[RFC 13/18] watchdog: add Atheros AR2315 watchdog driver

[Sergey Ryazanov <ryazanov.s.a@gmail.com>]

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: linux-watchdog@vger.kernel.org
---
 arch/mips/ar231x/ar2315.c     |  26 +++++-
 drivers/watchdog/Kconfig      |   7 ++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/ar2315-wtd.c | 202 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 235 insertions(+), 1 deletion(-)
 create mode 100644 drivers/watchdog/ar2315-wtd.c

diff --git a/arch/mips/ar231x/ar2315.c b/arch/mips/ar231x/ar2315.c
index cab3b76..62cf548 100644
--- a/arch/mips/ar231x/ar2315.c
+++ b/arch/mips/ar231x/ar2315.c
@@ -62,7 +62,10 @@ static void ar2315_misc_irq_handler(unsigned irq, struct irq_desc *desc)
 		generic_handle_irq(AR2315_MISC_IRQ_GPIO);
 	} else if (pending & AR2315_ISR_UART0)
 		generic_handle_irq(AR2315_MISC_IRQ_UART0);
-	else
+	else if (pending & AR2315_ISR_WD) {
+		ar231x_write_reg(AR2315_ISR, AR2315_ISR_WD);
+		generic_handle_irq(AR2315_MISC_IRQ_WATCHDOG);
+	} else
 		spurious_interrupt();
 }
 
@@ -148,6 +151,26 @@ static struct platform_device ar2315_spiflash = {
 	.num_resources = ARRAY_SIZE(ar2315_spiflash_res)
 };
 
+static struct resource ar2315_wdt_res[] = {
+	{
+		.flags = IORESOURCE_MEM,
+		.start = AR2315_WD,
+		.end = AR2315_WD + 8 - 1,
+	},
+	{
+		.flags = IORESOURCE_IRQ,
+		.start = AR2315_MISC_IRQ_WATCHDOG,
+		.end = AR2315_MISC_IRQ_WATCHDOG,
+	}
+};
+
+static struct platform_device ar2315_wdt = {
+	.id = -1,
+	.name = "ar2315-wdt",
+	.resource = ar2315_wdt_res,
+	.num_resources = ARRAY_SIZE(ar2315_wdt_res)
+};
+
 static struct resource ar2315_gpio_res[] = {
 	{
 		.name = "ar2315-gpio",
@@ -193,6 +216,7 @@ void __init ar2315_init_devices(void)
 	ar231x_find_config(ar2315_flash_limit);
 
 	platform_device_register(&ar2315_gpio);
+	platform_device_register(&ar2315_wdt);
 	platform_device_register(&ar2315_spiflash);
 }
 
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f57312f..0e84f3a 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1186,6 +1186,13 @@ config RALINK_WDT
 	help
 	  Hardware driver for the Ralink SoC Watchdog Timer.
 
+config AR2315_WDT
+	tristate "Atheros AR2315+ WiSoCs Watchdog Timer"
+	depends on SOC_AR2315
+	help
+	  Hardware driver for the built-in watchdog timer on the Atheros
+	  AR2315/AR2316 WiSoCs.
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 468c320..ef7f83b 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -133,6 +133,7 @@ obj-$(CONFIG_WDT_MTX1) += mtx-1_wdt.o
 obj-$(CONFIG_PNX833X_WDT) += pnx833x_wdt.o
 obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
 obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
+obj-$(CONFIG_AR2315_WDT) += ar2315-wtd.o
 obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
 obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
 octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
diff --git a/drivers/watchdog/ar2315-wtd.c b/drivers/watchdog/ar2315-wtd.c
new file mode 100644
index 0000000..8e1687a
--- /dev/null
+++ b/drivers/watchdog/ar2315-wtd.c
@@ -0,0 +1,202 @@
+/*
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (C) 2008 John Crispin <blogic@openwrt.org>
+ * Based on EP93xx and ifxmips wdt driver
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+#define DRIVER_NAME	"ar2315-wdt"
+
+#define CLOCK_RATE 40000000
+#define HEARTBEAT(x) (x < 1 || x > 90 ? 20 : x)
+
+#define WDT_REG_TIMER		0x00
+#define WDT_REG_CTRL		0x04
+
+#define WDT_CTRL_ACT_NONE	0x00000000	/* No action */
+#define WDT_CTRL_ACT_NMI	0x00000001	/* NMI on watchdog */
+#define WDT_CTRL_ACT_RESET	0x00000002	/* reset on watchdog */
+
+static int wdt_timeout = 20;
+static int started;
+static int in_use;
+static void __iomem *wdt_base;
+
+static inline void ar2315_wdt_wr(unsigned reg, u32 val)
+{
+	iowrite32(val, wdt_base + reg);
+}
+
+static void ar2315_wdt_enable(void)
+{
+	ar2315_wdt_wr(WDT_REG_TIMER, wdt_timeout * CLOCK_RATE);
+}
+
+static ssize_t ar2315_wdt_write(struct file *file, const char __user *data,
+				size_t len, loff_t *ppos)
+{
+	if (len)
+		ar2315_wdt_enable();
+	return len;
+}
+
+static int ar2315_wdt_open(struct inode *inode, struct file *file)
+{
+	if (in_use)
+		return -EBUSY;
+	ar2315_wdt_enable();
+	in_use = 1;
+	started = 1;
+	return nonseekable_open(inode, file);
+}
+
+static int ar2315_wdt_release(struct inode *inode, struct file *file)
+{
+	in_use = 0;
+	return 0;
+}
+
+static irqreturn_t ar2315_wdt_interrupt(int irq, void *dev)
+{
+	struct platform_device *pdev = (struct platform_device *)dev;
+
+	if (started) {
+		dev_crit(&pdev->dev, "watchdog expired, rebooting system\n");
+		emergency_restart();
+	} else {
+		ar2315_wdt_wr(WDT_REG_CTRL, 0);
+		ar2315_wdt_wr(WDT_REG_TIMER, 0);
+	}
+	return IRQ_HANDLED;
+}
+
+static struct watchdog_info ident = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	.identity = "ar2315 Watchdog",
+};
+
+static long ar2315_wdt_ioctl(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	int new_wdt_timeout;
+	int ret = -ENOIOCTLCMD;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		ret = copy_to_user((void __user *)arg, &ident, sizeof(ident)) ?
+		      -EFAULT : 0;
+		break;
+	case WDIOC_KEEPALIVE:
+		ar2315_wdt_enable();
+		ret = 0;
+		break;
+	case WDIOC_SETTIMEOUT:
+		ret = get_user(new_wdt_timeout, (int __user *)arg);
+		if (ret)
+			break;
+		wdt_timeout = HEARTBEAT(new_wdt_timeout);
+		ar2315_wdt_enable();
+		break;
+	case WDIOC_GETTIMEOUT:
+		ret = put_user(wdt_timeout, (int __user *)arg);
+		break;
+	}
+	return ret;
+}
+
+static const struct file_operations ar2315_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= ar2315_wdt_write,
+	.unlocked_ioctl	= ar2315_wdt_ioctl,
+	.open		= ar2315_wdt_open,
+	.release	= ar2315_wdt_release,
+};
+
+static struct miscdevice ar2315_wdt_miscdev = {
+	.minor	= WATCHDOG_MINOR,
+	.name	= "watchdog",
+	.fops	= &ar2315_wdt_fops,
+};
+
+static int ar2315_wdt_probe(struct platform_device *dev)
+{
+	struct resource *mem_res, *irq_res;
+	int ret = 0;
+
+	if (wdt_base)
+		return -EBUSY;
+
+	irq_res = platform_get_resource(dev, IORESOURCE_IRQ, 0);
+	if (!irq_res) {
+		dev_err(&dev->dev, "no IRQ resource\n");
+		return -ENOENT;
+	}
+
+	mem_res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	wdt_base = devm_ioremap_resource(&dev->dev, mem_res);
+	if (IS_ERR(wdt_base))
+		return PTR_ERR(wdt_base);
+
+	ret = devm_request_irq(&dev->dev, irq_res->start, ar2315_wdt_interrupt,
+			       IRQF_DISABLED, DRIVER_NAME, dev);
+	if (ret) {
+		dev_err(&dev->dev, "failed to register inetrrupt\n");
+		goto out;
+	}
+
+	ret = misc_register(&ar2315_wdt_miscdev);
+	if (ret)
+		dev_err(&dev->dev, "failed to register miscdev\n");
+
+out:
+	return ret;
+}
+
+static int ar2315_wdt_remove(struct platform_device *dev)
+{
+	misc_deregister(&ar2315_wdt_miscdev);
+	return 0;
+}
+
+static struct platform_driver ar2315_wdt_driver = {
+	.probe = ar2315_wdt_probe,
+	.remove = ar2315_wdt_remove,
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+	},
+};
+
+module_platform_driver(ar2315_wdt_driver);
+
+MODULE_DESCRIPTION("Atheros AR2315 hardware watchdog driver");
+MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
-- 
1.8.1.5