diff options
Diffstat (limited to 'hw/i2c/smbus_slave.c')
| -rw-r--r-- | hw/i2c/smbus_slave.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/hw/i2c/smbus_slave.c b/hw/i2c/smbus_slave.c new file mode 100644 index 000000000..5d10e2766 --- /dev/null +++ b/hw/i2c/smbus_slave.c @@ -0,0 +1,237 @@ +/* + * QEMU SMBus device emulation. + * + * This code is a helper for SMBus device emulation. It implements an + * I2C device inteface and runs the SMBus protocol from the device + * point of view and maps those to simple calls to emulate. + * + * Copyright (c) 2007 CodeSourcery. + * Written by Paul Brook + * + * This code is licensed under the LGPL. + */ + +/* TODO: Implement PEC. */ + +#include "qemu/osdep.h" +#include "hw/i2c/i2c.h" +#include "hw/i2c/smbus_slave.h" +#include "migration/vmstate.h" +#include "qemu/module.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_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); + + DPRINTF("Command %d len %d\n", dev->data_buf[0], dev->data_len); + if (sc->write_data) { + sc->write_data(dev, dev->data_buf, dev->data_len); + } +} + +static int 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_READ_DATA; + break; + + case SMBUS_WRITE_DATA: + if (dev->data_len == 0) { + BADF("Read after write with no data\n"); + dev->mode = SMBUS_CONFUSED; + } else { + smbus_do_write(dev); + DPRINTF("Read mode\n"); + 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: + if (dev->data_len == 0) { + if (dev->mode == SMBUS_WRITE_DATA || dev->mode == SMBUS_READ_DATA) { + smbus_do_quick_cmd(dev, dev->mode == SMBUS_READ_DATA); + } + } else { + switch (dev->mode) { + case SMBUS_WRITE_DATA: + smbus_do_write(dev); + 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; + } + } + + return 0; +} + +static uint8_t smbus_i2c_recv(I2CSlave *s) +{ + SMBusDevice *dev = SMBUS_DEVICE(s); + SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); + uint8_t ret = 0xff; + + switch (dev->mode) { + case SMBUS_READ_DATA: + if (sc->receive_byte) { + ret = sc->receive_byte(dev); + } + DPRINTF("Read data %02x\n", ret); + break; + + default: + BADF("Unexpected read in state %d\n", dev->mode); + dev->mode = SMBUS_CONFUSED; + 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); + if (dev->data_len >= sizeof(dev->data_buf)) { + BADF("Too many bytes sent\n"); + } else { + dev->data_buf[dev->data_len++] = data; + } + break; + + default: + BADF("Unexpected write in state %d\n", dev->mode); + break; + } + + return 0; +} + +static void smbus_device_class_init(ObjectClass *klass, void *data) +{ + I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass); + + sc->event = smbus_i2c_event; + sc->recv = smbus_i2c_recv; + sc->send = smbus_i2c_send; +} + +bool smbus_vmstate_needed(SMBusDevice *dev) +{ + return dev->mode != SMBUS_IDLE; +} + +const VMStateDescription vmstate_smbus_device = { + .name = TYPE_SMBUS_DEVICE, + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_I2C_SLAVE(i2c, SMBusDevice), + VMSTATE_INT32(mode, SMBusDevice), + VMSTATE_INT32(data_len, SMBusDevice), + VMSTATE_UINT8_ARRAY(data_buf, SMBusDevice, SMBUS_DATA_MAX_LEN), + VMSTATE_END_OF_LIST() + } +}; + +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) |