arch/arm/cpu/tegra20-common/timer.c

   1 /*
   2  * (C) Copyright 2010,2011
   3  * NVIDIA Corporation <www.nvidia.com>
   4  *
   5  * (C) Copyright 2008
   6  * Texas Instruments
   7  *
   8  * Richard Woodruff <r-woodruff2@ti.com>
   9  * Syed Moahmmed Khasim <khasim@ti.com>
  10  *
  11  * (C) Copyright 2002
  12  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  13  * Marius Groeger <mgroeger@sysgo.de>
  14  * Alex Zuepke <azu@sysgo.de>
  15  *
  16  * (C) Copyright 2002
  17  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  18  *
  19  * See file CREDITS for list of people who contributed to this
  20  * project.
  21  *
  22  * This program is free software; you can redistribute it and/or
  23  * modify it under the terms of the GNU General Public License as
  24  * published by the Free Software Foundation; either version 2 of
  25  * the License, or (at your option) any later version.
  26  *
  27  * This program is distributed in the hope that it will be useful,
  28  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  * GNU General Public License for more details.
  31  *
  32  * You should have received a copy of the GNU General Public License
  33  * along with this program; if not, write to the Free Software
  34  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  35  * MA 02111-1307 USA
  36  */
  37
  38 #include <common.h>
  39 #include <asm/io.h>
  40 #include <asm/arch/tegra20.h>
  41 #include <asm/arch/timer.h>
  42
  43 DECLARE_GLOBAL_DATA_PTR;
  44
  45 /* counter runs at 1MHz */
  46 #define TIMER_CLK       1000000
  47 #define TIMER_LOAD_VAL  0xffffffff
  48
  49 /* timer without interrupts */
  50 ulong get_timer(ulong base)
  51 {
  52         return get_timer_masked() - base;
  53 }
  54
  55 /* delay x useconds */
  56 void __udelay(unsigned long usec)
  57 {
  58         long tmo = usec * (TIMER_CLK / 1000) / 1000;
  59         unsigned long now, last = timer_get_us();
  60
  61         while (tmo > 0) {
  62                 now = timer_get_us();
  63                 if (last > now) /* count up timer overflow */
  64                         tmo -= TIMER_LOAD_VAL - last + now;
  65                 else
  66                         tmo -= now - last;
  67                 last = now;
  68         }
  69 }
  70
  71 ulong get_timer_masked(void)
  72 {
  73         ulong now;
  74
  75         /* current tick value */
  76         now = timer_get_us() / (TIMER_CLK / CONFIG_SYS_HZ);
  77
  78         if (now >= gd->lastinc) /* normal mode (non roll) */
  79                 /* move stamp forward with absolute diff ticks */
  80                 gd->tbl += (now - gd->lastinc);
  81         else    /* we have rollover of incrementer */
  82                 gd->tbl += ((TIMER_LOAD_VAL / (TIMER_CLK / CONFIG_SYS_HZ))
  83                                 - gd->lastinc) + now;
  84         gd->lastinc = now;
  85         return gd->tbl;
  86 }
  87
  88 /*
  89  * This function is derived from PowerPC code (read timebase as long long).
  90  * On ARM it just returns the timer value.
  91  */
  92 unsigned long long get_ticks(void)
  93 {
  94         return get_timer(0);
  95 }
  96
  97 /*
  98  * This function is derived from PowerPC code (timebase clock frequency).
  99  * On ARM it returns the number of timer ticks per second.
 100  */
 101 ulong get_tbclk(void)
 102 {
 103         return CONFIG_SYS_HZ;
 104 }
 105
 106 unsigned long timer_get_us(void)
 107 {
 108         struct timerus *timer_base = (struct timerus *)NV_PA_TMRUS_BASE;
 109
 110         return readl(&timer_base->cntr_1us);
 111 }