KVM: Handle spurious acks for PIT interrupts

[linux-2.6.git] / arch / m68k / mac / via.c

/*
 *      6522 Versatile Interface Adapter (VIA)
 *
 *      There are two of these on the Mac II. Some IRQs are vectored
 *      via them as are assorted bits and bobs - eg RTC, ADB.
 *
 * CSA: Motorola seems to have removed documentation on the 6522 from
 * their web site; try
 *     http://nerini.drf.com/vectrex/other/text/chips/6522/
 *     http://www.zymurgy.net/classic/vic20/vicdet1.htm
 * and
 *     http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html
 * for info.  A full-text web search on 6522 AND VIA will probably also
 * net some usefulness. <cananian@alumni.princeton.edu> 20apr1999
 *
 * Additional data is here (the SY6522 was used in the Mac II etc):
 *     http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf
 *     http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf
 *
 * PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b
 * by Erik Vogan and adapted to Linux by Joshua M. Thompson (funaho@jurai.org)
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/module.h>

#include <asm/bootinfo.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/machw.h>
#include <asm/mac_via.h>
#include <asm/mac_psc.h>

volatile __u8 *via1, *via2;
#if 0
/* See note in mac_via.h about how this is possibly not useful */
volatile long *via_memory_bogon=(long *)&via_memory_bogon;
#endif
int rbv_present;
int via_alt_mapping;
EXPORT_SYMBOL(via_alt_mapping);
static __u8 rbv_clear;

/*
 * Globals for accessing the VIA chip registers without having to
 * check if we're hitting a real VIA or an RBV. Normally you could
 * just hit the combined register (ie, vIER|rIER) but that seems to
 * break on AV Macs...probably because they actually decode more than
 * eight address bits. Why can't Apple engineers at least be
 * _consistently_ lazy?                          - 1999-05-21 (jmt)
 */

static int gIER,gIFR,gBufA,gBufB;

/*
 * Timer defs.
 */

#define TICK_SIZE               10000
#define MAC_CLOCK_TICK          (783300/HZ)             /* ticks per HZ */
#define MAC_CLOCK_LOW           (MAC_CLOCK_TICK&0xFF)
#define MAC_CLOCK_HIGH          (MAC_CLOCK_TICK>>8)

/* To disable a NuBus slot on Quadras we make the slot IRQ lines outputs, set
 * high. On RBV we just use the slot interrupt enable register. On Macs with
 * genuine VIA chips we must use nubus_disabled to keep track of disabled slot
 * interrupts. When any slot IRQ is disabled we mask the (edge triggered) CA1
 * or "SLOTS" interrupt. When no slot is disabled, we unmask the CA1 interrupt.
 * So, on genuine VIAs, having more than one NuBus IRQ can mean trouble,
 * because closing one of those drivers can mask all of the NuBus interrupts.
 * Also, since we can't mask the unregistered slot IRQs on genuine VIAs, it's
 * possible to get interrupts from cards that MacOS or the ROM has configured
 * but we have not. FWIW, "Designing Cards and Drivers for Macintosh II and
 * Macintosh SE", page 9-8, says, a slot IRQ with no driver would crash MacOS.
 */
static u8 nubus_disabled;

void via_debug_dump(void);
irqreturn_t via1_irq(int, void *);
irqreturn_t via2_irq(int, void *);
irqreturn_t via_nubus_irq(int, void *);
void via_irq_enable(int irq);
void via_irq_disable(int irq);
void via_irq_clear(int irq);

extern irqreturn_t mac_scc_dispatch(int, void *);
extern int oss_present;

/*
 * Initialize the VIAs
 *
 * First we figure out where they actually _are_ as well as what type of
 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.)
 * Then we pretty much clear them out and disable all IRQ sources.
 *
 * Note: the OSS is actually "detected" here and not in oss_init(). It just
 *       seems more logical to do it here since via_init() needs to know
 *       these things anyways.
 */

void __init via_init(void)
{
        switch(macintosh_config->via_type) {

                /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */

                case MAC_VIA_IIci:
                        via1 = (void *) VIA1_BASE;
                        if (macintosh_config->ident == MAC_MODEL_IIFX) {
                                via2 = NULL;
                                rbv_present = 0;
                                oss_present = 1;
                        } else {
                                via2 = (void *) RBV_BASE;
                                rbv_present = 1;
                                oss_present = 0;
                        }
                        if (macintosh_config->ident == MAC_MODEL_LCIII) {
                                rbv_clear = 0x00;
                        } else {
                                /* on most RBVs (& unlike the VIAs), you   */
                                /* need to set bit 7 when you write to IFR */
                                /* in order for your clear to occur.       */
                                rbv_clear = 0x80;
                        }
                        gIER = rIER;
                        gIFR = rIFR;
                        gBufA = rSIFR;
                        gBufB = rBufB;
                        break;

                /* Quadra and early MacIIs agree on the VIA locations */

                case MAC_VIA_QUADRA:
                case MAC_VIA_II:
                        via1 = (void *) VIA1_BASE;
                        via2 = (void *) VIA2_BASE;
                        rbv_present = 0;
                        oss_present = 0;
                        rbv_clear = 0x00;
                        gIER = vIER;
                        gIFR = vIFR;
                        gBufA = vBufA;
                        gBufB = vBufB;
                        break;
                default:
                        panic("UNKNOWN VIA TYPE");
        }

        printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);

        printk(KERN_INFO "VIA2 at %p is ", via2);
        if (rbv_present) {
                printk("an RBV\n");
        } else if (oss_present) {
                printk("an OSS\n");
        } else {
                printk("a 6522 or clone\n");
        }

#ifdef DEBUG_VIA
        via_debug_dump();
#endif

        /*
         * Shut down all IRQ sources, reset the timers, and
         * kill the timer latch on VIA1.
         */

        via1[vIER] = 0x7F;
        via1[vIFR] = 0x7F;
        via1[vT1LL] = 0;
        via1[vT1LH] = 0;
        via1[vT1CL] = 0;
        via1[vT1CH] = 0;
        via1[vT2CL] = 0;
        via1[vT2CH] = 0;
        via1[vACR] &= 0x3F;
        via1[vACR] &= ~0x03; /* disable port A & B latches */

        /*
         * SE/30: disable video IRQ
         * XXX: testing for SE/30 VBL
         */

        if (macintosh_config->ident == MAC_MODEL_SE30) {
                via1[vDirB] |= 0x40;
                via1[vBufB] |= 0x40;
        }

        /*
         * Set the RTC bits to a known state: all lines to outputs and
         * RTC disabled (yes that's 0 to enable and 1 to disable).
         */

        via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData);
        via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk);

        /* Everything below this point is VIA2/RBV only... */

        if (oss_present) return;

#if 1
        /* Some machines support an alternate IRQ mapping that spreads  */
        /* Ethernet and Sound out to their own autolevel IRQs and moves */
        /* VIA1 to level 6. A/UX uses this mapping and we do too.  Note */
        /* that the IIfx emulates this alternate mapping using the OSS. */

        switch(macintosh_config->ident) {
                case MAC_MODEL_P475:
                case MAC_MODEL_P475F:
                case MAC_MODEL_P575:
                case MAC_MODEL_Q605:
                case MAC_MODEL_Q605_ACC:
                case MAC_MODEL_C610:
                case MAC_MODEL_Q610:
                case MAC_MODEL_Q630:
                case MAC_MODEL_C650:
                case MAC_MODEL_Q650:
                case MAC_MODEL_Q700:
                case MAC_MODEL_Q800:
                case MAC_MODEL_Q900:
                case MAC_MODEL_Q950:
                        via_alt_mapping = 1;
                        via1[vDirB] |= 0x40;
                        via1[vBufB] &= ~0x40;
                        break;
                default:
                        via_alt_mapping = 0;
                        break;
        }
#else
        via_alt_mapping = 0;
#endif

        /*
         * Now initialize VIA2. For RBV we just kill all interrupts;
         * for a regular VIA we also reset the timers and stuff.
         */

        via2[gIER] = 0x7F;
        via2[gIFR] = 0x7F | rbv_clear;
        if (!rbv_present) {
                via2[vT1LL] = 0;
                via2[vT1LH] = 0;
                via2[vT1CL] = 0;
                via2[vT1CH] = 0;
                via2[vT2CL] = 0;
                via2[vT2CH] = 0;
                via2[vACR] &= 0x3F;
                via2[vACR] &= ~0x03; /* disable port A & B latches */
        }

        /*
         * Set vPCR for SCSI interrupts (but not on RBV)
         */
        if (!rbv_present) {
                if (macintosh_config->scsi_type == MAC_SCSI_OLD) {
                        /* CB2 (IRQ) indep. input, positive edge */
                        /* CA2 (DRQ) indep. input, positive edge */
                        via2[vPCR] = 0x66;
                } else {
                        /* CB2 (IRQ) indep. input, negative edge */
                        /* CA2 (DRQ) indep. input, negative edge */
                        via2[vPCR] = 0x22;
                }
        }
}

/*
 * Start the 100 Hz clock
 */

void __init via_init_clock(irq_handler_t func)
{
        via1[vACR] |= 0x40;
        via1[vT1LL] = MAC_CLOCK_LOW;
        via1[vT1LH] = MAC_CLOCK_HIGH;
        via1[vT1CL] = MAC_CLOCK_LOW;
        via1[vT1CH] = MAC_CLOCK_HIGH;

        request_irq(IRQ_MAC_TIMER_1, func, IRQ_FLG_LOCK, "timer", func);
}

/*
 * Register the interrupt dispatchers for VIA or RBV machines only.
 */

void __init via_register_interrupts(void)
{
        if (via_alt_mapping) {
                request_irq(IRQ_AUTO_1, via1_irq,
                                IRQ_FLG_LOCK|IRQ_FLG_FAST, "software",
                                (void *) via1);
                request_irq(IRQ_AUTO_6, via1_irq,
                                IRQ_FLG_LOCK|IRQ_FLG_FAST, "via1",
                                (void *) via1);
        } else {
                request_irq(IRQ_AUTO_1, via1_irq,
                                IRQ_FLG_LOCK|IRQ_FLG_FAST, "via1",
                                (void *) via1);
        }
        request_irq(IRQ_AUTO_2, via2_irq, IRQ_FLG_LOCK|IRQ_FLG_FAST,
                        "via2", (void *) via2);
        if (!psc_present) {
                request_irq(IRQ_AUTO_4, mac_scc_dispatch, IRQ_FLG_LOCK,
                                "scc", mac_scc_dispatch);
        }
        request_irq(IRQ_MAC_NUBUS, via_nubus_irq, IRQ_FLG_LOCK|IRQ_FLG_FAST,
                        "nubus", (void *) via2);
}

/*
 * Debugging dump, used in various places to see what's going on.
 */

void via_debug_dump(void)
{
        printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
                (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
        printk(KERN_DEBUG "         PCR = 0x%02X  IFR = 0x%02X IER = 0x%02X\n",
                (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
        if (oss_present) {
                printk(KERN_DEBUG "VIA2: <OSS>\n");
        } else if (rbv_present) {
                printk(KERN_DEBUG "VIA2:  IFR = 0x%02X  IER = 0x%02X\n",
                        (uint) via2[rIFR], (uint) via2[rIER]);
                printk(KERN_DEBUG "      SIFR = 0x%02X SIER = 0x%02X\n",
                        (uint) via2[rSIFR], (uint) via2[rSIER]);
        } else {
                printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
                        (uint) via2[vDirA], (uint) via2[vDirB],
                        (uint) via2[vACR]);
                printk(KERN_DEBUG "         PCR = 0x%02X  IFR = 0x%02X IER = 0x%02X\n",
                        (uint) via2[vPCR],
                        (uint) via2[vIFR], (uint) via2[vIER]);
        }
}

/*
 * This is always executed with interrupts disabled.
 *
 * TBI: get time offset between scheduling timer ticks
 */

unsigned long mac_gettimeoffset (void)
{
        unsigned long ticks, offset = 0;

        /* read VIA1 timer 2 current value */
        ticks = via1[vT1CL] | (via1[vT1CH] << 8);
        /* The probability of underflow is less than 2% */
        if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50)
                /* Check for pending timer interrupt in VIA1 IFR */
                if (via1[vIFR] & 0x40) offset = TICK_SIZE;

        ticks = MAC_CLOCK_TICK - ticks;
        ticks = ticks * 10000L / MAC_CLOCK_TICK;

        return ticks + offset;
}

/*
 * Flush the L2 cache on Macs that have it by flipping
 * the system into 24-bit mode for an instant.
 */

void via_flush_cache(void)
{
        via2[gBufB] &= ~VIA2B_vMode32;
        via2[gBufB] |= VIA2B_vMode32;
}

/*
 * Return the status of the L2 cache on a IIci
 */

int via_get_cache_disable(void)
{
        /* Safeguard against being called accidentally */
        if (!via2) {
                printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
                return 1;
        }

        return (int) via2[gBufB] & VIA2B_vCDis;
}

/*
 * Initialize VIA2 for Nubus access
 */

void __init via_nubus_init(void)
{
        /* unlock nubus transactions */

        if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
            (macintosh_config->adb_type != MAC_ADB_PB2)) {
                /* set the line to be an output on non-RBV machines */
                if (!rbv_present)
                        via2[vDirB] |= 0x02;

                /* this seems to be an ADB bit on PMU machines */
                /* according to MkLinux.  -- jmt               */
                via2[gBufB] |= 0x02;
        }

        /* Disable all the slot interrupts (where possible). */

        switch (macintosh_config->via_type) {
        case MAC_VIA_II:
                /* Just make the port A lines inputs. */
                switch(macintosh_config->ident) {
                case MAC_MODEL_II:
                case MAC_MODEL_IIX:
                case MAC_MODEL_IICX:
                case MAC_MODEL_SE30:
                        /* The top two bits are RAM size outputs. */
                        via2[vDirA] &= 0xC0;
                        break;
                default:
                        via2[vDirA] &= 0x80;
                }
                break;
        case MAC_VIA_IIci:
                /* RBV. Disable all the slot interrupts. SIER works like IER. */
                via2[rSIER] = 0x7F;
                break;
        case MAC_VIA_QUADRA:
                /* Disable the inactive slot interrupts by making those lines outputs. */
                if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
                    (macintosh_config->adb_type != MAC_ADB_PB2)) {
                        via2[vBufA] |= 0x7F;
                        via2[vDirA] |= 0x7F;
                }
                break;
        }
}

/*
 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
 * via6522.c :-), disable/pending masks added.
 */

irqreturn_t via1_irq(int irq, void *dev_id)
{
        int irq_num;
        unsigned char irq_bit, events;

        events = via1[vIFR] & via1[vIER] & 0x7F;
        if (!events)
                return IRQ_NONE;

        irq_num = VIA1_SOURCE_BASE;
        irq_bit = 1;
        do {
                if (events & irq_bit) {
                        via1[vIFR] = irq_bit;
                        m68k_handle_int(irq_num);
                }
                ++irq_num;
                irq_bit <<= 1;
        } while (events >= irq_bit);

#if 0 /* freakin' pmu is doing weird stuff */
        if (!oss_present) {
                /* This (still) seems to be necessary to get IDE
                   working.  However, if you enable VBL interrupts,
                   you're screwed... */
                /* FIXME: should we check the SLOTIRQ bit before
                   pulling this stunt? */
                /* No, it won't be set. that's why we're doing this. */
                via_irq_disable(IRQ_MAC_NUBUS);
                via_irq_clear(IRQ_MAC_NUBUS);
                m68k_handle_int(IRQ_MAC_NUBUS);
                via_irq_enable(IRQ_MAC_NUBUS);
        }
#endif
        return IRQ_HANDLED;
}

irqreturn_t via2_irq(int irq, void *dev_id)
{
        int irq_num;
        unsigned char irq_bit, events;

        events = via2[gIFR] & via2[gIER] & 0x7F;
        if (!events)
                return IRQ_NONE;

        irq_num = VIA2_SOURCE_BASE;
        irq_bit = 1;
        do {
                if (events & irq_bit) {
                        via2[gIFR] = irq_bit | rbv_clear;
                        m68k_handle_int(irq_num);
                }
                ++irq_num;
                irq_bit <<= 1;
        } while (events >= irq_bit);
        return IRQ_HANDLED;
}

/*
 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the
 * VIA2 dispatcher as a fast interrupt handler.
 */

irqreturn_t via_nubus_irq(int irq, void *dev_id)
{
        int slot_irq;
        unsigned char slot_bit, events;

        events = ~via2[gBufA] & 0x7F;
        if (rbv_present)
                events &= via2[rSIER];
        else
                events &= ~via2[vDirA];
        if (!events)
                return IRQ_NONE;

        do {
                slot_irq = IRQ_NUBUS_F;
                slot_bit = 0x40;
                do {
                        if (events & slot_bit) {
                                events &= ~slot_bit;
                                m68k_handle_int(slot_irq);
                        }
                        --slot_irq;
                        slot_bit >>= 1;
                } while (events);

                /* clear the CA1 interrupt and make certain there's no more. */
                via2[gIFR] = 0x02 | rbv_clear;
                events = ~via2[gBufA] & 0x7F;
                if (rbv_present)
                        events &= via2[rSIER];
                else
                        events &= ~via2[vDirA];
        } while (events);
        return IRQ_HANDLED;
}

void via_irq_enable(int irq) {
        int irq_src     = IRQ_SRC(irq);
        int irq_idx     = IRQ_IDX(irq);

#ifdef DEBUG_IRQUSE
        printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
#endif

        if (irq_src == 1) {
                via1[vIER] = IER_SET_BIT(irq_idx);
        } else if (irq_src == 2) {
                if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0)
                        via2[gIER] = IER_SET_BIT(irq_idx);
        } else if (irq_src == 7) {
                switch (macintosh_config->via_type) {
                case MAC_VIA_II:
                        nubus_disabled &= ~(1 << irq_idx);
                        /* Enable the CA1 interrupt when no slot is disabled. */
                        if (!nubus_disabled)
                                via2[gIER] = IER_SET_BIT(1);
                        break;
                case MAC_VIA_IIci:
                        /* On RBV, enable the slot interrupt.
                         * SIER works like IER.
                         */
                        via2[rSIER] = IER_SET_BIT(irq_idx);
                        break;
                case MAC_VIA_QUADRA:
                        /* Make the port A line an input to enable the slot irq.
                         * But not on PowerBooks, that's ADB.
                         */
                        if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
                            (macintosh_config->adb_type != MAC_ADB_PB2))
                                via2[vDirA] &= ~(1 << irq_idx);
                        break;
                }
        }
}

void via_irq_disable(int irq) {
        int irq_src     = IRQ_SRC(irq);
        int irq_idx     = IRQ_IDX(irq);

#ifdef DEBUG_IRQUSE
        printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
#endif

        if (irq_src == 1) {
                via1[vIER] = IER_CLR_BIT(irq_idx);
        } else if (irq_src == 2) {
                via2[gIER] = IER_CLR_BIT(irq_idx);
        } else if (irq_src == 7) {
                switch (macintosh_config->via_type) {
                case MAC_VIA_II:
                        nubus_disabled |= 1 << irq_idx;
                        if (nubus_disabled)
                                via2[gIER] = IER_CLR_BIT(1);
                        break;
                case MAC_VIA_IIci:
                        via2[rSIER] = IER_CLR_BIT(irq_idx);
                        break;
                case MAC_VIA_QUADRA:
                        if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
                            (macintosh_config->adb_type != MAC_ADB_PB2))
                                via2[vDirA] |= 1 << irq_idx;
                        break;
                }
        }
}

void via_irq_clear(int irq) {
        int irq_src     = IRQ_SRC(irq);
        int irq_idx     = IRQ_IDX(irq);
        int irq_bit     = 1 << irq_idx;

        if (irq_src == 1) {
                via1[vIFR] = irq_bit;
        } else if (irq_src == 2) {
                via2[gIFR] = irq_bit | rbv_clear;
        } else if (irq_src == 7) {
                /* FIXME: There is no way to clear an individual nubus slot
                 * IRQ flag, other than getting the device to do it.
                 */
        }
}

/*
 * Returns nonzero if an interrupt is pending on the given
 * VIA/IRQ combination.
 */

int via_irq_pending(int irq)
{
        int irq_src     = IRQ_SRC(irq);
        int irq_idx     = IRQ_IDX(irq);
        int irq_bit     = 1 << irq_idx;

        if (irq_src == 1) {
                return via1[vIFR] & irq_bit;
        } else if (irq_src == 2) {
                return via2[gIFR] & irq_bit;
        } else if (irq_src == 7) {
                /* Always 0 for MAC_VIA_QUADRA if the slot irq is disabled. */
                return ~via2[gBufA] & irq_bit;
        }
        return 0;
}