xref: /openbmc/u-boot/drivers/watchdog/ulp_wdog.c (revision d66ff4ba)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2016 Freescale Semiconductor, Inc.
4  */
5 
6 #include <common.h>
7 #include <asm/io.h>
8 #include <asm/arch/imx-regs.h>
9 
10 /*
11  * MX7ULP WDOG Register Map
12  */
13 struct wdog_regs {
14 	u8 cs1;
15 	u8 cs2;
16 	u16 reserve0;
17 	u32 cnt;
18 	u32 toval;
19 	u32 win;
20 };
21 
22 #ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
23 #define CONFIG_WATCHDOG_TIMEOUT_MSECS 0x1500
24 #endif
25 
26 #define REFRESH_WORD0 0xA602 /* 1st refresh word */
27 #define REFRESH_WORD1 0xB480 /* 2nd refresh word */
28 
29 #define UNLOCK_WORD0 0xC520 /* 1st unlock word */
30 #define UNLOCK_WORD1 0xD928 /* 2nd unlock word */
31 
32 #define WDGCS1_WDGE                      (1<<7)
33 #define WDGCS1_WDGUPDATE                 (1<<5)
34 
35 #define WDGCS2_FLG                       (1<<6)
36 
37 #define WDG_BUS_CLK                      (0x0)
38 #define WDG_LPO_CLK                      (0x1)
39 #define WDG_32KHZ_CLK                    (0x2)
40 #define WDG_EXT_CLK                      (0x3)
41 
42 void hw_watchdog_set_timeout(u16 val)
43 {
44 	/* setting timeout value */
45 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
46 
47 	writel(val, &wdog->toval);
48 }
49 
50 void hw_watchdog_reset(void)
51 {
52 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
53 
54 	writel(REFRESH_WORD0, &wdog->cnt);
55 	writel(REFRESH_WORD1, &wdog->cnt);
56 }
57 
58 void hw_watchdog_init(void)
59 {
60 	u8 val;
61 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
62 
63 	writel(UNLOCK_WORD0, &wdog->cnt);
64 	writel(UNLOCK_WORD1, &wdog->cnt);
65 
66 	val = readb(&wdog->cs2);
67 	val |= WDGCS2_FLG;
68 	writeb(val, &wdog->cs2);
69 
70 	hw_watchdog_set_timeout(CONFIG_WATCHDOG_TIMEOUT_MSECS);
71 	writel(0, &wdog->win);
72 
73 	writeb(WDG_LPO_CLK, &wdog->cs2);/* setting 1-kHz clock source */
74 	writeb((WDGCS1_WDGE | WDGCS1_WDGUPDATE), &wdog->cs1);/* enable counter running */
75 
76 	hw_watchdog_reset();
77 }
78 
79 void reset_cpu(ulong addr)
80 {
81 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
82 
83 	writel(UNLOCK_WORD0, &wdog->cnt);
84 	writel(UNLOCK_WORD1, &wdog->cnt);
85 
86 	hw_watchdog_set_timeout(5); /* 5ms timeout */
87 	writel(0, &wdog->win);
88 
89 	writeb(WDG_LPO_CLK, &wdog->cs2);/* setting 1-kHz clock source */
90 	writeb(WDGCS1_WDGE, &wdog->cs1);/* enable counter running */
91 
92 	hw_watchdog_reset();
93 
94 	while (1);
95 }
96