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/*

 *      linux/arch/i386/kernel/irq.c

 *

 *      Copyright (C) 1992 Linus Torvalds

 *

 * This file contains the code used by various IRQ handling routines:

 * asking for different IRQ's should be done through these routines

 * instead of just grabbing them. Thus setups with different IRQ numbers

 * shouldn't result in any weird surprises, and installing new handlers

 * should be easier.

 */

/*

 * IRQ's are in fact implemented a bit like signal handlers for the kernel.

 * Naturally it's not a 1:1 relation, but there are similarities.

 */

#include <linux/ptrace.h>

#include <linux/errno.h>

#include <linux/kernel_stat.h>

#include <linux/signal.h>

#include <linux/sched.h>

#include <linux/ioport.h>

#include <linux/interrupt.h>

#include <linux/timex.h>

#include <linux/malloc.h>

#include <linux/random.h>

#include <asm/system.h>

#include <asm/io.h>

#include <asm/irq.h>

#include <asm/bitops.h>

#include <asm/smp.h>

#define CR0_NE 32

static unsigned char cache_21 = 0xff;

static unsigned char cache_A1 = 0xff;

#ifdef __SMP_PROF__

static unsigned int int_count[NR_CPUS][NR_IRQS] = {{0},};

#endif

static inline void mask_irq(unsigned int irq_nr)

{

        unsigned char mask;

        mask = 1 << (irq_nr & 7);

        if (irq_nr < 8) {

                cache_21 |= mask;

                outb(cache_21,0x21);

        } else {

                cache_A1 |= mask;

                outb(cache_A1,0xA1);

        }

}

static inline void unmask_irq(unsigned int irq_nr)

{

        unsigned char mask;

        mask = ~(1 << (irq_nr & 7));

        if (irq_nr < 8) {

                cache_21 &= mask;

                outb(cache_21,0x21);

        } else {

                cache_A1 &= mask;

                outb(cache_A1,0xA1);

        }

}

void disable_irq(unsigned int irq_nr)

{

        unsigned long flags;

        save_flags(flags);

        cli();

        mask_irq(irq_nr);

        restore_flags(flags);

}

void enable_irq(unsigned int irq_nr)

{

        unsigned long flags;

        save_flags(flags);

        cli();

        unmask_irq(irq_nr);

        restore_flags(flags);

}

/*

 * This builds up the IRQ handler stubs using some ugly macros in irq.h

 *

 * These macros create the low-level assembly IRQ routines that do all

 * the operations that are needed to keep the AT interrupt-controller

 * happy. They are also written to be fast - and to disable interrupts

 * as little as humanly possible.

 *

 * NOTE! These macros expand to three different handlers for each line: one

 * complete handler that does all the fancy stuff (including signal handling),

 * and one fast handler that is meant for simple IRQ's that want to be

 * atomic. The specific handler is chosen depending on the SA_INTERRUPT

 * flag when installing a handler. Finally, one "bad interrupt" handler, that

 * is used when no handler is present.

 *

 * The timer interrupt is handled specially to insure that the jiffies

 * variable is updated at all times.  Specifically, the timer interrupt is

 * just like the complete handlers except that it is invoked with interrupts

 * disabled and should never re-enable them.  If other interrupts were

 * allowed to be processed while the timer interrupt is active, then the

 * other interrupts would have to avoid using the jiffies variable for delay

 * and interval timing operations to avoid hanging the system.

 */

BUILD_TIMER_IRQ(FIRST,0,0x01)

BUILD_IRQ(FIRST,1,0x02)

BUILD_IRQ(FIRST,2,0x04)

BUILD_IRQ(FIRST,3,0x08)

BUILD_IRQ(FIRST,4,0x10)

BUILD_IRQ(FIRST,5,0x20)

BUILD_IRQ(FIRST,6,0x40)

BUILD_IRQ(FIRST,7,0x80)

BUILD_IRQ(SECOND,8,0x01)

BUILD_IRQ(SECOND,9,0x02)

BUILD_IRQ(SECOND,10,0x04)

BUILD_IRQ(SECOND,11,0x08)

BUILD_IRQ(SECOND,12,0x10)

#ifdef __SMP__

BUILD_MSGIRQ(SECOND,13,0x20)

#else

BUILD_IRQ(SECOND,13,0x20)

#endif

BUILD_IRQ(SECOND,14,0x40)

BUILD_IRQ(SECOND,15,0x80)

#ifdef __SMP__

BUILD_RESCHEDIRQ(16)

#endif

/*

 * Pointers to the low-level handlers: first the general ones, then the

 * fast ones, then the bad ones.

 */

static void (*interrupt[17])(void) = {

        IRQ0_interrupt, IRQ1_interrupt, IRQ2_interrupt, IRQ3_interrupt,

        IRQ4_interrupt, IRQ5_interrupt, IRQ6_interrupt, IRQ7_interrupt,

        IRQ8_interrupt, IRQ9_interrupt, IRQ10_interrupt, IRQ11_interrupt,

        IRQ12_interrupt, IRQ13_interrupt, IRQ14_interrupt, IRQ15_interrupt

#ifdef __SMP__  

        ,IRQ16_interrupt

#endif

};

static void (*fast_interrupt[16])(void) = {

        fast_IRQ0_interrupt, fast_IRQ1_interrupt,

        fast_IRQ2_interrupt, fast_IRQ3_interrupt,

        fast_IRQ4_interrupt, fast_IRQ5_interrupt,

        fast_IRQ6_interrupt, fast_IRQ7_interrupt,

        fast_IRQ8_interrupt, fast_IRQ9_interrupt,

        fast_IRQ10_interrupt, fast_IRQ11_interrupt,

        fast_IRQ12_interrupt, fast_IRQ13_interrupt,

        fast_IRQ14_interrupt, fast_IRQ15_interrupt

};

static void (*bad_interrupt[16])(void) = {

        bad_IRQ0_interrupt, bad_IRQ1_interrupt,

        bad_IRQ2_interrupt, bad_IRQ3_interrupt,

        bad_IRQ4_interrupt, bad_IRQ5_interrupt,

        bad_IRQ6_interrupt, bad_IRQ7_interrupt,

        bad_IRQ8_interrupt, bad_IRQ9_interrupt,

        bad_IRQ10_interrupt, bad_IRQ11_interrupt,

        bad_IRQ12_interrupt, bad_IRQ13_interrupt,

        bad_IRQ14_interrupt, bad_IRQ15_interrupt

};

/*

 * Initial irq handlers.

 */

static void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }

#ifdef __SMP__

/*

 * On SMP boards, irq13 is used for interprocessor interrupts (IPI's).

 */

static struct irqaction irq13 = { smp_message_irq, SA_INTERRUPT, 0, "IPI", NULL, NULL };

#else

/*

 * Note that on a 486, we don't want to do a SIGFPE on a irq13

 * as the irq is unreliable, and exception 16 works correctly

 * (ie as explained in the intel literature). On a 386, you

 * can't use exception 16 due to bad IBM design, so we have to

 * rely on the less exact irq13.

 *

 * Careful.. Not only is IRQ13 unreliable, but it is also

 * leads to races. IBM designers who came up with it should

 * be shot.

 */

static void math_error_irq(int cpl, void *dev_id, struct pt_regs *regs)

{

        outb(0,0xF0);

        if (ignore_irq13 || !hard_math)

                return;

        math_error();

}

static struct irqaction irq13 = { math_error_irq, 0, 0, "math error", NULL, NULL };

#endif

/*

 * IRQ2 is cascade interrupt to second interrupt controller

 */

static struct irqaction irq2  = { no_action, 0, 0, "cascade", NULL, NULL};

static struct irqaction *irq_action[16] = {

        NULL, NULL, NULL, NULL,

        NULL, NULL, NULL, NULL,

        NULL, NULL, NULL, NULL,

        NULL, NULL, NULL, NULL

};

int get_irq_list(char *buf)

{

        int i, len = 0;

        struct irqaction * action;

        for (i = 0 ; i < 16 ; i++) {

                action = irq_action[i];

                if (!action)

                        continue;

                len += sprintf(buf+len, "%2d: %10u %c %s",

                        i, kstat.interrupts[i],

                        (action->flags & SA_INTERRUPT) ? '+' : ' ',

                        action->name);

                for (action=action->next; action; action = action->next) {

                        len += sprintf(buf+len, ",%s %s",

                                (action->flags & SA_INTERRUPT) ? " +" : "",

                                action->name);

                }

                len += sprintf(buf+len, "\n");

        }

/*

 *      Linus - should you add NMI counts here ?????

 */

#ifdef __SMP_PROF__

        len+=sprintf(buf+len, "IPI: %8lu received\n",

                ipi_count);

#endif          

        return len;

}

#ifdef __SMP_PROF__

int get_smp_prof_list(char *buf) {

        int i,j, len = 0;

        struct irqaction * action;

        unsigned long sum_spins = 0;

        unsigned long sum_spins_syscall = 0;

        unsigned long sum_spins_sys_idle = 0;

        unsigned long sum_smp_idle_count = 0;

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

                int cpunum = cpu_logical_map[i];

                sum_spins+=smp_spins[cpunum];

                sum_spins_syscall+=smp_spins_syscall[cpunum];

                sum_spins_sys_idle+=smp_spins_sys_idle[cpunum];

                sum_smp_idle_count+=smp_idle_count[cpunum];

        }

        len += sprintf(buf+len,"CPUS: %10i \n", smp_num_cpus);

        len += sprintf(buf+len,"            SUM ");

        for (i=0;i<smp_num_cpus;i++)

                len += sprintf(buf+len,"        P%1d ",cpu_logical_map[i]);

        len += sprintf(buf+len,"\n");

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

                action = *(i + irq_action);

                if (!action || !action->handler)

                        continue;

                len += sprintf(buf+len, "%3d: %10d ",

                        i, kstat.interrupts[i]);

                for (j=0;j<smp_num_cpus;j++)

                        len+=sprintf(buf+len, "%10d ",

                                int_count[cpu_logical_map[j]][i]);

                len += sprintf(buf+len, "%c %s",

                        (action->flags & SA_INTERRUPT) ? '+' : ' ',

                        action->name);

                for (action=action->next; action; action = action->next) {

                        len += sprintf(buf+len, ",%s %s",

                                (action->flags & SA_INTERRUPT) ? " +" : "",

                                action->name);

                }

                len += sprintf(buf+len, "\n");

        }

        len+=sprintf(buf+len, "LCK: %10lu",

                sum_spins);

        for (i=0;i<smp_num_cpus;i++)

                len+=sprintf(buf+len," %10lu",smp_spins[cpu_logical_map[i]]);

        len +=sprintf(buf+len,"   spins from int\n");

        len+=sprintf(buf+len, "LCK: %10lu",

                sum_spins_syscall);

        for (i=0;i<smp_num_cpus;i++)

                len+=sprintf(buf+len," %10lu",smp_spins_syscall[cpu_logical_map[i]]);

        len +=sprintf(buf+len,"   spins from syscall\n");

        len+=sprintf(buf+len, "LCK: %10lu",

                sum_spins_sys_idle);

        for (i=0;i<smp_num_cpus;i++)

                len+=sprintf(buf+len," %10lu",smp_spins_sys_idle[cpu_logical_map[i]]);

        len +=sprintf(buf+len,"   spins from sysidle\n");

        len+=sprintf(buf+len,"IDLE %10lu",sum_smp_idle_count);

        for (i=0;i<smp_num_cpus;i++)

                len+=sprintf(buf+len," %10lu",smp_idle_count[cpu_logical_map[i]]);

        len +=sprintf(buf+len,"   idle ticks\n");

        len+=sprintf(buf+len, "IPI: %10lu   received\n",

                ipi_count);

        return len;

}

#endif 

/*

 * do_IRQ handles IRQ's that have been installed without the

 * SA_INTERRUPT flag: it uses the full signal-handling return

 * and runs with other interrupts enabled. All relatively slow

 * IRQ's should use this format: notably the keyboard/timer

 * routines.

 */

asmlinkage void do_IRQ(int irq, struct pt_regs * regs)

{

        struct irqaction * action = *(irq + irq_action);

        int do_random = 0;

        int c,intm,mask;

#ifdef IRQ_DEBUG

        static int count;

        if (smp_processor_id() != 0 && count++ < 1000)

          printk("IRQ %d: done by CPU %d\n",irq,smp_processor_id());

#endif    

        if (irq  >= 8) {

          c = cache_A1;

          intm = inb(0xA1);

          mask =  1 << (irq - 8);

        } else {

          c = cache_21;

          intm = inb(0x21);

          mask =  1 << irq;

        }

        if (!(c & mask) || !(intm & mask)) {

#ifdef IRQ_DEBUG        

          printk("IRQ %d (proc %d):cache_x1=0x%x,INT mask=0x%x\n", irq, smp_processor_id(),c,intm);

#endif    

          /* better to return because the interrupt may be asserted again,

             the bad thing is that we may loose some interrupts */

          return;

        }

#ifdef __SMP__

        if(smp_threads_ready && active_kernel_processor!=smp_processor_id())

                panic("IRQ %d: active processor set wrongly(%d not %d).\n", irq, active_kernel_processor, smp_processor_id());

#endif

        kstat.interrupts[irq]++;

#ifdef __SMP_PROF__

        int_count[smp_processor_id()][irq]++;

#endif

        while (action) {

                do_random |= action->flags;

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

                action = action->next;

        }

        if (do_random & SA_SAMPLE_RANDOM)

                add_interrupt_randomness(irq);

}

/*

 * do_fast_IRQ handles IRQ's that don't need the fancy interrupt return

 * stuff - the handler is also running with interrupts disabled unless

 * it explicitly enables them later.

 */

asmlinkage void do_fast_IRQ(int irq)

{

        struct irqaction * action = *(irq + irq_action);

        int do_random = 0;

#ifdef __SMP__

        /* IRQ 13 is allowed - that's a flush tlb */

        if(smp_threads_ready && active_kernel_processor!=smp_processor_id() && irq!=13)

                panic("fast_IRQ %d: active processor set wrongly(%d not %d).\n", irq, active_kernel_processor, smp_processor_id());

#endif

        kstat.interrupts[irq]++;

#ifdef __SMP_PROF__

        int_count[smp_processor_id()][irq]++;

#endif

        while (action) {

                do_random |= action->flags;

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

                action = action->next;

        }

        if (do_random & SA_SAMPLE_RANDOM)

                add_interrupt_randomness(irq);

}

int setup_x86_irq(int irq, struct irqaction * new)

{

        int shared = 0;

        struct irqaction *old, **p;

        unsigned long flags;

        p = irq_action + irq;

        if ((old = *p) != NULL) {

                /* Can't share interrupts unless both agree to */

                if (!(old->flags & new->flags & SA_SHIRQ))

                        return -EBUSY;

                /* Can't share interrupts unless both are same type */

                if ((old->flags ^ new->flags) & SA_INTERRUPT)

                        return -EBUSY;

                /* add new interrupt at end of irq queue */

                do {

                        p = &old->next;

                        old = *p;

                } while (old);

                shared = 1;

        }

        if (new->flags & SA_SAMPLE_RANDOM)

                rand_initialize_irq(irq);

        save_flags(flags);

        cli();

        *p = new;

        if (!shared) {

                if (new->flags & SA_INTERRUPT)

                        set_intr_gate(0x20+irq,fast_interrupt[irq]);

                else

                        set_intr_gate(0x20+irq,interrupt[irq]);

                unmask_irq(irq);

        }

        restore_flags(flags);

        return 0;

}

int request_irq(unsigned int irq,

                void (*handler)(int, void *, struct pt_regs *),

                unsigned long irqflags,

                const char * devname,

                void *dev_id)

{

        int retval;

        struct irqaction * action;

        if (irq > 15)

                return -EINVAL;

        if (!handler)

                return -EINVAL;

        action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);

        if (!action)

                return -ENOMEM;

        action->handler = handler;

        action->flags = irqflags;

        action->mask = 0;

        action->name = devname;

        action->next = NULL;

        action->dev_id = dev_id;

        retval = setup_x86_irq(irq, action);

        if (retval)

                kfree(action);

        return retval;

}

void free_irq(unsigned int irq, void *dev_id)

{

        struct irqaction * action, **p;

        unsigned long flags;

        if (irq > 15) {

                printk("Trying to free IRQ%d\n",irq);

                return;

        }

        for (p = irq + irq_action; (action = *p) != NULL; p = &action->next) {

                if (action->dev_id != dev_id)

                        continue;

                /* Found it - now free it */

                save_flags(flags);

                cli();

                *p = action->next;

                if (!irq[irq_action]) {

                        mask_irq(irq);

                        set_intr_gate(0x20+irq,bad_interrupt[irq]);

                }

                restore_flags(flags);

                kfree(action);

                return;

        }

        printk("Trying to free free IRQ%d\n",irq);

}

unsigned long probe_irq_on (void)

{

        unsigned int i, irqs = 0, irqmask;

        unsigned long delay;

        /* first, enable any unassigned irqs */

        for (i = 15; i > 0; i--) {

                if (!irq_action[i]) {

                        enable_irq(i);

                        irqs |= (1 << i);

                }

        }

        /* wait for spurious interrupts to mask themselves out again */

        for (delay = jiffies + HZ/10; delay > jiffies; )

                /* about 100ms delay */;

        /* now filter out any obviously spurious interrupts */

        irqmask = (((unsigned int)cache_A1)<<8) | (unsigned int)cache_21;

        return irqs & ~irqmask;

}

int probe_irq_off (unsigned long irqs)

{

        unsigned int i, irqmask;

        irqmask = (((unsigned int)cache_A1)<<8) | (unsigned int)cache_21;

#ifdef DEBUG

        printk("probe_irq_off: irqs=0x%04lx irqmask=0x%04x\n", irqs, irqmask);

#endif

        irqs &= irqmask;

        if (!irqs)

                return 0;

        i = ffz(~irqs);

        if (irqs != (irqs & (1 << i)))

                i = -i;

        return i;

}

void init_IRQ(void)

{

        int i;

        static unsigned char smptrap=0;

        if(smptrap)

                return;

        smptrap=1;

        /* set the clock to 100 Hz */

        outb_p(0x34,0x43);              /* binary, mode 2, LSB/MSB, ch 0 */

        outb_p(LATCH & 0xff , 0x40);    /* LSB */

        outb(LATCH >> 8 , 0x40);        /* MSB */

        for (i = 0; i < 16 ; i++)

                set_intr_gate(0x20+i,bad_interrupt[i]);

        /* This bit is a hack because we don't send timer messages to all processors yet */

        /* It has to be here .. it doesn't work if you put it down the bottom - assembler explodes 8) */

#ifdef __SMP__  

        set_intr_gate(0x20+i, interrupt[i]);    /* IRQ '16' - IPI for rescheduling */

#endif  

        request_region(0x20,0x20,"pic1");

        request_region(0xa0,0x20,"pic2");

        setup_x86_irq(2, &irq2);

        setup_x86_irq(13, &irq13);

}