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1 /*
2  * watchdog.c - driver for i.mx on-chip watchdog
3  *
4  * Licensed under the GPL-2 or later.
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <asm/io.h>
10 #include <wdt.h>
11 #include <watchdog.h>
12 #include <asm/arch/imx-regs.h>
13 #ifdef CONFIG_FSL_LSCH2
14 #include <asm/arch/immap_lsch2.h>
15 #endif
16 #include <fsl_wdog.h>
17 
imx_watchdog_expire_now(struct watchdog_regs * wdog,bool ext_reset)18 static void imx_watchdog_expire_now(struct watchdog_regs *wdog, bool ext_reset)
19 {
20 	u16 wcr = WCR_WDE;
21 
22 	if (ext_reset)
23 		wcr |= WCR_SRS; /* do not assert internal reset */
24 	else
25 		wcr |= WCR_WDA; /* do not assert external reset */
26 
27 	/* Write 3 times to ensure it works, due to IMX6Q errata ERR004346 */
28 	writew(wcr, &wdog->wcr);
29 	writew(wcr, &wdog->wcr);
30 	writew(wcr, &wdog->wcr);
31 
32 	while (1) {
33 		/*
34 		 * spin before reset
35 		 */
36 	}
37 }
38 
39 #if !defined(CONFIG_IMX_WATCHDOG) || \
40     (defined(CONFIG_IMX_WATCHDOG) && !CONFIG_IS_ENABLED(WDT))
reset_cpu(ulong addr)41 void __attribute__((weak)) reset_cpu(ulong addr)
42 {
43 	struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
44 
45 	imx_watchdog_expire_now(wdog, true);
46 }
47 #endif
48 
49 #if defined(CONFIG_IMX_WATCHDOG)
imx_watchdog_reset(struct watchdog_regs * wdog)50 static void imx_watchdog_reset(struct watchdog_regs *wdog)
51 {
52 #ifndef CONFIG_WATCHDOG_RESET_DISABLE
53 	writew(0x5555, &wdog->wsr);
54 	writew(0xaaaa, &wdog->wsr);
55 #endif /* CONFIG_WATCHDOG_RESET_DISABLE*/
56 }
57 
imx_watchdog_init(struct watchdog_regs * wdog,bool ext_reset)58 static void imx_watchdog_init(struct watchdog_regs *wdog, bool ext_reset)
59 {
60 	u16 timeout;
61 	u16 wcr;
62 
63 	/*
64 	 * The timer watchdog can be set between
65 	 * 0.5 and 128 Seconds. If not defined
66 	 * in configuration file, sets 128 Seconds
67 	 */
68 #ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
69 #define CONFIG_WATCHDOG_TIMEOUT_MSECS 128000
70 #endif
71 	timeout = (CONFIG_WATCHDOG_TIMEOUT_MSECS / 500) - 1;
72 #ifdef CONFIG_FSL_LSCH2
73 	wcr = (WCR_WDA | WCR_SRS | WCR_WDE) << 8 | timeout;
74 #else
75 	wcr = WCR_WDZST | WCR_WDBG | WCR_WDE | WCR_SRS |
76 		WCR_WDA | SET_WCR_WT(timeout);
77 	if (ext_reset)
78 		wcr |= WCR_WDT;
79 #endif /* CONFIG_FSL_LSCH2*/
80 	writew(wcr, &wdog->wcr);
81 	imx_watchdog_reset(wdog);
82 }
83 
84 #if !CONFIG_IS_ENABLED(WDT)
hw_watchdog_reset(void)85 void hw_watchdog_reset(void)
86 {
87 	struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
88 
89 	imx_watchdog_reset(wdog);
90 }
91 
hw_watchdog_init(void)92 void hw_watchdog_init(void)
93 {
94 	struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
95 
96 	imx_watchdog_init(wdog, true);
97 }
98 #else
99 struct imx_wdt_priv {
100 	void __iomem *base;
101 	bool ext_reset;
102 };
103 
imx_wdt_reset(struct udevice * dev)104 static int imx_wdt_reset(struct udevice *dev)
105 {
106 	struct imx_wdt_priv *priv = dev_get_priv(dev);
107 
108 	imx_watchdog_reset(priv->base);
109 
110 	return 0;
111 }
112 
imx_wdt_expire_now(struct udevice * dev,ulong flags)113 static int imx_wdt_expire_now(struct udevice *dev, ulong flags)
114 {
115 	struct imx_wdt_priv *priv = dev_get_priv(dev);
116 
117 	imx_watchdog_expire_now(priv->base, priv->ext_reset);
118 	hang();
119 
120 	return 0;
121 }
122 
imx_wdt_start(struct udevice * dev,u64 timeout,ulong flags)123 static int imx_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
124 {
125 	struct imx_wdt_priv *priv = dev_get_priv(dev);
126 
127 	imx_watchdog_init(priv->base, priv->ext_reset);
128 
129 	return 0;
130 }
131 
imx_wdt_probe(struct udevice * dev)132 static int imx_wdt_probe(struct udevice *dev)
133 {
134 	struct imx_wdt_priv *priv = dev_get_priv(dev);
135 
136 	priv->base = dev_read_addr_ptr(dev);
137 	if (!priv->base)
138 		return -ENOENT;
139 
140 	priv->ext_reset = dev_read_bool(dev, "fsl,ext-reset-output");
141 
142 	return 0;
143 }
144 
145 static const struct wdt_ops imx_wdt_ops = {
146 	.start		= imx_wdt_start,
147 	.reset		= imx_wdt_reset,
148 	.expire_now	= imx_wdt_expire_now,
149 };
150 
151 static const struct udevice_id imx_wdt_ids[] = {
152 	{ .compatible = "fsl,imx21-wdt" },
153 	{}
154 };
155 
156 U_BOOT_DRIVER(imx_wdt) = {
157 	.name		= "imx_wdt",
158 	.id		= UCLASS_WDT,
159 	.of_match	= imx_wdt_ids,
160 	.probe		= imx_wdt_probe,
161 	.ops		= &imx_wdt_ops,
162 	.priv_auto_alloc_size = sizeof(struct imx_wdt_priv),
163 	.flags		= DM_FLAG_PRE_RELOC,
164 };
165 #endif
166 #endif
167