arch/arm/cpu/pxa/timer.c

   1 /*
   2  * (C) Copyright 2002
   3  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   4  * Marius Groeger <mgroeger@sysgo.de>
   5  *
   6  * (C) Copyright 2002
   7  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   8  * Alex Zuepke <azu@sysgo.de>
   9  *
  10  * See file CREDITS for list of people who contributed to this
  11  * project.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License as
  15  * published by the Free Software Foundation; either version 2 of
  16  * the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  26  * MA 02111-1307 USA
  27  */
  28
  29 #include <asm/arch/pxa-regs.h>
  30 #include <asm/io.h>
  31 #include <common.h>
  32 #include <div64.h>
  33
  34 #ifdef CONFIG_USE_IRQ
  35 #error: interrupts not implemented yet
  36 #endif
  37
  38 #if defined(CONFIG_PXA27X) || defined(CONFIG_CPU_MONAHANS)
  39 #define TIMER_FREQ_HZ 3250000
  40 #elif defined(CONFIG_PXA250)
  41 #define TIMER_FREQ_HZ 3686400
  42 #else
  43 #error "Timer frequency unknown - please config PXA CPU type"
  44 #endif
  45
  46 static inline unsigned long long tick_to_time(unsigned long long tick)
  47 {
  48         tick *= CONFIG_SYS_HZ;
  49         do_div(tick, TIMER_FREQ_HZ);
  50         return tick;
  51 }
  52
  53 static inline unsigned long long us_to_tick(unsigned long long us)
  54 {
  55         us = us * TIMER_FREQ_HZ + 999999;
  56         do_div(us, 1000000);
  57         return us;
  58 }
  59
  60 int timer_init (void)
  61 {
  62         reset_timer();
  63
  64         return 0;
  65 }
  66
  67 void reset_timer (void)
  68 {
  69         reset_timer_masked ();
  70 }
  71
  72 ulong get_timer (ulong base)
  73 {
  74         return get_timer_masked () - base;
  75 }
  76
  77 void __udelay (unsigned long usec)
  78 {
  79         udelay_masked (usec);
  80 }
  81
  82
  83 void reset_timer_masked (void)
  84 {
  85         writel(0, OSCR);
  86 }
  87
  88 ulong get_timer_masked (void)
  89 {
  90         return tick_to_time(get_ticks());
  91 }
  92
  93 void udelay_masked (unsigned long usec)
  94 {
  95         unsigned long long tmp;
  96         ulong tmo;
  97
  98         tmo = us_to_tick(usec);
  99         tmp = get_ticks() + tmo;        /* get current timestamp */
 100
 101         while (get_ticks() < tmp)       /* loop till event */
 102                  /*NOP*/;
 103
 104 }
 105
 106 /*
 107  * This function is derived from PowerPC code (read timebase as long long).
 108  * On ARM it just returns the timer value.
 109  */
 110 unsigned long long get_ticks(void)
 111 {
 112         return readl(OSCR);
 113 }
 114
 115 /*
 116  * This function is derived from PowerPC code (timebase clock frequency).
 117  * On ARM it returns the number of timer ticks per second.
 118  */
 119 ulong get_tbclk (void)
 120 {
 121         ulong tbclk;
 122         tbclk = TIMER_FREQ_HZ;
 123         return tbclk;
 124 }