xref: /openbmc/u-boot/drivers/watchdog/ulp_wdog.c (revision baefb63a)
1 /*
2  * Copyright (C) 2016 Freescale Semiconductor, Inc.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <asm/io.h>
9 #include <asm/arch/imx-regs.h>
10 
11 /*
12  * MX7ULP WDOG Register Map
13  */
14 struct wdog_regs {
15 	u8 cs1;
16 	u8 cs2;
17 	u16 reserve0;
18 	u32 cnt;
19 	u32 toval;
20 	u32 win;
21 };
22 
23 #ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
24 #define CONFIG_WATCHDOG_TIMEOUT_MSECS 0x1500
25 #endif
26 
27 #define REFRESH_WORD0 0xA602 /* 1st refresh word */
28 #define REFRESH_WORD1 0xB480 /* 2nd refresh word */
29 
30 #define UNLOCK_WORD0 0xC520 /* 1st unlock word */
31 #define UNLOCK_WORD1 0xD928 /* 2nd unlock word */
32 
33 #define WDGCS1_WDGE                      (1<<7)
34 #define WDGCS1_WDGUPDATE                 (1<<5)
35 
36 #define WDGCS2_FLG                       (1<<6)
37 
38 #define WDG_BUS_CLK                      (0x0)
39 #define WDG_LPO_CLK                      (0x1)
40 #define WDG_32KHZ_CLK                    (0x2)
41 #define WDG_EXT_CLK                      (0x3)
42 
43 DECLARE_GLOBAL_DATA_PTR;
44 
45 void hw_watchdog_set_timeout(u16 val)
46 {
47 	/* setting timeout value */
48 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
49 
50 	writel(val, &wdog->toval);
51 }
52 
53 void hw_watchdog_reset(void)
54 {
55 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
56 
57 	writel(REFRESH_WORD0, &wdog->cnt);
58 	writel(REFRESH_WORD1, &wdog->cnt);
59 }
60 
61 void hw_watchdog_init(void)
62 {
63 	u8 val;
64 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
65 
66 	writel(UNLOCK_WORD0, &wdog->cnt);
67 	writel(UNLOCK_WORD1, &wdog->cnt);
68 
69 	val = readb(&wdog->cs2);
70 	val |= WDGCS2_FLG;
71 	writeb(val, &wdog->cs2);
72 
73 	hw_watchdog_set_timeout(CONFIG_WATCHDOG_TIMEOUT_MSECS);
74 	writel(0, &wdog->win);
75 
76 	writeb(WDG_LPO_CLK, &wdog->cs2);/* setting 1-kHz clock source */
77 	writeb((WDGCS1_WDGE | WDGCS1_WDGUPDATE), &wdog->cs1);/* enable counter running */
78 
79 	hw_watchdog_reset();
80 }
81 
82 void reset_cpu(ulong addr)
83 {
84 	struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
85 
86 	writel(UNLOCK_WORD0, &wdog->cnt);
87 	writel(UNLOCK_WORD1, &wdog->cnt);
88 
89 	hw_watchdog_set_timeout(5); /* 5ms timeout */
90 	writel(0, &wdog->win);
91 
92 	writeb(WDG_LPO_CLK, &wdog->cs2);/* setting 1-kHz clock source */
93 	writeb(WDGCS1_WDGE, &wdog->cs1);/* enable counter running */
94 
95 	hw_watchdog_reset();
96 
97 	while (1);
98 }
99