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 <cpu_func.h>
9 #include <dm.h>
10 #include <hang.h>
11 #include <asm/io.h>
12 #include <wdt.h>
13 #include <watchdog.h>
14 #include <asm/arch/imx-regs.h>
15 #ifdef CONFIG_FSL_LSCH2
16 #include <asm/arch/immap_lsch2.h>
17 #endif
18 #include <fsl_wdog.h>
19 #include <div64.h>
20
21 #define TIMEOUT_MAX 128000
22 #define TIMEOUT_MIN 500
23
imx_watchdog_expire_now(struct watchdog_regs * wdog,bool ext_reset)24 static void imx_watchdog_expire_now(struct watchdog_regs *wdog, bool ext_reset)
25 {
26 u16 wcr = WCR_WDE;
27
28 if (ext_reset)
29 wcr |= WCR_SRS; /* do not assert internal reset */
30 else
31 wcr |= WCR_WDA; /* do not assert external reset */
32
33 /* Write 3 times to ensure it works, due to IMX6Q errata ERR004346 */
34 writew(wcr, &wdog->wcr);
35 writew(wcr, &wdog->wcr);
36 writew(wcr, &wdog->wcr);
37
38 while (1) {
39 /*
40 * spin before reset
41 */
42 }
43 }
44
45 #if !defined(CONFIG_IMX_WATCHDOG) || \
46 (defined(CONFIG_IMX_WATCHDOG) && !CONFIG_IS_ENABLED(WDT))
reset_cpu(void)47 void __attribute__((weak)) reset_cpu(void)
48 {
49 struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
50
51 imx_watchdog_expire_now(wdog, true);
52 }
53 #endif
54
55 #if defined(CONFIG_IMX_WATCHDOG)
imx_watchdog_reset(struct watchdog_regs * wdog)56 static void imx_watchdog_reset(struct watchdog_regs *wdog)
57 {
58 #ifndef CONFIG_WATCHDOG_RESET_DISABLE
59 writew(0x5555, &wdog->wsr);
60 writew(0xaaaa, &wdog->wsr);
61 #endif /* CONFIG_WATCHDOG_RESET_DISABLE*/
62 }
63
imx_watchdog_init(struct watchdog_regs * wdog,bool ext_reset,u64 timeout)64 static void imx_watchdog_init(struct watchdog_regs *wdog, bool ext_reset,
65 u64 timeout)
66 {
67 u16 wcr;
68
69 /*
70 * The timer watchdog can be set between
71 * 0.5 and 128 Seconds.
72 */
73 timeout = max_t(u64, timeout, TIMEOUT_MIN);
74 timeout = min_t(u64, timeout, TIMEOUT_MAX);
75 timeout = lldiv(timeout, 500) - 1;
76
77 #ifdef CONFIG_FSL_LSCH2
78 wcr = (WCR_WDA | WCR_SRS | WCR_WDE) << 8 | timeout;
79 #else
80 wcr = WCR_WDZST | WCR_WDBG | WCR_WDE | WCR_SRS |
81 WCR_WDA | SET_WCR_WT(timeout);
82 if (ext_reset)
83 wcr |= WCR_WDT;
84 #endif /* CONFIG_FSL_LSCH2*/
85 writew(wcr, &wdog->wcr);
86 imx_watchdog_reset(wdog);
87 }
88
89 #if !CONFIG_IS_ENABLED(WDT)
hw_watchdog_reset(void)90 void hw_watchdog_reset(void)
91 {
92 struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
93
94 imx_watchdog_reset(wdog);
95 }
96
hw_watchdog_init(void)97 void hw_watchdog_init(void)
98 {
99 struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
100
101 imx_watchdog_init(wdog, true, CONFIG_WATCHDOG_TIMEOUT_MSECS);
102 }
103 #else
104 struct imx_wdt_priv {
105 void __iomem *base;
106 bool ext_reset;
107 };
108
imx_wdt_reset(struct udevice * dev)109 static int imx_wdt_reset(struct udevice *dev)
110 {
111 struct imx_wdt_priv *priv = dev_get_priv(dev);
112
113 imx_watchdog_reset(priv->base);
114
115 return 0;
116 }
117
imx_wdt_expire_now(struct udevice * dev,ulong flags)118 static int imx_wdt_expire_now(struct udevice *dev, ulong flags)
119 {
120 struct imx_wdt_priv *priv = dev_get_priv(dev);
121
122 imx_watchdog_expire_now(priv->base, priv->ext_reset);
123 hang();
124
125 return 0;
126 }
127
imx_wdt_start(struct udevice * dev,u64 timeout,ulong flags)128 static int imx_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
129 {
130 struct imx_wdt_priv *priv = dev_get_priv(dev);
131
132 imx_watchdog_init(priv->base, priv->ext_reset, timeout);
133
134 return 0;
135 }
136
imx_wdt_probe(struct udevice * dev)137 static int imx_wdt_probe(struct udevice *dev)
138 {
139 struct imx_wdt_priv *priv = dev_get_priv(dev);
140
141 priv->base = dev_read_addr_ptr(dev);
142 if (!priv->base)
143 return -ENOENT;
144
145 priv->ext_reset = dev_read_bool(dev, "fsl,ext-reset-output");
146
147 return 0;
148 }
149
150 static const struct wdt_ops imx_wdt_ops = {
151 .start = imx_wdt_start,
152 .reset = imx_wdt_reset,
153 .expire_now = imx_wdt_expire_now,
154 };
155
156 static const struct udevice_id imx_wdt_ids[] = {
157 { .compatible = "fsl,imx21-wdt" },
158 {}
159 };
160
161 U_BOOT_DRIVER(imx_wdt) = {
162 .name = "imx_wdt",
163 .id = UCLASS_WDT,
164 .of_match = imx_wdt_ids,
165 .probe = imx_wdt_probe,
166 .ops = &imx_wdt_ops,
167 .priv_auto = sizeof(struct imx_wdt_priv),
168 .flags = DM_FLAG_PRE_RELOC,
169 };
170 #endif
171 #endif
172