arch/arm/cpu/arm926ejs/mb86r0x/timer.c

   1 /*
   2  * (C) Copyright 2007-2008
   3  * Stelian Pop <stelian@popies.net>
   4  * Lead Tech Design <www.leadtechdesign.com>
   5  *
   6  * (C) Copyright 2010
   7  * Matthias Weisser, Graf-Syteco <weisserm@arcor.de>
   8  *
   9  * SPDX-License-Identifier:     GPL-2.0+
  10  */
  11
  12 #include <div64.h>
  13 #include <common.h>
  14 #include <asm/io.h>
  15 #include <asm/arch/hardware.h>
  16
  17 #define TIMER_LOAD_VAL  0xffffffff
  18 #define TIMER_FREQ      (CONFIG_MB86R0x_IOCLK  / 256)
  19
  20 DECLARE_GLOBAL_DATA_PTR;
  21
  22 #define timestamp gd->arch.tbl
  23 #define lastdec gd->arch.lastinc
  24
  25 static inline unsigned long long tick_to_time(unsigned long long tick)
  26 {
  27         tick *= CONFIG_SYS_HZ;
  28         do_div(tick, TIMER_FREQ);
  29
  30         return tick;
  31 }
  32
  33 static inline unsigned long long usec_to_tick(unsigned long long usec)
  34 {
  35         usec *= TIMER_FREQ;
  36         do_div(usec, 1000000);
  37
  38         return usec;
  39 }
  40
  41 /* nothing really to do with interrupts, just starts up a counter. */
  42 int timer_init(void)
  43 {
  44         struct mb86r0x_timer * timer = (struct mb86r0x_timer *)
  45                                         MB86R0x_TIMER_BASE;
  46         ulong ctrl = readl(&timer->control);
  47
  48         writel(TIMER_LOAD_VAL, &timer->load);
  49
  50         ctrl |= MB86R0x_TIMER_ENABLE | MB86R0x_TIMER_PRS_8S |
  51                 MB86R0x_TIMER_SIZE_32;
  52
  53         writel(ctrl, &timer->control);
  54
  55         /* capture current value time */
  56         lastdec = readl(&timer->value);
  57         timestamp = 0; /* start "advancing" time stamp from 0 */
  58
  59         return 0;
  60 }
  61
  62 /*
  63  * timer without interrupts
  64  */
  65 unsigned long long get_ticks(void)
  66 {
  67         struct mb86r0x_timer * timer = (struct mb86r0x_timer *)
  68                                         MB86R0x_TIMER_BASE;
  69         ulong now = readl(&timer->value);
  70
  71         if (now <= lastdec) {
  72                 /* normal mode (non roll) */
  73                 /* move stamp forward with absolut diff ticks */
  74                 timestamp += lastdec - now;
  75         } else {
  76                 /* we have rollover of incrementer */
  77                 timestamp += lastdec + TIMER_LOAD_VAL - now;
  78         }
  79         lastdec = now;
  80         return timestamp;
  81 }
  82
  83 ulong get_timer_masked(void)
  84 {
  85         return tick_to_time(get_ticks());
  86 }
  87
  88 void __udelay(unsigned long usec)
  89 {
  90         unsigned long long tmp;
  91         ulong tmo;
  92
  93         tmo = usec_to_tick(usec);
  94         tmp = get_ticks();                      /* get current timestamp */
  95
  96         while ((get_ticks() - tmp) < tmo)       /* loop till event */
  97                  /*NOP*/;
  98 }
  99
 100 ulong get_timer(ulong base)
 101 {
 102         return get_timer_masked() - base;
 103 }
 104
 105 /*
 106  * This function is derived from PowerPC code (timebase clock frequency).
 107  * On ARM it returns the number of timer ticks per second.
 108  */
 109 ulong get_tbclk(void)
 110 {
 111         ulong tbclk;
 112
 113         tbclk = TIMER_FREQ;
 114         return tbclk;
 115 }