1 files changed, 122 insertions, 133 deletions

diff --git a/arch/m68k/mac/via.c b/arch/m68k/mac/via.c
index f1600ad26621..2d85662715fb 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);