watchdog: nic7018_wdt: Add NIC7018 watchdog driver

Add support for the watchdog timer on PXI Embedded Controller.

Signed-off-by: Hui Chun Ong <hui.chun.ong@ni.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 265 insertions, 0 deletions

diff --git a/drivers/watchdog/nic7018_wdt.c b/drivers/watchdog/nic7018_wdt.c
new file mode 100644
index 000000000000..dcd265685837
--- /dev/null
+++ b/drivers/watchdog/nic7018_wdt.c
@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2016 National Instruments Corp.
+ *
+ * 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.
+ */
+
+#include <linux/acpi.h>
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define LOCK			0xA5
+#define UNLOCK			0x5A
+
+#define WDT_CTRL_RESET_EN	BIT(7)
+#define WDT_RELOAD_PORT_EN	BIT(7)
+
+#define WDT_CTRL		1
+#define WDT_RELOAD_CTRL		2
+#define WDT_PRESET_PRESCALE	4
+#define WDT_REG_LOCK		5
+#define WDT_COUNT		6
+#define WDT_RELOAD_PORT		7
+
+#define WDT_MIN_TIMEOUT		1
+#define WDT_MAX_TIMEOUT		464
+#define WDT_DEFAULT_TIMEOUT	80
+
+#define WDT_MAX_COUNTER		15
+
+static unsigned int timeout;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout,
+		 "Watchdog timeout in seconds. (default="
+		 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
+
+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) ")");
+
+struct nic7018_wdt {
+	u16 io_base;
+	u32 period;
+	struct watchdog_device wdd;
+};
+
+struct nic7018_config {
+	u32 period;
+	u8 divider;
+};
+
+static const struct nic7018_config nic7018_configs[] = {
+	{  2, 4 },
+	{ 32, 5 },
+};
+
+static inline u32 nic7018_timeout(u32 period, u8 counter)
+{
+	return period * counter - period / 2;
+}
+
+static const struct nic7018_config *nic7018_get_config(u32 timeout,
+						       u8 *counter)
+{
+	const struct nic7018_config *config;
+	u8 count;
+
+	if (timeout < 30 && timeout != 16) {
+		config = &nic7018_configs[0];
+		count = timeout / 2 + 1;
+	} else {
+		config = &nic7018_configs[1];
+		count = DIV_ROUND_UP(timeout + 16, 32);
+
+		if (count > WDT_MAX_COUNTER)
+			count = WDT_MAX_COUNTER;
+	}
+	*counter = count;
+	return config;
+}
+
+static int nic7018_set_timeout(struct watchdog_device *wdd,
+			       unsigned int timeout)
+{
+	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
+	const struct nic7018_config *config;
+	u8 counter;
+
+	config = nic7018_get_config(timeout, &counter);
+
+	outb(counter << 4 | config->divider,
+	     wdt->io_base + WDT_PRESET_PRESCALE);
+
+	wdd->timeout = nic7018_timeout(config->period, counter);
+	wdt->period = config->period;
+
+	return 0;
+}
+
+static int nic7018_start(struct watchdog_device *wdd)
+{
+	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
+	u8 control;
+
+	nic7018_set_timeout(wdd, wdd->timeout);
+
+	control = inb(wdt->io_base + WDT_RELOAD_CTRL);
+	outb(control | WDT_RELOAD_PORT_EN, wdt->io_base + WDT_RELOAD_CTRL);
+
+	outb(1, wdt->io_base + WDT_RELOAD_PORT);
+
+	control = inb(wdt->io_base + WDT_CTRL);
+	outb(control | WDT_CTRL_RESET_EN, wdt->io_base + WDT_CTRL);
+
+	return 0;
+}
+
+static int nic7018_stop(struct watchdog_device *wdd)
+{
+	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	outb(0, wdt->io_base + WDT_CTRL);
+	outb(0, wdt->io_base + WDT_RELOAD_CTRL);
+	outb(0xF0, wdt->io_base + WDT_PRESET_PRESCALE);
+
+	return 0;
+}
+
+static int nic7018_ping(struct watchdog_device *wdd)
+{
+	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	outb(1, wdt->io_base + WDT_RELOAD_PORT);
+
+	return 0;
+}
+
+static unsigned int nic7018_get_timeleft(struct watchdog_device *wdd)
+{
+	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
+	u8 count;
+
+	count = inb(wdt->io_base + WDT_COUNT) & 0xF;
+	if (!count)
+		return 0;
+
+	return nic7018_timeout(wdt->period, count);
+}
+
+static const struct watchdog_info nic7018_wdd_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "NIC7018 Watchdog",
+};
+
+static const struct watchdog_ops nic7018_wdd_ops = {
+	.owner = THIS_MODULE,
+	.start = nic7018_start,
+	.stop = nic7018_stop,
+	.ping = nic7018_ping,
+	.set_timeout = nic7018_set_timeout,
+	.get_timeleft = nic7018_get_timeleft,
+};
+
+static int nic7018_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct watchdog_device *wdd;
+	struct nic7018_wdt *wdt;
+	struct resource *io_rc;
+	int ret;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, wdt);
+
+	io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (!io_rc) {
+		dev_err(dev, "missing IO resources\n");
+		return -EINVAL;
+	}
+
+	if (!devm_request_region(dev, io_rc->start, resource_size(io_rc),
+				 KBUILD_MODNAME)) {
+		dev_err(dev, "failed to get IO region\n");
+		return -EBUSY;
+	}
+
+	wdt->io_base = io_rc->start;
+	wdd = &wdt->wdd;
+	wdd->info = &nic7018_wdd_info;
+	wdd->ops = &nic7018_wdd_ops;
+	wdd->min_timeout = WDT_MIN_TIMEOUT;
+	wdd->max_timeout = WDT_MAX_TIMEOUT;
+	wdd->timeout = WDT_DEFAULT_TIMEOUT;
+	wdd->parent = dev;
+
+	watchdog_set_drvdata(wdd, wdt);
+	watchdog_set_nowayout(wdd, nowayout);
+
+	ret = watchdog_init_timeout(wdd, timeout, dev);
+	if (ret)
+		dev_warn(dev, "unable to set timeout value, using default\n");
+
+	/* Unlock WDT register */
+	outb(UNLOCK, wdt->io_base + WDT_REG_LOCK);
+
+	ret = watchdog_register_device(wdd);
+	if (ret) {
+		outb(LOCK, wdt->io_base + WDT_REG_LOCK);
+		dev_err(dev, "failed to register watchdog\n");
+		return ret;
+	}
+
+	dev_dbg(dev, "io_base=0x%04X, timeout=%d, nowayout=%d\n",
+		wdt->io_base, timeout, nowayout);
+	return 0;
+}
+
+static int nic7018_remove(struct platform_device *pdev)
+{
+	struct nic7018_wdt *wdt = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&wdt->wdd);
+
+	/* Lock WDT register */
+	outb(LOCK, wdt->io_base + WDT_REG_LOCK);
+
+	return 0;
+}
+
+static const struct acpi_device_id nic7018_device_ids[] = {
+	{"NIC7018", 0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, nic7018_device_ids);
+
+static struct platform_driver watchdog_driver = {
+	.probe = nic7018_probe,
+	.remove = nic7018_remove,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.acpi_match_table = ACPI_PTR(nic7018_device_ids),
+	},
+};
+
+module_platform_driver(watchdog_driver);
+
+MODULE_DESCRIPTION("National Instruments NIC7018 Watchdog driver");
+MODULE_AUTHOR("Hui Chun Ong <hui.chun.ong@ni.com>");
+MODULE_LICENSE("GPL");