arch/sh/lib/time_sh2.c

   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 }