arch/mips/kernel/csrc-bcm1480.c

   1 /*
   2  * Copyright (C) 2000,2001,2004 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14 #include <linux/clocksource.h>
  15 #include <linux/sched_clock.h>
  16
  17 #include <asm/addrspace.h>
  18 #include <asm/io.h>
  19 #include <asm/time.h>
  20
  21 #include <asm/sibyte/bcm1480_regs.h>
  22 #include <asm/sibyte/sb1250_regs.h>
  23 #include <asm/sibyte/bcm1480_int.h>
  24 #include <asm/sibyte/bcm1480_scd.h>
  25
  26 #include <asm/sibyte/sb1250.h>
  27
  28 static cycle_t bcm1480_hpt_read(struct clocksource *cs)
  29 {
  30         return (cycle_t) __raw_readq(IOADDR(A_SCD_ZBBUS_CYCLE_COUNT));
  31 }
  32
  33 struct clocksource bcm1480_clocksource = {
  34         .name   = "zbbus-cycles",
  35         .rating = 200,
  36         .read   = bcm1480_hpt_read,
  37         .mask   = CLOCKSOURCE_MASK(64),
  38         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
  39 };
  40
  41 static u64 notrace sb1480_read_sched_clock(void)
  42 {
  43         return __raw_readq(IOADDR(A_SCD_ZBBUS_CYCLE_COUNT));
  44 }
  45
  46 void __init sb1480_clocksource_init(void)
  47 {
  48         struct clocksource *cs = &bcm1480_clocksource;
  49         unsigned int plldiv;
  50         unsigned long zbbus;
  51
  52         plldiv = G_BCM1480_SYS_PLL_DIV(__raw_readq(IOADDR(A_SCD_SYSTEM_CFG)));
  53         zbbus = ((plldiv >> 1) * 50000000) + ((plldiv & 1) * 25000000);
  54         clocksource_register_hz(cs, zbbus);
  55
  56         sched_clock_register(sb1480_read_sched_clock, 64, zbbus);
  57 }