1/*
  2 * Watchdog driver for CSR SiRFprimaII and SiRFatlasVI
  3 *
  4 * Copyright (c) 2013 Cambridge Silicon Radio Limited, a CSR plc group company.
  5 *
  6 * Licensed under GPLv2 or later.
  7 */
  8
  9#include <linux/module.h>
 10#include <linux/watchdog.h>
 11#include <linux/platform_device.h>
 12#include <linux/moduleparam.h>
 13#include <linux/of.h>
 14#include <linux/io.h>
 15#include <linux/uaccess.h>
 16
 17#define CLOCK_FREQ	1000000
 18
 19#define SIRFSOC_TIMER_COUNTER_LO	0x0000
 20#define SIRFSOC_TIMER_MATCH_0		0x0008
 21#define SIRFSOC_TIMER_INT_EN		0x0024
 22#define SIRFSOC_TIMER_WATCHDOG_EN	0x0028
 23#define SIRFSOC_TIMER_LATCH		0x0030
 24#define SIRFSOC_TIMER_LATCHED_LO	0x0034
 25
 26#define SIRFSOC_TIMER_WDT_INDEX		5
 27
 28#define SIRFSOC_WDT_MIN_TIMEOUT		30		/* 30 secs */
 29#define SIRFSOC_WDT_MAX_TIMEOUT		(10 * 60)	/* 10 mins */
 30#define SIRFSOC_WDT_DEFAULT_TIMEOUT	30		/* 30 secs */
 31
 32static unsigned int timeout = SIRFSOC_WDT_DEFAULT_TIMEOUT;
 33static bool nowayout = WATCHDOG_NOWAYOUT;
 34
 35module_param(timeout, uint, 0);
 36module_param(nowayout, bool, 0);
 37
 38MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
 39MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 40			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 41
 42static unsigned int sirfsoc_wdt_gettimeleft(struct watchdog_device *wdd)
 43{
 44	u32 counter, match;
 45	void __iomem *wdt_base;
 46	int time_left;
 47
 48	wdt_base = watchdog_get_drvdata(wdd);
 49	counter = readl(wdt_base + SIRFSOC_TIMER_COUNTER_LO);
 50	match = readl(wdt_base +
 51		SIRFSOC_TIMER_MATCH_0 + (SIRFSOC_TIMER_WDT_INDEX << 2));
 52
 53	time_left = match - counter;
 54
 55	return time_left / CLOCK_FREQ;
 56}
 57
 58static int sirfsoc_wdt_updatetimeout(struct watchdog_device *wdd)
 59{
 60	u32 counter, timeout_ticks;
 61	void __iomem *wdt_base;
 62
 63	timeout_ticks = wdd->timeout * CLOCK_FREQ;
 64	wdt_base = watchdog_get_drvdata(wdd);
 65
 66	/* Enable the latch before reading the LATCH_LO register */
 67	writel(1, wdt_base + SIRFSOC_TIMER_LATCH);
 68
 69	/* Set the TO value */
 70	counter = readl(wdt_base + SIRFSOC_TIMER_LATCHED_LO);
 71
 72	counter += timeout_ticks;
 73
 74	writel(counter, wdt_base +
 75		SIRFSOC_TIMER_MATCH_0 + (SIRFSOC_TIMER_WDT_INDEX << 2));
 76
 77	return 0;
 78}
 79
 80static int sirfsoc_wdt_enable(struct watchdog_device *wdd)
 81{
 82	void __iomem *wdt_base = watchdog_get_drvdata(wdd);
 83	sirfsoc_wdt_updatetimeout(wdd);
 84
 85	/*
 86	 * NOTE: If interrupt is not enabled
 87	 * then WD-Reset doesn't get generated at all.
 88	 */
 89	writel(readl(wdt_base + SIRFSOC_TIMER_INT_EN)
 90		| (1 << SIRFSOC_TIMER_WDT_INDEX),
 91		wdt_base + SIRFSOC_TIMER_INT_EN);
 92	writel(1, wdt_base + SIRFSOC_TIMER_WATCHDOG_EN);
 93
 94	return 0;
 95}
 96
 97static int sirfsoc_wdt_disable(struct watchdog_device *wdd)
 98{
 99	void __iomem *wdt_base = watchdog_get_drvdata(wdd);
100
101	writel(0, wdt_base + SIRFSOC_TIMER_WATCHDOG_EN);
102	writel(readl(wdt_base + SIRFSOC_TIMER_INT_EN)
103		& (~(1 << SIRFSOC_TIMER_WDT_INDEX)),
104		wdt_base + SIRFSOC_TIMER_INT_EN);
105
106	return 0;
107}
108
109static int sirfsoc_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
110{
111	wdd->timeout = to;
112	sirfsoc_wdt_updatetimeout(wdd);
113
114	return 0;
115}
116
117#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
118
119static const struct watchdog_info sirfsoc_wdt_ident = {
120	.options          =     OPTIONS,
121	.firmware_version =	0,
122	.identity         =	"SiRFSOC Watchdog",
123};
124
125static struct watchdog_ops sirfsoc_wdt_ops = {
126	.owner = THIS_MODULE,
127	.start = sirfsoc_wdt_enable,
128	.stop = sirfsoc_wdt_disable,
129	.get_timeleft = sirfsoc_wdt_gettimeleft,
130	.ping = sirfsoc_wdt_updatetimeout,
131	.set_timeout = sirfsoc_wdt_settimeout,
132};
133
134static struct watchdog_device sirfsoc_wdd = {
135	.info = &sirfsoc_wdt_ident,
136	.ops = &sirfsoc_wdt_ops,
137	.timeout = SIRFSOC_WDT_DEFAULT_TIMEOUT,
138	.min_timeout = SIRFSOC_WDT_MIN_TIMEOUT,
139	.max_timeout = SIRFSOC_WDT_MAX_TIMEOUT,
140};
141
142static int sirfsoc_wdt_probe(struct platform_device *pdev)
143{
144	struct resource *res;
145	int ret;
146	void __iomem *base;
147
148	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
149	base = devm_ioremap_resource(&pdev->dev, res);
150	if (IS_ERR(base))
151		return PTR_ERR(base);
152
153	watchdog_set_drvdata(&sirfsoc_wdd, base);
154
155	watchdog_init_timeout(&sirfsoc_wdd, timeout, &pdev->dev);
156	watchdog_set_nowayout(&sirfsoc_wdd, nowayout);
157	sirfsoc_wdd.parent = &pdev->dev;
158
159	ret = watchdog_register_device(&sirfsoc_wdd);
160	if (ret)
161		return ret;
162
163	platform_set_drvdata(pdev, &sirfsoc_wdd);
164
165	return 0;
166}
167
168static void sirfsoc_wdt_shutdown(struct platform_device *pdev)
169{
170	struct watchdog_device *wdd = platform_get_drvdata(pdev);
171
172	sirfsoc_wdt_disable(wdd);
173}
174
175static int sirfsoc_wdt_remove(struct platform_device *pdev)
176{
177	sirfsoc_wdt_shutdown(pdev);
178	return 0;
179}
180
181#ifdef	CONFIG_PM_SLEEP
182static int sirfsoc_wdt_suspend(struct device *dev)
183{
184	return 0;
185}
186
187static int sirfsoc_wdt_resume(struct device *dev)
188{
189	struct watchdog_device *wdd = dev_get_drvdata(dev);
190
191	/*
192	 * NOTE: Since timer controller registers settings are saved
193	 * and restored back by the timer-prima2.c, so we need not
194	 * update WD settings except refreshing timeout.
195	 */
196	sirfsoc_wdt_updatetimeout(wdd);
197
198	return 0;
199}
200#endif
201
202static SIMPLE_DEV_PM_OPS(sirfsoc_wdt_pm_ops,
203		sirfsoc_wdt_suspend, sirfsoc_wdt_resume);
204
205static const struct of_device_id sirfsoc_wdt_of_match[] = {
206	{ .compatible = "sirf,prima2-tick"},
207	{},
208};
209MODULE_DEVICE_TABLE(of, sirfsoc_wdt_of_match);
210
211static struct platform_driver sirfsoc_wdt_driver = {
212	.driver = {
213		.name = "sirfsoc-wdt",
214		.pm = &sirfsoc_wdt_pm_ops,
215		.of_match_table	= sirfsoc_wdt_of_match,
216	},
217	.probe = sirfsoc_wdt_probe,
218	.remove = sirfsoc_wdt_remove,
219	.shutdown = sirfsoc_wdt_shutdown,
220};
221module_platform_driver(sirfsoc_wdt_driver);
222
223MODULE_DESCRIPTION("SiRF SoC watchdog driver");
224MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
225MODULE_LICENSE("GPL v2");
226MODULE_ALIAS("platform:sirfsoc-wdt");