arch/arm/cpu/pxa/timer.c

   1 /*
   2  * Marvell PXA2xx/3xx timer driver
   3  *
   4  * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
   5  *
   6  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  */
  24
  25 #include <asm/arch/pxa-regs.h>
  26 #include <asm/io.h>
  27 #include <common.h>
  28 #include <div64.h>
  29
  30 DECLARE_GLOBAL_DATA_PTR;
  31
  32 #define TIMER_LOAD_VAL  0xffffffff
  33
  34 #define timestamp       (gd->tbl)
  35 #define lastinc         (gd->lastinc)
  36
  37 #if defined(CONFIG_CPU_PXA27X) || defined(CONFIG_CPU_MONAHANS)
  38 #define TIMER_FREQ_HZ   3250000
  39 #elif defined(CONFIG_CPU_PXA25X)
  40 #define TIMER_FREQ_HZ   3686400
  41 #else
  42 #error "Timer frequency unknown - please config PXA CPU type"
  43 #endif
  44
  45 static unsigned long long tick_to_time(unsigned long long tick)
  46 {
  47         return tick * CONFIG_SYS_HZ / TIMER_FREQ_HZ;
  48 }
  49
  50 static unsigned long long us_to_tick(unsigned long long us)
  51 {
  52         return (us * TIMER_FREQ_HZ) / 1000000;
  53 }
  54
  55 int timer_init(void)
  56 {
  57         writel(0, OSCR);
  58         return 0;
  59 }
  60
  61 unsigned long long get_ticks(void)
  62 {
  63         /* Current tick value */
  64         uint32_t now = readl(OSCR);
  65
  66         if (now >= lastinc) {
  67                 /*
  68                  * Normal mode (non roll)
  69                  * Move stamp forward with absolute diff ticks
  70                  */
  71                 timestamp += (now - lastinc);
  72         } else {
  73                 /* We have rollover of incrementer */
  74                 timestamp += (TIMER_LOAD_VAL - lastinc) + now;
  75         }
  76
  77         lastinc = now;
  78         return timestamp;
  79 }
  80
  81 ulong get_timer(ulong base)
  82 {
  83         return tick_to_time(get_ticks()) - base;
  84 }
  85
  86 void __udelay(unsigned long usec)
  87 {
  88         unsigned long long tmp;
  89         ulong tmo;
  90
  91         tmo = us_to_tick(usec);
  92         tmp = get_ticks() + tmo;        /* get current timestamp */
  93
  94         while (get_ticks() < tmp)       /* loop till event */
  95                  /*NOP*/;
  96 }
  97
  98 ulong get_tbclk(void)
  99 {
 100         return TIMER_FREQ_HZ;
 101 }