xref: /OK3568_Linux_fs/u-boot/arch/powerpc/lib/time.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun  * (C) Copyright 2000, 2001
3*4882a593Smuzhiyun  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  * SPDX-License-Identifier:	GPL-2.0+
6*4882a593Smuzhiyun  */
7*4882a593Smuzhiyun 
8*4882a593Smuzhiyun #include <common.h>
9*4882a593Smuzhiyun #include <asm/io.h>
10*4882a593Smuzhiyun 
11*4882a593Smuzhiyun /* ------------------------------------------------------------------------- */
12*4882a593Smuzhiyun 
13*4882a593Smuzhiyun /*
14*4882a593Smuzhiyun  * This function is intended for SHORT delays only.
15*4882a593Smuzhiyun  * It will overflow at around 10 seconds @ 400MHz,
16*4882a593Smuzhiyun  * or 20 seconds @ 200MHz.
17*4882a593Smuzhiyun  */
usec2ticks(unsigned long usec)18*4882a593Smuzhiyun unsigned long usec2ticks(unsigned long usec)
19*4882a593Smuzhiyun {
20*4882a593Smuzhiyun 	ulong ticks;
21*4882a593Smuzhiyun 
22*4882a593Smuzhiyun 	if (usec < 1000) {
23*4882a593Smuzhiyun 		ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
24*4882a593Smuzhiyun 	} else {
25*4882a593Smuzhiyun 		ticks = ((usec / 10) * (get_tbclk() / 100000));
26*4882a593Smuzhiyun 	}
27*4882a593Smuzhiyun 
28*4882a593Smuzhiyun 	return (ticks);
29*4882a593Smuzhiyun }
30*4882a593Smuzhiyun 
31*4882a593Smuzhiyun /* ------------------------------------------------------------------------- */
32*4882a593Smuzhiyun 
33*4882a593Smuzhiyun /*
34*4882a593Smuzhiyun  * We implement the delay by converting the delay (the number of
35*4882a593Smuzhiyun  * microseconds to wait) into a number of time base ticks; then we
36*4882a593Smuzhiyun  * watch the time base until it has incremented by that amount.
37*4882a593Smuzhiyun  */
__udelay(unsigned long usec)38*4882a593Smuzhiyun void __udelay(unsigned long usec)
39*4882a593Smuzhiyun {
40*4882a593Smuzhiyun 	ulong ticks = usec2ticks (usec);
41*4882a593Smuzhiyun 	wait_ticks (ticks);
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun 
44*4882a593Smuzhiyun /* ------------------------------------------------------------------------- */
45*4882a593Smuzhiyun #ifndef CONFIG_NAND_SPL
ticks2usec(unsigned long ticks)46*4882a593Smuzhiyun unsigned long ticks2usec(unsigned long ticks)
47*4882a593Smuzhiyun {
48*4882a593Smuzhiyun 	ulong tbclk = get_tbclk();
49*4882a593Smuzhiyun 
50*4882a593Smuzhiyun 	/* usec = ticks * 1000000 / tbclk
51*4882a593Smuzhiyun 	 * Multiplication would overflow at ~4.2e3 ticks,
52*4882a593Smuzhiyun 	 * so we break it up into
53*4882a593Smuzhiyun 	 * usec = ( ( ticks * 1000) / tbclk ) * 1000;
54*4882a593Smuzhiyun 	 */
55*4882a593Smuzhiyun 	ticks *= 1000L;
56*4882a593Smuzhiyun 	ticks /= tbclk;
57*4882a593Smuzhiyun 	ticks *= 1000L;
58*4882a593Smuzhiyun 
59*4882a593Smuzhiyun 	return ((ulong)ticks);
60*4882a593Smuzhiyun }
61*4882a593Smuzhiyun #endif
62*4882a593Smuzhiyun /* ------------------------------------------------------------------------- */
63*4882a593Smuzhiyun 
timer_init(void)64*4882a593Smuzhiyun int timer_init(void)
65*4882a593Smuzhiyun {
66*4882a593Smuzhiyun 	unsigned long temp;
67*4882a593Smuzhiyun 
68*4882a593Smuzhiyun 	/* reset */
69*4882a593Smuzhiyun 	asm volatile("li %0,0 ; mttbl %0 ; mttbu %0;"
70*4882a593Smuzhiyun 	     : "=&r"(temp) );
71*4882a593Smuzhiyun 
72*4882a593Smuzhiyun 	return (0);
73*4882a593Smuzhiyun }
74*4882a593Smuzhiyun /* ------------------------------------------------------------------------- */
75