watchdog: add driver for the Atheros AR71XX/AR724X/AR913X SoCs
This patch adds a driver for the built-in hardware watchdog device
of the Atheros AR71XX/AR724X/AR913X SoCs.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/ath79_wdt.c b/drivers/watchdog/ath79_wdt.c
new file mode 100644
index 0000000..725c84b
--- /dev/null
+++ b/drivers/watchdog/ath79_wdt.c
@@ -0,0 +1,305 @@
+/*
+ * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ * Copyright 2004 (c) MontaVista, Software, Inc.
+ *
+ * which again was based on sa1100 driver,
+ * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+
+#define DRIVER_NAME "ath79-wdt"
+
+#define WDT_TIMEOUT 15 /* seconds */
+
+#define WDOG_CTRL_LAST_RESET BIT(31)
+#define WDOG_CTRL_ACTION_MASK 3
+#define WDOG_CTRL_ACTION_NONE 0 /* no action */
+#define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */
+#define WDOG_CTRL_ACTION_NMI 2 /* NMI */
+#define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */
+
+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) ")");
+
+static int timeout = WDT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
+ "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
+
+static unsigned long wdt_flags;
+
+#define WDT_FLAGS_BUSY 0
+#define WDT_FLAGS_EXPECT_CLOSE 1
+
+static struct clk *wdt_clk;
+static unsigned long wdt_freq;
+static int boot_status;
+static int max_timeout;
+
+static inline void ath79_wdt_keepalive(void)
+{
+ ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout);
+}
+
+static inline void ath79_wdt_enable(void)
+{
+ ath79_wdt_keepalive();
+ ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
+}
+
+static inline void ath79_wdt_disable(void)
+{
+ ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
+}
+
+static int ath79_wdt_set_timeout(int val)
+{
+ if (val < 1 || val > max_timeout)
+ return -EINVAL;
+
+ timeout = val;
+ ath79_wdt_keepalive();
+
+ return 0;
+}
+
+static int ath79_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
+ return -EBUSY;
+
+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
+ ath79_wdt_enable();
+
+ return nonseekable_open(inode, file);
+}
+
+static int ath79_wdt_release(struct inode *inode, struct file *file)
+{
+ if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
+ ath79_wdt_disable();
+ else {
+ pr_crit(DRIVER_NAME ": device closed unexpectedly, "
+ "watchdog timer will not stop!\n");
+ ath79_wdt_keepalive();
+ }
+
+ clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
+
+ return 0;
+}
+
+static ssize_t ath79_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
+
+ for (i = 0; i != len; i++) {
+ char c;
+
+ if (get_user(c, data + i))
+ return -EFAULT;
+
+ if (c == 'V')
+ set_bit(WDT_FLAGS_EXPECT_CLOSE,
+ &wdt_flags);
+ }
+ }
+
+ ath79_wdt_keepalive();
+ }
+
+ return len;
+}
+
+static const struct watchdog_info ath79_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
+ .firmware_version = 0,
+ .identity = "ATH79 watchdog",
+};
+
+static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int err;
+ int t;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ err = copy_to_user(argp, &ath79_wdt_info,
+ sizeof(ath79_wdt_info)) ? -EFAULT : 0;
+ break;
+
+ case WDIOC_GETSTATUS:
+ err = put_user(0, p);
+ break;
+
+ case WDIOC_GETBOOTSTATUS:
+ err = put_user(boot_status, p);
+ break;
+
+ case WDIOC_KEEPALIVE:
+ ath79_wdt_keepalive();
+ err = 0;
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ err = get_user(t, p);
+ if (err)
+ break;
+
+ err = ath79_wdt_set_timeout(t);
+ if (err)
+ break;
+
+ /* fallthrough */
+ case WDIOC_GETTIMEOUT:
+ err = put_user(timeout, p);
+ break;
+
+ default:
+ err = -ENOTTY;
+ break;
+ }
+
+ return err;
+}
+
+static const struct file_operations ath79_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = ath79_wdt_write,
+ .unlocked_ioctl = ath79_wdt_ioctl,
+ .open = ath79_wdt_open,
+ .release = ath79_wdt_release,
+};
+
+static struct miscdevice ath79_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &ath79_wdt_fops,
+};
+
+static int __devinit ath79_wdt_probe(struct platform_device *pdev)
+{
+ u32 ctrl;
+ int err;
+
+ wdt_clk = clk_get(&pdev->dev, "wdt");
+ if (IS_ERR(wdt_clk))
+ return PTR_ERR(wdt_clk);
+
+ err = clk_enable(wdt_clk);
+ if (err)
+ goto err_clk_put;
+
+ wdt_freq = clk_get_rate(wdt_clk);
+ if (!wdt_freq) {
+ err = -EINVAL;
+ goto err_clk_disable;
+ }
+
+ max_timeout = (0xfffffffful / wdt_freq);
+ if (timeout < 1 || timeout > max_timeout) {
+ timeout = max_timeout;
+ dev_info(&pdev->dev,
+ "timeout value must be 0 < timeout < %d, using %d\n",
+ max_timeout, timeout);
+ }
+
+ ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
+ boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
+
+ err = misc_register(&ath79_wdt_miscdev);
+ if (err) {
+ dev_err(&pdev->dev,
+ "unable to register misc device, err=%d\n", err);
+ goto err_clk_disable;
+ }
+
+ return 0;
+
+err_clk_disable:
+ clk_disable(wdt_clk);
+err_clk_put:
+ clk_put(wdt_clk);
+ return err;
+}
+
+static int __devexit ath79_wdt_remove(struct platform_device *pdev)
+{
+ misc_deregister(&ath79_wdt_miscdev);
+ clk_disable(wdt_clk);
+ clk_put(wdt_clk);
+ return 0;
+}
+
+static void ath97_wdt_shutdown(struct platform_device *pdev)
+{
+ ath79_wdt_disable();
+}
+
+static struct platform_driver ath79_wdt_driver = {
+ .remove = __devexit_p(ath79_wdt_remove),
+ .shutdown = ath97_wdt_shutdown,
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init ath79_wdt_init(void)
+{
+ return platform_driver_probe(&ath79_wdt_driver, ath79_wdt_probe);
+}
+module_init(ath79_wdt_init);
+
+static void __exit ath79_wdt_exit(void)
+{
+ platform_driver_unregister(&ath79_wdt_driver);
+}
+module_exit(ath79_wdt_exit);
+
+MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
+MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);