1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com>
  4 */
  5
  6#include <linux/clk.h>
  7#include <linux/io.h>
  8#include <linux/module.h>
  9#include <linux/of.h>
 10#include <linux/platform_device.h>
 11#include <linux/watchdog.h>
 12
 13/* Loongson 1 Watchdog Register Definitions */
 14#define WDT_EN			0x0
 15#define WDT_TIMER		0x4
 16#define WDT_SET			0x8
 17
 18#define DEFAULT_HEARTBEAT	30
 19
 20static bool nowayout = WATCHDOG_NOWAYOUT;
 21module_param(nowayout, bool, 0444);
 22
 23static unsigned int heartbeat;
 24module_param(heartbeat, uint, 0444);
 25
 26struct ls1x_wdt_drvdata {
 27	void __iomem *base;
 28	struct clk *clk;
 29	unsigned long clk_rate;
 30	struct watchdog_device wdt;
 31};
 32
 33static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
 34{
 35	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 36
 37	writel(0x1, drvdata->base + WDT_SET);
 38
 39	return 0;
 40}
 41
 42static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
 43				unsigned int timeout)
 44{
 45	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 46	unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000;
 47	unsigned int counts;
 48
 49	wdt_dev->timeout = timeout;
 50
 51	counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
 52	writel(counts, drvdata->base + WDT_TIMER);
 53
 54	return 0;
 55}
 56
 57static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
 58{
 59	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 60
 61	writel(0x1, drvdata->base + WDT_EN);
 62
 63	return 0;
 64}
 65
 66static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
 67{
 68	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 69
 70	writel(0x0, drvdata->base + WDT_EN);
 71
 72	return 0;
 73}
 74
 75static int ls1x_wdt_restart(struct watchdog_device *wdt_dev,
 76			    unsigned long action, void *data)
 77{
 78	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 79
 80	writel(0x1, drvdata->base + WDT_EN);
 81	writel(0x1, drvdata->base + WDT_TIMER);
 82	writel(0x1, drvdata->base + WDT_SET);
 83
 84	return 0;
 85}
 86
 87static const struct watchdog_info ls1x_wdt_info = {
 88	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 89	.identity = "Loongson1 Watchdog",
 90};
 91
 92static const struct watchdog_ops ls1x_wdt_ops = {
 93	.owner = THIS_MODULE,
 94	.start = ls1x_wdt_start,
 95	.stop = ls1x_wdt_stop,
 96	.ping = ls1x_wdt_ping,
 97	.set_timeout = ls1x_wdt_set_timeout,
 98	.restart = ls1x_wdt_restart,
 99};
100
101static int ls1x_wdt_probe(struct platform_device *pdev)
102{
103	struct device *dev = &pdev->dev;
104	struct ls1x_wdt_drvdata *drvdata;
105	struct watchdog_device *ls1x_wdt;
106	unsigned long clk_rate;
107	int err;
108
109	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
110	if (!drvdata)
111		return -ENOMEM;
112
113	drvdata->base = devm_platform_ioremap_resource(pdev, 0);
114	if (IS_ERR(drvdata->base))
115		return PTR_ERR(drvdata->base);
116
117	drvdata->clk = devm_clk_get_enabled(dev, NULL);
118	if (IS_ERR(drvdata->clk))
119		return PTR_ERR(drvdata->clk);
120
121	clk_rate = clk_get_rate(drvdata->clk);
122	if (!clk_rate)
123		return -EINVAL;
124	drvdata->clk_rate = clk_rate;
125
126	ls1x_wdt = &drvdata->wdt;
127	ls1x_wdt->info = &ls1x_wdt_info;
128	ls1x_wdt->ops = &ls1x_wdt_ops;
129	ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
130	ls1x_wdt->min_timeout = 1;
131	ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
132	ls1x_wdt->parent = dev;
133
134	watchdog_init_timeout(ls1x_wdt, heartbeat, dev);
135	watchdog_set_nowayout(ls1x_wdt, nowayout);
136	watchdog_set_drvdata(ls1x_wdt, drvdata);
137
138	err = devm_watchdog_register_device(dev, &drvdata->wdt);
139	if (err)
140		return err;
141
142	platform_set_drvdata(pdev, drvdata);
143
144	dev_info(dev, "Loongson1 Watchdog driver registered\n");
145
146	return 0;
147}
148
149#ifdef CONFIG_OF
150static const struct of_device_id ls1x_wdt_dt_ids[] = {
151	{ .compatible = "loongson,ls1b-wdt", },
152	{ .compatible = "loongson,ls1c-wdt", },
153	{ /* sentinel */ }
154};
155MODULE_DEVICE_TABLE(of, ls1x_wdt_dt_ids);
156#endif
157
158static struct platform_driver ls1x_wdt_driver = {
159	.probe = ls1x_wdt_probe,
160	.driver = {
161		.name = "ls1x-wdt",
162		.of_match_table = of_match_ptr(ls1x_wdt_dt_ids),
163	},
164};
165
166module_platform_driver(ls1x_wdt_driver);
167
168MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>");
169MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
170MODULE_LICENSE("GPL");