1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2008
4  * Texas Instruments
5  *
6  * Richard Woodruff <r-woodruff2@ti.com>
7  * Syed Moahmmed Khasim <khasim@ti.com>
8  *
9  * (C) Copyright 2002
10  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
11  * Marius Groeger <mgroeger@sysgo.de>
12  * Alex Zuepke <azu@sysgo.de>
13  *
14  * (C) Copyright 2002
15  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
16  */
17 
18 #include <common.h>
19 #include <init.h>
20 #include <time.h>
21 #include <asm/global_data.h>
22 #include <asm/io.h>
23 #include <asm/arch/cpu.h>
24 #include <asm/arch/clock.h>
25 #include <linux/delay.h>
26 
27 DECLARE_GLOBAL_DATA_PTR;
28 
29 static struct gptimer *timer_base = (struct gptimer *)CONFIG_SYS_TIMERBASE;
30 static ulong get_timer_masked(void);
31 
32 /*
33  * Nothing really to do with interrupts, just starts up a counter.
34  */
35 
36 #define TIMER_CLOCK		(V_SCLK / (2 << CONFIG_SYS_PTV))
37 #define TIMER_OVERFLOW_VAL	0xffffffff
38 #define TIMER_LOAD_VAL		0
39 
timer_init(void)40 int timer_init(void)
41 {
42 	/* start the counter ticking up, reload value on overflow */
43 	writel(TIMER_LOAD_VAL, &timer_base->tldr);
44 	/* enable timer */
45 	writel((CONFIG_SYS_PTV << 2) | TCLR_PRE | TCLR_AR | TCLR_ST,
46 		&timer_base->tclr);
47 
48 	return 0;
49 }
50 
51 /*
52  * timer without interrupts
53  */
get_timer(ulong base)54 ulong get_timer(ulong base)
55 {
56 	return get_timer_masked() - base;
57 }
58 
59 /* delay x useconds */
__udelay(unsigned long usec)60 void __udelay(unsigned long usec)
61 {
62 	long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
63 	unsigned long now, last = readl(&timer_base->tcrr);
64 
65 	while (tmo > 0) {
66 		now = readl(&timer_base->tcrr);
67 		if (last > now) /* count up timer overflow */
68 			tmo -= TIMER_OVERFLOW_VAL - last + now + 1;
69 		else
70 			tmo -= now - last;
71 		last = now;
72 	}
73 }
74 
get_timer_masked(void)75 static ulong get_timer_masked(void)
76 {
77 	/* current tick value */
78 	ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
79 
80 	if (now >= gd->arch.lastinc) {	/* normal mode (non roll) */
81 		/* move stamp fordward with absoulte diff ticks */
82 		gd->arch.tbl += (now - gd->arch.lastinc);
83 	} else {	/* we have rollover of incrementer */
84 		gd->arch.tbl += ((TIMER_OVERFLOW_VAL / (TIMER_CLOCK /
85 				CONFIG_SYS_HZ)) - gd->arch.lastinc) + now;
86 	}
87 	gd->arch.lastinc = now;
88 	return gd->arch.tbl;
89 }
90 
91 /*
92  * This function is derived from PowerPC code (read timebase as long long).
93  * On ARM it just returns the timer value.
94  */
get_ticks(void)95 unsigned long long get_ticks(void)
96 {
97 	return get_timer(0);
98 }
99 
100 /*
101  * This function is derived from PowerPC code (timebase clock frequency).
102  * On ARM it returns the number of timer ticks per second.
103  */
get_tbclk(void)104 ulong get_tbclk(void)
105 {
106 	return CONFIG_SYS_HZ;
107 }
108