arch/nds32/cpu/n1213/ag101/timer.c

   1 /*
   2  * (C) Copyright 2009 Faraday Technology
   3  * Po-Yu Chuang <ratbert@faraday-tech.com>
   4  *
   5  * Copyright (C) 2011 Andes Technology Corporation
   6  * Shawn Lin, Andes Technology Corporation <nobuhiro@andestech.com>
   7  * Macpaul Lin, Andes Technology Corporation <macpaul@andestech.com>
   8  *
   9  * See file CREDITS for list of people who contributed to this
  10  * project.
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  25  */
  26
  27 #include <common.h>
  28 #include <asm/io.h>
  29 #include <faraday/fttmr010.h>
  30
  31 static ulong timestamp;
  32 static ulong lastdec;
  33
  34 int timer_init(void)
  35 {
  36         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
  37         unsigned int cr;
  38
  39         debug("%s()\n", __func__);
  40
  41         /* disable timers */
  42         writel(0, &tmr->cr);
  43
  44 #ifdef CONFIG_FTTMR010_EXT_CLK
  45         /* use 32768Hz oscillator for RTC, WDT, TIMER */
  46         ftpmu010_32768osc_enable();
  47 #endif
  48
  49         /* setup timer */
  50         writel(TIMER_LOAD_VAL, &tmr->timer3_load);
  51         writel(TIMER_LOAD_VAL, &tmr->timer3_counter);
  52         writel(0, &tmr->timer3_match1);
  53         writel(0, &tmr->timer3_match2);
  54
  55         /* we don't want timer to issue interrupts */
  56         writel(FTTMR010_TM3_MATCH1 |
  57                FTTMR010_TM3_MATCH2 |
  58                FTTMR010_TM3_OVERFLOW,
  59                &tmr->interrupt_mask);
  60
  61         cr = readl(&tmr->cr);
  62 #ifdef CONFIG_FTTMR010_EXT_CLK
  63         cr |= FTTMR010_TM3_CLOCK;       /* use external clock */
  64 #endif
  65         cr |= FTTMR010_TM3_ENABLE;
  66         writel(cr, &tmr->cr);
  67
  68         /* init the timestamp and lastdec value */
  69         reset_timer_masked();
  70
  71         return 0;
  72 }
  73
  74 /*
  75  * timer without interrupts
  76  */
  77
  78 /*
  79  * reset time
  80  */
  81 void reset_timer_masked(void)
  82 {
  83         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
  84
  85         /* capure current decrementer value time */
  86 #ifdef CONFIG_FTTMR010_EXT_CLK
  87         lastdec = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ);
  88 #else
  89         lastdec = readl(&tmr->timer3_counter) / (CONFIG_SYS_CLK_FREQ / 2);
  90 #endif
  91         timestamp = 0;          /* start "advancing" time stamp from 0 */
  92
  93         debug("%s(): lastdec = %lx\n", __func__, lastdec);
  94 }
  95
  96 void reset_timer(void)
  97 {
  98         debug("%s()\n", __func__);
  99         reset_timer_masked();
 100 }
 101
 102 /*
 103  * return timer ticks
 104  */
 105 ulong get_timer_masked(void)
 106 {
 107         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
 108
 109         /* current tick value */
 110 #ifdef CONFIG_FTTMR010_EXT_CLK
 111         ulong now = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ);
 112 #else
 113         ulong now = readl(&tmr->timer3_counter) / \
 114                         (CONFIG_SYS_CLK_FREQ / 2 / 1024);
 115 #endif
 116
 117         debug("%s(): now = %lx, lastdec = %lx\n", __func__, now, lastdec);
 118
 119         if (lastdec >= now) {
 120                 /*
 121                  * normal mode (non roll)
 122                  * move stamp fordward with absoulte diff ticks
 123                  */
 124                 timestamp += lastdec - now;
 125         } else {
 126                 /*
 127                  * we have overflow of the count down timer
 128                  *
 129                  * nts = ts + ld + (TLV - now)
 130                  * ts=old stamp, ld=time that passed before passing through -1
 131                  * (TLV-now) amount of time after passing though -1
 132                  * nts = new "advancing time stamp"...it could also roll and
 133                  * cause problems.
 134                  */
 135                 timestamp += lastdec + TIMER_LOAD_VAL - now;
 136         }
 137
 138         lastdec = now;
 139
 140         debug("%s() returns %lx\n", __func__, timestamp);
 141
 142         return timestamp;
 143 }
 144
 145 /*
 146  * return difference between timer ticks and base
 147  */
 148 ulong get_timer(ulong base)
 149 {
 150         debug("%s(%lx)\n", __func__, base);
 151         return get_timer_masked() - base;
 152 }
 153
 154 void set_timer(ulong t)
 155 {
 156         debug("%s(%lx)\n", __func__, t);
 157         timestamp = t;
 158 }
 159
 160 /* delay x useconds AND preserve advance timestamp value */
 161 void __udelay(unsigned long usec)
 162 {
 163         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
 164
 165 #ifdef CONFIG_FTTMR010_EXT_CLK
 166         long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
 167 #else
 168         long tmo = usec * ((CONFIG_SYS_CLK_FREQ / 2) / 1000) / 1000;
 169 #endif
 170         unsigned long now, last = readl(&tmr->timer3_counter);
 171
 172         debug("%s(%lu)\n", __func__, usec);
 173         while (tmo > 0) {
 174                 now = readl(&tmr->timer3_counter);
 175                 if (now > last) /* count down timer overflow */
 176                         tmo -= TIMER_LOAD_VAL + last - now;
 177                 else
 178                         tmo -= last - now;
 179                 last = now;
 180         }
 181 }
 182
 183 /*
 184  * This function is derived from PowerPC code (read timebase as long long).
 185  * On ARM it just returns the timer value.
 186  */
 187 unsigned long long get_ticks(void)
 188 {
 189         debug("%s()\n", __func__);
 190         return get_timer(0);
 191 }
 192
 193 /*
 194  * This function is derived from PowerPC code (timebase clock frequency).
 195  * On ARM it returns the number of timer ticks per second.
 196  */
 197 ulong get_tbclk(void)
 198 {
 199         debug("%s()\n", __func__);
 200 #ifdef CONFIG_FTTMR010_EXT_CLK
 201         return CONFIG_SYS_HZ;
 202 #else
 203         return CONFIG_SYS_CLK_FREQ;
 204 #endif
 205 }