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[PATCH v2 06/16] watchdog: add driver for the Atheros AR71XX/AR724X/AR91

To: Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH v2 06/16] watchdog: add driver for the Atheros AR71XX/AR724X/AR913X SoCs
From: Gabor Juhos <juhosg@openwrt.org>
Date: Wed, 22 Dec 2010 21:30:51 +0100
Cc: linux-mips@linux-mips.org, Imre Kaloz <kaloz@openwrt.org>, "Luis R. Rodriguez" <lrodriguez@atheros.com>, Cliff Holden <Cliff.Holden@Atheros.com>, Kathy Giori <Kathy.Giori@Atheros.com>, Gabor Juhos <juhosg@openwrt.org>, Wim Van Sebroeck <wim@iguana.be>, linux-watchdog@vger.kernel.org
In-reply-to: <1293049861-28913-1-git-send-email-juhosg@openwrt.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1293049861-28913-1-git-send-email-juhosg@openwrt.org>
Sender: linux-mips-bounce@linux-mips.org
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>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: linux-watchdog@vger.kernel.org
---

Changes since RFC: ---

Changes since v1:
    - rebased against 2.6.37-rc7

 drivers/watchdog/Kconfig     |    8 +
 drivers/watchdog/Makefile    |    1 +
 drivers/watchdog/ath79_wdt.c |  293 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 302 insertions(+), 0 deletions(-)
 create mode 100644 drivers/watchdog/ath79_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index a5ad77e..7833e44 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -930,6 +930,14 @@ config BCM63XX_WDT
          To compile this driver as a loadable module, choose M here.
          The module will be called bcm63xx_wdt.
 
+config ATH79_WDT
+       tristate "Atheros AR71XX/AR724X/AR913X hardware watchdog"
+       depends on ATH79
+       help
+         Hardware driver for the built-in watchdog timer on the Atheros
+         AR71XX/AR724X/AR913X SoCs.
+
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 4b0ef38..6d7af07 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -117,6 +117,7 @@ obj-$(CONFIG_PNX833X_WDT) += pnx833x_wdt.o
 obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
 obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
 obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
+obj-$(CONFIG_ATH79_WDT) += ath79_wdt.o
 obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
 octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
 
diff --git a/drivers/watchdog/ath79_wdt.c b/drivers/watchdog/ath79_wdt.c
new file mode 100644
index 0000000..f8e027b
--- /dev/null
+++ b/drivers/watchdog/ath79_wdt.c
@@ -0,0 +1,293 @@
+/*
+ * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
+ *
+ * Copyright (C) 2008-2010 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/reboot.h>
+#include <linux/watchdog.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+
+#define DRIVER_NAME    "ath79-wdt"
+#define DRIVER_DESC    "Atheros AR71XX/AR724X/AR913X hardware watchdog driver"
+
+#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;
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+                          "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+#endif
+
+static unsigned long wdt_flags;
+
+#define WDT_FLAGS_BUSY         0
+#define WDT_FLAGS_EXPECT_CLOSE 1
+
+static int wdt_timeout = WDT_TIMEOUT;
+static int boot_status;
+static int max_timeout;
+
+static inline void ath79_wdt_keepalive(void)
+{
+       ath79_reset_wr(AR71XX_RESET_REG_WDOG, ath79_ahb_freq * wdt_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;
+
+       wdt_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");
+
+       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(wdt_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 int ath79_wdt_notify_sys(struct notifier_block *this,
+                               unsigned long code, void *unused)
+{
+       if (code == SYS_DOWN || code == SYS_HALT)
+               ath79_wdt_disable();
+
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block ath79_wdt_notifier = {
+       .notifier_call = ath79_wdt_notify_sys,
+};
+
+static struct miscdevice ath79_wdt_miscdev = {
+       .minor = WATCHDOG_MINOR,
+       .name = "watchdog",
+       .fops = &ath79_wdt_fops,
+};
+
+static int __init ath79_wdt_probe(struct platform_device *pdev)
+{
+       u32 ctrl;
+       int err;
+
+       max_timeout = (0xfffffffful / ath79_ahb_freq);
+       wdt_timeout = (max_timeout < WDT_TIMEOUT) ? max_timeout : WDT_TIMEOUT;
+
+       ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
+       boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
+
+       err = register_reboot_notifier(&ath79_wdt_notifier);
+       if (err) {
+               dev_err(&pdev->dev,
+                       "unable to register reboot notifier, err=%d\n", err);
+               goto err;
+       }
+
+       err = misc_register(&ath79_wdt_miscdev);
+       if (err) {
+               dev_err(&pdev->dev,
+                       "unable to register misc device, err=%d\n", err);
+               goto err_unregister;
+       }
+
+       return 0;
+
+err_unregister:
+       unregister_reboot_notifier(&ath79_wdt_notifier);
+
+err:
+       return err;
+}
+
+static int __exit ath79_wdt_remove(struct platform_device *pdev)
+{
+       misc_deregister(&ath79_wdt_miscdev);
+       return 0;
+}
+
+static struct platform_driver ath79_wdt_driver = {
+       .remove         = __exit_p(ath79_wdt_remove),
+       .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(DRIVER_DESC);
+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);
-- 
1.7.2.1


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