hw/misc/max111x.c

   1 /*
   2  * Maxim MAX1110/1111 ADC chip emulation.
   3  *
   4  * Copyright (c) 2006 Openedhand Ltd.
   5  * Written by Andrzej Zaborowski <balrog@zabor.org>
   6  *
   7  * This code is licensed under the GNU GPLv2.
   8  *
   9  * Contributions after 2012-01-13 are licensed under the terms of the
  10  * GNU GPL, version 2 or (at your option) any later version.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "hw/irq.h"
  15 #include "hw/ssi/ssi.h"
  16 #include "migration/vmstate.h"
  17 #include "qemu/module.h"
  18
  19 typedef struct {
  20     SSISlave parent_obj;
  21
  22     qemu_irq interrupt;
  23     uint8_t tb1, rb2, rb3;
  24     int cycle;
  25
  26     uint8_t input[8];
  27     int inputs, com;
  28 } MAX111xState;
  29
  30 #define TYPE_MAX_111X "max111x"
  31
  32 #define MAX_111X(obj) \
  33     OBJECT_CHECK(MAX111xState, (obj), TYPE_MAX_111X)
  34
  35 #define TYPE_MAX_1110 "max1110"
  36 #define TYPE_MAX_1111 "max1111"
  37
  38 /* Control-byte bitfields */
  39 #define CB_PD0          (1 << 0)
  40 #define CB_PD1          (1 << 1)
  41 #define CB_SGL          (1 << 2)
  42 #define CB_UNI          (1 << 3)
  43 #define CB_SEL0         (1 << 4)
  44 #define CB_SEL1         (1 << 5)
  45 #define CB_SEL2         (1 << 6)
  46 #define CB_START        (1 << 7)
  47
  48 #define CHANNEL_NUM(v, b0, b1, b2)      \
  49                         ((((v) >> (2 + (b0))) & 4) |    \
  50                          (((v) >> (3 + (b1))) & 2) |    \
  51                          (((v) >> (4 + (b2))) & 1))
  52
  53 static uint32_t max111x_read(MAX111xState *s)
  54 {
  55     if (!s->tb1)
  56         return 0;
  57
  58     switch (s->cycle ++) {
  59     case 1:
  60         return s->rb2;
  61     case 2:
  62         return s->rb3;
  63     }
  64
  65     return 0;
  66 }
  67
  68 /* Interpret a control-byte */
  69 static void max111x_write(MAX111xState *s, uint32_t value)
  70 {
  71     int measure, chan;
  72
  73     /* Ignore the value if START bit is zero */
  74     if (!(value & CB_START))
  75         return;
  76
  77     s->cycle = 0;
  78
  79     if (!(value & CB_PD1)) {
  80         s->tb1 = 0;
  81         return;
  82     }
  83
  84     s->tb1 = value;
  85
  86     if (s->inputs == 8)
  87         chan = CHANNEL_NUM(value, 1, 0, 2);
  88     else
  89         chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);
  90
  91     if (value & CB_SGL)
  92         measure = s->input[chan] - s->com;
  93     else
  94         measure = s->input[chan] - s->input[chan ^ 1];
  95
  96     if (!(value & CB_UNI))
  97         measure ^= 0x80;
  98
  99     s->rb2 = (measure >> 2) & 0x3f;
 100     s->rb3 = (measure << 6) & 0xc0;
 101
 102     /* FIXME: When should the IRQ be lowered?  */
 103     qemu_irq_raise(s->interrupt);
 104 }
 105
 106 static uint32_t max111x_transfer(SSISlave *dev, uint32_t value)
 107 {
 108     MAX111xState *s = MAX_111X(dev);
 109     max111x_write(s, value);
 110     return max111x_read(s);
 111 }
 112
 113 static const VMStateDescription vmstate_max111x = {
 114     .name = "max111x",
 115     .version_id = 1,
 116     .minimum_version_id = 1,
 117     .fields = (VMStateField[]) {
 118         VMSTATE_SSI_SLAVE(parent_obj, MAX111xState),
 119         VMSTATE_UINT8(tb1, MAX111xState),
 120         VMSTATE_UINT8(rb2, MAX111xState),
 121         VMSTATE_UINT8(rb3, MAX111xState),
 122         VMSTATE_INT32_EQUAL(inputs, MAX111xState, NULL),
 123         VMSTATE_INT32(com, MAX111xState),
 124         VMSTATE_ARRAY_INT32_UNSAFE(input, MAX111xState, inputs,
 125                                    vmstate_info_uint8, uint8_t),
 126         VMSTATE_END_OF_LIST()
 127     }
 128 };
 129
 130 static int max111x_init(SSISlave *d, int inputs)
 131 {
 132     DeviceState *dev = DEVICE(d);
 133     MAX111xState *s = MAX_111X(dev);
 134
 135     qdev_init_gpio_out(dev, &s->interrupt, 1);
 136
 137     s->inputs = inputs;
 138     /* TODO: add a user interface for setting these */
 139     s->input[0] = 0xf0;
 140     s->input[1] = 0xe0;
 141     s->input[2] = 0xd0;
 142     s->input[3] = 0xc0;
 143     s->input[4] = 0xb0;
 144     s->input[5] = 0xa0;
 145     s->input[6] = 0x90;
 146     s->input[7] = 0x80;
 147     s->com = 0;
 148
 149     vmstate_register(VMSTATE_IF(dev), VMSTATE_INSTANCE_ID_ANY,
 150                      &vmstate_max111x, s);
 151     return 0;
 152 }
 153
 154 static void max1110_realize(SSISlave *dev, Error **errp)
 155 {
 156     max111x_init(dev, 8);
 157 }
 158
 159 static void max1111_realize(SSISlave *dev, Error **errp)
 160 {
 161     max111x_init(dev, 4);
 162 }
 163
 164 void max111x_set_input(DeviceState *dev, int line, uint8_t value)
 165 {
 166     MAX111xState *s = MAX_111X(dev);
 167     assert(line >= 0 && line < s->inputs);
 168     s->input[line] = value;
 169 }
 170
 171 static void max111x_class_init(ObjectClass *klass, void *data)
 172 {
 173     SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
 174
 175     k->transfer = max111x_transfer;
 176 }
 177
 178 static const TypeInfo max111x_info = {
 179     .name          = TYPE_MAX_111X,
 180     .parent        = TYPE_SSI_SLAVE,
 181     .instance_size = sizeof(MAX111xState),
 182     .class_init    = max111x_class_init,
 183     .abstract      = true,
 184 };
 185
 186 static void max1110_class_init(ObjectClass *klass, void *data)
 187 {
 188     SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
 189
 190     k->realize = max1110_realize;
 191 }
 192
 193 static const TypeInfo max1110_info = {
 194     .name          = TYPE_MAX_1110,
 195     .parent        = TYPE_MAX_111X,
 196     .class_init    = max1110_class_init,
 197 };
 198
 199 static void max1111_class_init(ObjectClass *klass, void *data)
 200 {
 201     SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
 202
 203     k->realize = max1111_realize;
 204 }
 205
 206 static const TypeInfo max1111_info = {
 207     .name          = TYPE_MAX_1111,
 208     .parent        = TYPE_MAX_111X,
 209     .class_init    = max1111_class_init,
 210 };
 211
 212 static void max111x_register_types(void)
 213 {
 214     type_register_static(&max111x_info);
 215     type_register_static(&max1110_info);
 216     type_register_static(&max1111_info);
 217 }
 218
 219 type_init(max111x_register_types)