linux-user: stack_base is now mandatory on all targets
[qemu.git] / hw / 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 "ssi.h"
14
15 typedef struct {
16 SSISlave ssidev;
17 qemu_irq interrupt;
18 uint8_t tb1, rb2, rb3;
19 int cycle;
20
21 uint8_t input[8];
22 int inputs, com;
23 } MAX111xState;
24
25 /* Control-byte bitfields */
26 #define CB_PD0 (1 << 0)
27 #define CB_PD1 (1 << 1)
28 #define CB_SGL (1 << 2)
29 #define CB_UNI (1 << 3)
30 #define CB_SEL0 (1 << 4)
31 #define CB_SEL1 (1 << 5)
32 #define CB_SEL2 (1 << 6)
33 #define CB_START (1 << 7)
34
35 #define CHANNEL_NUM(v, b0, b1, b2) \
36 ((((v) >> (2 + (b0))) & 4) | \
37 (((v) >> (3 + (b1))) & 2) | \
38 (((v) >> (4 + (b2))) & 1))
39
40 static uint32_t max111x_read(MAX111xState *s)
41 {
42 if (!s->tb1)
43 return 0;
44
45 switch (s->cycle ++) {
46 case 1:
47 return s->rb2;
48 case 2:
49 return s->rb3;
50 }
51
52 return 0;
53 }
54
55 /* Interpret a control-byte */
56 static void max111x_write(MAX111xState *s, uint32_t value)
57 {
58 int measure, chan;
59
60 /* Ignore the value if START bit is zero */
61 if (!(value & CB_START))
62 return;
63
64 s->cycle = 0;
65
66 if (!(value & CB_PD1)) {
67 s->tb1 = 0;
68 return;
69 }
70
71 s->tb1 = value;
72
73 if (s->inputs == 8)
74 chan = CHANNEL_NUM(value, 1, 0, 2);
75 else
76 chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);
77
78 if (value & CB_SGL)
79 measure = s->input[chan] - s->com;
80 else
81 measure = s->input[chan] - s->input[chan ^ 1];
82
83 if (!(value & CB_UNI))
84 measure ^= 0x80;
85
86 s->rb2 = (measure >> 2) & 0x3f;
87 s->rb3 = (measure << 6) & 0xc0;
88
89 /* FIXME: When should the IRQ be lowered? */
90 qemu_irq_raise(s->interrupt);
91 }
92
93 static uint32_t max111x_transfer(SSISlave *dev, uint32_t value)
94 {
95 MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev);
96 max111x_write(s, value);
97 return max111x_read(s);
98 }
99
100 static const VMStateDescription vmstate_max111x = {
101 .name = "max111x",
102 .version_id = 0,
103 .minimum_version_id = 0,
104 .minimum_version_id_old = 0,
105 .fields = (VMStateField[]) {
106 VMSTATE_UINT8(tb1, MAX111xState),
107 VMSTATE_UINT8(rb2, MAX111xState),
108 VMSTATE_UINT8(rb3, MAX111xState),
109 VMSTATE_INT32_EQUAL(inputs, MAX111xState),
110 VMSTATE_INT32(com, MAX111xState),
111 VMSTATE_ARRAY_INT32_UNSAFE(input, MAX111xState, inputs,
112 vmstate_info_uint8, uint8_t),
113 VMSTATE_END_OF_LIST()
114 }
115 };
116
117 static int max111x_init(SSISlave *dev, int inputs)
118 {
119 MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev);
120
121 qdev_init_gpio_out(&dev->qdev, &s->interrupt, 1);
122
123 s->inputs = inputs;
124 /* TODO: add a user interface for setting these */
125 s->input[0] = 0xf0;
126 s->input[1] = 0xe0;
127 s->input[2] = 0xd0;
128 s->input[3] = 0xc0;
129 s->input[4] = 0xb0;
130 s->input[5] = 0xa0;
131 s->input[6] = 0x90;
132 s->input[7] = 0x80;
133 s->com = 0;
134
135 vmstate_register(&dev->qdev, -1, &vmstate_max111x, s);
136 return 0;
137 }
138
139 static int max1110_init(SSISlave *dev)
140 {
141 return max111x_init(dev, 8);
142 }
143
144 static int max1111_init(SSISlave *dev)
145 {
146 return max111x_init(dev, 4);
147 }
148
149 void max111x_set_input(DeviceState *dev, int line, uint8_t value)
150 {
151 MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, SSI_SLAVE_FROM_QDEV(dev));
152 assert(line >= 0 && line < s->inputs);
153 s->input[line] = value;
154 }
155
156 static void max1110_class_init(ObjectClass *klass, void *data)
157 {
158 SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
159
160 k->init = max1110_init;
161 k->transfer = max111x_transfer;
162 }
163
164 static DeviceInfo max1110_info = {
165 .name = "max1110",
166 .size = sizeof(MAX111xState),
167 .class_init = max1110_class_init,
168 };
169
170 static void max1111_class_init(ObjectClass *klass, void *data)
171 {
172 SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
173
174 k->init = max1111_init;
175 k->transfer = max111x_transfer;
176 }
177
178 static DeviceInfo max1111_info = {
179 .name = "max1111",
180 .size = sizeof(MAX111xState),
181 .class_init = max1111_class_init,
182 };
183
184 static void max111x_register_devices(void)
185 {
186 ssi_register_slave(&max1110_info);
187 ssi_register_slave(&max1111_info);
188 }
189
190 device_init(max111x_register_devices)