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[mascara-docs.git] / i386 / linux / linux-2.3.21 / arch / mips / baget / irq.c

/*
 * Code to handle Baget/MIPS IRQs plus some generic interrupt stuff.
 *
 * Copyright (C) 1998 Vladimir Roganov & Gleb Raiko
 *      Code (mostly sleleton and comments) derived from DECstation IRQ
 *      handling.
 *
 * $Id$
 */
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/timex.h>
#include <linux/malloc.h>
#include <linux/random.h>
#include <linux/delay.h>

#include <asm/bitops.h>
#include <asm/bootinfo.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mipsregs.h>
#include <asm/system.h>

#include <asm/baget/baget.h>

unsigned int local_bh_count[NR_CPUS];
unsigned int local_irq_count[NR_CPUS];
unsigned long spurious_count = 0;

atomic_t __mips_bh_counter;

/*
 * This table is a correspondence between IRQ numbers and CPU PILs
 */
 
static int irq_to_pil_map[BAGET_IRQ_NR] = { 
        7/*fixme: dma_err -1*/,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* 0x00 - 0x0f */
        -1,-1,-1,-1, 3,-1,-1,-1, 2, 2, 2,-1, 3,-1,-1,3/*fixme: lance*/, /* 0x10 - 0x1f */
        -1,-1,-1,-1,-1,-1, 5,-1,-1,-1,-1,-1, 7,-1,-1,-1, /* 0x20 - 0x2f */
        -1, 3, 2/*fixme systimer:3*/, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3  /* 0x30 - 0x3f */
};

static inline int irq_to_pil(int irq_nr) 
{
        int pil = -1;

        if (irq_nr >= BAGET_IRQ_NR) 
                baget_printk("irq_to_pil: too large irq_nr = 0x%x\n", irq_nr);
        else {
                pil = irq_to_pil_map[irq_nr];
                if (pil == -1)
                        baget_printk("irq_to_pil: unknown irq = 0x%x\n", irq_nr);
        }

        return pil;
}

/* Function for careful CP0 interrupt mask access */

static inline void modify_cp0_intmask(unsigned clr_mask, unsigned set_mask)
{
        unsigned long status = read_32bit_cp0_register(CP0_STATUS);
        status &= ~((clr_mask & 0xFF) << 8);
        status |=   (set_mask & 0xFF) << 8;
        write_32bit_cp0_register(CP0_STATUS, status);
}

/* 
 *  These two functions may be used for unconditional IRQ
 *  masking via their PIL protection.
 */

static inline void mask_irq(unsigned int irq_nr)
{
        modify_cp0_intmask(irq_to_pil(irq_nr), 0);
}

static inline void unmask_irq(unsigned int irq_nr)
{
        modify_cp0_intmask(0, irq_to_pil(irq_nr));
}

/*
 * The following section is introduced for masking/unasking IRQ
 * only while no more IRQs uses same CPU PIL.
 *
 * These functions are used in request_irq, free_irq, but it looks
 * they cannot change something: CP0_STATUS is private for any
 * process, and their action is invisible for system.
 */

static volatile unsigned int pil_in_use[BAGET_PIL_NR] = { 0, };

void mask_irq_count(int irq_nr) 
{
        unsigned long flags;
        int pil = irq_to_pil(irq_nr);
        
        save_and_cli(flags);
        if (!--pil_in_use[pil])
                mask_irq(irq_nr);
        restore_flags(flags);
}

void unmask_irq_count(int irq_nr) 
{
        unsigned long flags;
        int pil = irq_to_pil(irq_nr);
        
        save_and_cli(flags);
        if (!pil_in_use[pil]++)
                unmask_irq(irq_nr);
        restore_flags(flags);
}

/*
 * Two functions below are exported versions of mask/unmask IRQ
 */

void disable_irq(unsigned int irq_nr)
{
        unsigned long flags;

        save_and_cli(flags);
        mask_irq(irq_nr);
        restore_flags(flags);
}

void enable_irq(unsigned int irq_nr)
{
        unsigned long flags;

        save_and_cli(flags);
        unmask_irq(irq_nr);
        restore_flags(flags);
}

/*
 * Data definition for static irqaction allocation.
 * It is used while SLAB module is not initialized.
 */

#define MAX_STATIC_ALLOC 4 
struct irqaction static_irqaction[MAX_STATIC_ALLOC];
int static_irq_count = 0;
 
/*
 * Pointers to the low-level handlers: first the general ones, then the
 * fast ones, then the bad ones.
 */
static struct irqaction *irq_action[BAGET_IRQ_NR] = { NULL, };

int get_irq_list(char *buf)
{
        int i, len = 0;
        struct irqaction * action;

        for (i = 0 ; i < BAGET_IRQ_NR ; i++) {
                action = irq_action[i];
                if (!action) 
                        continue;
                len += sprintf(buf+len, "%2d: %8d %c %s",
                        i, kstat.irqs[0][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");
        }
        return len;
}


/*
 * 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.
 */
static void do_IRQ(int irq, struct pt_regs * regs)
{
        struct irqaction *action;
        int do_random, cpu;

        cpu = smp_processor_id();
        hardirq_enter(cpu);
        kstat.irqs[cpu][irq]++;

        mask_irq(irq);  
        action = *(irq + irq_action);
        if (action) {
                if (!(action->flags & SA_INTERRUPT))
                        __sti();
                action = *(irq + irq_action);
                do_random = 0;
                do {
                        do_random |= action->flags;
                        action->handler(irq, action->dev_id, regs);
                        action = action->next;
                } while (action);
                if (do_random & SA_SAMPLE_RANDOM)
                        add_interrupt_randomness(irq);
                __cli();
        } else {
                printk("do_IRQ: Unregistered IRQ (0x%X) occured\n", irq);
        }
        unmask_irq(irq);
        hardirq_exit(cpu);

        /* unmasking and bottom half handling is done magically for us. */
}

/*
 *  What to do in case of 'no VIC register available' for current interrupt
 */
static void vic_reg_error(unsigned long address, unsigned char active_pils) 
{
        printk("\nNo VIC register found: reg=%08lx active_pils=%02x\n"
               "Current interrupt mask from CP0_CAUSE: %02x\n", 
               address, 0xff & active_pils, 
               0xff & (read_32bit_cp0_register(CP0_CAUSE)>>8));
        { int i; for (i=0; i<10000; i++) udelay(1000); }
}       

static char baget_fpu_irq = BAGET_FPU_IRQ;
#define BAGET_INT_FPU {(unsigned long)&baget_fpu_irq, 1}

/*
 *  Main interrupt handler: interrupt demultiplexer
 */
asmlinkage void baget_interrupt(struct pt_regs *regs)
{
        static struct baget_int_reg int_reg[BAGET_PIL_NR] = { 
                BAGET_INT_NONE, BAGET_INT_NONE, BAGET_INT0_ACK, BAGET_INT1_ACK,
                BAGET_INT_NONE, BAGET_INT_FPU,  BAGET_INT_NONE, BAGET_INT5_ACK 
        };
        unsigned char active_pils;
        while ((active_pils = read_32bit_cp0_register(CP0_CAUSE)>>8)) {
                int pil;
                struct baget_int_reg* reg;

                for (pil = 0; pil < BAGET_PIL_NR; pil++) {
                        if (!(active_pils & (1<<pil))) continue;
                        
                        reg = &int_reg[pil];

                        if (reg->address) {
                                extern int try_read(unsigned long,int);
                                int irq  = try_read(reg->address, reg->size);

                                if (irq != -1) 
                                      do_IRQ(BAGET_IRQ_MASK(irq), regs);
                                else 
                                      vic_reg_error(reg->address, active_pils);
                        } else {
                                printk("baget_interrupt: unknown interrupt "
                                       "(pil = %d)\n", pil);
                        }
                }
        }
}

/*
 * Idea is to put all interrupts
 * in a single table and differenciate them just by number.
 */
int setup_baget_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_and_cli(flags);
        *p = new;
        restore_flags(flags);

        if (!shared) {
                unmask_irq_count(irq);
        }

        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 = NULL;

        if (irq >= BAGET_IRQ_NR)
                return -EINVAL;
        if (!handler)
                return -EINVAL;
        if (irq_to_pil_map[irq] < 0) 
                return -EINVAL;

        if (irqflags & SA_STATIC_ALLOC) {
                unsigned long flags;

                save_and_cli(flags);
                if (static_irq_count < MAX_STATIC_ALLOC)
                        action = &static_irqaction[static_irq_count++];
                else 
                        printk("Request for IRQ%d (%s) SA_STATIC_ALLOC failed "
                               "using kmalloc\n", irq, devname);
                restore_flags(flags);
        }
  
        if (action == NULL)
                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_baget_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 >= BAGET_IRQ_NR) 
                printk("Trying to free IRQ%d\n",irq);

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

                /* Found it - now free it */
                save_and_cli(flags);
                *p = action->next;
                if (!irq[irq_action])
                        unmask_irq_count(irq);
                restore_flags(flags);

                if (action->flags & SA_STATIC_ALLOC)
                {
                        /* This interrupt is marked as specially allocated
                         * so it is a bad idea to free it.
                         */
                        printk("Attempt to free statically allocated "
                               "IRQ%d (%s)\n", irq, action->name);
                        return;
                }
 
                kfree(action);
                return;
        }
        printk("Trying to free free IRQ%d\n",irq);
}

static int baget_irq_canonicalize(int irq) 
{
        return irq;
}

int (*irq_cannonicalize)(int irq) = baget_irq_canonicalize; 

unsigned long probe_irq_on (void)
{
        /* TODO */
        return 0;
}

int probe_irq_off (unsigned long irqs)
{
        /* TODO */
        return 0;
}


static void write_err_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        *(volatile char*) BAGET_WRERR_ACK = 0;
}

void __init init_IRQ(void)
{
        irq_setup();

        /* Enable access to VIC interrupt registers */
        vac_outw(0xacef | 0x8200, VAC_PIO_FUNC);

        /* Enable interrupts for pils 2 and 3 (lines 0 and 1) */
        modify_cp0_intmask(0, (1<<2)|(1<<3));

        if (request_irq(0/*fixme*/, write_err_interrupt, 
                        SA_INTERRUPT|SA_STATIC_ALLOC, "write_err", NULL) < 0) 
                printk("init_IRQ: unable to register write_err irq\n");
}