[PATCH v1.1 1/2] watchdog: loongson1: Add Loongson1 SoC watchdog driver

[Yang Ling]

Add watchdog timer specific driver for Loongson1 SoC.

Signed-off-by: Yang Ling <gnaygnil@xxxxxxxxx>

---
V1.1:
 Add a little debugging information.
---
 drivers/watchdog/Kconfig         |   7 ++
 drivers/watchdog/Makefile        |   1 +
 drivers/watchdog/loongson1_wdt.c | 160 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 168 insertions(+)
 create mode 100644 drivers/watchdog/loongson1_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 50dbaa8..28c44f2 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1553,6 +1553,13 @@ config PIC32_DMT
 	  To compile this driver as a loadable module, choose M here.
 	  The module will be called pic32-dmt.
 
+config LOONGSON1_WDT
+	tristate "Loongson1 SoC hardware watchdog"
+	depends on MACH_LOONGSON32
+	select WATCHDOG_CORE
+	help
+	  Hardware driver for the Loongson1 SoC Watchdog Timer.
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index cba0043..bd3b00e 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -162,6 +162,7 @@ obj-$(CONFIG_IMGPDC_WDT) += imgpdc_wdt.o
 obj-$(CONFIG_MT7621_WDT) += mt7621_wdt.o
 obj-$(CONFIG_PIC32_WDT) += pic32-wdt.o
 obj-$(CONFIG_PIC32_DMT) += pic32-dmt.o
+obj-$(CONFIG_LOONGSON1_WDT) += loongson1_wdt.o
 
 # PARISC Architecture
 
diff --git a/drivers/watchdog/loongson1_wdt.c b/drivers/watchdog/loongson1_wdt.c
new file mode 100644
index 0000000..77b11f9
--- /dev/null
+++ b/drivers/watchdog/loongson1_wdt.c
@@ -0,0 +1,160 @@
+/*
+ * Copyright (c) 2016 Yang Ling <gnaygnil@xxxxxxxxx>
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+
+#include <loongson1.h>
+
+#define MIN_HEARTBEAT		1
+#define MAX_HEARTBEAT		30
+#define DEFAULT_HEARTBEAT	10
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+
+static unsigned int heartbeat = DEFAULT_HEARTBEAT;
+module_param(heartbeat, uint, 0);
+
+struct ls1x_wdt_drvdata {
+	struct watchdog_device wdt;
+	void __iomem *base;
+	unsigned int count;
+	struct clk *clk;
+};
+
+static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
+{
+	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+	writel(0x1, drvdata->base + WDT_EN);
+	writel(drvdata->count, drvdata->base + WDT_TIMER);
+	writel(0x1, drvdata->base + WDT_SET);
+
+	return 0;
+}
+
+static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
+				unsigned int new_timeout)
+{
+	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+	int counts_per_second;
+
+	if (watchdog_init_timeout(wdt_dev, new_timeout, NULL))
+		return -EINVAL;
+
+	counts_per_second = clk_get_rate(drvdata->clk);
+	drvdata->count = counts_per_second * wdt_dev->timeout;
+
+	ls1x_wdt_ping(wdt_dev);
+
+	return 0;
+}
+
+static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
+{
+	ls1x_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
+
+	return 0;
+}
+
+static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+	writel(0x0, drvdata->base + WDT_EN);
+
+	return 0;
+}
+
+static const struct watchdog_info ls1x_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "Loongson1 Watchdog",
+};
+
+static const struct watchdog_ops ls1x_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = ls1x_wdt_start,
+	.stop = ls1x_wdt_stop,
+	.ping = ls1x_wdt_ping,
+	.set_timeout = ls1x_wdt_set_timeout,
+};
+
+static int ls1x_wdt_probe(struct platform_device *pdev)
+{
+	struct ls1x_wdt_drvdata *drvdata;
+	struct watchdog_device *ls1x_wdt;
+	struct resource *res;
+	int ret;
+
+	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	drvdata->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(drvdata->base))
+		return PTR_ERR(drvdata->base);
+
+	drvdata->clk = devm_clk_get(&pdev->dev, pdev->name);
+	if (IS_ERR(drvdata->clk)) {
+		dev_err(&pdev->dev, "failed to get %s clock\n", pdev->name);
+		return PTR_ERR(drvdata->clk);
+	}
+	clk_prepare_enable(drvdata->clk);
+
+	ls1x_wdt = &drvdata->wdt;
+	ls1x_wdt->info = &ls1x_wdt_info;
+	ls1x_wdt->ops = &ls1x_wdt_ops;
+	ls1x_wdt->timeout = heartbeat;
+	ls1x_wdt->min_timeout = MIN_HEARTBEAT;
+	ls1x_wdt->max_timeout = MAX_HEARTBEAT;
+	ls1x_wdt->parent = &pdev->dev;
+	watchdog_set_nowayout(ls1x_wdt, nowayout);
+	watchdog_set_drvdata(ls1x_wdt, drvdata);
+
+	ret = watchdog_register_device(&drvdata->wdt);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to register watchdog device\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, drvdata);
+
+	dev_info(&pdev->dev, "Loongson1 Watchdog driver registered\n");
+
+	return 0;
+}
+
+static int ls1x_wdt_remove(struct platform_device *pdev)
+{
+	struct ls1x_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
+
+	ls1x_wdt_stop(&drvdata->wdt);
+	watchdog_unregister_device(&drvdata->wdt);
+	clk_disable_unprepare(drvdata->clk);
+
+	return 0;
+}
+
+static struct platform_driver ls1x_wdt_driver = {
+	.probe = ls1x_wdt_probe,
+	.remove = ls1x_wdt_remove,
+	.driver = {
+		.name = "ls1x-wdt",
+	},
+};
+
+module_platform_driver(ls1x_wdt_driver);
+
+MODULE_AUTHOR("Yang Ling <gnaygnil@xxxxxxxxx>");
+MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
+MODULE_LICENSE("GPL");
-- 
1.9.1