arch/arm/cpu/armv7/vf610/timer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright 2013 Freescale Semiconductor, Inc.
   4  */
   5
   6 #include <common.h>
   7 #include <init.h>
   8 #include <time.h>
   9 #include <asm/io.h>
  10 #include <div64.h>
  11 #include <asm/arch/imx-regs.h>
  12 #include <asm/arch/clock.h>
  13 #include <linux/delay.h>
  14
  15 static struct pit_reg *cur_pit = (struct pit_reg *)PIT_BASE_ADDR;
  16
  17 DECLARE_GLOBAL_DATA_PTR;
  18
  19 #define TIMER_LOAD_VAL  0xffffffff
  20
  21 static inline unsigned long long tick_to_time(unsigned long long tick)
  22 {
  23         tick *= CONFIG_SYS_HZ;
  24         do_div(tick, mxc_get_clock(MXC_IPG_CLK));
  25
  26         return tick;
  27 }
  28
  29 static inline unsigned long long us_to_tick(unsigned long long usec)
  30 {
  31         usec = usec * mxc_get_clock(MXC_IPG_CLK)  + 999999;
  32         do_div(usec, 1000000);
  33
  34         return usec;
  35 }
  36
  37 int timer_init(void)
  38 {
  39         __raw_writel(0, &cur_pit->mcr);
  40
  41         __raw_writel(TIMER_LOAD_VAL, &cur_pit->ldval1);
  42         __raw_writel(0, &cur_pit->tctrl1);
  43         __raw_writel(1, &cur_pit->tctrl1);
  44
  45         gd->arch.tbl = 0;
  46         gd->arch.tbu = 0;
  47
  48         return 0;
  49 }
  50
  51 unsigned long long get_ticks(void)
  52 {
  53         ulong now = TIMER_LOAD_VAL - __raw_readl(&cur_pit->cval1);
  54
  55         /* increment tbu if tbl has rolled over */
  56         if (now < gd->arch.tbl)
  57                 gd->arch.tbu++;
  58         gd->arch.tbl = now;
  59
  60         return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
  61 }
  62
  63 ulong get_timer(ulong base)
  64 {
  65         return tick_to_time(get_ticks()) - base;
  66 }
  67
  68 /* delay x useconds AND preserve advance timstamp value */
  69 void __udelay(unsigned long usec)
  70 {
  71         unsigned long long start;
  72         ulong tmo;
  73
  74         start = get_ticks();                    /* get current timestamp */
  75         tmo = us_to_tick(usec);                 /* convert usecs to ticks */
  76         while ((get_ticks() - start) < tmo)
  77                 ;                               /* loop till time has passed */
  78 }
  79
  80 /*
  81  * This function is derived from PowerPC code (timebase clock frequency).
  82  * On ARM it returns the number of timer ticks per second.
  83  */
  84 ulong get_tbclk(void)
  85 {
  86         return mxc_get_clock(MXC_IPG_CLK);
  87 }