1 files changed, 122 insertions, 133 deletions

diff --git a/arch/m68k/mac/via.c b/arch/m68k/mac/via.c
index f1600ad2662..2d85662715f 100644
--- a/arch/m68k/mac/via.c
+++ b/arch/m68k/mac/via.c
@@ -63,24 +63,50 @@ static int gIER,gIFR,gBufA,gBufB;
 #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.
+
+/*
+ * On Macs with a genuine VIA chip there is no way to mask an individual slot
+ * interrupt. This limitation also seems to apply to VIA clone logic cores in
+ * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.)
+ *
+ * We used to fake it by configuring the relevent VIA pin as an output
+ * (to mask the interrupt) or input (to unmask). That scheme did not work on
+ * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector
+ * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE,
+ * p. 10-11 etc) but VIA outputs are not (see datasheet).
+ *
+ * Driving these outputs high must cause the VIA to source current and the
+ * card to sink current when it asserts /NMRQ. Current will flow but the pin
+ * voltage is uncertain and so the /NMRQ condition may still cause a transition
+ * at the VIA2 CA1 input (which explains the lost interrupts). A side effect
+ * is that a disabled slot IRQ can never be tested as pending or not.
+ *
+ * Driving these outputs low doesn't work either. All the slot /NMRQ lines are
+ * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see
+ * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a
+ * disabled /NMRQ line low, the falling edge immediately triggers a CA1
+ * interrupt and all slot interrupts after that will generate no transition
+ * and therefore no interrupt, even after being re-enabled.
+ *
+ * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep
+ * track of their states. When any slot IRQ becomes disabled we mask the CA1
+ * umbrella interrupt. Only when all slot IRQs become enabled do we unmask
+ * the CA1 interrupt. It must remain enabled even when cards have no interrupt
+ * handler registered. Drivers must therefore disable a slot interrupt at the
+ * device before they call free_irq (like shared and autovector interrupts).
+ *
+ * There is also a related problem when MacOS is used to boot Linux. A network
+ * card brought up by a MacOS driver may raise an interrupt while Linux boots.
+ * This can be fatal since it can't be handled until the right driver loads
+ * (if such a driver exists at all). Apparently related to this hardware
+ * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot
+ * interrupt with no driver would crash MacOS (the book was written before
+ * the appearance of Macs with RBV or OSS).
  */
+
 static u8 nubus_disabled;
 
 void via_debug_dump(void);
-void via_irq_enable(int irq);
-void via_irq_disable(int irq);
-void via_irq_clear(int irq);
 
 /*
  * Initialize the VIAs
@@ -100,7 +126,7 @@ void __init via_init(void)
 
 		/* IIci, IIsi, IIvx, IIvi (P6xx), LC series */
 
-		case MAC_VIA_IIci:
+		case MAC_VIA_IICI:
 			via1 = (void *) VIA1_BASE;
 			if (macintosh_config->ident == MAC_MODEL_IIFX) {
 				via2 = NULL;
@@ -197,38 +223,17 @@ void __init via_init(void)
 	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;
-		}
+	if ((macintosh_config->via_type == MAC_VIA_QUADRA) &&
+	    (macintosh_config->adb_type != MAC_ADB_PB1) &&
+	    (macintosh_config->adb_type != MAC_ADB_PB2) &&
+	    (macintosh_config->ident    != MAC_MODEL_C660) &&
+	    (macintosh_config->ident    != MAC_MODEL_Q840)) {
+		via_alt_mapping = 1;
+		via1[vDirB] |= 0x40;
+		via1[vBufB] &= ~0x40;
+	} else {
+		via_alt_mapping = 0;
+	}
 
 	/*
 	 * Now initialize VIA2. For RBV we just kill all interrupts;
@@ -248,22 +253,28 @@ void __init via_init(void)
 		via2[vACR] &= ~0x03; /* disable port A & B latches */
 	}
 
+	/* Everything below this point is VIA2 only... */
+
+	if (rbv_present)
+		return;
+
 	/*
-	 * Set vPCR for control line interrupts (but not on RBV)
+	 * Set vPCR for control line interrupts.
+	 *
+	 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger.
+	 *
+	 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt.
+	 * Testing reveals that PowerBooks do too. However, the SE/30
+	 * schematic diagram shows an active high NCR5380 IRQ line.
 	 */
-	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;
-		}
+
+	pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]);
+	if (macintosh_config->via_type == MAC_VIA_II) {
+		/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */
+		via2[vPCR] = 0x66;
+	} else {
+		/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */
+		via2[vPCR] = 0x22;
 	}
 }
 
@@ -378,34 +389,55 @@ void __init via_nubus_init(void)
 		via2[gBufB] |= 0x02;
 	}
 
-	/* Disable all the slot interrupts (where possible). */
+	/*
+	 * Disable the slot interrupts. On some hardware that's not possible.
+	 * On some hardware it's unclear what all of these I/O lines do.
+	 */
 
 	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;
-		}
+	case MAC_VIA_QUADRA:
+		pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
 		break;
-	case MAC_VIA_IIci:
+	case MAC_VIA_IICI:
 		/* RBV. Disable all the slot interrupts. SIER works like IER. */
 		via2[rSIER] = 0x7F;
 		break;
+	}
+}
+
+void via_nubus_irq_startup(int irq)
+{
+	int irq_idx = IRQ_IDX(irq);
+
+	switch (macintosh_config->via_type) {
+	case MAC_VIA_II:
 	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;
+		/* Make the port A line an input. Probably redundant. */
+		if (macintosh_config->via_type == MAC_VIA_II) {
+			/* The top two bits are RAM size outputs. */
+			via2[vDirA] &= 0xC0 | ~(1 << irq_idx);
+		} else {
+			/* Allow NuBus slots 9 through F. */
+			via2[vDirA] &= 0x80 | ~(1 << irq_idx);
 		}
+		/* fall through */
+	case MAC_VIA_IICI:
+		via_irq_enable(irq);
+		break;
+	}
+}
+
+void via_nubus_irq_shutdown(int irq)
+{
+	switch (macintosh_config->via_type) {
+	case MAC_VIA_II:
+	case MAC_VIA_QUADRA:
+		/* Ensure that the umbrella CA1 interrupt remains enabled. */
+		via_irq_enable(irq);
+		break;
+	case MAC_VIA_IICI:
+		via_irq_disable(irq);
 		break;
 	}
 }
@@ -531,25 +563,18 @@ void via_irq_enable(int irq) {
 	} else if (irq_src == 7) {
 		switch (macintosh_config->via_type) {
 		case MAC_VIA_II:
+		case MAC_VIA_QUADRA:
 			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:
+		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;
 		}
 	}
 }
@@ -569,60 +594,18 @@ void via_irq_disable(int irq) {
 	} else if (irq_src == 7) {
 		switch (macintosh_config->via_type) {
 		case MAC_VIA_II:
+		case MAC_VIA_QUADRA:
 			nubus_disabled |= 1 << irq_idx;
 			if (nubus_disabled)
 				via2[gIER] = IER_CLR_BIT(1);
 			break;
-		case MAC_VIA_IIci:
+		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;
-}
-
 void via1_set_head(int head)
 {
 	if (head == 0)
@@ -631,3 +614,9 @@ void via1_set_head(int head)
 		via1[vBufA] |= VIA1A_vHeadSel;
 }
 EXPORT_SYMBOL(via1_set_head);
+
+int via2_scsi_drq_pending(void)
+{
+	return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ));
+}
+EXPORT_SYMBOL(via2_scsi_drq_pending);