xref: /openbmc/u-boot/arch/sh/lib/time_sh2.c (revision e8f80a5a)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2007,2008 Nobobuhiro Iwamatsu <iwamatsu@nigauri.org>
4  * Copyright (C) 2008 Renesas Solutions Corp.
5  *
6  * (C) Copyright 2003
7  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
8  */
9 
10 #include <common.h>
11 #include <asm/io.h>
12 #include <asm/processor.h>
13 
14 #define CMT_CMCSR_INIT	0x0001	/* PCLK/32 */
15 #define CMT_CMCSR_CALIB 0x0000
16 #define CMT_MAX_COUNTER (0xFFFFFFFF)
17 #define CMT_TIMER_RESET (0xFFFF)
18 
19 static vu_long cmt0_timer;
20 
cmt_timer_start(unsigned int timer)21 static void cmt_timer_start(unsigned int timer)
22 {
23 	writew(readw(CMSTR) | 0x01, CMSTR);
24 }
25 
cmt_timer_stop(unsigned int timer)26 static void cmt_timer_stop(unsigned int timer)
27 {
28 	writew(readw(CMSTR) & ~0x01, CMSTR);
29 }
30 
timer_init(void)31 int timer_init(void)
32 {
33 	cmt0_timer = 0;
34 	/* Divide clock by 32 */
35 	readw(CMCSR_0);
36 	writew(CMT_CMCSR_INIT, CMCSR_0);
37 
38 	/* User Device 0 only */
39 	cmt_timer_stop(0);
40 	writew(CMT_TIMER_RESET, CMCOR_0);
41 	cmt_timer_start(0);
42 
43 	return 0;
44 }
45 
get_ticks(void)46 unsigned long long get_ticks(void)
47 {
48 	return cmt0_timer;
49 }
50 
51 static vu_long cmcnt = 0;
get_usec(void)52 static unsigned long get_usec (void)
53 {
54 	ulong data = readw(CMCNT_0);
55 
56 	if (data >= cmcnt)
57 		cmcnt = data - cmcnt;
58 	else
59 		cmcnt = (CMT_TIMER_RESET - cmcnt) + data;
60 
61 	if ((cmt0_timer + cmcnt) > CMT_MAX_COUNTER)
62 		cmt0_timer = ((cmt0_timer + cmcnt) - CMT_MAX_COUNTER);
63 	else
64 		cmt0_timer += cmcnt;
65 
66 	cmcnt = data;
67 	return cmt0_timer;
68 }
69 
70 /* return msec */
get_timer(ulong base)71 ulong get_timer(ulong base)
72 {
73 	return (get_usec() / 1000) - base;
74 }
75 
__udelay(unsigned long usec)76 void __udelay(unsigned long usec)
77 {
78 	unsigned long end = get_usec() + usec;
79 
80 	while (get_usec() < end)
81 		continue;
82 }
83 
get_tbclk(void)84 unsigned long get_tbclk(void)
85 {
86 	return CONFIG_SH_CMT_CLK_FREQ;
87 }
88