arch/m68k/mac/macints.c

   1 /*
   2  *      Macintosh interrupts
   3  *
   4  * General design:
   5  * In contrary to the Amiga and Atari platforms, the Mac hardware seems to
   6  * exclusively use the autovector interrupts (the 'generic level0-level7'
   7  * interrupts with exception vectors 0x19-0x1f). The following interrupt levels
   8  * are used:
   9  *      1       - VIA1
  10  *                - slot 0: one second interrupt (CA2)
  11  *                - slot 1: VBlank (CA1)
  12  *                - slot 2: ADB data ready (SR full)
  13  *                - slot 3: ADB data  (CB2)
  14  *                - slot 4: ADB clock (CB1)
  15  *                - slot 5: timer 2
  16  *                - slot 6: timer 1
  17  *                - slot 7: status of IRQ; signals 'any enabled int.'
  18  *
  19  *      2       - VIA2 or RBV
  20  *                - slot 0: SCSI DRQ (CA2)
  21  *                - slot 1: NUBUS IRQ (CA1) need to read port A to find which
  22  *                - slot 2: /EXP IRQ (only on IIci)
  23  *                - slot 3: SCSI IRQ (CB2)
  24  *                - slot 4: ASC IRQ (CB1)
  25  *                - slot 5: timer 2 (not on IIci)
  26  *                - slot 6: timer 1 (not on IIci)
  27  *                - slot 7: status of IRQ; signals 'any enabled int.'
  28  *
  29  * Levels 3-6 vary by machine type. For VIA or RBV Macintoshes:
  30  *
  31  *      3       - unused (?)
  32  *
  33  *      4       - SCC
  34  *
  35  *      5       - unused (?)
  36  *                [serial errors or special conditions seem to raise level 6
  37  *                interrupts on some models (LC4xx?)]
  38  *
  39  *      6       - off switch (?)
  40  *
  41  * Machines with Quadra-like VIA hardware, except PSC and PMU machines, support
  42  * an alternate interrupt mapping, as used by A/UX. It spreads ethernet and
  43  * sound out to their own autovector IRQs and gives VIA1 a higher priority:
  44  *
  45  *      1       - unused (?)
  46  *
  47  *      3       - on-board SONIC
  48  *
  49  *      5       - Apple Sound Chip (ASC)
  50  *
  51  *      6       - VIA1
  52  *
  53  * For OSS Macintoshes (IIfx only), we apply an interrupt mapping similar to
  54  * the Quadra (A/UX) mapping:
  55  *
  56  *      1       - ISM IOP (ADB)
  57  *
  58  *      2       - SCSI
  59  *
  60  *      3       - NuBus
  61  *
  62  *      4       - SCC IOP
  63  *
  64  *      6       - VIA1
  65  *
  66  * For PSC Macintoshes (660AV, 840AV):
  67  *
  68  *      3       - PSC level 3
  69  *                - slot 0: MACE
  70  *
  71  *      4       - PSC level 4
  72  *                - slot 1: SCC channel A interrupt
  73  *                - slot 2: SCC channel B interrupt
  74  *                - slot 3: MACE DMA
  75  *
  76  *      5       - PSC level 5
  77  *
  78  *      6       - PSC level 6
  79  *
  80  * Finally we have good 'ole level 7, the non-maskable interrupt:
  81  *
  82  *      7       - NMI (programmer's switch on the back of some Macs)
  83  *                Also RAM parity error on models which support it (IIc, IIfx?)
  84  *
  85  * The current interrupt logic looks something like this:
  86  *
  87  * - We install dispatchers for the autovector interrupts (1-7). These
  88  *   dispatchers are responsible for querying the hardware (the
  89  *   VIA/RBV/OSS/PSC chips) to determine the actual interrupt source. Using
  90  *   this information a machspec interrupt number is generated by placing the
  91  *   index of the interrupt hardware into the low three bits and the original
  92  *   autovector interrupt number in the upper 5 bits. The handlers for the
  93  *   resulting machspec interrupt are then called.
  94  *
  95  * - Nubus is a special case because its interrupts are hidden behind two
  96  *   layers of hardware. Nubus interrupts come in as index 1 on VIA #2,
  97  *   which translates to IRQ number 17. In this spot we install _another_
  98  *   dispatcher. This dispatcher finds the interrupting slot number (9-F) and
  99  *   then forms a new machspec interrupt number as above with the slot number
 100  *   minus 9 in the low three bits and the pseudo-level 7 in the upper five
 101  *   bits.  The handlers for this new machspec interrupt number are then
 102  *   called. This puts Nubus interrupts into the range 56-62.
 103  *
 104  * - The Baboon interrupts (used on some PowerBooks) are an even more special
 105  *   case. They're hidden behind the Nubus slot $C interrupt thus adding a
 106  *   third layer of indirection. Why oh why did the Apple engineers do that?
 107  *
 108  */
 109
 110 #include <linux/types.h>
 111 #include <linux/kernel.h>
 112 #include <linux/sched.h>
 113 #include <linux/sched/debug.h>
 114 #include <linux/interrupt.h>
 115 #include <linux/irq.h>
 116 #include <linux/delay.h>
 117
 118 #include <asm/irq.h>
 119 #include <asm/macintosh.h>
 120 #include <asm/macints.h>
 121 #include <asm/mac_via.h>
 122 #include <asm/mac_psc.h>
 123 #include <asm/mac_oss.h>
 124 #include <asm/mac_iop.h>
 125 #include <asm/mac_baboon.h>
 126 #include <asm/hwtest.h>
 127 #include <asm/irq_regs.h>
 128
 129 extern void show_registers(struct pt_regs *);
 130
 131 irqreturn_t mac_nmi_handler(int, void *);
 132
 133 static unsigned int mac_irq_startup(struct irq_data *);
 134 static void mac_irq_shutdown(struct irq_data *);
 135
 136 static struct irq_chip mac_irq_chip = {
 137         .name           = "mac",
 138         .irq_enable     = mac_irq_enable,
 139         .irq_disable    = mac_irq_disable,
 140         .irq_startup    = mac_irq_startup,
 141         .irq_shutdown   = mac_irq_shutdown,
 142 };
 143
 144 void __init mac_init_IRQ(void)
 145 {
 146         m68k_setup_irq_controller(&mac_irq_chip, handle_simple_irq, IRQ_USER,
 147                                   NUM_MAC_SOURCES - IRQ_USER);
 148
 149         /*
 150          * Now register the handlers for the master IRQ handlers
 151          * at levels 1-7. Most of the work is done elsewhere.
 152          */
 153
 154         if (oss_present)
 155                 oss_register_interrupts();
 156         else
 157                 via_register_interrupts();
 158         if (psc)
 159                 psc_register_interrupts();
 160         if (baboon_present)
 161                 baboon_register_interrupts();
 162         iop_register_interrupts();
 163         if (request_irq(IRQ_AUTO_7, mac_nmi_handler, 0, "NMI",
 164                         mac_nmi_handler))
 165                 pr_err("Couldn't register NMI\n");
 166 }
 167
 168 /*
 169  *  mac_irq_enable - enable an interrupt source
 170  * mac_irq_disable - disable an interrupt source
 171  *
 172  * These routines are just dispatchers to the VIA/OSS/PSC routines.
 173  */
 174
 175 void mac_irq_enable(struct irq_data *data)
 176 {
 177         int irq = data->irq;
 178         int irq_src = IRQ_SRC(irq);
 179
 180         switch(irq_src) {
 181         case 1:
 182         case 2:
 183         case 7:
 184                 if (oss_present)
 185                         oss_irq_enable(irq);
 186                 else
 187                         via_irq_enable(irq);
 188                 break;
 189         case 3:
 190         case 4:
 191         case 5:
 192         case 6:
 193                 if (psc)
 194                         psc_irq_enable(irq);
 195                 else if (oss_present)
 196                         oss_irq_enable(irq);
 197                 break;
 198         case 8:
 199                 if (baboon_present)
 200                         baboon_irq_enable(irq);
 201                 break;
 202         }
 203 }
 204
 205 void mac_irq_disable(struct irq_data *data)
 206 {
 207         int irq = data->irq;
 208         int irq_src = IRQ_SRC(irq);
 209
 210         switch(irq_src) {
 211         case 1:
 212         case 2:
 213         case 7:
 214                 if (oss_present)
 215                         oss_irq_disable(irq);
 216                 else
 217                         via_irq_disable(irq);
 218                 break;
 219         case 3:
 220         case 4:
 221         case 5:
 222         case 6:
 223                 if (psc)
 224                         psc_irq_disable(irq);
 225                 else if (oss_present)
 226                         oss_irq_disable(irq);
 227                 break;
 228         case 8:
 229                 if (baboon_present)
 230                         baboon_irq_disable(irq);
 231                 break;
 232         }
 233 }
 234
 235 static unsigned int mac_irq_startup(struct irq_data *data)
 236 {
 237         int irq = data->irq;
 238
 239         if (IRQ_SRC(irq) == 7 && !oss_present)
 240                 via_nubus_irq_startup(irq);
 241         else
 242                 mac_irq_enable(data);
 243
 244         return 0;
 245 }
 246
 247 static void mac_irq_shutdown(struct irq_data *data)
 248 {
 249         int irq = data->irq;
 250
 251         if (IRQ_SRC(irq) == 7 && !oss_present)
 252                 via_nubus_irq_shutdown(irq);
 253         else
 254                 mac_irq_disable(data);
 255 }
 256
 257 static volatile int in_nmi;
 258
 259 irqreturn_t mac_nmi_handler(int irq, void *dev_id)
 260 {
 261         if (in_nmi)
 262                 return IRQ_HANDLED;
 263         in_nmi = 1;
 264
 265         pr_info("Non-Maskable Interrupt\n");
 266         show_registers(get_irq_regs());
 267
 268         in_nmi = 0;
 269         return IRQ_HANDLED;
 270 }