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/*

 * Carsten Langgaard, carstenl@mips.com

 * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.

 *

 * ########################################################################

 *

 *  This program is free software; you can distribute it and/or modify it

 *  under the terms of the GNU General Public License (Version 2) as

 *  published by the Free Software Foundation.

 *

 *  This program is distributed in the hope 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.

 *

 * ########################################################################

 *

 * Routines for generic manipulation of the interrupts found on the

 * Lasat boards.

 *

 */

#include <linux/config.h>

#include <linux/init.h>

#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/interrupt.h>

#include <linux/kernel_stat.h>

#include <asm/bootinfo.h>

#include <asm/irq.h>

#include <asm/lasat/lasatint.h>

#include <asm/gdb-stub.h>

static volatile int *lasat_int_status = NULL;

static volatile int *lasat_int_mask = NULL;

static volatile int lasat_int_mask_shift;

extern asmlinkage void mipsIRQ(void);

#if 0

#define DEBUG_INT(x...) printk(x)

#else

#define DEBUG_INT(x...)

#endif

void disable_lasat_irq(unsigned int irq_nr)

{

        unsigned long flags;

        DEBUG_INT("disable_lasat_irq: %d", irq_nr);

        local_irq_save(flags);

        *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;

        local_irq_restore(flags);

}

void enable_lasat_irq(unsigned int irq_nr)

{

        unsigned long flags;

        DEBUG_INT("enable_lasat_irq: %d", irq_nr);

        local_irq_save(flags);

        *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;

        local_irq_restore(flags);

}

static unsigned int startup_lasat_irq(unsigned int irq)

{

        enable_lasat_irq(irq);

        return 0; /* never anything pending */

}

#define shutdown_lasat_irq      disable_lasat_irq

#define mask_and_ack_lasat_irq disable_lasat_irq

static void end_lasat_irq(unsigned int irq)

{

        if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))

                enable_lasat_irq(irq);

}

static struct hw_interrupt_type lasat_irq_type = {

        "Lasat",

        startup_lasat_irq,

        shutdown_lasat_irq,

        enable_lasat_irq,

        disable_lasat_irq,

        mask_and_ack_lasat_irq,

        end_lasat_irq,

        NULL

};

static inline int ls1bit32(unsigned int x)

{

        int b = 31, s;

        s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;

        s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;

        s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;

        s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;

        s =  1; if (x <<  1 == 0) s = 0; b -= s;

        return b;

}

static unsigned long (* get_int_status)(void);

static unsigned long get_int_status_100(void)

{

        return (*lasat_int_status & *lasat_int_mask);

}

static unsigned long get_int_status_200(void)

{

        unsigned long int_status;

        int_status = *lasat_int_status;

        int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;

        return int_status;

}

void lasat_hw0_irqdispatch(struct pt_regs *regs)

{

        struct irqaction *action;

        unsigned long int_status;

        int irq, cpu = smp_processor_id();

        int_status = get_int_status();

        /* if int_status == 0, then the interrupt has already been cleared */

        if (int_status == 0)

                return;

        irq = ls1bit32(int_status);

        action = irq_desc[irq].action;

        DEBUG_INT("lasat_hw0_irqdispatch: irq=%d\n", irq);

        /* if action == NULL, then we don't have a handler for the irq */

        if (action == NULL) {

                printk("No handler for hw0 irq: %i\n", irq);

                atomic_inc(&irq_err_count);

                return;

        }

        irq_enter(cpu, irq);

        kstat.irqs[0][irq]++;

        action->handler(irq, action->dev_id, regs);

        irq_exit(cpu, irq);

        return;

}

void __init init_IRQ(void)

{

        int i;

        init_generic_irq();

        switch (mips_machtype) {

        case MACH_LASAT_100:

                lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;

                lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;

                lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;

                get_int_status = get_int_status_100;

                *lasat_int_mask = 0;

                break;

        case MACH_LASAT_200:

                lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;

                lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;

                lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;

                get_int_status = get_int_status_200;

                *lasat_int_mask &= 0xffff;

                break;

        default:

                panic("init_IRQ: mips_machtype incorrect");

        }

        /* Now safe to set the exception vector. */

        set_except_vector(0, mipsIRQ);

        for (i = 0; i <= LASATINT_END; i++) {

                irq_desc[i].status      = IRQ_DISABLED;

                irq_desc[i].action      = 0;

                irq_desc[i].depth       = 1;

                irq_desc[i].handler     = &lasat_irq_type;

        }

}