hw/m68k/q800-glue.c

   1 /*
   2  * QEMU q800 logic GLUE (General Logic Unit)
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a copy
   5  * of this software and associated documentation files (the "Software"), to deal
   6  * in the Software without restriction, including without limitation the rights
   7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8  * copies of the Software, and to permit persons to whom the Software is
   9  * furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  20  * THE SOFTWARE.
  21  */
  22
  23 #include "qemu/osdep.h"
  24 #include "cpu.h"
  25 #include "hw/m68k/q800-glue.h"
  26 #include "hw/boards.h"
  27 #include "hw/irq.h"
  28 #include "hw/nmi.h"
  29 #include "hw/qdev-properties.h"
  30 #include "migration/vmstate.h"
  31
  32 /*
  33  * The GLUE (General Logic Unit) is an Apple custom integrated circuit chip
  34  * that performs a variety of functions (RAM management, clock generation, ...).
  35  * The GLUE chip receives interrupt requests from various devices,
  36  * assign priority to each, and asserts one or more interrupt line to the
  37  * CPU.
  38  */
  39
  40 /*
  41  * The GLUE logic on the Quadra 800 supports 2 different IRQ routing modes
  42  * controlled from the VIA1 auxmode GPIO (port B bit 6) which are documented
  43  * in NetBSD as follows:
  44  *
  45  * A/UX mode (Linux, NetBSD, auxmode GPIO low)
  46  *
  47  *   Level 0:        Spurious: ignored
  48  *   Level 1:        Software
  49  *   Level 2:        VIA2 (except ethernet, sound)
  50  *   Level 3:        Ethernet
  51  *   Level 4:        Serial (SCC)
  52  *   Level 5:        Sound
  53  *   Level 6:        VIA1
  54  *   Level 7:        NMIs: parity errors, RESET button, YANCC error
  55  *
  56  * Classic mode (default: used by MacOS, A/UX 3.0.1, auxmode GPIO high)
  57  *
  58  *   Level 0:        Spurious: ignored
  59  *   Level 1:        VIA1 (clock, ADB)
  60  *   Level 2:        VIA2 (NuBus, SCSI)
  61  *   Level 3:
  62  *   Level 4:        Serial (SCC)
  63  *   Level 5:
  64  *   Level 6:
  65  *   Level 7:        Non-maskable: parity errors, RESET button
  66  *
  67  * Note that despite references to A/UX mode in Linux and NetBSD, at least
  68  * A/UX 3.0.1 still uses Classic mode.
  69  */
  70
  71 static void GLUE_set_irq(void *opaque, int irq, int level)
  72 {
  73     GLUEState *s = opaque;
  74     int i;
  75
  76     if (s->auxmode) {
  77         /* Classic mode */
  78         switch (irq) {
  79         case GLUE_IRQ_IN_VIA1:
  80             irq = 0;
  81             break;
  82
  83         case GLUE_IRQ_IN_VIA2:
  84             irq = 1;
  85             break;
  86
  87         case GLUE_IRQ_IN_SONIC:
  88             /* Route to VIA2 instead */
  89             qemu_set_irq(s->irqs[GLUE_IRQ_NUBUS_9], level);
  90             return;
  91
  92         case GLUE_IRQ_IN_ESCC:
  93             irq = 3;
  94             break;
  95
  96         case GLUE_IRQ_IN_NMI:
  97             irq = 6;
  98             break;
  99
 100         case GLUE_IRQ_IN_ASC:
 101             /* Route to VIA2 instead, negative edge-triggered */
 102             qemu_set_irq(s->irqs[GLUE_IRQ_ASC], !level);
 103             return;
 104
 105         default:
 106             g_assert_not_reached();
 107         }
 108     } else {
 109         /* A/UX mode */
 110         switch (irq) {
 111         case GLUE_IRQ_IN_VIA1:
 112             irq = 5;
 113             break;
 114
 115         case GLUE_IRQ_IN_VIA2:
 116             irq = 1;
 117             break;
 118
 119         case GLUE_IRQ_IN_SONIC:
 120             irq = 2;
 121             break;
 122
 123         case GLUE_IRQ_IN_ESCC:
 124             irq = 3;
 125             break;
 126
 127         case GLUE_IRQ_IN_NMI:
 128             irq = 6;
 129             break;
 130
 131         case GLUE_IRQ_IN_ASC:
 132             irq = 4;
 133             break;
 134
 135         default:
 136             g_assert_not_reached();
 137         }
 138     }
 139
 140     if (level) {
 141         s->ipr |= 1 << irq;
 142     } else {
 143         s->ipr &= ~(1 << irq);
 144     }
 145
 146     for (i = 7; i >= 0; i--) {
 147         if ((s->ipr >> i) & 1) {
 148             m68k_set_irq_level(s->cpu, i + 1, i + 25);
 149             return;
 150         }
 151     }
 152     m68k_set_irq_level(s->cpu, 0, 0);
 153 }
 154
 155 static void glue_auxmode_set_irq(void *opaque, int irq, int level)
 156 {
 157     GLUEState *s = GLUE(opaque);
 158
 159     s->auxmode = level;
 160 }
 161
 162 static void glue_nmi(NMIState *n, int cpu_index, Error **errp)
 163 {
 164     GLUEState *s = GLUE(n);
 165
 166     /* Hold NMI active for 100ms */
 167     GLUE_set_irq(s, GLUE_IRQ_IN_NMI, 1);
 168     timer_mod(s->nmi_release, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 100);
 169 }
 170
 171 static void glue_nmi_release(void *opaque)
 172 {
 173     GLUEState *s = GLUE(opaque);
 174
 175     GLUE_set_irq(s, GLUE_IRQ_IN_NMI, 0);
 176 }
 177
 178 static void glue_reset_hold(Object *obj)
 179 {
 180     GLUEState *s = GLUE(obj);
 181
 182     s->ipr = 0;
 183     s->auxmode = 0;
 184
 185     timer_del(s->nmi_release);
 186 }
 187
 188 static const VMStateDescription vmstate_glue = {
 189     .name = "q800-glue",
 190     .version_id = 0,
 191     .minimum_version_id = 0,
 192     .fields = (VMStateField[]) {
 193         VMSTATE_UINT8(ipr, GLUEState),
 194         VMSTATE_UINT8(auxmode, GLUEState),
 195         VMSTATE_TIMER_PTR(nmi_release, GLUEState),
 196         VMSTATE_END_OF_LIST(),
 197     },
 198 };
 199
 200 /*
 201  * If the m68k CPU implemented its inbound irq lines as GPIO lines
 202  * rather than via the m68k_set_irq_level() function we would not need
 203  * this cpu link property and could instead provide outbound IRQ lines
 204  * that the board could wire up to the CPU.
 205  */
 206 static Property glue_properties[] = {
 207     DEFINE_PROP_LINK("cpu", GLUEState, cpu, TYPE_M68K_CPU, M68kCPU *),
 208     DEFINE_PROP_END_OF_LIST(),
 209 };
 210
 211 static void glue_finalize(Object *obj)
 212 {
 213     GLUEState *s = GLUE(obj);
 214
 215     timer_free(s->nmi_release);
 216 }
 217
 218 static void glue_init(Object *obj)
 219 {
 220     DeviceState *dev = DEVICE(obj);
 221     GLUEState *s = GLUE(dev);
 222
 223     qdev_init_gpio_in(dev, GLUE_set_irq, 8);
 224     qdev_init_gpio_in_named(dev, glue_auxmode_set_irq, "auxmode", 1);
 225
 226     qdev_init_gpio_out(dev, s->irqs, 2);
 227
 228     /* NMI release timer */
 229     s->nmi_release = timer_new_ms(QEMU_CLOCK_VIRTUAL, glue_nmi_release, s);
 230 }
 231
 232 static void glue_class_init(ObjectClass *klass, void *data)
 233 {
 234     DeviceClass *dc = DEVICE_CLASS(klass);
 235     ResettableClass *rc = RESETTABLE_CLASS(klass);
 236     NMIClass *nc = NMI_CLASS(klass);
 237
 238     dc->vmsd = &vmstate_glue;
 239     device_class_set_props(dc, glue_properties);
 240     rc->phases.hold = glue_reset_hold;
 241     nc->nmi_monitor_handler = glue_nmi;
 242 }
 243
 244 static const TypeInfo glue_info_types[] = {
 245     {
 246         .name = TYPE_GLUE,
 247         .parent = TYPE_SYS_BUS_DEVICE,
 248         .instance_size = sizeof(GLUEState),
 249         .instance_init = glue_init,
 250         .instance_finalize = glue_finalize,
 251         .class_init = glue_class_init,
 252         .interfaces = (InterfaceInfo[]) {
 253              { TYPE_NMI },
 254              { }
 255         },
 256     },
 257 };
 258
 259 DEFINE_TYPES(glue_info_types)