package/boot/uboot-oxnas/src/arch/arm/cpu/arm1136/nas782x/timer.c

   1 /*
   2  * (C) Copyright 2004
   3  * Texas Instruments
   4  * Richard Woodruff <r-woodruff2@ti.com>
   5  *
   6  * (C) Copyright 2002
   7  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   8  * Marius Groeger <mgroeger@sysgo.de>
   9  * Alex Zuepke <azu@sysgo.de>
  10  *
  11  * (C) Copyright 2002
  12  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  13  *
  14  * See file CREDITS for list of people who contributed to this
  15  * project.
  16  *
  17  * This program is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU General Public License as
  19  * published by the Free Software Foundation; either version 2 of
  20  * the License, or (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program; if not, write to the Free Software
  29  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  30  * MA 02111-1307 USA
  31  */
  32
  33 #include <common.h>
  34 #include <asm/io.h>
  35
  36 #define TIMER_CLOCK     (CONFIG_SYS_CLK_FREQ / (1 << (CONFIG_TIMER_PRESCALE * 4)))
  37 #define TIMER_LOAD_VAL 0xFFFFFF
  38
  39 /* macro to read the 32 bit timer */
  40 #define READ_TIMER      (TIMER_LOAD_VAL - readl(CONFIG_SYS_TIMERBASE + TIMER_CURR)) \
  41                         / (TIMER_CLOCK / CONFIG_SYS_HZ)
  42
  43 #define READ_TIMER_HW   (TIMER_LOAD_VAL - readl(CONFIG_SYS_TIMERBASE + TIMER_CURR))
  44
  45 DECLARE_GLOBAL_DATA_PTR;
  46
  47 int timer_init (void)
  48 {
  49         int32_t val;
  50
  51         /* Start the counter ticking up */
  52         writel(TIMER_LOAD_VAL, CONFIG_SYS_TIMERBASE + TIMER_LOAD);      /* reload value on overflow*/
  53
  54         val = (CONFIG_TIMER_PRESCALE << TIMER_PRESCALE_SHIFT) |
  55                         (TIMER_MODE_PERIODIC << TIMER_MODE_SHIFT) |
  56                         (TIMER_ENABLE << TIMER_ENABLE_SHIFT);           /* mask to enable timer*/
  57         writel(val, CONFIG_SYS_TIMERBASE + TIMER_CTRL); /* start timer */
  58
  59         /* reset time */
  60         gd->arch.lastinc = READ_TIMER;  /* capture current incrementer value */
  61         gd->arch.tbl = 0;               /* start "advancing" time stamp */
  62
  63         return(0);
  64 }
  65 /*
  66  * timer without interrupts
  67  */
  68 ulong get_timer (ulong base)
  69 {
  70         return get_timer_masked () - base;
  71 }
  72
  73 /* delay x useconds AND preserve advance timestamp value */
  74 void __udelay (unsigned long usec)
  75 {
  76         ulong tmo, tmp;
  77
  78         if (usec > 100000) {            /* if "big" number, spread normalization to seconds */
  79                 tmo = usec / 1000;      /* start to normalize for usec to ticks per sec */
  80                 tmo *= CONFIG_SYS_HZ;   /* find number of "ticks" to wait to achieve target */
  81                 tmo /= 1000;            /* finish normalize. */
  82
  83                 tmp = get_timer (0);            /* get current timestamp */
  84                 while (get_timer (tmp) < tmo)/* loop till event */
  85                         /*NOP*/;
  86         } else {                        /* else small number, convert to hw ticks */
  87                 tmo = usec * (TIMER_CLOCK / 1000) / 1000;
  88                 /* timeout is no more than 0.1s, and the hw timer will roll over at most once */
  89                 tmp = READ_TIMER_HW;
  90                 while (((READ_TIMER_HW -tmp) & TIMER_LOAD_VAL) < tmo)/* loop till event */
  91                         /*NOP*/;
  92         }
  93 }
  94
  95 ulong get_timer_masked (void)
  96 {
  97         ulong now = READ_TIMER;         /* current tick value */
  98
  99         if (now >= gd->arch.lastinc) {          /* normal mode (non roll) */
 100                 /* move stamp fordward with absoulte diff ticks */
 101                 gd->arch.tbl += (now - gd->arch.lastinc);
 102         } else {
 103                 /* we have rollover of incrementer */
 104                 gd->arch.tbl += ((TIMER_LOAD_VAL / (TIMER_CLOCK / CONFIG_SYS_HZ))
 105                                  - gd->arch.lastinc) + now;
 106         }
 107         gd->arch.lastinc = now;
 108         return gd->arch.tbl;
 109 }
 110
 111
 112 /*
 113  * This function is derived from PowerPC code (read timebase as long long).
 114  * On ARM it just returns the timer value.
 115  */
 116 unsigned long long get_ticks(void)
 117 {
 118         return get_timer(0);
 119 }
 120 /*
 121  * This function is derived from PowerPC code (timebase clock frequency).
 122  * On ARM it returns the number of timer ticks per second.
 123  */
 124 ulong get_tbclk (void)
 125 {
 126         ulong tbclk;
 127         tbclk = CONFIG_SYS_HZ;
 128         return tbclk;
 129 }