diff options
Diffstat (limited to 'hw/i2c/smbus.c')
| -rw-r--r-- | hw/i2c/smbus.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/hw/i2c/smbus.c b/hw/i2c/smbus.c new file mode 100644 index 0000000..25d2d04 --- /dev/null +++ b/hw/i2c/smbus.c @@ -0,0 +1,335 @@ +/* + * QEMU SMBus device emulation. + * + * Copyright (c) 2007 CodeSourcery. + * Written by Paul Brook + * + * This code is licensed under the LGPL. + */ + +/* TODO: Implement PEC. */ + +#include "hw/hw.h" +#include "hw/i2c/i2c.h" +#include "hw/i2c/smbus.h" + +//#define DEBUG_SMBUS 1 + +#ifdef DEBUG_SMBUS +#define DPRINTF(fmt, ...) \ +do { printf("smbus(%02x): " fmt , dev->i2c.address, ## __VA_ARGS__); } while (0) +#define BADF(fmt, ...) \ +do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__); exit(1);} while (0) +#else +#define DPRINTF(fmt, ...) do {} while(0) +#define BADF(fmt, ...) \ +do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__);} while (0) +#endif + +enum { + SMBUS_IDLE, + SMBUS_WRITE_DATA, + SMBUS_RECV_BYTE, + SMBUS_READ_DATA, + SMBUS_DONE, + SMBUS_CONFUSED = -1 +}; + +static void smbus_do_quick_cmd(SMBusDevice *dev, int recv) +{ + SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); + + DPRINTF("Quick Command %d\n", recv); + if (sc->quick_cmd) { + sc->quick_cmd(dev, recv); + } +} + +static void smbus_do_write(SMBusDevice *dev) +{ + SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); + + if (dev->data_len == 0) { + smbus_do_quick_cmd(dev, 0); + } else if (dev->data_len == 1) { + DPRINTF("Send Byte\n"); + if (sc->send_byte) { + sc->send_byte(dev, dev->data_buf[0]); + } + } else { + dev->command = dev->data_buf[0]; + DPRINTF("Command %d len %d\n", dev->command, dev->data_len - 1); + if (sc->write_data) { + sc->write_data(dev, dev->command, dev->data_buf + 1, + dev->data_len - 1); + } + } +} + +static void smbus_i2c_event(I2CSlave *s, enum i2c_event event) +{ + SMBusDevice *dev = SMBUS_DEVICE(s); + + switch (event) { + case I2C_START_SEND: + switch (dev->mode) { + case SMBUS_IDLE: + DPRINTF("Incoming data\n"); + dev->mode = SMBUS_WRITE_DATA; + break; + default: + BADF("Unexpected send start condition in state %d\n", dev->mode); + dev->mode = SMBUS_CONFUSED; + break; + } + break; + + case I2C_START_RECV: + switch (dev->mode) { + case SMBUS_IDLE: + DPRINTF("Read mode\n"); + dev->mode = SMBUS_RECV_BYTE; + break; + case SMBUS_WRITE_DATA: + if (dev->data_len == 0) { + BADF("Read after write with no data\n"); + dev->mode = SMBUS_CONFUSED; + } else { + if (dev->data_len > 1) { + smbus_do_write(dev); + } else { + dev->command = dev->data_buf[0]; + DPRINTF("%02x: Command %d\n", dev->i2c.address, + dev->command); + } + DPRINTF("Read mode\n"); + dev->data_len = 0; + dev->mode = SMBUS_READ_DATA; + } + break; + default: + BADF("Unexpected recv start condition in state %d\n", dev->mode); + dev->mode = SMBUS_CONFUSED; + break; + } + break; + + case I2C_FINISH: + switch (dev->mode) { + case SMBUS_WRITE_DATA: + smbus_do_write(dev); + break; + case SMBUS_RECV_BYTE: + smbus_do_quick_cmd(dev, 1); + break; + case SMBUS_READ_DATA: + BADF("Unexpected stop during receive\n"); + break; + default: + /* Nothing to do. */ + break; + } + dev->mode = SMBUS_IDLE; + dev->data_len = 0; + break; + + case I2C_NACK: + switch (dev->mode) { + case SMBUS_DONE: + /* Nothing to do. */ + break; + case SMBUS_READ_DATA: + dev->mode = SMBUS_DONE; + break; + default: + BADF("Unexpected NACK in state %d\n", dev->mode); + dev->mode = SMBUS_CONFUSED; + break; + } + } +} + +static int smbus_i2c_recv(I2CSlave *s) +{ + SMBusDevice *dev = SMBUS_DEVICE(s); + SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); + int ret; + + switch (dev->mode) { + case SMBUS_RECV_BYTE: + if (sc->receive_byte) { + ret = sc->receive_byte(dev); + } else { + ret = 0; + } + DPRINTF("Receive Byte %02x\n", ret); + dev->mode = SMBUS_DONE; + break; + case SMBUS_READ_DATA: + if (sc->read_data) { + ret = sc->read_data(dev, dev->command, dev->data_len); + dev->data_len++; + } else { + ret = 0; + } + DPRINTF("Read data %02x\n", ret); + break; + default: + BADF("Unexpected read in state %d\n", dev->mode); + dev->mode = SMBUS_CONFUSED; + ret = 0; + break; + } + return ret; +} + +static int smbus_i2c_send(I2CSlave *s, uint8_t data) +{ + SMBusDevice *dev = SMBUS_DEVICE(s); + + switch (dev->mode) { + case SMBUS_WRITE_DATA: + DPRINTF("Write data %02x\n", data); + dev->data_buf[dev->data_len++] = data; + break; + default: + BADF("Unexpected write in state %d\n", dev->mode); + break; + } + return 0; +} + +static int smbus_device_init(I2CSlave *i2c) +{ + SMBusDevice *dev = SMBUS_DEVICE(i2c); + SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); + + return sc->init(dev); +} + +/* Master device commands. */ +void smbus_quick_command(i2c_bus *bus, uint8_t addr, int read) +{ + i2c_start_transfer(bus, addr, read); + i2c_end_transfer(bus); +} + +uint8_t smbus_receive_byte(i2c_bus *bus, uint8_t addr) +{ + uint8_t data; + + i2c_start_transfer(bus, addr, 1); + data = i2c_recv(bus); + i2c_nack(bus); + i2c_end_transfer(bus); + return data; +} + +void smbus_send_byte(i2c_bus *bus, uint8_t addr, uint8_t data) +{ + i2c_start_transfer(bus, addr, 0); + i2c_send(bus, data); + i2c_end_transfer(bus); +} + +uint8_t smbus_read_byte(i2c_bus *bus, uint8_t addr, uint8_t command) +{ + uint8_t data; + i2c_start_transfer(bus, addr, 0); + i2c_send(bus, command); + i2c_start_transfer(bus, addr, 1); + data = i2c_recv(bus); + i2c_nack(bus); + i2c_end_transfer(bus); + return data; +} + +void smbus_write_byte(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t data) +{ + i2c_start_transfer(bus, addr, 0); + i2c_send(bus, command); + i2c_send(bus, data); + i2c_end_transfer(bus); +} + +uint16_t smbus_read_word(i2c_bus *bus, uint8_t addr, uint8_t command) +{ + uint16_t data; + i2c_start_transfer(bus, addr, 0); + i2c_send(bus, command); + i2c_start_transfer(bus, addr, 1); + data = i2c_recv(bus); + data |= i2c_recv(bus) << 8; + i2c_nack(bus); + i2c_end_transfer(bus); + return data; +} + +void smbus_write_word(i2c_bus *bus, uint8_t addr, uint8_t command, uint16_t data) +{ + i2c_start_transfer(bus, addr, 0); + i2c_send(bus, command); + i2c_send(bus, data & 0xff); + i2c_send(bus, data >> 8); + i2c_end_transfer(bus); +} + +int smbus_read_block(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t *data) +{ + int len; + int i; + + i2c_start_transfer(bus, addr, 0); + i2c_send(bus, command); + i2c_start_transfer(bus, addr, 1); + len = i2c_recv(bus); + if (len > 32) + len = 0; + for (i = 0; i < len; i++) + data[i] = i2c_recv(bus); + i2c_nack(bus); + i2c_end_transfer(bus); + return len; +} + +void smbus_write_block(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t *data, + int len) +{ + int i; + + if (len > 32) + len = 32; + + i2c_start_transfer(bus, addr, 0); + i2c_send(bus, command); + i2c_send(bus, len); + for (i = 0; i < len; i++) + i2c_send(bus, data[i]); + i2c_end_transfer(bus); +} + +static void smbus_device_class_init(ObjectClass *klass, void *data) +{ + I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass); + + sc->init = smbus_device_init; + sc->event = smbus_i2c_event; + sc->recv = smbus_i2c_recv; + sc->send = smbus_i2c_send; +} + +static const TypeInfo smbus_device_type_info = { + .name = TYPE_SMBUS_DEVICE, + .parent = TYPE_I2C_SLAVE, + .instance_size = sizeof(SMBusDevice), + .abstract = true, + .class_size = sizeof(SMBusDeviceClass), + .class_init = smbus_device_class_init, +}; + +static void smbus_device_register_types(void) +{ + type_register_static(&smbus_device_type_info); +} + +type_init(smbus_device_register_types) |