1/*
  2 * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com>
  3 *
  4 * This program is free software; you can redistribute it and/or modify it
  5 * under the terms of the GNU General Public License as published by the
  6 * Free Software Foundation; either version 2 of the License, or (at your
  7 * option) any later version.
  8 */
  9
 10#include <linux/clk.h>
 11#include <linux/module.h>
 12#include <linux/platform_device.h>
 13#include <linux/watchdog.h>
 14#include <loongson1.h>
 15
 16#define DEFAULT_HEARTBEAT	30
 17
 18static bool nowayout = WATCHDOG_NOWAYOUT;
 19module_param(nowayout, bool, 0444);
 20
 21static unsigned int heartbeat;
 22module_param(heartbeat, uint, 0444);
 23
 24struct ls1x_wdt_drvdata {
 25	void __iomem *base;
 26	struct clk *clk;
 27	unsigned long clk_rate;
 28	struct watchdog_device wdt;
 29};
 30
 31static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
 32{
 33	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 34
 35	writel(0x1, drvdata->base + WDT_SET);
 36
 37	return 0;
 38}
 39
 40static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
 41				unsigned int timeout)
 42{
 43	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 44	unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000;
 45	unsigned int counts;
 46
 47	wdt_dev->timeout = timeout;
 48
 49	counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
 50	writel(counts, drvdata->base + WDT_TIMER);
 51
 52	return 0;
 53}
 54
 55static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
 56{
 57	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 58
 59	writel(0x1, drvdata->base + WDT_EN);
 60
 61	return 0;
 62}
 63
 64static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
 65{
 66	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 67
 68	writel(0x0, drvdata->base + WDT_EN);
 69
 70	return 0;
 71}
 72
 73static const struct watchdog_info ls1x_wdt_info = {
 74	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 75	.identity = "Loongson1 Watchdog",
 76};
 77
 78static const struct watchdog_ops ls1x_wdt_ops = {
 79	.owner = THIS_MODULE,
 80	.start = ls1x_wdt_start,
 81	.stop = ls1x_wdt_stop,
 82	.ping = ls1x_wdt_ping,
 83	.set_timeout = ls1x_wdt_set_timeout,
 84};
 85
 86static int ls1x_wdt_probe(struct platform_device *pdev)
 87{
 88	struct ls1x_wdt_drvdata *drvdata;
 89	struct watchdog_device *ls1x_wdt;
 90	unsigned long clk_rate;
 91	struct resource *res;
 92	int err;
 93
 94	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 95	if (!drvdata)
 96		return -ENOMEM;
 97
 98	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 99	drvdata->base = devm_ioremap_resource(&pdev->dev, res);
100	if (IS_ERR(drvdata->base))
101		return PTR_ERR(drvdata->base);
102
103	drvdata->clk = devm_clk_get(&pdev->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(&pdev->dev, "clk enable failed\n");
110		return err;
111	}
112
113	clk_rate = clk_get_rate(drvdata->clk);
114	if (!clk_rate) {
115		err = -EINVAL;
116		goto err0;
117	}
118	drvdata->clk_rate = clk_rate;
119
120	ls1x_wdt = &drvdata->wdt;
121	ls1x_wdt->info = &ls1x_wdt_info;
122	ls1x_wdt->ops = &ls1x_wdt_ops;
123	ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
124	ls1x_wdt->min_timeout = 1;
125	ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
126	ls1x_wdt->parent = &pdev->dev;
127
128	watchdog_init_timeout(ls1x_wdt, heartbeat, &pdev->dev);
129	watchdog_set_nowayout(ls1x_wdt, nowayout);
130	watchdog_set_drvdata(ls1x_wdt, drvdata);
131
132	err = watchdog_register_device(&drvdata->wdt);
133	if (err) {
134		dev_err(&pdev->dev, "failed to register watchdog device\n");
135		goto err0;
136	}
137
138	platform_set_drvdata(pdev, drvdata);
139
140	dev_info(&pdev->dev, "Loongson1 Watchdog driver registered\n");
141
142	return 0;
143err0:
144	clk_disable_unprepare(drvdata->clk);
145	return err;
146}
147
148static int ls1x_wdt_remove(struct platform_device *pdev)
149{
150	struct ls1x_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
151
152	watchdog_unregister_device(&drvdata->wdt);
153	clk_disable_unprepare(drvdata->clk);
154
155	return 0;
156}
157
158static struct platform_driver ls1x_wdt_driver = {
159	.probe = ls1x_wdt_probe,
160	.remove = ls1x_wdt_remove,
161	.driver = {
162		.name = "ls1x-wdt",
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");