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/module.h>
  8#include <linux/platform_device.h>
  9#include <linux/watchdog.h>
 10#include <loongson1.h>
 11
 12#define DEFAULT_HEARTBEAT	30
 13
 14static bool nowayout = WATCHDOG_NOWAYOUT;
 15module_param(nowayout, bool, 0444);
 16
 17static unsigned int heartbeat;
 18module_param(heartbeat, uint, 0444);
 19
 20struct ls1x_wdt_drvdata {
 21	void __iomem *base;
 22	struct clk *clk;
 23	unsigned long clk_rate;
 24	struct watchdog_device wdt;
 25};
 26
 27static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
 28{
 29	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 30
 31	writel(0x1, drvdata->base + WDT_SET);
 32
 33	return 0;
 34}
 35
 36static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
 37				unsigned int timeout)
 38{
 39	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 40	unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000;
 41	unsigned int counts;
 42
 43	wdt_dev->timeout = timeout;
 44
 45	counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
 46	writel(counts, drvdata->base + WDT_TIMER);
 47
 48	return 0;
 49}
 50
 51static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
 52{
 53	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 54
 55	writel(0x1, drvdata->base + WDT_EN);
 56
 57	return 0;
 58}
 59
 60static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
 61{
 62	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 63
 64	writel(0x0, drvdata->base + WDT_EN);
 65
 66	return 0;
 67}
 68
 69static const struct watchdog_info ls1x_wdt_info = {
 70	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 71	.identity = "Loongson1 Watchdog",
 72};
 73
 74static const struct watchdog_ops ls1x_wdt_ops = {
 75	.owner = THIS_MODULE,
 76	.start = ls1x_wdt_start,
 77	.stop = ls1x_wdt_stop,
 78	.ping = ls1x_wdt_ping,
 79	.set_timeout = ls1x_wdt_set_timeout,
 80};
 81
 82static void ls1x_clk_disable_unprepare(void *data)
 83{
 84	clk_disable_unprepare(data);
 85}
 86
 87static int ls1x_wdt_probe(struct platform_device *pdev)
 88{
 89	struct device *dev = &pdev->dev;
 90	struct ls1x_wdt_drvdata *drvdata;
 91	struct watchdog_device *ls1x_wdt;
 92	unsigned long clk_rate;
 93	int err;
 94
 95	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
 96	if (!drvdata)
 97		return -ENOMEM;
 98
 99	drvdata->base = devm_platform_ioremap_resource(pdev, 0);
100	if (IS_ERR(drvdata->base))
101		return PTR_ERR(drvdata->base);
102
103	drvdata->clk = devm_clk_get(dev, pdev->name);
104	if (IS_ERR(drvdata->clk))
105		return PTR_ERR(drvdata->clk);
106
107	err = clk_prepare_enable(drvdata->clk);
108	if (err) {
109		dev_err(dev, "clk enable failed\n");
110		return err;
111	}
112	err = devm_add_action_or_reset(dev, ls1x_clk_disable_unprepare,
113				       drvdata->clk);
114	if (err)
115		return err;
116
117	clk_rate = clk_get_rate(drvdata->clk);
118	if (!clk_rate)
119		return -EINVAL;
120	drvdata->clk_rate = clk_rate;
121
122	ls1x_wdt = &drvdata->wdt;
123	ls1x_wdt->info = &ls1x_wdt_info;
124	ls1x_wdt->ops = &ls1x_wdt_ops;
125	ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
126	ls1x_wdt->min_timeout = 1;
127	ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
128	ls1x_wdt->parent = dev;
129
130	watchdog_init_timeout(ls1x_wdt, heartbeat, dev);
131	watchdog_set_nowayout(ls1x_wdt, nowayout);
132	watchdog_set_drvdata(ls1x_wdt, drvdata);
133
134	err = devm_watchdog_register_device(dev, &drvdata->wdt);
135	if (err)
136		return err;
137
138	platform_set_drvdata(pdev, drvdata);
139
140	dev_info(dev, "Loongson1 Watchdog driver registered\n");
141
142	return 0;
143}
144
145static struct platform_driver ls1x_wdt_driver = {
146	.probe = ls1x_wdt_probe,
147	.driver = {
148		.name = "ls1x-wdt",
149	},
150};
151
152module_platform_driver(ls1x_wdt_driver);
153
154MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>");
155MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
156MODULE_LICENSE("GPL");