[PATCH] watchdog: Add watchdog timer support for the WinSystems EBC-C384

[William Breathitt Gray <vilhelm.gray@gmail.com>]

The WinSystems EBC-C384 has an onboard watchdog timer. The timeout range
supported by the watchdog timer is 1 second to 255 minutes. Timeouts
under 256 seconds have a 1 second resolution, while the rest have a 1
minute resolution.

This driver adds watchdog timer support for this onboard watchdog timer.
The timeout may be configured via the timeout module parameter.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 MAINTAINERS                     |   6 ++
 drivers/watchdog/Kconfig        |   9 ++
 drivers/watchdog/Makefile       |   1 +
 drivers/watchdog/ebc-c384_wdt.c | 226 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 242 insertions(+)
 create mode 100644 drivers/watchdog/ebc-c384_wdt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index b1e3da7..c058abf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11629,6 +11629,12 @@ M:	David Härdeman <david@hardeman.nu>
 S:	Maintained
 F:	drivers/media/rc/winbond-cir.c
 
+WINSYSTEMS EBC-C384 WATCHDOG DRIVER
+M:	William Breathitt Gray <vilhelm.gray@gmail.com>
+L:	linux-watchdog@vger.kernel.org
+S:	Maintained
+F:	drivers/watchdog/ebc-c384_wdt.c
+
 WIMAX STACK
 M:	Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 M:	linux-wimax@intel.com
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 4f0e7be..94569ec 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -711,6 +711,15 @@ config ALIM7101_WDT
 
 	  Most people will say N.
 
+config EBC_C386_WDT
+	tristate "WinSystems EBC-C384 watchdog timer support"
+	depends on X86
+	select WATCHDOG_CORE
+	help
+	  Enables watchdog timer support for the watchdog timer on the
+	  WinSystems EBC-C384 motherboard. The timeout may be configured via
+	  the timeout module parameter.
+
 config F71808E_WDT
 	tristate "Fintek F71808E, F71862FG, F71869, F71882FG and F71889FG Watchdog"
 	depends on X86
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index f566753..1522316 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
 obj-$(CONFIG_ADVANTECH_WDT) += advantechwdt.o
 obj-$(CONFIG_ALIM1535_WDT) += alim1535_wdt.o
 obj-$(CONFIG_ALIM7101_WDT) += alim7101_wdt.o
+obj-$(CONFIG_EBC_C386_WDT) += ebc-c384_wdt.o
 obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
 obj-$(CONFIG_SP5100_TCO) += sp5100_tco.o
 obj-$(CONFIG_GEODE_WDT) += geodewdt.o
diff --git a/drivers/watchdog/ebc-c384_wdt.c b/drivers/watchdog/ebc-c384_wdt.c
new file mode 100644
index 0000000..1d7bd67
--- /dev/null
+++ b/drivers/watchdog/ebc-c384_wdt.c
@@ -0,0 +1,226 @@
+/*
+ * Watchdog timer driver for the WinSystems EBC-C384
+ * Copyright (C) 2016 William Breathitt Gray
+ *
+ * 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.
+ *
+ * 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.
+ */
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define MODULE_NAME "ebc-c384_wdt"
+#define WATCHDOG_TIMEOUT 60
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static unsigned timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
+	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+/**
+ * struct ebc_c384_wdt - Watchdog timer device private data structure
+ * @wdd:	instance of struct watchdog_device
+ * @lock:	synchronization lock to prevent race conditions
+ * @base:	base port address of the device
+ * @extent:	extent of port address region of the device
+ */
+struct ebc_c384_wdt {
+	struct watchdog_device wdd;
+	spinlock_t lock;
+	unsigned base;
+	unsigned extent;
+};
+
+static int ebc_c384_wdt_start(struct watchdog_device *wdev)
+{
+	struct ebc_c384_wdt *wdt = watchdog_get_drvdata(wdev);
+
+	return wdt->wdd.ops->set_timeout(wdev, wdt->wdd.timeout);
+}
+
+static int ebc_c384_wdt_stop(struct watchdog_device *wdev)
+{
+	struct ebc_c384_wdt *wdt = watchdog_get_drvdata(wdev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+
+	outb(0x00, wdt->base + 2);
+
+	spin_unlock_irqrestore(&wdt->lock, flags);
+
+	return 0;
+}
+
+static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t)
+{
+	struct ebc_c384_wdt *wdt = watchdog_get_drvdata(wdev);
+	unsigned long flags;
+	unsigned minutes = 0;
+
+	if (!t || t > wdt->wdd.max_timeout)
+		return -EINVAL;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+
+	/* resolution is in minutes for timeouts greater than 255 seconds */
+	if (t > 255) {
+		/* truncate seconds to minute resolution */
+		minutes = t/60;
+
+		/* set watchdog timer for minutes */
+		outb(0x80, wdt->base + 1);
+		outb(minutes, wdt->base + 2);
+
+		wdt->wdd.timeout = minutes * 60;
+	} else {
+		/* set watchdog timer for seconds */
+		outb(0x00, wdt->base + 1);
+		outb(t, wdt->base + 2);
+
+		wdt->wdd.timeout = t;
+	}
+
+	spin_unlock_irqrestore(&wdt->lock, flags);
+
+	return 0;
+}
+
+static const struct watchdog_ops ebc_c384_wdt_ops = {
+	.start = ebc_c384_wdt_start,
+	.stop = ebc_c384_wdt_stop,
+	.set_timeout = ebc_c384_wdt_set_timeout
+};
+
+static const struct watchdog_info ebc_c384_wdt_info = {
+	.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,
+	.identity = MODULE_NAME
+};
+
+static int __init ebc_c384_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ebc_c384_wdt *wdt;
+	const unsigned base = 0x564;
+	const unsigned extent = 5;
+	const char *const name = dev_name(dev);
+	int err;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	if (!request_region(base, extent, name)) {
+		dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n",
+			name, base, base + extent);
+		err = -EBUSY;
+		goto err_lock_io_port;
+	}
+
+	dev_set_drvdata(dev, wdt);
+
+	wdt->wdd.info = &ebc_c384_wdt_info;
+	wdt->wdd.ops = &ebc_c384_wdt_ops;
+	wdt->wdd.min_timeout = 1;
+	wdt->wdd.max_timeout = 15300;
+	wdt->base = base;
+	wdt->extent = extent;
+
+	spin_lock_init(&wdt->lock);
+
+	watchdog_set_nowayout(&wdt->wdd, nowayout);
+	watchdog_set_drvdata(&wdt->wdd, wdt);
+
+	err = watchdog_init_timeout(&wdt->wdd, timeout, dev);
+	if (err)
+		goto err_init_timeout;
+
+	err = watchdog_register_device(&wdt->wdd);
+	if (err)
+		goto err_register_wdt;
+
+	return 0;
+
+err_register_wdt:
+err_init_timeout:
+	release_region(base, extent);
+err_lock_io_port:
+	return err;
+}
+
+static int ebc_c384_wdt_remove(struct platform_device *pdev)
+{
+	struct ebc_c384_wdt *wdt = platform_get_drvdata(pdev);
+
+	release_region(wdt->base, wdt->extent);
+
+	return 0;
+}
+
+static struct platform_driver ebc_c384_wdt_driver = {
+	.driver = {
+		.name = MODULE_NAME
+	},
+	.remove = ebc_c384_wdt_remove
+};
+
+static struct platform_device *ebc_c384_wdt_device;
+
+static int __init ebc_c384_wdt_init(void)
+{
+	int err;
+
+	ebc_c384_wdt_device = platform_device_alloc(
+		ebc_c384_wdt_driver.driver.name, -1);
+	if (!ebc_c384_wdt_device)
+		return -ENOMEM;
+
+	err = platform_device_add(ebc_c384_wdt_device);
+	if (err)
+		goto err_platform_device;
+
+	err = platform_driver_probe(&ebc_c384_wdt_driver, ebc_c384_wdt_probe);
+	if (err)
+		goto err_platform_driver;
+
+	return 0;
+
+err_platform_driver:
+	platform_device_del(ebc_c384_wdt_device);
+err_platform_device:
+	platform_device_put(ebc_c384_wdt_device);
+	return err;
+
+	return 0;
+}
+
+static void __exit ebc_c384_wdt_exit(void)
+{
+	platform_device_unregister(ebc_c384_wdt_device);
+	platform_driver_unregister(&ebc_c384_wdt_driver);
+}
+
+module_init(ebc_c384_wdt_init);
+module_exit(ebc_c384_wdt_exit);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");
+MODULE_LICENSE("GPL");
-- 
2.4.10