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 granularity, while the rest have a 1
minute granularity.

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.g...@gmail.com>
Reviewed-by: Guenter Roeck <li...@roeck-us.net>
---
 MAINTAINERS                     |   6 ++
 drivers/watchdog/Kconfig        |   9 ++
 drivers/watchdog/Makefile       |   1 +
 drivers/watchdog/ebc-c384_wdt.c | 188 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 204 insertions(+)
 create mode 100644 drivers/watchdog/ebc-c384_wdt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 28eb61b..66107fd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11860,6 +11860,12 @@ M:     David Härdeman <da...@hardeman.nu>
 S:     Maintained
 F:     drivers/media/rc/winbond-cir.c
 
+WINSYSTEMS EBC-C384 WATCHDOG DRIVER
+M:     William Breathitt Gray <vilhelm.g...@gmail.com>
+L:     linux-watch...@vger.kernel.org
+S:     Maintained
+F:     drivers/watchdog/ebc-c384_wdt.c
+
 WIMAX STACK
 M:     Inaky Perez-Gonzalez <inaky.perez-gonza...@intel.com>
 M:     linux-wi...@intel.com
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0f6d851..11f3a3d 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -713,6 +713,15 @@ config ALIM7101_WDT
 
          Most people will say N.
 
+config EBC_C384_WDT
+       tristate "WinSystems EBC-C384 Watchdog Timer"
+       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..15762c8 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-$(CONFIG_EBC_C384_WDT) += ebc-c384_wdt.o
 obj-$(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..21a4e95
--- /dev/null
+++ b/drivers/watchdog/ebc-c384_wdt.c
@@ -0,0 +1,188 @@
+/*
+ * 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/dmi.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define MODULE_NAME            "ebc-c384_wdt"
+#define WATCHDOG_TIMEOUT       60
+/*
+ * The timeout value in minutes must fit in a single byte when sent to the
+ * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds.
+ */
+#define WATCHDOG_MAX_TIMEOUT   15300
+#define BASE_ADDR              0x564
+#define ADDR_EXTENT            5
+#define CFG_ADDR               (BASE_ADDR + 1)
+#define PET_ADDR               (BASE_ADDR + 2)
+
+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;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
+       __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+static int ebc_c384_wdt_start(struct watchdog_device *wdev)
+{
+       unsigned t = wdev->timeout;
+
+       /* resolution is in minutes for timeouts greater than 255 seconds */
+       if (t > 255)
+               t = DIV_ROUND_UP(t, 60);
+
+       outb(t, PET_ADDR);
+
+       return 0;
+}
+
+static int ebc_c384_wdt_stop(struct watchdog_device *wdev)
+{
+       outb(0x00, PET_ADDR);
+
+       return 0;
+}
+
+static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t)
+{
+       /* resolution is in minutes for timeouts greater than 255 seconds */
+       if (t > 255) {
+               /* round second resolution up to minute granularity */
+               wdev->timeout = DIV_ROUND_UP(t, 60) * 60;
+
+               /* set watchdog timer for minutes */
+               outb(0x00, CFG_ADDR);
+       } else {
+               wdev->timeout = t;
+
+               /* set watchdog timer for seconds */
+               outb(0x80, CFG_ADDR);
+       }
+
+       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 watchdog_device *wdd;
+
+       if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) {
+               dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
+                       BASE_ADDR, BASE_ADDR + ADDR_EXTENT);
+               return -EBUSY;
+       }
+
+       wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
+       if (!wdd)
+               return -ENOMEM;
+
+       wdd->info = &ebc_c384_wdt_info;
+       wdd->ops = &ebc_c384_wdt_ops;
+       wdd->timeout = WATCHDOG_TIMEOUT;
+       wdd->min_timeout = 1;
+       wdd->max_timeout = WATCHDOG_MAX_TIMEOUT;
+
+       watchdog_set_nowayout(wdd, nowayout);
+
+       if (watchdog_init_timeout(wdd, timeout, dev))
+               dev_warn(dev, "Invalid timeout (%u seconds), using default (%u 
seconds)\n",
+                       timeout, WATCHDOG_TIMEOUT);
+
+       platform_set_drvdata(pdev, wdd);
+
+       return watchdog_register_device(wdd);
+}
+
+static int ebc_c384_wdt_remove(struct platform_device *pdev)
+{
+       struct watchdog_device *wdd = platform_get_drvdata(pdev);
+
+       watchdog_unregister_device(wdd);
+
+       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;
+
+       if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC"))
+               return -ENODEV;
+
+       ebc_c384_wdt_device = platform_device_alloc(MODULE_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;
+}
+
+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.g...@gmail.com>");
+MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" MODULE_NAME);
-- 
2.4.10

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