xref: /openbmc/u-boot/arch/sh/lib/time_sh2.c (revision 425faf74)
1  /*
2   * Copyright (C) 2007,2008 Nobobuhiro Iwamatsu <iwamatsu@nigauri.org>
3   * Copyright (C) 2008 Renesas Solutions Corp.
4   *
5   * (C) Copyright 2003
6   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
7   *
8   * SPDX-License-Identifier:	GPL-2.0+
9   */
10  
11  #include <common.h>
12  #include <asm/io.h>
13  #include <asm/processor.h>
14  
15  #define CMT_CMCSR_INIT	0x0001	/* PCLK/32 */
16  #define CMT_CMCSR_CALIB 0x0000
17  #define CMT_MAX_COUNTER (0xFFFFFFFF)
18  #define CMT_TIMER_RESET (0xFFFF)
19  
20  static vu_long cmt0_timer;
21  
22  static void cmt_timer_start(unsigned int timer)
23  {
24  	writew(readw(CMSTR) | 0x01, CMSTR);
25  }
26  
27  static void cmt_timer_stop(unsigned int timer)
28  {
29  	writew(readw(CMSTR) & ~0x01, CMSTR);
30  }
31  
32  int timer_init(void)
33  {
34  	cmt0_timer = 0;
35  	/* Divide clock by 32 */
36  	readw(CMCSR_0);
37  	writew(CMT_CMCSR_INIT, CMCSR_0);
38  
39  	/* User Device 0 only */
40  	cmt_timer_stop(0);
41  	writew(CMT_TIMER_RESET, CMCOR_0);
42  	cmt_timer_start(0);
43  
44  	return 0;
45  }
46  
47  unsigned long long get_ticks(void)
48  {
49  	return cmt0_timer;
50  }
51  
52  static vu_long cmcnt = 0;
53  static unsigned long get_usec (void)
54  {
55  	ulong data = readw(CMCNT_0);
56  
57  	if (data >= cmcnt)
58  		cmcnt = data - cmcnt;
59  	else
60  		cmcnt = (CMT_TIMER_RESET - cmcnt) + data;
61  
62  	if ((cmt0_timer + cmcnt) > CMT_MAX_COUNTER)
63  		cmt0_timer = ((cmt0_timer + cmcnt) - CMT_MAX_COUNTER);
64  	else
65  		cmt0_timer += cmcnt;
66  
67  	cmcnt = data;
68  	return cmt0_timer;
69  }
70  
71  /* return msec */
72  ulong get_timer(ulong base)
73  {
74  	return (get_usec() / 1000) - base;
75  }
76  
77  void __udelay(unsigned long usec)
78  {
79  	unsigned long end = get_usec() + usec;
80  
81  	while (get_usec() < end)
82  		continue;
83  }
84  
85  unsigned long get_tbclk(void)
86  {
87  	return CONFIG_SYS_HZ;
88  }
89