irq.c

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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1992 Linus Torvalds
 * Copyright (C) 1994 - 2001, 2003, 07 Ralf Baechle
 */
#include <linux/clockchips.h>
#include <linux/i8253.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/irq.h>

#include <asm/irq_cpu.h>
#include <asm/i8259.h>
#include <asm/io.h>
#include <asm/jazz.h>
#include <asm/pgtable.h>
#include <asm/tlbmisc.h>

static DEFINE_RAW_SPINLOCK(r4030_lock);

static void enable_r4030_irq(struct irq_data *d)
{
    unsigned int mask = 1 << (d->irq - JAZZ_IRQ_START);
    unsigned long flags;

    raw_spin_lock_irqsave(&r4030_lock, flags);
    mask |= r4030_read_reg16(JAZZ_IO_IRQ_ENABLE);
    r4030_write_reg16(JAZZ_IO_IRQ_ENABLE, mask);
    raw_spin_unlock_irqrestore(&r4030_lock, flags);
}

void disable_r4030_irq(struct irq_data *d)
{
    unsigned int mask = ~(1 << (d->irq - JAZZ_IRQ_START));
    unsigned long flags;

    raw_spin_lock_irqsave(&r4030_lock, flags);
    mask &= r4030_read_reg16(JAZZ_IO_IRQ_ENABLE);
    r4030_write_reg16(JAZZ_IO_IRQ_ENABLE, mask);
    raw_spin_unlock_irqrestore(&r4030_lock, flags);
}

static struct irq_chip r4030_irq_type = {
    .name = "R4030",
    .irq_mask = disable_r4030_irq,
    .irq_unmask = enable_r4030_irq,
};

void __init init_r4030_ints(void)
{
    int i;

    for (i = JAZZ_IRQ_START; i <= JAZZ_IRQ_END; i++)
        irq_set_chip_and_handler(i, &r4030_irq_type, handle_level_irq);

    r4030_write_reg16(JAZZ_IO_IRQ_ENABLE, 0);
    r4030_read_reg16(JAZZ_IO_IRQ_SOURCE);       /* clear pending IRQs */
    r4030_read_reg32(JAZZ_R4030_INVAL_ADDR);    /* clear error bits */
}

/*
 * On systems with i8259-style interrupt controllers we assume for
 * driver compatibility reasons interrupts 0 - 15 to be the i8259
 * interrupts even if the hardware uses a different interrupt numbering.
 */
void __init arch_init_irq(void)
{
    /*
     * this is a hack to get back the still needed wired mapping
     * killed by init_mm()
     */

    /* Map 0xe0000000 -> 0x0:800005C0, 0xe0010000 -> 0x1:30000580 */
    add_wired_entry(0x02000017, 0x03c00017, 0xe0000000, PM_64K);
    /* Map 0xe2000000 -> 0x0:900005C0, 0xe3010000 -> 0x0:910005C0 */
    add_wired_entry(0x02400017, 0x02440017, 0xe2000000, PM_16M);
    /* Map 0xe4000000 -> 0x0:600005C0, 0xe4100000 -> 400005C0 */
    add_wired_entry(0x01800017, 0x01000017, 0xe4000000, PM_4M);

    init_i8259_irqs();          /* Integrated i8259  */
    mips_cpu_irq_init();
    init_r4030_ints();

    change_c0_status(ST0_IM, IE_IRQ2 | IE_IRQ1);
}

asmlinkage void plat_irq_dispatch(void)
{
    unsigned int pending = read_c0_cause() & read_c0_status();
    unsigned int irq;

    if (pending & IE_IRQ4) {
        r4030_read_reg32(JAZZ_TIMER_REGISTER);
        do_IRQ(JAZZ_TIMER_IRQ);
    } else if (pending & IE_IRQ2) {
        irq = *(volatile u8 *)JAZZ_EISA_IRQ_ACK;
        do_IRQ(irq);
    } else if (pending & IE_IRQ1) {
        irq = *(volatile u8 *)JAZZ_IO_IRQ_SOURCE >> 2;
        if (likely(irq > 0))
            do_IRQ(irq + JAZZ_IRQ_START - 1);
        else
            panic("Unimplemented loc_no_irq handler");
    }
}

static void r4030_set_mode(enum clock_event_mode mode,
                           struct clock_event_device *evt)
{
    /* Nothing to do ...  */
}

struct clock_event_device r4030_clockevent = {
    .name       = "r4030",
    .features   = CLOCK_EVT_FEAT_PERIODIC,
    .rating     = 300,
    .irq        = JAZZ_TIMER_IRQ,
    .set_mode   = r4030_set_mode,
};

static irqreturn_t r4030_timer_interrupt(int irq, void *dev_id)
{
    struct clock_event_device *cd = dev_id;

    cd->event_handler(cd);
    return IRQ_HANDLED;
}

static struct irqaction r4030_timer_irqaction = {
    .handler    = r4030_timer_interrupt,
    .flags      = IRQF_TIMER,
    .name       = "R4030 timer",
};

void __init plat_time_init(void)
{
    struct clock_event_device *cd = &r4030_clockevent;
    struct irqaction *action = &r4030_timer_irqaction;
    unsigned int cpu = smp_processor_id();

    BUG_ON(HZ != 100);

    cd->cpumask             = cpumask_of(cpu);
    clockevents_register_device(cd);
    action->dev_id = cd;
    setup_irq(JAZZ_TIMER_IRQ, action);

    /*
     * Set clock to 100Hz.
     *
     * The R4030 timer receives an input clock of 1kHz which is divieded by
     * a programmable 4-bit divider.  This makes it fairly inflexible.
     */
    r4030_write_reg32(JAZZ_TIMER_INTERVAL, 9);
    setup_pit_timer();
}