[mirror_ubuntu-jammy-kernel.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/mac_via.h>
#include <asm/mac_psc.h>

volatile __u8 *via1, *via2;
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 that slot IRQ line an output 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] &= ~0xC0; /* setup T1 timer with no PB7 output */
	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;

	/* 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. */

	via_alt_mapping = 0;
	if (macintosh_config->via_type == MAC_VIA_QUADRA)
		switch (macintosh_config->ident) {
		case MAC_MODEL_C660:
		case MAC_MODEL_Q840:
			/* not applicable */
			break;
		case MAC_MODEL_P588:
		case MAC_MODEL_TV:
		case MAC_MODEL_PB140:
		case MAC_MODEL_PB145:
		case MAC_MODEL_PB160:
		case MAC_MODEL_PB165:
		case MAC_MODEL_PB165C:
		case MAC_MODEL_PB170:
		case MAC_MODEL_PB180:
		case MAC_MODEL_PB180C:
		case MAC_MODEL_PB190:
		case MAC_MODEL_PB520:
			/* not yet tested */
			break;
		default:
			via_alt_mapping = 1;
			via1[vDirB] |= 0x40;
			via1[vBufB] &= ~0x40;
			break;
		}

	/*
	 * 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] &= ~0xC0; /* setup T1 timer with no PB7 output */
		via2[vACR] &= ~0x03; /* disable port A & B latches */
	}

	/*
	 * Set vPCR for control line interrupts (but not on RBV)
	 */
	if (!rbv_present) {
		/* For all VIA types, CA1 (SLOTS IRQ) and CB1 (ASC IRQ)
		 * are made negative edge triggered here.
		 */
		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);
	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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* 6522 Versatile Interface Adapter (VIA)
	3	*
0c79cf6a	4	* There are two of these on the Mac II. Some IRQs are vectored
1da177e4 LT	5	* via them as are assorted bits and bobs - eg RTC, ADB.
	6	*
	7	* CSA: Motorola seems to have removed documentation on the 6522 from
	8	* their web site; try
	9	* http://nerini.drf.com/vectrex/other/text/chips/6522/
	10	* http://www.zymurgy.net/classic/vic20/vicdet1.htm
	11	* and
	12	* http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html
	13	* for info. A full-text web search on 6522 AND VIA will probably also
	14	* net some usefulness. <cananian@alumni.princeton.edu> 20apr1999
	15	*
67dfb153 FT	16	* Additional data is here (the SY6522 was used in the Mac II etc):
	17	* http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf
	18	* http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf
	19	*
1da177e4 LT	20	* PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b
	21	* by Erik Vogan and adapted to Linux by Joshua M. Thompson (funaho@jurai.org)
	22	*
	23	*/
	24
	25	#include <linux/types.h>
	26	#include <linux/kernel.h>
	27	#include <linux/mm.h>
	28	#include <linux/delay.h>
	29	#include <linux/init.h>
deea7775	30	#include <linux/module.h>
1da177e4	31
1da177e4 LT	32	#include <asm/bootinfo.h>
	33	#include <asm/macintosh.h>
	34	#include <asm/macints.h>
1da177e4 LT	35	#include <asm/mac_via.h>
	36	#include <asm/mac_psc.h>
	37
	38	volatile __u8 via1, via2;
deea7775 AB	39	int rbv_present;
	40	int via_alt_mapping;
	41	EXPORT_SYMBOL(via_alt_mapping);
8dfbdf4a	42	static __u8 rbv_clear;
1da177e4 LT	43
	44	/*
	45	* Globals for accessing the VIA chip registers without having to
	46	* check if we're hitting a real VIA or an RBV. Normally you could
	47	* just hit the combined register (ie, vIER\|rIER) but that seems to
	48	* break on AV Macs...probably because they actually decode more than
	49	* eight address bits. Why can't Apple engineers at least be
	50	* _consistently_ lazy? - 1999-05-21 (jmt)
	51	*/
	52
	53	static int gIER,gIFR,gBufA,gBufB;
	54
	55	/*
	56	* Timer defs.
	57	*/
	58
	59	#define TICK_SIZE 10000
	60	#define MAC_CLOCK_TICK (783300/HZ) /* ticks per HZ */
	61	#define MAC_CLOCK_LOW (MAC_CLOCK_TICK&0xFF)
	62	#define MAC_CLOCK_HIGH (MAC_CLOCK_TICK>>8)
	63
4a973592	64	/* To disable a NuBus slot on Quadras we make that slot IRQ line an output set
cd713ddc FT	65	* high. On RBV we just use the slot interrupt enable register. On Macs with
	66	* genuine VIA chips we must use nubus_disabled to keep track of disabled slot
	67	* interrupts. When any slot IRQ is disabled we mask the (edge triggered) CA1
	68	* or "SLOTS" interrupt. When no slot is disabled, we unmask the CA1 interrupt.
	69	* So, on genuine VIAs, having more than one NuBus IRQ can mean trouble,
	70	* because closing one of those drivers can mask all of the NuBus interrupts.
	71	* Also, since we can't mask the unregistered slot IRQs on genuine VIAs, it's
	72	* possible to get interrupts from cards that MacOS or the ROM has configured
	73	* but we have not. FWIW, "Designing Cards and Drivers for Macintosh II and
	74	* Macintosh SE", page 9-8, says, a slot IRQ with no driver would crash MacOS.
	75	*/
	76	static u8 nubus_disabled;
1da177e4 LT	77
1da177e4 LT	78	void via_debug_dump(void);
2850bc27 AV	79	irqreturn_t via1_irq(int, void *);
	80	irqreturn_t via2_irq(int, void *);
	81	irqreturn_t via_nubus_irq(int, void *);
1da177e4 LT	82	void via_irq_enable(int irq);
	83	void via_irq_disable(int irq);
	84	void via_irq_clear(int irq);
	85
2850bc27	86	extern irqreturn_t mac_scc_dispatch(int, void *);
1da177e4 LT	87	extern int oss_present;
	88
	89	/*
	90	* Initialize the VIAs
	91	*
	92	* First we figure out where they actually _are_ as well as what type of
	93	* VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.)
	94	* Then we pretty much clear them out and disable all IRQ sources.
	95	*
	96	* Note: the OSS is actually "detected" here and not in oss_init(). It just
	97	* seems more logical to do it here since via_init() needs to know
	98	* these things anyways.
	99	*/
	100
	101	void __init via_init(void)
	102	{
	103	switch(macintosh_config->via_type) {
	104
	105	/* IIci, IIsi, IIvx, IIvi (P6xx), LC series */
	106
	107	case MAC_VIA_IIci:
	108	via1 = (void *) VIA1_BASE;
	109	if (macintosh_config->ident == MAC_MODEL_IIFX) {
	110	via2 = NULL;
	111	rbv_present = 0;
	112	oss_present = 1;
	113	} else {
	114	via2 = (void *) RBV_BASE;
	115	rbv_present = 1;
	116	oss_present = 0;
	117	}
	118	if (macintosh_config->ident == MAC_MODEL_LCIII) {
	119	rbv_clear = 0x00;
	120	} else {
	121	/* on most RBVs (& unlike the VIAs), you */
	122	/* need to set bit 7 when you write to IFR */
	123	/* in order for your clear to occur. */
	124	rbv_clear = 0x80;
	125	}
	126	gIER = rIER;
	127	gIFR = rIFR;
	128	gBufA = rSIFR;
	129	gBufB = rBufB;
	130	break;
	131
	132	/* Quadra and early MacIIs agree on the VIA locations */
	133
	134	case MAC_VIA_QUADRA:
	135	case MAC_VIA_II:
	136	via1 = (void *) VIA1_BASE;
	137	via2 = (void *) VIA2_BASE;
	138	rbv_present = 0;
	139	oss_present = 0;
	140	rbv_clear = 0x00;
	141	gIER = vIER;
	142	gIFR = vIFR;
	143	gBufA = vBufA;
	144	gBufB = vBufB;
	145	break;
	146	default:
	147	panic("UNKNOWN VIA TYPE");
	148	}
	149
	150	printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);
151
152	printk(KERN_INFO "VIA2 at %p is ", via2);
153	if (rbv_present) {
67dfb153	154	printk("an RBV\n");
1da177e4	155	} else if (oss_present) {
67dfb153	156	printk("an OSS\n");
1da177e4	157	} else {
67dfb153	158	printk("a 6522 or clone\n");
1da177e4 LT	159	}
	160
	161	#ifdef DEBUG_VIA
	162	via_debug_dump();
	163	#endif
	164
	165	/*
	166	* Shut down all IRQ sources, reset the timers, and
	167	* kill the timer latch on VIA1.
	168	*/
	169
	170	via1[vIER] = 0x7F;
	171	via1[vIFR] = 0x7F;
	172	via1[vT1LL] = 0;
	173	via1[vT1LH] = 0;
	174	via1[vT1CL] = 0;
	175	via1[vT1CH] = 0;
	176	via1[vT2CL] = 0;
	177	via1[vT2CH] = 0;
4a973592	178	via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
67dfb153	179	via1[vACR] &= ~0x03; /* disable port A & B latches */
1da177e4 LT	180
	181	/*
	182	* SE/30: disable video IRQ
	183	* XXX: testing for SE/30 VBL
	184	*/
	185
	186	if (macintosh_config->ident == MAC_MODEL_SE30) {
	187	via1[vDirB] \|= 0x40;
	188	via1[vBufB] \|= 0x40;
	189	}
	190
	191	/*
	192	* Set the RTC bits to a known state: all lines to outputs and
	193	* RTC disabled (yes that's 0 to enable and 1 to disable).
	194	*/
	195
	196	via1[vDirB] \|= (VIA1B_vRTCEnb \| VIA1B_vRTCClk \| VIA1B_vRTCData);
	197	via1[vBufB] \|= (VIA1B_vRTCEnb \| VIA1B_vRTCClk);
	198
	199	/* Everything below this point is VIA2/RBV only... */
	200
4a973592 FT	201	if (oss_present)
4a973592 FT	202	return;
1da177e4	203
1da177e4 LT	204	/* Some machines support an alternate IRQ mapping that spreads */
	205	/* Ethernet and Sound out to their own autolevel IRQs and moves */
	206	/* VIA1 to level 6. A/UX uses this mapping and we do too. Note */
	207	/* that the IIfx emulates this alternate mapping using the OSS. */
	208
4a973592 FT	209	via_alt_mapping = 0;
	210	if (macintosh_config->via_type == MAC_VIA_QUADRA)
	211	switch (macintosh_config->ident) {
	212	case MAC_MODEL_C660:
	213	case MAC_MODEL_Q840:
	214	/* not applicable */
	215	break;
	216	case MAC_MODEL_P588:
	217	case MAC_MODEL_TV:
	218	case MAC_MODEL_PB140:
	219	case MAC_MODEL_PB145:
	220	case MAC_MODEL_PB160:
	221	case MAC_MODEL_PB165:
	222	case MAC_MODEL_PB165C:
	223	case MAC_MODEL_PB170:
	224	case MAC_MODEL_PB180:
	225	case MAC_MODEL_PB180C:
	226	case MAC_MODEL_PB190:
	227	case MAC_MODEL_PB520:
	228	/* not yet tested */
	229	break;
	230	default:
1da177e4 LT	231	via_alt_mapping = 1;
	232	via1[vDirB] \|= 0x40;
	233	via1[vBufB] &= ~0x40;
	234	break;
4a973592	235	}
1da177e4 LT	236
	237	/*
	238	* Now initialize VIA2. For RBV we just kill all interrupts;
	239	* for a regular VIA we also reset the timers and stuff.
	240	*/
	241
	242	via2[gIER] = 0x7F;
	243	via2[gIFR] = 0x7F \| rbv_clear;
	244	if (!rbv_present) {
	245	via2[vT1LL] = 0;
	246	via2[vT1LH] = 0;
	247	via2[vT1CL] = 0;
	248	via2[vT1CH] = 0;
	249	via2[vT2CL] = 0;
	250	via2[vT2CH] = 0;
4a973592	251	via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
67dfb153 FT	252	via2[vACR] &= ~0x03; /* disable port A & B latches */
	253	}
	254
	255	/*
4a973592	256	* Set vPCR for control line interrupts (but not on RBV)
67dfb153 FT	257	*/
67dfb153 FT	258	if (!rbv_present) {
4a973592 FT	259	/* For all VIA types, CA1 (SLOTS IRQ) and CB1 (ASC IRQ)
	260	* are made negative edge triggered here.
	261	*/
67dfb153 FT	262	if (macintosh_config->scsi_type == MAC_SCSI_OLD) {
	263	/* CB2 (IRQ) indep. input, positive edge */
	264	/* CA2 (DRQ) indep. input, positive edge */
	265	via2[vPCR] = 0x66;
	266	} else {
	267	/* CB2 (IRQ) indep. input, negative edge */
	268	/* CA2 (DRQ) indep. input, negative edge */
	269	via2[vPCR] = 0x22;
	270	}
1da177e4 LT	271	}
	272	}
	273
	274	/*
	275	* Start the 100 Hz clock
	276	*/
	277
40220c1a	278	void __init via_init_clock(irq_handler_t func)
1da177e4 LT	279	{
	280	via1[vACR] \|= 0x40;
	281	via1[vT1LL] = MAC_CLOCK_LOW;
	282	via1[vT1LH] = MAC_CLOCK_HIGH;
	283	via1[vT1CL] = MAC_CLOCK_LOW;
	284	via1[vT1CH] = MAC_CLOCK_HIGH;
	285
	286	request_irq(IRQ_MAC_TIMER_1, func, IRQ_FLG_LOCK, "timer", func);
	287	}
	288
	289	/*
	290	* Register the interrupt dispatchers for VIA or RBV machines only.
	291	*/
	292
	293	void __init via_register_interrupts(void)
	294	{
	295	if (via_alt_mapping) {
9c5f4afd	296	request_irq(IRQ_AUTO_1, via1_irq,
1da177e4 LT	297	IRQ_FLG_LOCK\|IRQ_FLG_FAST, "software",
1da177e4 LT	298	(void *) via1);
9c5f4afd	299	request_irq(IRQ_AUTO_6, via1_irq,
1da177e4 LT	300	IRQ_FLG_LOCK\|IRQ_FLG_FAST, "via1",
	301	(void *) via1);
	302	} else {
9c5f4afd	303	request_irq(IRQ_AUTO_1, via1_irq,
1da177e4 LT	304	IRQ_FLG_LOCK\|IRQ_FLG_FAST, "via1",
1da177e4 LT	305	(void *) via1);
1da177e4	306	}
9c5f4afd	307	request_irq(IRQ_AUTO_2, via2_irq, IRQ_FLG_LOCK\|IRQ_FLG_FAST,
1da177e4 LT	308	"via2", (void *) via2);
1da177e4 LT	309	if (!psc_present) {
9c5f4afd	310	request_irq(IRQ_AUTO_4, mac_scc_dispatch, IRQ_FLG_LOCK,
1da177e4 LT	311	"scc", mac_scc_dispatch);
	312	}
	313	request_irq(IRQ_MAC_NUBUS, via_nubus_irq, IRQ_FLG_LOCK\|IRQ_FLG_FAST,
	314	"nubus", (void *) via2);
	315	}
	316
	317	/*
	318	* Debugging dump, used in various places to see what's going on.
	319	*/
	320
	321	void via_debug_dump(void)
	322	{
	323	printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
	324	(uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
	325	printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
	326	(uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
	327	if (oss_present) {
	328	printk(KERN_DEBUG "VIA2: <OSS>\n");
	329	} else if (rbv_present) {
	330	printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n",
	331	(uint) via2[rIFR], (uint) via2[rIER]);
	332	printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n",
	333	(uint) via2[rSIFR], (uint) via2[rSIER]);
	334	} else {
	335	printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
	336	(uint) via2[vDirA], (uint) via2[vDirB],
	337	(uint) via2[vACR]);
	338	printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
	339	(uint) via2[vPCR],
	340	(uint) via2[vIFR], (uint) via2[vIER]);
	341	}
	342	}
	343
	344	/*
	345	* This is always executed with interrupts disabled.
	346	*
	347	* TBI: get time offset between scheduling timer ticks
	348	*/
	349
	350	unsigned long mac_gettimeoffset (void)
	351	{
	352	unsigned long ticks, offset = 0;
	353
	354	/* read VIA1 timer 2 current value */
	355	ticks = via1[vT1CL] \| (via1[vT1CH] << 8);
	356	/* The probability of underflow is less than 2% */
	357	if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50)
	358	/* Check for pending timer interrupt in VIA1 IFR */
	359	if (via1[vIFR] & 0x40) offset = TICK_SIZE;
	360
	361	ticks = MAC_CLOCK_TICK - ticks;
	362	ticks = ticks * 10000L / MAC_CLOCK_TICK;
	363
	364	return ticks + offset;
	365	}
	366
	367	/*
	368	* Flush the L2 cache on Macs that have it by flipping
	369	* the system into 24-bit mode for an instant.
	370	*/
	371
	372	void via_flush_cache(void)
	373	{
	374	via2[gBufB] &= ~VIA2B_vMode32;
375	via2[gBufB] \|= VIA2B_vMode32;
376	}
377
378	/*
379	* Return the status of the L2 cache on a IIci
380	*/
381
382	int via_get_cache_disable(void)
383	{
384	/* Safeguard against being called accidentally */
385	if (!via2) {
386	printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
387	return 1;
388	}
389
390	return (int) via2[gBufB] & VIA2B_vCDis;
391	}
392
393	/*
394	* Initialize VIA2 for Nubus access
395	*/
396
397	void __init via_nubus_init(void)
398	{
1da177e4 LT	399	/* unlock nubus transactions */
1da177e4 LT	400
67dfb153 FT	401	if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
67dfb153 FT	402	(macintosh_config->adb_type != MAC_ADB_PB2)) {
1da177e4	403	/* set the line to be an output on non-RBV machines */
67dfb153	404	if (!rbv_present)
1da177e4	405	via2[vDirB] \|= 0x02;
1da177e4	406
67dfb153 FT	407	/* this seems to be an ADB bit on PMU machines */
67dfb153 FT	408	/* according to MkLinux. -- jmt */
1da177e4 LT	409	via2[gBufB] \|= 0x02;
	410	}
	411
cd713ddc FT	412	/* Disable all the slot interrupts (where possible). */
	413
	414	switch (macintosh_config->via_type) {
	415	case MAC_VIA_II:
	416	/* Just make the port A lines inputs. */
	417	switch(macintosh_config->ident) {
	418	case MAC_MODEL_II:
	419	case MAC_MODEL_IIX:
	420	case MAC_MODEL_IICX:
	421	case MAC_MODEL_SE30:
	422	/* The top two bits are RAM size outputs. */
	423	via2[vDirA] &= 0xC0;
	424	break;
	425	default:
	426	via2[vDirA] &= 0x80;
	427	}
	428	break;
	429	case MAC_VIA_IIci:
	430	/* RBV. Disable all the slot interrupts. SIER works like IER. */
1da177e4	431	via2[rSIER] = 0x7F;
cd713ddc FT	432	break;
	433	case MAC_VIA_QUADRA:
	434	/* Disable the inactive slot interrupts by making those lines outputs. */
1da177e4	435	if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
cd713ddc FT	436	(macintosh_config->adb_type != MAC_ADB_PB2)) {
	437	via2[vBufA] \|= 0x7F;
	438	via2[vDirA] \|= 0x7F;
1da177e4	439	}
cd713ddc	440	break;
1da177e4 LT	441	}
	442	}
	443
	444	/*
	445	* The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
	446	* via6522.c :-), disable/pending masks added.
1da177e4 LT	447	*/
1da177e4 LT	448
2850bc27	449	irqreturn_t via1_irq(int irq, void *dev_id)
1da177e4	450	{
67dfb153 FT	451	int irq_num;
67dfb153 FT	452	unsigned char irq_bit, events;
1da177e4	453
67dfb153 FT	454	events = via1[vIFR] & via1[vIER] & 0x7F;
67dfb153 FT	455	if (!events)
1da177e4 LT	456	return IRQ_NONE;
1da177e4 LT	457
67dfb153 FT	458	irq_num = VIA1_SOURCE_BASE;
	459	irq_bit = 1;
	460	do {
1da177e4	461	if (events & irq_bit) {
1da177e4	462	via1[vIFR] = irq_bit;
67dfb153	463	m68k_handle_int(irq_num);
1da177e4	464	}
67dfb153 FT	465	++irq_num;
	466	irq_bit <<= 1;
	467	} while (events >= irq_bit);
1da177e4 LT	468	return IRQ_HANDLED;
	469	}
	470
2850bc27	471	irqreturn_t via2_irq(int irq, void *dev_id)
1da177e4	472	{
67dfb153 FT	473	int irq_num;
67dfb153 FT	474	unsigned char irq_bit, events;
1da177e4	475
67dfb153 FT	476	events = via2[gIFR] & via2[gIER] & 0x7F;
67dfb153 FT	477	if (!events)
1da177e4 LT	478	return IRQ_NONE;
1da177e4 LT	479
67dfb153 FT	480	irq_num = VIA2_SOURCE_BASE;
	481	irq_bit = 1;
	482	do {
1da177e4	483	if (events & irq_bit) {
1da177e4	484	via2[gIFR] = irq_bit \| rbv_clear;
67dfb153	485	m68k_handle_int(irq_num);
1da177e4	486	}
67dfb153 FT	487	++irq_num;
	488	irq_bit <<= 1;
	489	} while (events >= irq_bit);
1da177e4 LT	490	return IRQ_HANDLED;
	491	}
	492
	493	/*
	494	* Dispatch Nubus interrupts. We are called as a secondary dispatch by the
	495	* VIA2 dispatcher as a fast interrupt handler.
	496	*/
	497
2850bc27	498	irqreturn_t via_nubus_irq(int irq, void *dev_id)
1da177e4	499	{
67dfb153 FT	500	int slot_irq;
	501	unsigned char slot_bit, events;
	502
	503	events = ~via2[gBufA] & 0x7F;
	504	if (rbv_present)
	505	events &= via2[rSIER];
	506	else
cd713ddc	507	events &= ~via2[vDirA];
67dfb153	508	if (!events)
1da177e4 LT	509	return IRQ_NONE;
1da177e4 LT	510
67dfb153 FT	511	do {
	512	slot_irq = IRQ_NUBUS_F;
	513	slot_bit = 0x40;
	514	do {
	515	if (events & slot_bit) {
	516	events &= ~slot_bit;
	517	m68k_handle_int(slot_irq);
	518	}
	519	--slot_irq;
	520	slot_bit >>= 1;
	521	} while (events);
	522
	523	/* clear the CA1 interrupt and make certain there's no more. */
	524	via2[gIFR] = 0x02 \| rbv_clear;
	525	events = ~via2[gBufA] & 0x7F;
	526	if (rbv_present)
	527	events &= via2[rSIER];
	528	else
cd713ddc	529	events &= ~via2[vDirA];
67dfb153	530	} while (events);
1da177e4 LT	531	return IRQ_HANDLED;
	532	}
	533
	534	void via_irq_enable(int irq) {
	535	int irq_src = IRQ_SRC(irq);
	536	int irq_idx = IRQ_IDX(irq);
1da177e4 LT	537
	538	#ifdef DEBUG_IRQUSE
	539	printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
	540	#endif
	541
	542	if (irq_src == 1) {
cd713ddc	543	via1[vIER] = IER_SET_BIT(irq_idx);
1da177e4	544	} else if (irq_src == 2) {
cd713ddc FT	545	if (irq != IRQ_MAC_NUBUS \|\| nubus_disabled == 0)
cd713ddc FT	546	via2[gIER] = IER_SET_BIT(irq_idx);
1da177e4	547	} else if (irq_src == 7) {
cd713ddc FT	548	switch (macintosh_config->via_type) {
	549	case MAC_VIA_II:
	550	nubus_disabled &= ~(1 << irq_idx);
	551	/* Enable the CA1 interrupt when no slot is disabled. */
	552	if (!nubus_disabled)
	553	via2[gIER] = IER_SET_BIT(1);
	554	break;
	555	case MAC_VIA_IIci:
	556	/* On RBV, enable the slot interrupt.
	557	* SIER works like IER.
	558	*/
1da177e4	559	via2[rSIER] = IER_SET_BIT(irq_idx);
cd713ddc FT	560	break;
	561	case MAC_VIA_QUADRA:
	562	/* Make the port A line an input to enable the slot irq.
	563	* But not on PowerBooks, that's ADB.
	564	*/
1da177e4	565	if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
cd713ddc FT	566	(macintosh_config->adb_type != MAC_ADB_PB2))
	567	via2[vDirA] &= ~(1 << irq_idx);
	568	break;
1da177e4	569	}
1da177e4 LT	570	}
	571	}
	572
	573	void via_irq_disable(int irq) {
	574	int irq_src = IRQ_SRC(irq);
	575	int irq_idx = IRQ_IDX(irq);
1da177e4 LT	576
	577	#ifdef DEBUG_IRQUSE
	578	printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
	579	#endif
	580
	581	if (irq_src == 1) {
cd713ddc	582	via1[vIER] = IER_CLR_BIT(irq_idx);
1da177e4	583	} else if (irq_src == 2) {
cd713ddc	584	via2[gIER] = IER_CLR_BIT(irq_idx);
1da177e4	585	} else if (irq_src == 7) {
cd713ddc FT	586	switch (macintosh_config->via_type) {
	587	case MAC_VIA_II:
	588	nubus_disabled \|= 1 << irq_idx;
	589	if (nubus_disabled)
	590	via2[gIER] = IER_CLR_BIT(1);
	591	break;
	592	case MAC_VIA_IIci:
1da177e4	593	via2[rSIER] = IER_CLR_BIT(irq_idx);
cd713ddc FT	594	break;
cd713ddc FT	595	case MAC_VIA_QUADRA:
1da177e4	596	if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
cd713ddc FT	597	(macintosh_config->adb_type != MAC_ADB_PB2))
	598	via2[vDirA] \|= 1 << irq_idx;
	599	break;
1da177e4	600	}
1da177e4 LT	601	}
	602	}
	603
	604	void via_irq_clear(int irq) {
	605	int irq_src = IRQ_SRC(irq);
	606	int irq_idx = IRQ_IDX(irq);
	607	int irq_bit = 1 << irq_idx;
	608
	609	if (irq_src == 1) {
	610	via1[vIFR] = irq_bit;
	611	} else if (irq_src == 2) {
	612	via2[gIFR] = irq_bit \| rbv_clear;
	613	} else if (irq_src == 7) {
67dfb153 FT	614	/* FIXME: There is no way to clear an individual nubus slot
	615	* IRQ flag, other than getting the device to do it.
	616	*/
1da177e4 LT	617	}
	618	}
	619
	620	/*
	621	* Returns nonzero if an interrupt is pending on the given
	622	* VIA/IRQ combination.
	623	*/
	624
	625	int via_irq_pending(int irq)
	626	{
	627	int irq_src = IRQ_SRC(irq);
	628	int irq_idx = IRQ_IDX(irq);
	629	int irq_bit = 1 << irq_idx;
	630
	631	if (irq_src == 1) {
	632	return via1[vIFR] & irq_bit;
	633	} else if (irq_src == 2) {
	634	return via2[gIFR] & irq_bit;
	635	} else if (irq_src == 7) {
cd713ddc	636	/* Always 0 for MAC_VIA_QUADRA if the slot irq is disabled. */
1da177e4 LT	637	return ~via2[gBufA] & irq_bit;
	638	}
	639	return 0;
	640	}