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/*

 * arch/m68k/atari/ataints.c -- Atari Linux interrupt handling code

 *

 * 5/2/94 Roman Hodek:

 *  Added support for TT interrupts; setup for TT SCU (may someone has

 *  twiddled there and we won't get the right interrupts :-()

 *

 *  Major change: The device-independent code in m68k/ints.c didn't know

 *  about non-autovec ints yet. It hardcoded the number of possible ints to

 *  7 (IRQ1...IRQ7). But the Atari has lots of non-autovec ints! I made the

 *  number of possible ints a constant defined in interrupt.h, which is

 *  47 for the Atari. So we can call add_isr() for all Atari interrupts just

 *  the normal way. Additionally, all vectors >= 48 are initialized to call

 *  trap() instead of inthandler(). This must be changed here, too.

 *

 * 1995-07-16 Lars Brinkhoff <f93labr@dd.chalmers.se>:

 *  Corrected a bug in atari_add_isr() which rejected all SCC

 *  interrupt sources if there were no TT MFP!

 *

 * 12/13/95: New interface functions atari_level_triggered_int() and

 *  atari_register_vme_int() as support for level triggered VME interrupts.

 *

 * 02/12/96: (Roman)

 *  Total rewrite of Atari interrupt handling, for new scheme see comments

 *  below.

 *

 * 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.

 *

 */

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/ptrace.h>

#include <linux/kernel_stat.h>

#include <asm/system.h>

#include <asm/traps.h>

#include <asm/atarihw.h>

#include <asm/atariints.h>

#include <asm/atari_stdma.h>

#include <asm/bootinfo.h>

#include <asm/irq.h>

/*

 * Atari interrupt handling scheme:

 * --------------------------------

 *

 * All interrupt source have an internal number (defined in

 * <asm/atariints.h>): Autovector interrupts are 1..7, then follow ST-MFP,

 * TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can

 * be allocated by atari_register_vme_int(). Currently, all int source numbers

 * have the IRQ_MACHSPEC bit set, to keep the general int handling functions

 * in kernel/ints.c from them.

 *

 * Each interrupt can be of three types:

 *

 *  - SLOW: The handler runs with all interrupts enabled, except the one it

 *    was called by (to avoid reentering). This should be the usual method.

 *    But it is currently possible only for MFP ints, since only the MFP

 *    offers an easy way to mask interrupts.

 *

 *  - FAST: The handler runs with all interrupts disabled. This should be used

 *    only for really fast handlers, that just do actions immediately

 *    necessary, and let the rest do a bottom half or task queue.

 *

 *  - PRIORITIZED: The handler can be interrupted by higher-level ints

 *    (greater IPL, no MFP priorities!). This is the method of choice for ints

 *    which should be slow, but are not from a MFP.

 *

 * The feature of more than one handler for one int source is still there, but

 * only applicable if all handers are of the same type. To not slow down

 * processing of ints with only one handler by the chaining feature, the list

 * calling function atari_call_isr_list() is only plugged in at the time the

 * second handler is registered.

 *

 * Implementation notes: For fast-as-possible int handling, there are separate

 * entry points for each type (slow/fast/prio). The assembler handler calls

 * the isr directly in the usual case, no C wrapper is involved. In case of

 * multiple handlers, atari_call_isr_list() is registered as handler and calls

 * in turn the real isr's. To ease access from assembler level to the isr

 * function pointer and accompanying data, these two are stored in a separate

 * array, irq_handler[]. The rest of data (type, name) are put into a second

 * array, irq_param, that is accessed from C only. For each slow interrupt (32

 * in all) there are separate handler functions, which makes it possible to

 * hard-code the MFP register address and value, are necessary to mask the

 * int. If there'd be only one generic function, lots of calculations would be

 * needed to determine MFP register and int mask from the vector number :-(

 *

 * Furthermore, slow ints may not lower the IPL below its previous value

 * (before the int happened). This is needed so that an int of class PRIO, on

 * that this int may be stacked, cannot be reentered. This feature is

 * implemented as follows: If the stack frame format is 1 (throwaway), the int

 * is not stacked, and the IPL is anded with 0xfbff, resulting in a new level

 * 2, which still blocks the HSYNC, but no interrupts of interest. If the

 * frame format is 0, the int is nested, and the old IPL value can be found in

 * the sr copy in the frame.

 */

#define NUM_INT_SOURCES (8 + NUM_ATARI_SOURCES)

typedef void (*asm_irq_handler)(void);

struct irqhandler {

        isrfunc isr;

        void    *data;

};

struct irqparam {

        int type;

        char *name;

};

/*

 * Array with isr's and their parameter data. This array is accessed from low

 * level assembler code, so an element size of 8 allows usage of index scaling

 * addressing mode.

 */

static struct irqhandler irq_handler[NUM_INT_SOURCES];

/*

 * This array hold the rest of parameters of int handlers: type

 * (slow,fast,prio) and the name of the handler. These values are only

 * accessed from C

 */

static struct irqparam irq_param[NUM_INT_SOURCES];

/*

 * Counter for next free interrupt vector number

 * (new vectors starting from 0x70 can be allocated by

 * atari_register_vme_int())

 */

static int next_free_vme_vec = VME_SOURCE_BASE;

/* check for valid int number (complex, sigh...) */

#define IS_VALID_INTNO(n)                                                                                       \

        ((n) > 0 &&                                                                                                              \

         /* autovec and ST-MFP ok anyway */                                                             \

         (((n) < TTMFP_SOURCE_BASE) ||                                                                  \

          /* TT-MFP ok if present */                                                                    \

          ((n) >= TTMFP_SOURCE_BASE && (n) < SCC_SOURCE_BASE &&                 \

           ATARIHW_PRESENT(TT_MFP)) ||                                                                  \

          /* SCC ok if present and number even */                                               \

          ((n) >= SCC_SOURCE_BASE && (n) < VME_SOURCE_BASE &&                   \

           !((n) & 1) && ATARIHW_PRESENT(SCC)) ||                                               \

          /* greater numbers ok if less than #registered VME vectors */ \

          ((n) >= VME_SOURCE_BASE && (n) < next_free_vme_vec)))

/*

 * Here start the assembler entry points for interrupts

 */

#define IRQ_NAME(nr) atari_slow_irq_##nr##_handler(void)

#define MFP_MK_BASE     "0xfa13"

/* This must agree with head.S.  */

#define ORIG_DO "0x20"

#define FORMATVEC "0x2E"

#define SR "0x28"

#define SAVE_ALL                                \

        "clrl   %%sp@-;"    /* stk_adj */       \

        "clrl   %%sp@-;"                        \

        "subql  #1,%%sp@;"  /* orig d0 = -1 */  \

        "movel  %%d0,%%sp@-;" /* d0 */          \

        "moveml %%d1-%%d5/%%a0-%%a1,%%sp@-"

#define BUILD_SLOW_IRQ(n)                                                  \

asmlinkage void IRQ_NAME(n);                                               \

/* Dummy function to allow asm with operands.  */                          \

void atari_slow_irq_##n##_dummy (void) {                                   \

__asm__ (ALIGN_STR "\n"                                                    \

SYMBOL_NAME_STR(atari_slow_irq_) #n "_handler:\t"                          \

        SAVE_ALL "\n"                                                      \

"       addql   #1,"SYMBOL_NAME_STR(intr_count)"\n"                        \

"       andb    #~(1<<(" #n "&7)),"     /* mask this interrupt */          \

        "("MFP_MK_BASE"+(((" #n "&8)^8)>>2)+((" #n "&16)<<3)):w\n"         \

"       movew   %%sp@("SR"),%%d0\n"     /* get old IPL from stack frame */ \

"       movew   %%sr,%%d1\n"                                               \

"       andw    #0x0700,%%d0\n"                                            \

"       andw    #0xf8ff,%%d1\n"                                            \

"       orw     %%d0,%%d1\n"                                               \

"       movew   %%d1,%%sr\n"            /* set IPL = previous value */     \

"       addql   #1,%a0\n"                                                  \

"       lea     "SYMBOL_NAME_STR(irq_handler)"+("#n"+8)*8,%%a0\n"          \

"       movel   %%a0@(4),%%sp@-\n"      /* push handler data */            \

"       pea     %%sp@(4)\n"             /* push addr of frame */           \

"       pea     (" #n "+8):w\n"         /* push int number */              \

"       movel   %%a0@,%%a0\n"                                              \

"       jbsr    %%a0@\n"                /* call the handler */             \

"       addql   #8,%%sp\n"                                                 \

"       addql   #4,%%sp\n"                                                 \

"       orw     #0x0600,%%sr\n"                                            \

"       andw    #0xfeff,%%sr\n"         /* set IPL = 6 again */            \

"       orb     #(1<<(" #n "&7)),"      /* now unmask the int again */     \

            "("MFP_MK_BASE"+(((" #n "&8)^8)>>2)+((" #n "&16)<<3)):w\n"     \

"       jbra    "SYMBOL_NAME_STR(ret_from_interrupt)"\n"                   \

         : : "i" (&kstat.interrupts[n+8])                                  \

);                                                                         \

}

BUILD_SLOW_IRQ(0);

BUILD_SLOW_IRQ(1);

BUILD_SLOW_IRQ(2);

BUILD_SLOW_IRQ(3);

BUILD_SLOW_IRQ(4);

BUILD_SLOW_IRQ(5);

BUILD_SLOW_IRQ(6);

BUILD_SLOW_IRQ(7);

BUILD_SLOW_IRQ(8);

BUILD_SLOW_IRQ(9);

BUILD_SLOW_IRQ(10);

BUILD_SLOW_IRQ(11);

BUILD_SLOW_IRQ(12);

BUILD_SLOW_IRQ(13);

BUILD_SLOW_IRQ(14);

BUILD_SLOW_IRQ(15);

BUILD_SLOW_IRQ(16);

BUILD_SLOW_IRQ(17);

BUILD_SLOW_IRQ(18);

BUILD_SLOW_IRQ(19);

BUILD_SLOW_IRQ(20);

BUILD_SLOW_IRQ(21);

BUILD_SLOW_IRQ(22);

BUILD_SLOW_IRQ(23);

BUILD_SLOW_IRQ(24);

BUILD_SLOW_IRQ(25);

BUILD_SLOW_IRQ(26);

BUILD_SLOW_IRQ(27);

BUILD_SLOW_IRQ(28);

BUILD_SLOW_IRQ(29);

BUILD_SLOW_IRQ(30);

BUILD_SLOW_IRQ(31);

asm_irq_handler slow_handlers[32] = {

        atari_slow_irq_0_handler,

        atari_slow_irq_1_handler,

        atari_slow_irq_2_handler,

        atari_slow_irq_3_handler,

        atari_slow_irq_4_handler,

        atari_slow_irq_5_handler,

        atari_slow_irq_6_handler,

        atari_slow_irq_7_handler,

        atari_slow_irq_8_handler,

        atari_slow_irq_9_handler,

        atari_slow_irq_10_handler,

        atari_slow_irq_11_handler,

        atari_slow_irq_12_handler,

        atari_slow_irq_13_handler,

        atari_slow_irq_14_handler,

        atari_slow_irq_15_handler,

        atari_slow_irq_16_handler,

        atari_slow_irq_17_handler,

        atari_slow_irq_18_handler,

        atari_slow_irq_19_handler,

        atari_slow_irq_20_handler,

        atari_slow_irq_21_handler,

        atari_slow_irq_22_handler,

        atari_slow_irq_23_handler,

        atari_slow_irq_24_handler,

        atari_slow_irq_25_handler,

        atari_slow_irq_26_handler,

        atari_slow_irq_27_handler,

        atari_slow_irq_28_handler,

        atari_slow_irq_29_handler,

        atari_slow_irq_30_handler,

        atari_slow_irq_31_handler

};

asmlinkage void atari_fast_irq_handler( void );

asmlinkage void atari_prio_irq_handler( void );

/* Dummy function to allow asm with operands.  */

void atari_fast_prio_irq_dummy (void) {

__asm__ (ALIGN_STR "\n"

SYMBOL_NAME_STR(atari_fast_irq_handler) ":

        orw     #0x700,%%sr             /* disable all interrupts */

"SYMBOL_NAME_STR(atari_prio_irq_handler) ":\t"

        SAVE_ALL "

        addql   #1,"SYMBOL_NAME_STR(intr_count)"

        movew   %%sp@(" FORMATVEC "),%%d0       /* get vector number from stack frame */

        andil   #0xfff,%%d0             /* mask off format nibble */

        lsrl    #2,%%d0                 /* convert vector to source */

        subl    #(0x40-8),%%d0

        jpl     1f

        addl    #(0x40-8-0x18),%%d0

1:      lea     %a0,%%a0

        addql   #1,%%a0@(%%d0:l:4)

        lea     "SYMBOL_NAME_STR(irq_handler)",%%a0

        lea     %%a0@(%%d0:l:8),%%a0

        movel   %%a0@(4),%%sp@-         /* push handler data */

        pea     %%sp@(4)                /* push frame address */

        movel   %%d0,%%sp@-             /* push int number */

        movel   %%a0@,%%a0

        jsr     %%a0@                   /* and call the handler */

        addql   #8,%%sp

        addql   #4,%%sp

        jbra    "SYMBOL_NAME_STR(ret_from_interrupt)

         : : "i" (&kstat.interrupts)

);

}

/* GK:

 * HBL IRQ handler for Falcon. Nobody needs it :-)

 * ++andreas: raise ipl to disable further HBLANK interrupts.

 */

asmlinkage void falcon_hblhandler(void);

asm(".text\n"

ALIGN_STR "\n"

SYMBOL_NAME_STR(falcon_hblhandler) ":

        movel   %d0,%sp@-

        movew   %sp@(4),%d0

        andw    #0xf8ff,%d0

        orw     #0x0200,%d0     /* set saved ipl to 2 */

        movew   %d0,%sp@(4)

        movel   %sp@+,%d0

        rte");

/* Defined in entry.S; only increments 'num_spurious' */

asmlinkage void bad_interrupt(void);

extern void atari_microwire_cmd( int cmd );

/*

 * void atari_init_INTS (void)

 *

 * Parameters:  None

 *

 * Returns:     Nothing

 *

 * This function should be called during kernel startup to initialize

 * the atari IRQ handling routines.

 */

void atari_init_INTS(void)

{

        int i;

        /* initialize the vector table */

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

                vectors[IRQ_SOURCE_TO_VECTOR(i)] = bad_interrupt;

        }

        /* Initialize the MFP(s) */

#ifdef ATARI_USE_SOFTWARE_EOI

        mfp.vec_adr  = 0x48;    /* Software EOI-Mode */

#else

        mfp.vec_adr  = 0x40;    /* Automatic EOI-Mode */

#endif

        mfp.int_en_a =              /* turn off MFP-Ints */

        mfp.int_en_b = 0x00;

        mfp.int_mk_a =                  /* no Masking */

        mfp.int_mk_b = 0xff;

        if (ATARIHW_PRESENT(TT_MFP)) {

#ifdef ATARI_USE_SOFTWARE_EOI

                tt_mfp.vec_adr  = 0x58;         /* Software EOI-Mode */

#else

                tt_mfp.vec_adr  = 0x50;         /* Automatic EOI-Mode */

#endif

                tt_mfp.int_en_a =                       /* turn off MFP-Ints */

                tt_mfp.int_en_b = 0x00;

                tt_mfp.int_mk_a =                       /* no Masking */

                tt_mfp.int_mk_b = 0xff;

        }

        if (ATARIHW_PRESENT(SCC)) {

                scc.cha_a_ctrl = 9;

                MFPDELAY();

                scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */

        }

        if (ATARIHW_PRESENT(SCU)) {

                /* init the SCU if present */

                tt_scu.sys_mask = 0x10;         /* enable VBL (for the cursor) and

                                                                         * disable HSYNC interrupts (who

                                                                         * needs them?)  MFP and SCC are

                                                                         * enabled in VME mask

                                                                         */

                tt_scu.vme_mask = 0x60;         /* enable MFP and SCC ints */

        }

        else {

                /* If no SCU, the HSYNC interrupt needs to be disabled this

                 * way. (Else _inthandler in kernel/sys_call.S gets overruns)

                 */

                vectors[VEC_INT2] = falcon_hblhandler;

        }

        if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {

                /* Initialize the LM1992 Sound Controller to enable

                   the PSG sound.  This is misplaced here, it should

                   be in a atasound_init(), that doesn't exist yet. */

                atari_microwire_cmd(MW_LM1992_PSG_HIGH);

        }

        stdma_init();

        /* Initialize the PSG: all sounds off, both ports output */

        sound_ym.rd_data_reg_sel = 7;

        sound_ym.wd_data = 0xff;

}

static void atari_call_isr_list( int irq, struct pt_regs *fp, void *_p )

{

  isr_node_t *p;

  for( p = (isr_node_t *)_p; p; p = p->next )

    p->isr( irq, fp, p->data );

}

/*

 * atari_add_isr : add an interrupt service routine for a particular

 *                 machine specific interrupt source.

 *                 If the addition was successful, it returns 1, otherwise

 *                 it returns 0.  It will fail if the interrupt is already

 *                 occupied of another handler with different type

 */

int atari_add_isr(unsigned long source, isrfunc isr, int type, void

                  *data, char *name)

{

        int vector;

        source &= ~IRQ_MACHSPEC;

        if (type < IRQ_TYPE_SLOW || type > IRQ_TYPE_PRIO) {

                printk ("atari_add_isr: Bad irq type %d requested from %s\n",

                                type, name );

                return( 0 );

        }

        if (!IS_VALID_INTNO(source)) {

                printk ("atari_add_isr: Unknown irq %ld requested from %s\n",

                                source, name );

                return( 0 );

        }

        vector = IRQ_SOURCE_TO_VECTOR(source);

        /*

         * Check type/source combination: slow ints are (currently)

         * only possible for MFP-interrupts.

         */

        if (type == IRQ_TYPE_SLOW &&

                (source < STMFP_SOURCE_BASE || source >= SCC_SOURCE_BASE)) {

                printk ("atari_add_isr: Slow irq requested for non-MFP source %ld from %s\n",

                                source, name );

                return( 0 );

        }

        if (vectors[vector] == bad_interrupt) {

                /* int has no handler yet */

                irq_handler[source].isr = isr;

                irq_handler[source].data = data;

                irq_param[source].type = type;

                irq_param[source].name = name;

                vectors[vector] =

                        (type == IRQ_TYPE_SLOW) ? slow_handlers[source-STMFP_SOURCE_BASE] :

                        (type == IRQ_TYPE_FAST) ? atari_fast_irq_handler :

                                                                          atari_prio_irq_handler;

                /* If MFP int, also enable and umask it */

                atari_turnon_irq(source);

                atari_enable_irq(source);

                return 1;

        }

        else if (irq_param[source].type == type) {

                /* old handler is of same type -> handlers can be chained */

                isr_node_t *p;

                unsigned long flags;

                save_flags(flags);

                cli();

                if (irq_handler[source].isr != atari_call_isr_list) {

                        /* Only one handler yet, make a node for this first one */

                        p = new_isr_node();

                        if (p == NULL) return 0;

                        p->isr = irq_handler[source].isr;

                        p->data = irq_handler[source].data;

                        p->name = irq_param[source].name;

                        p->next = NULL;

                        irq_handler[source].isr = atari_call_isr_list;

                        irq_handler[source].data = p;

                        irq_param[source].name = "chained";

                }

                p = new_isr_node();

                if (p == NULL) return 0;

                p->isr = isr;

                p->data = data;

                p->name = name;

                /* new handlers are put in front of the queue */

                p->next = irq_handler[source].data;

                irq_handler[source].data = p;

                restore_flags(flags);

                return 1;

        }

        else {

                printk ("atari_add_isr: Irq %ld allocated by other type int (call from %s)\n",

                                source, name );

                return( 0 );

        }

}

int atari_remove_isr(unsigned long source, isrfunc isr, void *data)

{

        unsigned long flags;

        int vector;

        isr_node_t **p, *q;

        source &= ~IRQ_MACHSPEC;

        if (!IS_VALID_INTNO(source)) {

                printk("atari_remove_isr: Unknown irq %ld\n", source);

                return 0;

        }

        vector = IRQ_SOURCE_TO_VECTOR(source);

        if (vectors[vector] == bad_interrupt)

                goto not_found;

        save_flags(flags);

        cli();

        if (irq_handler[source].isr != atari_call_isr_list) {

                /* It's the only handler for the interrupt */

                if (irq_handler[source].isr != isr &&

                    irq_handler[source].data != data) {

                        restore_flags(flags);

                        goto not_found;

                }

                irq_handler[source].isr = NULL;

                irq_handler[source].data = NULL;

                irq_param[source].name = NULL;

                vectors[vector] = bad_interrupt;

                /* If MFP int, also disable it */

                atari_disable_irq(source);

                atari_turnoff_irq(source);

                restore_flags(flags);

                return 1;

        }

        /* The interrupt is chained, find the isr on the list */

        for( p = (isr_node_t **)&irq_handler[source].data; *p; p = &(*p)->next ) {

                if ((*p)->isr == isr) break;

        }

        if (!*p) {

                restore_flags(flags);

                goto not_found;

        }

        (*p)->isr = NULL; /* Mark it as free for reallocation */

        *p = (*p)->next;

        /* If there's now only one handler, unchain the interrupt, i.e. plug in

         * the handler directly again and omit atari_call_isr_list */

        q = (isr_node_t *)irq_handler[source].data;

        if (q && !q->next) {

                irq_handler[source].isr = q->isr;

                irq_handler[source].data = q->data;

                irq_param[source].name = q->name;

                q->isr = NULL; /* Mark it as free for reallocation */

        }

        restore_flags(flags);

        return 1;

  not_found:

        printk("atari_remove_isr: isr %p not found on list!\n", isr);

        return 0;

}

/*

 * atari_register_vme_int() returns the number of a free interrupt vector for

 * hardware with a programmable int vector (probably a VME board).

 */

unsigned long atari_register_vme_int(void)

{

        unsigned long source;

        if (next_free_vme_vec == NUM_ATARI_SOURCES)

                return 0;

        source = next_free_vme_vec | IRQ_MACHSPEC;

        next_free_vme_vec++;

        return source;

}

int atari_get_irq_list(char *buf, int len)

{

        int i;

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

                if (vectors[IRQ_SOURCE_TO_VECTOR(i)] == bad_interrupt)

                        continue;

                if (i < STMFP_SOURCE_BASE)

                        len += sprintf(buf+len, "auto %2d: %8d ",

                                       i, kstat.interrupts[i]);

                else

                        len += sprintf(buf+len, "vec $%02x: %8d ",

                                       IRQ_SOURCE_TO_VECTOR(i),

                                       kstat.interrupts[i]);

                if (irq_handler[i].isr != atari_call_isr_list) {

                        len += sprintf(buf+len, "%s\n", irq_param[i].name);

                }

                else {

                        isr_node_t *p;

                        for( p = (isr_node_t *)irq_handler[i].data; p; p = p->next ) {

                                len += sprintf(buf+len, "%s\n", p->name);

                                if (p->next)

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

                        }

                }

        }

        if (num_spurious)

                len += sprintf(buf+len, "spurio.: %8ld\n", num_spurious);

        return len;

}