1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2015 Broadcom Corporation
4 *
5 */
6
7#include <linux/clk.h>
8#include <linux/init.h>
9#include <linux/io.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/platform_data/bcm7038_wdt.h>
14#include <linux/pm.h>
15#include <linux/watchdog.h>
16
17#define WDT_START_1		0xff00
18#define WDT_START_2		0x00ff
19#define WDT_STOP_1		0xee00
20#define WDT_STOP_2		0x00ee
21
22#define WDT_TIMEOUT_REG		0x0
23#define WDT_CMD_REG		0x4
24
25#define WDT_MIN_TIMEOUT		1 /* seconds */
26#define WDT_DEFAULT_TIMEOUT	30 /* seconds */
27#define WDT_DEFAULT_RATE	27000000
28
29struct bcm7038_watchdog {
30	void __iomem		*base;
31	struct watchdog_device	wdd;
32	u32			rate;
33	struct clk		*clk;
34};
35
36static bool nowayout = WATCHDOG_NOWAYOUT;
37
38static inline void bcm7038_wdt_write(u32 value, void __iomem *addr)
39{
40	/* MIPS chips strapped for BE will automagically configure the
41	 * peripheral registers for CPU-native byte order.
42	 */
43	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
44		__raw_writel(value, addr);
45	else
46		writel_relaxed(value, addr);
47}
48
49static inline u32 bcm7038_wdt_read(void __iomem *addr)
50{
51	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
52		return __raw_readl(addr);
53	else
54		return readl_relaxed(addr);
55}
56
57static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
58{
59	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
60	u32 timeout;
61
62	timeout = wdt->rate * wdog->timeout;
63
64	bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG);
65}
66
67static int bcm7038_wdt_ping(struct watchdog_device *wdog)
68{
69	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
70
71	bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG);
72	bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG);
73
74	return 0;
75}
76
77static int bcm7038_wdt_start(struct watchdog_device *wdog)
78{
79	bcm7038_wdt_set_timeout_reg(wdog);
80	bcm7038_wdt_ping(wdog);
81
82	return 0;
83}
84
85static int bcm7038_wdt_stop(struct watchdog_device *wdog)
86{
87	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
88
89	bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG);
90	bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG);
91
92	return 0;
93}
94
95static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,
96				   unsigned int t)
97{
98	/* Can't modify timeout value if watchdog timer is running */
99	bcm7038_wdt_stop(wdog);
100	wdog->timeout = t;
101	bcm7038_wdt_start(wdog);
102
103	return 0;
104}
105
106static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
107{
108	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
109	u32 time_left;
110
111	time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG);
112
113	return time_left / wdt->rate;
114}
115
116static const struct watchdog_info bcm7038_wdt_info = {
117	.identity	= "Broadcom BCM7038 Watchdog Timer",
118	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
119				WDIOF_MAGICCLOSE
120};
121
122static const struct watchdog_ops bcm7038_wdt_ops = {
123	.owner		= THIS_MODULE,
124	.start		= bcm7038_wdt_start,
125	.stop		= bcm7038_wdt_stop,
126	.set_timeout	= bcm7038_wdt_set_timeout,
127	.get_timeleft	= bcm7038_wdt_get_timeleft,
128};
129
130static int bcm7038_wdt_probe(struct platform_device *pdev)
131{
132	struct bcm7038_wdt_platform_data *pdata = pdev->dev.platform_data;
133	struct device *dev = &pdev->dev;
134	struct bcm7038_watchdog *wdt;
135	const char *clk_name = NULL;
136	int err;
137
138	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
139	if (!wdt)
140		return -ENOMEM;
141
142	platform_set_drvdata(pdev, wdt);
143
144	wdt->base = devm_platform_ioremap_resource(pdev, 0);
145	if (IS_ERR(wdt->base))
146		return PTR_ERR(wdt->base);
147
148	if (pdata && pdata->clk_name)
149		clk_name = pdata->clk_name;
150
151	wdt->clk = devm_clk_get_enabled(dev, clk_name);
152	/* If unable to get clock, use default frequency */
153	if (!IS_ERR(wdt->clk)) {
154		wdt->rate = clk_get_rate(wdt->clk);
155		/* Prevent divide-by-zero exception */
156		if (!wdt->rate)
157			wdt->rate = WDT_DEFAULT_RATE;
158	} else {
159		wdt->rate = WDT_DEFAULT_RATE;
160		wdt->clk = NULL;
161	}
162
163	wdt->wdd.info		= &bcm7038_wdt_info;
164	wdt->wdd.ops		= &bcm7038_wdt_ops;
165	wdt->wdd.min_timeout	= WDT_MIN_TIMEOUT;
166	wdt->wdd.timeout	= WDT_DEFAULT_TIMEOUT;
167	wdt->wdd.max_timeout	= 0xffffffff / wdt->rate;
168	wdt->wdd.parent		= dev;
169	watchdog_set_drvdata(&wdt->wdd, wdt);
170
171	watchdog_stop_on_reboot(&wdt->wdd);
172	watchdog_stop_on_unregister(&wdt->wdd);
173	err = devm_watchdog_register_device(dev, &wdt->wdd);
174	if (err)
175		return err;
176
177	dev_info(dev, "Registered BCM7038 Watchdog\n");
178
179	return 0;
180}
181
182static int bcm7038_wdt_suspend(struct device *dev)
183{
184	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
185
186	if (watchdog_active(&wdt->wdd))
187		return bcm7038_wdt_stop(&wdt->wdd);
188
189	return 0;
190}
191
192static int bcm7038_wdt_resume(struct device *dev)
193{
194	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
195
196	if (watchdog_active(&wdt->wdd))
197		return bcm7038_wdt_start(&wdt->wdd);
198
199	return 0;
200}
201
202static DEFINE_SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops,
203				bcm7038_wdt_suspend, bcm7038_wdt_resume);
204
205static const struct of_device_id bcm7038_wdt_match[] = {
206	{ .compatible = "brcm,bcm6345-wdt" },
207	{ .compatible = "brcm,bcm7038-wdt" },
208	{},
209};
210MODULE_DEVICE_TABLE(of, bcm7038_wdt_match);
211
212static const struct platform_device_id bcm7038_wdt_devtype[] = {
213	{ .name = "bcm63xx-wdt" },
214	{ /* sentinel */ },
215};
216MODULE_DEVICE_TABLE(platform, bcm7038_wdt_devtype);
217
218static struct platform_driver bcm7038_wdt_driver = {
219	.probe		= bcm7038_wdt_probe,
220	.id_table	= bcm7038_wdt_devtype,
221	.driver		= {
222		.name		= "bcm7038-wdt",
223		.of_match_table	= bcm7038_wdt_match,
224		.pm		= pm_sleep_ptr(&bcm7038_wdt_pm_ops),
225	}
226};
227module_platform_driver(bcm7038_wdt_driver);
228
229module_param(nowayout, bool, 0);
230MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
231	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
232MODULE_LICENSE("GPL");
233MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
234MODULE_AUTHOR("Justin Chen");
235