| 1 | /* |
| 2 | * QEMU SMBus device emulation. |
| 3 | * |
| 4 | * This code is a helper for SMBus device emulation. It implements an |
| 5 | * I2C device interface and runs the SMBus protocol from the device |
| 6 | * point of view and maps those to simple calls to emulate. |
| 7 | * |
| 8 | * Copyright (c) 2007 CodeSourcery. |
| 9 | * Written by Paul Brook |
| 10 | * |
| 11 | * This code is licensed under the LGPL. |
| 12 | */ |
| 13 | |
| 14 | /* TODO: Implement PEC. */ |
| 15 | |
| 16 | #include "qemu/osdep.h" |
| 17 | #include "hw/i2c/i2c.h" |
| 18 | #include "hw/i2c/smbus_slave.h" |
| 19 | #include "migration/vmstate.h" |
| 20 | #include "qemu/module.h" |
| 21 | |
| 22 | //#define DEBUG_SMBUS 1 |
| 23 | |
| 24 | #ifdef DEBUG_SMBUS |
| 25 | #define DPRINTF(fmt, ...) \ |
| 26 | do { printf("smbus(%02x): " fmt , dev->i2c.address, ## __VA_ARGS__); } while (0) |
| 27 | #define BADF(fmt, ...) \ |
| 28 | do { g_autofree char *qom_path = object_get_canonical_path(OBJECT(dev)); \ |
| 29 | fprintf(stderr, "%s: smbus: error: " fmt , qom_path, ## __VA_ARGS__); \ |
| 30 | exit(1); } while (0) |
| 31 | #else |
| 32 | #define DPRINTF(fmt, ...) do {} while(0) |
| 33 | #define BADF(fmt, ...) \ |
| 34 | do { g_autofree char *qom_path = object_get_canonical_path(OBJECT(dev)); \ |
| 35 | fprintf(stderr, "%s: smbus: error: " fmt , qom_path, ## __VA_ARGS__); \ |
| 36 | } while (0) |
| 37 | #endif |
| 38 | |
| 39 | enum { |
| 40 | SMBUS_IDLE, |
| 41 | SMBUS_WRITE_DATA, |
| 42 | SMBUS_READ_DATA, |
| 43 | SMBUS_DONE, |
| 44 | SMBUS_CONFUSED = -1 |
| 45 | }; |
| 46 | |
| 47 | static void smbus_do_quick_cmd(SMBusDevice *dev, int recv) |
| 48 | { |
| 49 | SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); |
| 50 | |
| 51 | DPRINTF("Quick Command %d\n", recv); |
| 52 | if (sc->quick_cmd) { |
| 53 | sc->quick_cmd(dev, recv); |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | static void smbus_do_write(SMBusDevice *dev) |
| 58 | { |
| 59 | SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); |
| 60 | |
| 61 | DPRINTF("Command %d len %d\n", dev->data_buf[0], dev->data_len); |
| 62 | if (sc->write_data) { |
| 63 | sc->write_data(dev, dev->data_buf, dev->data_len); |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | static int smbus_i2c_event(I2CSlave *s, enum i2c_event event) |
| 68 | { |
| 69 | SMBusDevice *dev = SMBUS_DEVICE(s); |
| 70 | |
| 71 | switch (event) { |
| 72 | case I2C_START_SEND: |
| 73 | switch (dev->mode) { |
| 74 | case SMBUS_IDLE: |
| 75 | DPRINTF("Incoming data\n"); |
| 76 | dev->mode = SMBUS_WRITE_DATA; |
| 77 | break; |
| 78 | |
| 79 | default: |
| 80 | BADF("Unexpected send start condition in state %d\n", dev->mode); |
| 81 | dev->mode = SMBUS_CONFUSED; |
| 82 | break; |
| 83 | } |
| 84 | break; |
| 85 | |
| 86 | case I2C_START_RECV: |
| 87 | switch (dev->mode) { |
| 88 | case SMBUS_IDLE: |
| 89 | DPRINTF("Read mode\n"); |
| 90 | dev->mode = SMBUS_READ_DATA; |
| 91 | break; |
| 92 | |
| 93 | case SMBUS_WRITE_DATA: |
| 94 | if (dev->data_len == 0) { |
| 95 | BADF("Read after write with no data\n"); |
| 96 | dev->mode = SMBUS_CONFUSED; |
| 97 | } else { |
| 98 | smbus_do_write(dev); |
| 99 | DPRINTF("Read mode\n"); |
| 100 | dev->mode = SMBUS_READ_DATA; |
| 101 | } |
| 102 | break; |
| 103 | |
| 104 | default: |
| 105 | BADF("Unexpected recv start condition in state %d\n", dev->mode); |
| 106 | dev->mode = SMBUS_CONFUSED; |
| 107 | break; |
| 108 | } |
| 109 | break; |
| 110 | |
| 111 | case I2C_FINISH: |
| 112 | if (dev->data_len == 0) { |
| 113 | if (dev->mode == SMBUS_WRITE_DATA || dev->mode == SMBUS_READ_DATA) { |
| 114 | smbus_do_quick_cmd(dev, dev->mode == SMBUS_READ_DATA); |
| 115 | } |
| 116 | } else { |
| 117 | switch (dev->mode) { |
| 118 | case SMBUS_WRITE_DATA: |
| 119 | smbus_do_write(dev); |
| 120 | break; |
| 121 | |
| 122 | case SMBUS_READ_DATA: |
| 123 | BADF("Unexpected stop during receive\n"); |
| 124 | break; |
| 125 | |
| 126 | default: |
| 127 | /* Nothing to do. */ |
| 128 | break; |
| 129 | } |
| 130 | } |
| 131 | dev->mode = SMBUS_IDLE; |
| 132 | dev->data_len = 0; |
| 133 | break; |
| 134 | |
| 135 | case I2C_NACK: |
| 136 | switch (dev->mode) { |
| 137 | case SMBUS_DONE: |
| 138 | /* Nothing to do. */ |
| 139 | break; |
| 140 | |
| 141 | case SMBUS_READ_DATA: |
| 142 | dev->mode = SMBUS_DONE; |
| 143 | break; |
| 144 | |
| 145 | default: |
| 146 | BADF("Unexpected NACK in state %d\n", dev->mode); |
| 147 | dev->mode = SMBUS_CONFUSED; |
| 148 | break; |
| 149 | } |
| 150 | break; |
| 151 | |
| 152 | default: |
| 153 | return -1; |
| 154 | } |
| 155 | |
| 156 | return 0; |
| 157 | } |
| 158 | |
| 159 | static uint8_t smbus_i2c_recv(I2CSlave *s) |
| 160 | { |
| 161 | SMBusDevice *dev = SMBUS_DEVICE(s); |
| 162 | SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); |
| 163 | uint8_t ret = 0xff; |
| 164 | |
| 165 | switch (dev->mode) { |
| 166 | case SMBUS_READ_DATA: |
| 167 | if (sc->receive_byte) { |
| 168 | ret = sc->receive_byte(dev); |
| 169 | } |
| 170 | DPRINTF("Read data %02x\n", ret); |
| 171 | break; |
| 172 | |
| 173 | default: |
| 174 | BADF("Unexpected read in state %d\n", dev->mode); |
| 175 | dev->mode = SMBUS_CONFUSED; |
| 176 | break; |
| 177 | } |
| 178 | |
| 179 | return ret; |
| 180 | } |
| 181 | |
| 182 | static int smbus_i2c_send(I2CSlave *s, uint8_t data) |
| 183 | { |
| 184 | SMBusDevice *dev = SMBUS_DEVICE(s); |
| 185 | |
| 186 | switch (dev->mode) { |
| 187 | case SMBUS_WRITE_DATA: |
| 188 | DPRINTF("Write data %02x\n", data); |
| 189 | if (dev->data_len >= sizeof(dev->data_buf)) { |
| 190 | BADF("Too many bytes sent\n"); |
| 191 | } else { |
| 192 | dev->data_buf[dev->data_len++] = data; |
| 193 | } |
| 194 | break; |
| 195 | |
| 196 | default: |
| 197 | BADF("Unexpected write in state %d\n", dev->mode); |
| 198 | break; |
| 199 | } |
| 200 | |
| 201 | return 0; |
| 202 | } |
| 203 | |
| 204 | static void smbus_device_class_init(ObjectClass *klass, const void *data) |
| 205 | { |
| 206 | I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass); |
| 207 | |
| 208 | sc->event = smbus_i2c_event; |
| 209 | sc->recv = smbus_i2c_recv; |
| 210 | sc->send = smbus_i2c_send; |
| 211 | } |
| 212 | |
| 213 | bool smbus_vmstate_needed(SMBusDevice *dev) |
| 214 | { |
| 215 | return dev->mode != SMBUS_IDLE; |
| 216 | } |
| 217 | |
| 218 | const VMStateDescription vmstate_smbus_device = { |
| 219 | .name = TYPE_SMBUS_DEVICE, |
| 220 | .version_id = 1, |
| 221 | .minimum_version_id = 1, |
| 222 | .fields = (const VMStateField[]) { |
| 223 | VMSTATE_I2C_SLAVE(i2c, SMBusDevice), |
| 224 | VMSTATE_INT32(mode, SMBusDevice), |
| 225 | VMSTATE_INT32(data_len, SMBusDevice), |
| 226 | VMSTATE_UINT8_ARRAY(data_buf, SMBusDevice, SMBUS_DATA_MAX_LEN), |
| 227 | VMSTATE_END_OF_LIST() |
| 228 | } |
| 229 | }; |
| 230 | |
| 231 | static const TypeInfo smbus_device_type_info = { |
| 232 | .name = TYPE_SMBUS_DEVICE, |
| 233 | .parent = TYPE_I2C_SLAVE, |
| 234 | .instance_size = sizeof(SMBusDevice), |
| 235 | .abstract = true, |
| 236 | .class_size = sizeof(SMBusDeviceClass), |
| 237 | .class_init = smbus_device_class_init, |
| 238 | }; |
| 239 | |
| 240 | static void smbus_device_register_types(void) |
| 241 | { |
| 242 | type_register_static(&smbus_device_type_info); |
| 243 | } |
| 244 | |
| 245 | type_init(smbus_device_register_types) |