cevt-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/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/percpu.h>
#include <linux/smp.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 IMR_IP2_VAL K_INT_MAP_I0
#define IMR_IP3_VAL K_INT_MAP_I1
#define IMR_IP4_VAL K_INT_MAP_I2

/*
 * The general purpose timer ticks at 1MHz independent if
 * the rest of the system
 */
static void sibyte_set_mode(enum clock_event_mode mode,
                           struct clock_event_device *evt)
{
    unsigned int cpu = smp_processor_id();
    void __iomem *cfg, *init;

    cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
    init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));

    switch (mode) {
    case CLOCK_EVT_MODE_PERIODIC:
        __raw_writeq(0, cfg);
        __raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, init);
        __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
                 cfg);
        break;

    case CLOCK_EVT_MODE_ONESHOT:
        /* Stop the timer until we actually program a shot */
    case CLOCK_EVT_MODE_SHUTDOWN:
        __raw_writeq(0, cfg);
        break;

    case CLOCK_EVT_MODE_UNUSED: /* shuddup gcc */
    case CLOCK_EVT_MODE_RESUME:
        ;
    }
}

static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
{
    unsigned int cpu = smp_processor_id();
    void __iomem *cfg, *init;

    cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
    init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));

    __raw_writeq(0, cfg);
    __raw_writeq(delta - 1, init);
    __raw_writeq(M_SCD_TIMER_ENABLE, cfg);

    return 0;
}

static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
{
    unsigned int cpu = smp_processor_id();
    struct clock_event_device *cd = dev_id;
    void __iomem *cfg;
    unsigned long tmode;

    if (cd->mode == CLOCK_EVT_MODE_PERIODIC)
        tmode = M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS;
    else
        tmode = 0;

    /* ACK interrupt */
    cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
    ____raw_writeq(tmode, cfg);

    cd->event_handler(cd);

    return IRQ_HANDLED;
}

static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
static DEFINE_PER_CPU(struct irqaction, sibyte_hpt_irqaction);
static DEFINE_PER_CPU(char [18], sibyte_hpt_name);

void __cpuinit sb1250_clockevent_init(void)
{
    unsigned int cpu = smp_processor_id();
    unsigned int irq = K_INT_TIMER_0 + cpu;
    struct irqaction *action = &per_cpu(sibyte_hpt_irqaction, cpu);
    struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
    unsigned char *name = per_cpu(sibyte_hpt_name, cpu);

    /* Only have 4 general purpose timers, and we use last one as hpt */
    BUG_ON(cpu > 2);

    sprintf(name, "sb1250-counter-%d", cpu);
    cd->name        = name;
    cd->features        = CLOCK_EVT_FEAT_PERIODIC |
                  CLOCK_EVT_FEAT_ONESHOT;
    clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
    cd->max_delta_ns    = clockevent_delta2ns(0x7fffff, cd);
    cd->min_delta_ns    = clockevent_delta2ns(2, cd);
    cd->rating      = 200;
    cd->irq         = irq;
    cd->cpumask     = cpumask_of(cpu);
    cd->set_next_event  = sibyte_next_event;
    cd->set_mode        = sibyte_set_mode;
    clockevents_register_device(cd);

    sb1250_mask_irq(cpu, irq);

    /*
     * Map the timer interrupt to IP[4] of this cpu
     */
    __raw_writeq(IMR_IP4_VAL,
             IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
                (irq << 3)));

    sb1250_unmask_irq(cpu, irq);

    action->handler = sibyte_counter_handler;
    action->flags   = IRQF_PERCPU | IRQF_TIMER;
    action->name    = name;
    action->dev_id  = cd;

    irq_set_affinity(irq, cpumask_of(cpu));
    setup_irq(irq, action);
}