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1 | 5fafdf24 | ths | /*
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2 | 0ff596d0 | pbrook | * QEMU I2C bus interface.
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3 | 0ff596d0 | pbrook | *
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4 | 0ff596d0 | pbrook | * Copyright (c) 2007 CodeSourcery.
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5 | 0ff596d0 | pbrook | * Written by Paul Brook
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6 | 0ff596d0 | pbrook | *
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7 | 0ff596d0 | pbrook | * This code is licenced under the LGPL.
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8 | 0ff596d0 | pbrook | */
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9 | 0ff596d0 | pbrook | |
10 | 0ff596d0 | pbrook | #include "vl.h" |
11 | 0ff596d0 | pbrook | |
12 | 0ff596d0 | pbrook | struct i2c_bus
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13 | 0ff596d0 | pbrook | { |
14 | 0ff596d0 | pbrook | i2c_slave *current_dev; |
15 | 0ff596d0 | pbrook | i2c_slave *dev; |
16 | 0ff596d0 | pbrook | }; |
17 | 0ff596d0 | pbrook | |
18 | 0ff596d0 | pbrook | /* Create a new I2C bus. */
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19 | 0ff596d0 | pbrook | i2c_bus *i2c_init_bus(void)
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20 | 0ff596d0 | pbrook | { |
21 | 0ff596d0 | pbrook | i2c_bus *bus; |
22 | 0ff596d0 | pbrook | |
23 | 0ff596d0 | pbrook | bus = (i2c_bus *)qemu_mallocz(sizeof(i2c_bus));
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24 | 0ff596d0 | pbrook | return bus;
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25 | 0ff596d0 | pbrook | } |
26 | 0ff596d0 | pbrook | |
27 | 0ff596d0 | pbrook | /* Create a new slave device. */
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28 | 0ff596d0 | pbrook | i2c_slave *i2c_slave_init(i2c_bus *bus, int address, int size) |
29 | 0ff596d0 | pbrook | { |
30 | 0ff596d0 | pbrook | i2c_slave *dev; |
31 | 0ff596d0 | pbrook | |
32 | 0ff596d0 | pbrook | if (size < sizeof(i2c_slave)) |
33 | 0ff596d0 | pbrook | cpu_abort(cpu_single_env, "I2C struct too small");
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34 | 0ff596d0 | pbrook | |
35 | 0ff596d0 | pbrook | dev = (i2c_slave *)qemu_mallocz(size); |
36 | 0ff596d0 | pbrook | dev->address = address; |
37 | 0ff596d0 | pbrook | dev->next = bus->dev; |
38 | 0ff596d0 | pbrook | bus->dev = dev; |
39 | 0ff596d0 | pbrook | |
40 | 0ff596d0 | pbrook | return dev;
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41 | 0ff596d0 | pbrook | } |
42 | 0ff596d0 | pbrook | |
43 | 0ff596d0 | pbrook | void i2c_set_slave_address(i2c_slave *dev, int address) |
44 | 0ff596d0 | pbrook | { |
45 | 0ff596d0 | pbrook | dev->address = address; |
46 | 0ff596d0 | pbrook | } |
47 | 0ff596d0 | pbrook | |
48 | 0ff596d0 | pbrook | /* Return nonzero if bus is busy. */
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49 | 0ff596d0 | pbrook | int i2c_bus_busy(i2c_bus *bus)
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50 | 0ff596d0 | pbrook | { |
51 | 0ff596d0 | pbrook | return bus->current_dev != NULL; |
52 | 0ff596d0 | pbrook | } |
53 | 0ff596d0 | pbrook | |
54 | 0ff596d0 | pbrook | /* Returns nonzero if the bus is already busy, or is the address is not
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55 | 0ff596d0 | pbrook | valid. */
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56 | 0ff596d0 | pbrook | /* TODO: Make this handle multiple masters. */
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57 | 0ff596d0 | pbrook | int i2c_start_transfer(i2c_bus *bus, int address, int recv) |
58 | 0ff596d0 | pbrook | { |
59 | 0ff596d0 | pbrook | i2c_slave *dev; |
60 | 0ff596d0 | pbrook | |
61 | 0ff596d0 | pbrook | for (dev = bus->dev; dev; dev = dev->next) {
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62 | 0ff596d0 | pbrook | if (dev->address == address)
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63 | 0ff596d0 | pbrook | break;
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64 | 0ff596d0 | pbrook | } |
65 | 0ff596d0 | pbrook | |
66 | 0ff596d0 | pbrook | if (!dev)
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67 | 0ff596d0 | pbrook | return 1; |
68 | 0ff596d0 | pbrook | |
69 | 0ff596d0 | pbrook | /* If the bus is already busy, assume this is a repeated
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70 | 0ff596d0 | pbrook | start condition. */
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71 | 0ff596d0 | pbrook | bus->current_dev = dev; |
72 | 0ff596d0 | pbrook | dev->event(dev, recv ? I2C_START_RECV : I2C_START_SEND); |
73 | 0ff596d0 | pbrook | return 0; |
74 | 0ff596d0 | pbrook | } |
75 | 0ff596d0 | pbrook | |
76 | 0ff596d0 | pbrook | void i2c_end_transfer(i2c_bus *bus)
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77 | 0ff596d0 | pbrook | { |
78 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
79 | 0ff596d0 | pbrook | |
80 | 0ff596d0 | pbrook | if (!dev)
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81 | 0ff596d0 | pbrook | return;
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82 | 0ff596d0 | pbrook | |
83 | 0ff596d0 | pbrook | dev->event(dev, I2C_FINISH); |
84 | 0ff596d0 | pbrook | |
85 | 0ff596d0 | pbrook | bus->current_dev = NULL;
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86 | 0ff596d0 | pbrook | } |
87 | 0ff596d0 | pbrook | |
88 | 0ff596d0 | pbrook | int i2c_send(i2c_bus *bus, uint8_t data)
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89 | 0ff596d0 | pbrook | { |
90 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
91 | 0ff596d0 | pbrook | |
92 | 0ff596d0 | pbrook | if (!dev)
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93 | 0ff596d0 | pbrook | return -1; |
94 | 0ff596d0 | pbrook | |
95 | 0ff596d0 | pbrook | return dev->send(dev, data);
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96 | 0ff596d0 | pbrook | } |
97 | 0ff596d0 | pbrook | |
98 | 0ff596d0 | pbrook | int i2c_recv(i2c_bus *bus)
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99 | 0ff596d0 | pbrook | { |
100 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
101 | 0ff596d0 | pbrook | |
102 | 0ff596d0 | pbrook | if (!dev)
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103 | 0ff596d0 | pbrook | return -1; |
104 | 0ff596d0 | pbrook | |
105 | 0ff596d0 | pbrook | return dev->recv(dev);
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106 | 0ff596d0 | pbrook | } |
107 | 0ff596d0 | pbrook | |
108 | 0ff596d0 | pbrook | void i2c_nack(i2c_bus *bus)
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109 | 0ff596d0 | pbrook | { |
110 | 0ff596d0 | pbrook | i2c_slave *dev = bus->current_dev; |
111 | 0ff596d0 | pbrook | |
112 | 0ff596d0 | pbrook | if (!dev)
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113 | 0ff596d0 | pbrook | return;
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114 | 0ff596d0 | pbrook | |
115 | 0ff596d0 | pbrook | dev->event(dev, I2C_NACK); |
116 | 0ff596d0 | pbrook | } |
117 | 0ff596d0 | pbrook | |
118 | aa941b94 | balrog | void i2c_bus_save(QEMUFile *f, i2c_bus *bus)
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119 | aa941b94 | balrog | { |
120 | aa941b94 | balrog | qemu_put_byte(f, bus->current_dev ? bus->current_dev->address : 0x00);
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121 | aa941b94 | balrog | } |
122 | aa941b94 | balrog | |
123 | aa941b94 | balrog | void i2c_bus_load(QEMUFile *f, i2c_bus *bus)
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124 | aa941b94 | balrog | { |
125 | aa941b94 | balrog | i2c_slave *dev; |
126 | aa941b94 | balrog | uint8_t address = qemu_get_byte(f); |
127 | aa941b94 | balrog | |
128 | aa941b94 | balrog | if (address) {
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129 | aa941b94 | balrog | for (dev = bus->dev; dev; dev = dev->next)
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130 | aa941b94 | balrog | if (dev->address == address) {
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131 | aa941b94 | balrog | bus->current_dev = dev; |
132 | aa941b94 | balrog | return;
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133 | aa941b94 | balrog | } |
134 | aa941b94 | balrog | |
135 | aa941b94 | balrog | fprintf(stderr, "%s: I2C slave with address %02x disappeared\n",
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136 | aa941b94 | balrog | __FUNCTION__, address); |
137 | aa941b94 | balrog | } |
138 | aa941b94 | balrog | } |
139 | aa941b94 | balrog | |
140 | aa941b94 | balrog | void i2c_slave_save(QEMUFile *f, i2c_slave *dev)
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141 | aa941b94 | balrog | { |
142 | aa941b94 | balrog | qemu_put_byte(f, dev->address); |
143 | aa941b94 | balrog | } |
144 | aa941b94 | balrog | |
145 | aa941b94 | balrog | void i2c_slave_load(QEMUFile *f, i2c_slave *dev)
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146 | aa941b94 | balrog | { |
147 | aa941b94 | balrog | dev->address = qemu_get_byte(f); |
148 | aa941b94 | balrog | } |