watchdog: loongson1: Add Loongson1 SoC watchdog driver

Add watchdog timer specific driver for Loongson1 SoC.

Signed-off-by: Yang Ling <[e-mail]>
Reviewed-by: Guenter Roeck <[e-mail]>
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/watchdog/Kconfig

···
 	help
 	  Hardware driver for the Lantiq SoC Watchdog Timer.
 
+config LOONGSON1_WDT
+	tristate "Loongson1 SoC hardware watchdog"
+	depends on MACH_LOONGSON32
+	select WATCHDOG_CORE
+	help
+	  Hardware driver for the Loongson1 SoC Watchdog Timer.
+
 config RALINK_WDT
 	tristate "Ralink SoC watchdog"
 	select WATCHDOG_CORE

drivers/watchdog/Makefile

···
 obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
 octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
 obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
+obj-$(CONFIG_LOONGSON1_WDT) += loongson1_wdt.o
 obj-$(CONFIG_RALINK_WDT) += rt2880_wdt.o
 obj-$(CONFIG_IMGPDC_WDT) += imgpdc_wdt.o
 obj-$(CONFIG_MT7621_WDT) += mt7621_wdt.o

drivers/watchdog/loongson1_wdt.c

···
+/*
+ * Copyright (c) 2016 Yang Ling <[e-mail]>
+ *
+ * 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/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <loongson1.h>
+
+#define DEFAULT_HEARTBEAT	30
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0444);
+
+static unsigned int heartbeat;
+module_param(heartbeat, uint, 0444);
+
+struct ls1x_wdt_drvdata {
+	void __iomem *base;
+	struct clk *clk;
+	unsigned long clk_rate;
+	struct watchdog_device wdt;
+};
+
+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_SET);
+
+	return 0;
+}
+
+static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
+				unsigned int timeout)
+{
+	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+	unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000;
+	unsigned int counts;
+
+	wdt_dev->timeout = timeout;
+
+	counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
+	writel(counts, drvdata->base + WDT_TIMER);
+
+	return 0;
+}
+
+static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
+{
+	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+	writel(0x1, drvdata->base + WDT_EN);
+
+	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;
+	unsigned long clk_rate;
+	struct resource *res;
+	int err;
+
+	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))
+		return PTR_ERR(drvdata->clk);
+
+	err = clk_prepare_enable(drvdata->clk);
+	if (err) {
+		dev_err(&pdev->dev, "clk enable failed\n");
+		return err;
+	}
+
+	clk_rate = clk_get_rate(drvdata->clk);
+	if (!clk_rate) {
+		err = -EINVAL;
+		goto err0;
+	}
+	drvdata->clk_rate = clk_rate;
+
+	ls1x_wdt = &drvdata->wdt;
+	ls1x_wdt->info = &ls1x_wdt_info;
+	ls1x_wdt->ops = &ls1x_wdt_ops;
+	ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
+	ls1x_wdt->min_timeout = 1;
+	ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
+	ls1x_wdt->parent = &pdev->dev;
+
+	watchdog_init_timeout(ls1x_wdt, heartbeat, &pdev->dev);
+	watchdog_set_nowayout(ls1x_wdt, nowayout);
+	watchdog_set_drvdata(ls1x_wdt, drvdata);
+
+	err = watchdog_register_device(&drvdata->wdt);
+	if (err) {
+		dev_err(&pdev->dev, "failed to register watchdog device\n");
+		goto err0;
+	}
+
+	platform_set_drvdata(pdev, drvdata);
+
+	dev_info(&pdev->dev, "Loongson1 Watchdog driver registered\n");
+
+	return 0;
+err0:
+	clk_disable_unprepare(drvdata->clk);
+	return err;
+}
+
+static int ls1x_wdt_remove(struct platform_device *pdev)
+{
+	struct ls1x_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
+
+	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 <[e-mail]>");
+MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
+MODULE_LICENSE("GPL");