hw/m68k/mcf_intc.c

   1 /*
   2  * ColdFire Interrupt Controller emulation.
   3  *
   4  * Copyright (c) 2007 CodeSourcery.
   5  *
   6  * This code is licensed under the GPL
   7  */
   8 #include "hw/hw.h"
   9 #include "hw/mcf.h"
  10 #include "exec/address-spaces.h"
  11
  12 typedef struct {
  13     MemoryRegion iomem;
  14     uint64_t ipr;
  15     uint64_t imr;
  16     uint64_t ifr;
  17     uint64_t enabled;
  18     uint8_t icr[64];
  19     M68kCPU *cpu;
  20     int active_vector;
  21 } mcf_intc_state;
  22
  23 static void mcf_intc_update(mcf_intc_state *s)
  24 {
  25     uint64_t active;
  26     int i;
  27     int best;
  28     int best_level;
  29
  30     active = (s->ipr | s->ifr) & s->enabled & ~s->imr;
  31     best_level = 0;
  32     best = 64;
  33     if (active) {
  34         for (i = 0; i < 64; i++) {
  35             if ((active & 1) != 0 && s->icr[i] >= best_level) {
  36                 best_level = s->icr[i];
  37                 best = i;
  38             }
  39             active >>= 1;
  40         }
  41     }
  42     s->active_vector = ((best == 64) ? 24 : (best + 64));
  43     m68k_set_irq_level(s->cpu, best_level, s->active_vector);
  44 }
  45
  46 static uint64_t mcf_intc_read(void *opaque, hwaddr addr,
  47                               unsigned size)
  48 {
  49     int offset;
  50     mcf_intc_state *s = (mcf_intc_state *)opaque;
  51     offset = addr & 0xff;
  52     if (offset >= 0x40 && offset < 0x80) {
  53         return s->icr[offset - 0x40];
  54     }
  55     switch (offset) {
  56     case 0x00:
  57         return (uint32_t)(s->ipr >> 32);
  58     case 0x04:
  59         return (uint32_t)s->ipr;
  60     case 0x08:
  61         return (uint32_t)(s->imr >> 32);
  62     case 0x0c:
  63         return (uint32_t)s->imr;
  64     case 0x10:
  65         return (uint32_t)(s->ifr >> 32);
  66     case 0x14:
  67         return (uint32_t)s->ifr;
  68     case 0xe0: /* SWIACK.  */
  69         return s->active_vector;
  70     case 0xe1: case 0xe2: case 0xe3: case 0xe4:
  71     case 0xe5: case 0xe6: case 0xe7:
  72         /* LnIACK */
  73         hw_error("mcf_intc_read: LnIACK not implemented\n");
  74     default:
  75         return 0;
  76     }
  77 }
  78
  79 static void mcf_intc_write(void *opaque, hwaddr addr,
  80                            uint64_t val, unsigned size)
  81 {
  82     int offset;
  83     mcf_intc_state *s = (mcf_intc_state *)opaque;
  84     offset = addr & 0xff;
  85     if (offset >= 0x40 && offset < 0x80) {
  86         int n = offset - 0x40;
  87         s->icr[n] = val;
  88         if (val == 0)
  89             s->enabled &= ~(1ull << n);
  90         else
  91             s->enabled |= (1ull << n);
  92         mcf_intc_update(s);
  93         return;
  94     }
  95     switch (offset) {
  96     case 0x00: case 0x04:
  97         /* Ignore IPR writes.  */
  98         return;
  99     case 0x08:
 100         s->imr = (s->imr & 0xffffffff) | ((uint64_t)val << 32);
 101         break;
 102     case 0x0c:
 103         s->imr = (s->imr & 0xffffffff00000000ull) | (uint32_t)val;
 104         break;
 105     default:
 106         hw_error("mcf_intc_write: Bad write offset %d\n", offset);
 107         break;
 108     }
 109     mcf_intc_update(s);
 110 }
 111
 112 static void mcf_intc_set_irq(void *opaque, int irq, int level)
 113 {
 114     mcf_intc_state *s = (mcf_intc_state *)opaque;
 115     if (irq >= 64)
 116         return;
 117     if (level)
 118         s->ipr |= 1ull << irq;
 119     else
 120         s->ipr &= ~(1ull << irq);
 121     mcf_intc_update(s);
 122 }
 123
 124 static void mcf_intc_reset(mcf_intc_state *s)
 125 {
 126     s->imr = ~0ull;
 127     s->ipr = 0;
 128     s->ifr = 0;
 129     s->enabled = 0;
 130     memset(s->icr, 0, 64);
 131     s->active_vector = 24;
 132 }
 133
 134 static const MemoryRegionOps mcf_intc_ops = {
 135     .read = mcf_intc_read,
 136     .write = mcf_intc_write,
 137     .endianness = DEVICE_NATIVE_ENDIAN,
 138 };
 139
 140 qemu_irq *mcf_intc_init(MemoryRegion *sysmem,
 141                         hwaddr base,
 142                         M68kCPU *cpu)
 143 {
 144     mcf_intc_state *s;
 145
 146     s = g_malloc0(sizeof(mcf_intc_state));
 147     s->cpu = cpu;
 148     mcf_intc_reset(s);
 149
 150     memory_region_init_io(&s->iomem, &mcf_intc_ops, s, "mcf", 0x100);
 151     memory_region_add_subregion(sysmem, base, &s->iomem);
 152
 153     return qemu_allocate_irqs(mcf_intc_set_irq, s, 64);
 154 }