arch/mips/cobalt/time.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Cobalt time initialization.
   4  *
   5  *  Copyright (C) 2007  Yoichi Yuasa <yuasa@linux-mips.org>
   6  */
   7 #include <linux/i8253.h>
   8 #include <linux/init.h>
   9
  10 #include <asm/gt64120.h>
  11 #include <asm/time.h>
  12
  13 #define GT641XX_BASE_CLOCK      50000000        /* 50MHz */
  14
  15 void __init plat_time_init(void)
  16 {
  17         u32 start, end;
  18         int i = HZ / 10;
  19
  20         setup_pit_timer();
  21
  22         gt641xx_set_base_clock(GT641XX_BASE_CLOCK);
  23
  24         /*
  25          * MIPS counter frequency is measured during a 100msec interval
  26          * using GT64111 timer0.
  27          */
  28         while (!gt641xx_timer0_state())
  29                 ;
  30
  31         start = read_c0_count();
  32
  33         while (i--)
  34                 while (!gt641xx_timer0_state())
  35                         ;
  36
  37         end = read_c0_count();
  38
  39         mips_hpt_frequency = (end - start) * 10;
  40         printk(KERN_INFO "MIPS counter frequency %dHz\n", mips_hpt_frequency);
  41 }