arch/arm/cpu/ixp/timer.c

   1 /*
   2  * (C) Copyright 2010
   3  * Michael Schwingen, michael@schwingen.org
   4  *
   5  * (C) Copyright 2006
   6  * Stefan Roese, DENX Software Engineering, sr@denx.de.
   7  *
   8  * (C) Copyright 2002
   9  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  10  * Marius Groeger <mgroeger@sysgo.de>
  11  *
  12  * (C) Copyright 2002
  13  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  14  * Alex Zuepke <azu@sysgo.de>
  15  *
  16  * See file CREDITS for list of people who contributed to this
  17  * project.
  18  *
  19  * This program is free software; you can redistribute it and/or
  20  * modify it under the terms of the GNU General Public License as
  21  * published by the Free Software Foundation; either version 2 of
  22  * the License, or (at your option) any later version.
  23  *
  24  * This program is distributed in the hope that it will be useful,
  25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  * GNU General Public License for more details.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * along with this program; if not, write to the Free Software
  31  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  32  * MA 02111-1307 USA
  33  */
  34
  35 #include <common.h>
  36 #include <asm/arch/ixp425.h>
  37 #include <asm/io.h>
  38 #include <div64.h>
  39
  40 DECLARE_GLOBAL_DATA_PTR;
  41
  42 /*
  43  * The IXP42x time-stamp timer runs at 2*OSC_IN (66.666MHz when using a
  44  * 33.333MHz crystal).
  45  */
  46 static inline unsigned long long tick_to_time(unsigned long long tick)
  47 {
  48         tick *= CONFIG_SYS_HZ;
  49         do_div(tick, CONFIG_IXP425_TIMER_CLK);
  50         return tick;
  51 }
  52
  53 static inline unsigned long long time_to_tick(unsigned long long time)
  54 {
  55         time *= CONFIG_IXP425_TIMER_CLK;
  56         do_div(time, CONFIG_SYS_HZ);
  57         return time;
  58 }
  59
  60 static inline unsigned long long us_to_tick(unsigned long long us)
  61 {
  62         us = us * CONFIG_IXP425_TIMER_CLK + 999999;
  63         do_div(us, 1000000);
  64         return us;
  65 }
  66
  67 unsigned long long get_ticks(void)
  68 {
  69         ulong now = readl(IXP425_OSTS_B);
  70
  71         if (readl(IXP425_OSST) & IXP425_OSST_TIMER_TS_PEND) {
  72                 /* rollover of timestamp timer register */
  73                 gd->timestamp += (0xFFFFFFFF - gd->lastinc) + now + 1;
  74                 writel(IXP425_OSST_TIMER_TS_PEND, IXP425_OSST);
  75         } else {
  76                 /* move stamp forward with absolut diff ticks */
  77                 gd->timestamp += (now - gd->lastinc);
  78         }
  79         gd->lastinc = now;
  80         return gd->timestamp;
  81 }
  82
  83
  84 void reset_timer_masked(void)
  85 {
  86         /* capture current timestamp counter */
  87         gd->lastinc = readl(IXP425_OSTS_B);
  88         /* start "advancing" time stamp from 0 */
  89         gd->timestamp = 0;
  90 }
  91
  92 ulong get_timer_masked(void)
  93 {
  94         return tick_to_time(get_ticks());
  95 }
  96
  97 ulong get_timer(ulong base)
  98 {
  99         return get_timer_masked() - base;
 100 }
 101
 102 /* delay x useconds AND preserve advance timestamp value */
 103 void __udelay(unsigned long usec)
 104 {
 105         unsigned long long tmp;
 106
 107         tmp = get_ticks() + us_to_tick(usec);
 108
 109         while (get_ticks() < tmp)
 110                 ;
 111 }
 112
 113 int timer_init(void)
 114 {
 115         writel(IXP425_OSST_TIMER_TS_PEND, IXP425_OSST);
 116         return 0;
 117 }