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  * SPDX-License-Identifier:     GPL-2.0+
  10  */
  11
  12 #include <common.h>
  13 #include <asm/io.h>
  14 #include <faraday/fttmr010.h>
  15
  16 static ulong timestamp;
  17 static ulong lastdec;
  18
  19 int timer_init(void)
  20 {
  21         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
  22         unsigned int cr;
  23
  24         debug("%s()\n", __func__);
  25
  26         /* disable timers */
  27         writel(0, &tmr->cr);
  28
  29 #ifdef CONFIG_FTTMR010_EXT_CLK
  30         /* use 32768Hz oscillator for RTC, WDT, TIMER */
  31         ftpmu010_32768osc_enable();
  32 #endif
  33
  34         /* setup timer */
  35         writel(TIMER_LOAD_VAL, &tmr->timer3_load);
  36         writel(TIMER_LOAD_VAL, &tmr->timer3_counter);
  37         writel(0, &tmr->timer3_match1);
  38         writel(0, &tmr->timer3_match2);
  39
  40         /* we don't want timer to issue interrupts */
  41         writel(FTTMR010_TM3_MATCH1 |
  42                FTTMR010_TM3_MATCH2 |
  43                FTTMR010_TM3_OVERFLOW,
  44                &tmr->interrupt_mask);
  45
  46         cr = readl(&tmr->cr);
  47 #ifdef CONFIG_FTTMR010_EXT_CLK
  48         cr |= FTTMR010_TM3_CLOCK;       /* use external clock */
  49 #endif
  50         cr |= FTTMR010_TM3_ENABLE;
  51         writel(cr, &tmr->cr);
  52
  53         /* init the timestamp and lastdec value */
  54         reset_timer_masked();
  55
  56         return 0;
  57 }
  58
  59 /*
  60  * timer without interrupts
  61  */
  62
  63 /*
  64  * reset time
  65  */
  66 void reset_timer_masked(void)
  67 {
  68         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
  69
  70         /* capure current decrementer value time */
  71 #ifdef CONFIG_FTTMR010_EXT_CLK
  72         lastdec = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ);
  73 #else
  74         lastdec = readl(&tmr->timer3_counter) /
  75                         (CONFIG_SYS_CLK_FREQ / 2 / CONFIG_SYS_HZ);
  76 #endif
  77         timestamp = 0;          /* start "advancing" time stamp from 0 */
  78
  79         debug("%s(): lastdec = %lx\n", __func__, lastdec);
  80 }
  81
  82 void reset_timer(void)
  83 {
  84         debug("%s()\n", __func__);
  85         reset_timer_masked();
  86 }
  87
  88 /*
  89  * return timer ticks
  90  */
  91 ulong get_timer_masked(void)
  92 {
  93         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
  94
  95         /* current tick value */
  96 #ifdef CONFIG_FTTMR010_EXT_CLK
  97         ulong now = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ);
  98 #else
  99         ulong now = readl(&tmr->timer3_counter) /
 100                         (CONFIG_SYS_CLK_FREQ / 2 / CONFIG_SYS_HZ);
 101 #endif
 102
 103         debug("%s(): now = %lx, lastdec = %lx\n", __func__, now, lastdec);
 104
 105         if (lastdec >= now) {
 106                 /*
 107                  * normal mode (non roll)
 108                  * move stamp fordward with absoulte diff ticks
 109                  */
 110                 timestamp += lastdec - now;
 111         } else {
 112                 /*
 113                  * we have overflow of the count down timer
 114                  *
 115                  * nts = ts + ld + (TLV - now)
 116                  * ts=old stamp, ld=time that passed before passing through -1
 117                  * (TLV-now) amount of time after passing though -1
 118                  * nts = new "advancing time stamp"...it could also roll and
 119                  * cause problems.
 120                  */
 121                 timestamp += lastdec + TIMER_LOAD_VAL - now;
 122         }
 123
 124         lastdec = now;
 125
 126         debug("%s() returns %lx\n", __func__, timestamp);
 127
 128         return timestamp;
 129 }
 130
 131 /*
 132  * return difference between timer ticks and base
 133  */
 134 ulong get_timer(ulong base)
 135 {
 136         debug("%s(%lx)\n", __func__, base);
 137         return get_timer_masked() - base;
 138 }
 139
 140 void set_timer(ulong t)
 141 {
 142         debug("%s(%lx)\n", __func__, t);
 143         timestamp = t;
 144 }
 145
 146 /* delay x useconds AND preserve advance timestamp value */
 147 void __udelay(unsigned long usec)
 148 {
 149         struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
 150
 151 #ifdef CONFIG_FTTMR010_EXT_CLK
 152         long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
 153 #else
 154         long tmo = usec * ((CONFIG_SYS_CLK_FREQ / 2) / 1000) / 1000;
 155 #endif
 156         unsigned long now, last = readl(&tmr->timer3_counter);
 157
 158         debug("%s(%lu)\n", __func__, usec);
 159         while (tmo > 0) {
 160                 now = readl(&tmr->timer3_counter);
 161                 if (now > last) /* count down timer overflow */
 162                         tmo -= TIMER_LOAD_VAL + last - now;
 163                 else
 164                         tmo -= last - now;
 165                 last = now;
 166         }
 167 }
 168
 169 /*
 170  * This function is derived from PowerPC code (read timebase as long long).
 171  * On ARM it just returns the timer value.
 172  */
 173 unsigned long long get_ticks(void)
 174 {
 175         debug("%s()\n", __func__);
 176         return get_timer(0);
 177 }
 178
 179 /*
 180  * This function is derived from PowerPC code (timebase clock frequency).
 181  * On ARM it returns the number of timer ticks per second.
 182  */
 183 ulong get_tbclk(void)
 184 {
 185         debug("%s()\n", __func__);
 186 #ifdef CONFIG_FTTMR010_EXT_CLK
 187         return CONFIG_SYS_HZ;
 188 #else
 189         return CONFIG_SYS_CLK_FREQ;
 190 #endif
 191 }