+/* Pointer to the remapped WDT IO space */
+static struct ar7_wdt *ar7_wdt;
+
+static struct clk *vbus_clk;
+
+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;
+ }
+ }
+ pr_err("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;
+ }
+ }
+ pr_err("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;
+ }
+ }
+ pr_err("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;
+ }
+ }
+ }
+ pr_err("failed to unlock WDT disable reg\n");
+}
+
+static void ar7_wdt_update_margin(int new_margin)
+{
+ u32 change;
+ u32 vbus_rate;
+
+ vbus_rate = clk_get_rate(vbus_clk);
+ change = new_margin * (vbus_rate / prescale_value);
+ if (change < 1)
+ change = 1;
+ if (change > 0xffff)
+ change = 0xffff;
+ ar7_wdt_change(change);
+ margin = change * prescale_value / vbus_rate;
+ pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
+ margin, prescale_value, change, vbus_rate);
+}
+
+static void ar7_wdt_enable_wdt(void)
+{
+ pr_debug("enabling watchdog timer\n");
+ ar7_wdt_disable(1);
+ ar7_wdt_kick(1);
+}
+
+static void ar7_wdt_disable_wdt(void)
+{
+ pr_debug("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 (test_and_set_bit(0, &wdt_is_open))
+ 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)
+ pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
+ else if (!nowayout)
+ ar7_wdt_disable_wdt();
+ clear_bit(0, &wdt_is_open);
+ return 0;
+}
+
+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;
+
+ spin_lock(&wdt_lock);
+ ar7_wdt_kick(1);
+ spin_unlock(&wdt_lock);
+
+ 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 long ar7_wdt_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ static const struct watchdog_info ident = {
+ .identity = LONGNAME,
+ .firmware_version = 1,
+ .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE),
+ };
+ int new_margin;
+
+ switch (cmd) {
+ 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;
+
+ spin_lock(&wdt_lock);
+ ar7_wdt_update_margin(new_margin);
+ ar7_wdt_kick(1);
+ spin_unlock(&wdt_lock);
+
+ case WDIOC_GETTIMEOUT:
+ if (put_user(margin, (int *)arg))
+ return -EFAULT;
+ return 0;
+ default:
+ return -ENOTTY;
+ }
+}
+
+static const struct file_operations ar7_wdt_fops = {
+ .owner = THIS_MODULE,
+ .write = ar7_wdt_write,
+ .unlocked_ioctl = ar7_wdt_ioctl,
+ .open = ar7_wdt_open,
+ .release = ar7_wdt_release,
+ .llseek = no_llseek,
+};
+
+static struct miscdevice ar7_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &ar7_wdt_fops,
+};
+
+static int ar7_wdt_probe(struct platform_device *pdev)
+{
+ int rc;
+
+ ar7_regs_wdt =
+ platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
+ ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt);
+ if (IS_ERR(ar7_wdt))
+ return PTR_ERR(ar7_wdt);
+
+ vbus_clk = clk_get(NULL, "vbus");
+ if (IS_ERR(vbus_clk)) {
+ pr_err("could not get vbus clock\n");
+ return PTR_ERR(vbus_clk);
+ }
+
+ ar7_wdt_disable_wdt();
+ ar7_wdt_prescale(prescale_value);
+ ar7_wdt_update_margin(margin);
+
+ rc = misc_register(&ar7_wdt_miscdev);
+ if (rc) {
+ pr_err("unable to register misc device\n");
+ goto out;
+ }
+ return 0;
+
+out:
+ clk_put(vbus_clk);
+ vbus_clk = NULL;
+ return rc;
+}
+
+static int ar7_wdt_remove(struct platform_device *pdev)
+{
+ misc_deregister(&ar7_wdt_miscdev);
+ clk_put(vbus_clk);
+ vbus_clk = NULL;
+ return 0;
+}
+
+static void ar7_wdt_shutdown(struct platform_device *pdev)
+{
+ if (!nowayout)
+ ar7_wdt_disable_wdt();
+}
+
+static struct platform_driver ar7_wdt_driver = {
+ .probe = ar7_wdt_probe,
+ .remove = ar7_wdt_remove,
+ .shutdown = ar7_wdt_shutdown,
+ .driver = {
+ .name = "ar7_wdt",
+ },
+};
+
+module_platform_driver(ar7_wdt_driver);
Code Review / kvmfornfv.git / blobdiff