xref: /openbmc/u-boot/arch/arm/mach-davinci/timer.c (revision dd1033e4)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2003
4  * Texas Instruments <www.ti.com>
5  *
6  * (C) Copyright 2002
7  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
8  * Marius Groeger <mgroeger@sysgo.de>
9  *
10  * (C) Copyright 2002
11  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
12  * Alex Zuepke <azu@sysgo.de>
13  *
14  * (C) Copyright 2002-2004
15  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
16  *
17  * (C) Copyright 2004
18  * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
19  *
20  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
21  */
22 
23 #include <common.h>
24 #include <asm/io.h>
25 #include <asm/arch/timer_defs.h>
26 #include <div64.h>
27 
28 DECLARE_GLOBAL_DATA_PTR;
29 
30 static struct davinci_timer * const timer =
31 	(struct davinci_timer *)CONFIG_SYS_TIMERBASE;
32 
33 #define TIMER_LOAD_VAL	0xffffffff
34 
35 #define TIM_CLK_DIV	16
36 
37 int timer_init(void)
38 {
39 	/* We are using timer34 in unchained 32-bit mode, full speed */
40 	writel(0x0, &timer->tcr);
41 	writel(0x0, &timer->tgcr);
42 	writel(0x06 | ((TIM_CLK_DIV - 1) << 8), &timer->tgcr);
43 	writel(0x0, &timer->tim34);
44 	writel(TIMER_LOAD_VAL, &timer->prd34);
45 	writel(2 << 22, &timer->tcr);
46 	gd->arch.timer_rate_hz = CONFIG_SYS_HZ_CLOCK / TIM_CLK_DIV;
47 	gd->arch.timer_reset_value = 0;
48 
49 	return(0);
50 }
51 
52 /*
53  * Get the current 64 bit timer tick count
54  */
55 unsigned long long get_ticks(void)
56 {
57 	unsigned long now = readl(&timer->tim34);
58 
59 	/* increment tbu if tbl has rolled over */
60 	if (now < gd->arch.tbl)
61 		gd->arch.tbu++;
62 	gd->arch.tbl = now;
63 
64 	return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
65 }
66 
67 ulong get_timer(ulong base)
68 {
69 	unsigned long long timer_diff;
70 
71 	timer_diff = get_ticks() - gd->arch.timer_reset_value;
72 
73 	return lldiv(timer_diff,
74 		     (gd->arch.timer_rate_hz / CONFIG_SYS_HZ)) - base;
75 }
76 
77 void __udelay(unsigned long usec)
78 {
79 	unsigned long long endtime;
80 
81 	endtime = lldiv((unsigned long long)usec * gd->arch.timer_rate_hz,
82 			1000000UL);
83 	endtime += get_ticks();
84 
85 	while (get_ticks() < endtime)
86 		;
87 }
88 
89 /*
90  * This function is derived from PowerPC code (timebase clock frequency).
91  * On ARM it returns the number of timer ticks per second.
92  */
93 ulong get_tbclk(void)
94 {
95 	return gd->arch.timer_rate_hz;
96 }
97 
98 #ifdef CONFIG_HW_WATCHDOG
99 static struct davinci_timer * const wdttimer =
100 	(struct davinci_timer *)CONFIG_SYS_WDTTIMERBASE;
101 
102 /*
103  * See prufw2.pdf for using Timer as a WDT
104  */
105 void davinci_hw_watchdog_enable(void)
106 {
107 	writel(0x0, &wdttimer->tcr);
108 	writel(0x0, &wdttimer->tgcr);
109 	/* TIMMODE = 2h */
110 	writel(0x08 | 0x03 | ((TIM_CLK_DIV - 1) << 8), &wdttimer->tgcr);
111 	writel(CONFIG_SYS_WDT_PERIOD_LOW, &wdttimer->prd12);
112 	writel(CONFIG_SYS_WDT_PERIOD_HIGH, &wdttimer->prd34);
113 	writel(2 << 22, &wdttimer->tcr);
114 	writel(0x0, &wdttimer->tim12);
115 	writel(0x0, &wdttimer->tim34);
116 	/* set WDEN bit, WDKEY 0xa5c6 */
117 	writel(0xa5c64000, &wdttimer->wdtcr);
118 	/* clear counter register */
119 	writel(0xda7e4000, &wdttimer->wdtcr);
120 }
121 
122 void davinci_hw_watchdog_reset(void)
123 {
124 	writel(0xa5c64000, &wdttimer->wdtcr);
125 	writel(0xda7e4000, &wdttimer->wdtcr);
126 }
127 #endif
128