1 /*
2  * (C) Copyright 2013
3  * David Feng <fenghua@phytium.com.cn>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <command.h>
10 #include <asm/system.h>
11 
12 /*
13  * Generic timer implementation of get_tbclk()
14  */
15 unsigned long get_tbclk(void)
16 {
17 	unsigned long cntfrq;
18 	asm volatile("mrs %0, cntfrq_el0" : "=r" (cntfrq));
19 	return cntfrq;
20 }
21 
22 /*
23  * Generic timer implementation of timer_read_counter()
24  */
25 unsigned long timer_read_counter(void)
26 {
27 	unsigned long cntpct;
28 #ifdef CONFIG_SYS_FSL_ERRATUM_A008585
29 	/* This erratum number needs to be confirmed to match ARM document */
30 	unsigned long temp;
31 #endif
32 	isb();
33 	asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
34 #ifdef CONFIG_SYS_FSL_ERRATUM_A008585
35 	asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
36 	while (temp != cntpct) {
37 		asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
38 		asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
39 	}
40 #endif
41 	return cntpct;
42 }
43 
44 unsigned long usec2ticks(unsigned long usec)
45 {
46 	ulong ticks;
47 	if (usec < 1000)
48 		ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
49 	else
50 		ticks = ((usec / 10) * (get_tbclk() / 100000));
51 
52 	return ticks;
53 }
54