2 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
4 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/types.h>
16 #include <linux/miscdevice.h>
17 #include <linux/watchdog.h>
18 #include <linux/init.h>
19 #include <linux/platform_device.h>
20 #include <linux/clk.h>
21 #include <linux/err.h>
23 #include <asm/txx9tmr.h>
25 #define WD_TIMER_CCD 7 /* 1/256 */
26 #define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
27 #define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
28 #define TIMER_MARGIN 60 /* Default is 60 seconds */
30 static unsigned int timeout = TIMER_MARGIN; /* in seconds */
31 module_param(timeout, uint, 0);
32 MODULE_PARM_DESC(timeout,
33 "Watchdog timeout in seconds. "
34 "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
35 "default=" __MODULE_STRING(TIMER_MARGIN) ")");
37 static bool nowayout = WATCHDOG_NOWAYOUT;
38 module_param(nowayout, bool, 0);
39 MODULE_PARM_DESC(nowayout,
40 "Watchdog cannot be stopped once started "
41 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
43 static struct txx9_tmr_reg __iomem *txx9wdt_reg;
44 static struct clk *txx9_imclk;
45 static DEFINE_SPINLOCK(txx9_lock);
47 static int txx9wdt_ping(struct watchdog_device *wdt_dev)
49 spin_lock(&txx9_lock);
50 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
51 spin_unlock(&txx9_lock);
55 static int txx9wdt_start(struct watchdog_device *wdt_dev)
57 spin_lock(&txx9_lock);
58 __raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra);
59 __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
60 __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
61 __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
63 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
64 spin_unlock(&txx9_lock);
68 static int txx9wdt_stop(struct watchdog_device *wdt_dev)
70 spin_lock(&txx9_lock);
71 __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
72 __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
74 spin_unlock(&txx9_lock);
78 static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev,
79 unsigned int new_timeout)
81 wdt_dev->timeout = new_timeout;
82 txx9wdt_stop(wdt_dev);
83 txx9wdt_start(wdt_dev);
87 static const struct watchdog_info txx9wdt_info = {
88 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
89 .identity = "Hardware Watchdog for TXx9",
92 static const struct watchdog_ops txx9wdt_ops = {
94 .start = txx9wdt_start,
97 .set_timeout = txx9wdt_set_timeout,
100 static struct watchdog_device txx9wdt = {
101 .info = &txx9wdt_info,
105 static int __init txx9wdt_probe(struct platform_device *dev)
107 struct resource *res;
110 txx9_imclk = clk_get(NULL, "imbus_clk");
111 if (IS_ERR(txx9_imclk)) {
112 ret = PTR_ERR(txx9_imclk);
116 ret = clk_enable(txx9_imclk);
123 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
124 txx9wdt_reg = devm_ioremap_resource(&dev->dev, res);
125 if (IS_ERR(txx9wdt_reg)) {
126 ret = PTR_ERR(txx9wdt_reg);
130 if (timeout < 1 || timeout > WD_MAX_TIMEOUT)
131 timeout = TIMER_MARGIN;
132 txx9wdt.timeout = timeout;
133 txx9wdt.min_timeout = 1;
134 txx9wdt.max_timeout = WD_MAX_TIMEOUT;
135 watchdog_set_nowayout(&txx9wdt, nowayout);
137 ret = watchdog_register_device(&txx9wdt);
141 pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n",
142 timeout, WD_MAX_TIMEOUT, nowayout);
147 clk_disable(txx9_imclk);
153 static int __exit txx9wdt_remove(struct platform_device *dev)
155 watchdog_unregister_device(&txx9wdt);
156 clk_disable(txx9_imclk);
161 static void txx9wdt_shutdown(struct platform_device *dev)
163 txx9wdt_stop(&txx9wdt);
166 static struct platform_driver txx9wdt_driver = {
167 .remove = __exit_p(txx9wdt_remove),
168 .shutdown = txx9wdt_shutdown,
171 .owner = THIS_MODULE,
175 module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe);
177 MODULE_DESCRIPTION("TXx9 Watchdog Driver");
178 MODULE_LICENSE("GPL");
179 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
180 MODULE_ALIAS("platform:txx9wdt");