csrc-sb1250.c

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/*
 * Copyright (C) 2000, 2001 Broadcom Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
#include <linux/clocksource.h>

#include <asm/addrspace.h>
#include <asm/io.h>
#include <asm/time.h>

#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>
#include <asm/sibyte/sb1250_scd.h>

#define SB1250_HPT_NUM      3
#define SB1250_HPT_VALUE    M_SCD_TIMER_CNT /* max value */

/*
 * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
 * again.
 */
static cycle_t sb1250_hpt_read(struct clocksource *cs)
{
    unsigned int count;

    count = G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT))));

    return SB1250_HPT_VALUE - count;
}

struct clocksource bcm1250_clocksource = {
    .name   = "bcm1250-counter-3",
    .rating = 200,
    .read   = sb1250_hpt_read,
    .mask   = CLOCKSOURCE_MASK(23),
    .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
};

void __init sb1250_clocksource_init(void)
{
    struct clocksource *cs = &bcm1250_clocksource;

    /* Setup hpt using timer #3 but do not enable irq for it */
    __raw_writeq(0,
             IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
                         R_SCD_TIMER_CFG)));
    __raw_writeq(SB1250_HPT_VALUE,
             IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
                         R_SCD_TIMER_INIT)));
    __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
             IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
                         R_SCD_TIMER_CFG)));

    clocksource_register_hz(cs, V_SCD_TIMER_FREQ);
}