LXR linux/arch/mips/kernel/csrc-sb1250.c

   1/*
   2 * Copyright (C) 2000, 2001 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 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17 */
  18#include <linux/clocksource.h>
  19
  20#include <asm/addrspace.h>
  21#include <asm/io.h>
  22#include <asm/time.h>
  23
  24#include <asm/sibyte/sb1250.h>
  25#include <asm/sibyte/sb1250_regs.h>
  26#include <asm/sibyte/sb1250_int.h>
  27#include <asm/sibyte/sb1250_scd.h>
  28
  29#define SB1250_HPT_NUM          3
  30#define SB1250_HPT_VALUE        M_SCD_TIMER_CNT /* max value */
  31
  32/*
  33 * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
  34 * again.
  35 */
  36static cycle_t sb1250_hpt_read(struct clocksource *cs)
  37{
  38        unsigned int count;
  39
  40        count = G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT))));
  41
  42        return SB1250_HPT_VALUE - count;
  43}
  44
  45struct clocksource bcm1250_clocksource = {
  46        .name   = "bcm1250-counter-3",
  47        .rating = 200,
  48        .read   = sb1250_hpt_read,
  49        .mask   = CLOCKSOURCE_MASK(23),
  50        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
  51};
  52
  53void __init sb1250_clocksource_init(void)
  54{
  55        struct clocksource *cs = &bcm1250_clocksource;
  56
  57        /* Setup hpt using timer #3 but do not enable irq for it */
  58        __raw_writeq(0,
  59                     IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
  60                                                 R_SCD_TIMER_CFG)));
  61        __raw_writeq(SB1250_HPT_VALUE,
  62                     IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
  63                                                 R_SCD_TIMER_INIT)));
  64        __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
  65                     IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
  66                                                 R_SCD_TIMER_CFG)));
  67
  68        clocksource_set_clock(cs, V_SCD_TIMER_FREQ);
  69        clocksource_register(cs);
  70}
  71