ataints.c

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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 request_irq() 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 <[email protected]>:
 *  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.
 *
 * 1996-09-03 lars brinkhoff <[email protected]>:
 *  Added new function atari_unregister_vme_int(), and
 *  modified atari_register_vme_int() as well as IS_VALID_INTNO()
 *  to work with it.
 *
 * 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/kernel_stat.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/module.h>

#include <asm/traps.h>

#include <asm/atarihw.h>
#include <asm/atariints.h>
#include <asm/atari_stdma.h>
#include <asm/irq.h>
#include <asm/entry.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().
 */

/*
 * Bitmap for free interrupt vector numbers
 * (new vectors starting from 0x70 can be allocated by
 * atari_register_vme_int())
 */
static int free_vme_vec_bitmap;

/* 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\t"
"falcon_hblhandler:\n\t"
    "orw    #0x200,%sp@\n\t"    /* set saved ipl to 2 */
    "rte");

extern void atari_microwire_cmd(int cmd);

static unsigned int atari_irq_startup(struct irq_data *data)
{
    unsigned int irq = data->irq;

    m68k_irq_startup(data);
    atari_turnon_irq(irq);
    atari_enable_irq(irq);
    return 0;
}

static void atari_irq_shutdown(struct irq_data *data)
{
    unsigned int irq = data->irq;

    atari_disable_irq(irq);
    atari_turnoff_irq(irq);
    m68k_irq_shutdown(data);

    if (irq == IRQ_AUTO_4)
        vectors[VEC_INT4] = falcon_hblhandler;
}

static void atari_irq_enable(struct irq_data *data)
{
    atari_enable_irq(data->irq);
}

static void atari_irq_disable(struct irq_data *data)
{
    atari_disable_irq(data->irq);
}

static struct irq_chip atari_irq_chip = {
    .name       = "atari",
    .irq_startup    = atari_irq_startup,
    .irq_shutdown   = atari_irq_shutdown,
    .irq_enable = atari_irq_enable,
    .irq_disable    = atari_irq_disable,
};

/*
 * void atari_init_IRQ (void)
 *
 * Parameters:  None
 *
 * Returns: Nothing
 *
 * This function should be called during kernel startup to initialize
 * the atari IRQ handling routines.
 */

void __init atari_init_IRQ(void)
{
    m68k_setup_user_interrupt(VEC_USER, NUM_ATARI_SOURCES - IRQ_USER);
    m68k_setup_irq_controller(&atari_irq_chip, handle_simple_irq, 1,
                  NUM_ATARI_SOURCES - 1);

    /* Initialize the MFP(s) */

#ifdef ATARI_USE_SOFTWARE_EOI
    st_mfp.vec_adr  = 0x48; /* Software EOI-Mode */
#else
    st_mfp.vec_adr  = 0x40; /* Automatic EOI-Mode */
#endif
    st_mfp.int_en_a = 0x00; /* turn off MFP-Ints */
    st_mfp.int_en_b = 0x00;
    st_mfp.int_mk_a = 0xff; /* no Masking */
    st_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 = 0x00;     /* turn off MFP-Ints */
        tt_mfp.int_en_b = 0x00;
        tt_mfp.int_mk_a = 0xff;     /* no Masking */
        tt_mfp.int_mk_b = 0xff;
    }

    if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
        atari_scc.cha_a_ctrl = 9;
        MFPDELAY();
        atari_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 and no Hades, the HSYNC interrupt needs to be
         * disabled this way. (Else _inthandler in kernel/sys_call.S
         * gets overruns)
         */

        vectors[VEC_INT2] = falcon_hblhandler;
        vectors[VEC_INT4] = 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 an 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;
}


/*
 * atari_register_vme_int() returns the number of a free interrupt vector for
 * hardware with a programmable int vector (probably a VME board).
 */

unsigned int atari_register_vme_int(void)
{
    int i;

    for (i = 0; i < 32; i++)
        if ((free_vme_vec_bitmap & (1 << i)) == 0)
            break;

    if (i == 16)
        return 0;

    free_vme_vec_bitmap |= 1 << i;
    return VME_SOURCE_BASE + i;
}
EXPORT_SYMBOL(atari_register_vme_int);


void atari_unregister_vme_int(unsigned int irq)
{
    if (irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
        irq -= VME_SOURCE_BASE;
        free_vme_vec_bitmap &= ~(1 << irq);
    }
}
EXPORT_SYMBOL(atari_unregister_vme_int);