diff options
Diffstat (limited to 'hw/i2c/aspeed_i2c.c')
| -rw-r--r-- | hw/i2c/aspeed_i2c.c | 65 |
1 files changed, 55 insertions, 10 deletions
diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c index ce5b1f0fa4..c762c7366a 100644 --- a/hw/i2c/aspeed_i2c.c +++ b/hw/i2c/aspeed_i2c.c @@ -169,12 +169,33 @@ static uint64_t aspeed_i2c_bus_read(void *opaque, hwaddr offset, } } +static void aspeed_i2c_set_state(AspeedI2CBus *bus, uint8_t state) +{ + bus->cmd &= ~(I2CD_TX_STATE_MASK << I2CD_TX_STATE_SHIFT); + bus->cmd |= (state & I2CD_TX_STATE_MASK) << I2CD_TX_STATE_SHIFT; +} + +static uint8_t aspeed_i2c_get_state(AspeedI2CBus *bus) +{ + return (bus->cmd >> I2CD_TX_STATE_SHIFT) & I2CD_TX_STATE_MASK; +} + +/* + * The state machine needs some refinement. It is only used to track + * invalid STOP commands for the moment. + */ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value) { + bus->cmd &= ~0xFFFF; bus->cmd |= value & 0xFFFF; bus->intr_status = 0; if (bus->cmd & I2CD_M_START_CMD) { + uint8_t state = aspeed_i2c_get_state(bus) & I2CD_MACTIVE ? + I2CD_MSTARTR : I2CD_MSTART; + + aspeed_i2c_set_state(bus, state); + if (i2c_start_transfer(bus->bus, extract32(bus->buf, 1, 7), extract32(bus->buf, 0, 1))) { bus->intr_status |= I2CD_INTR_TX_NAK; @@ -182,16 +203,34 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value) bus->intr_status |= I2CD_INTR_TX_ACK; } - } else if (bus->cmd & I2CD_M_TX_CMD) { + /* START command is also a TX command, as the slave address is + * sent on the bus */ + bus->cmd &= ~(I2CD_M_START_CMD | I2CD_M_TX_CMD); + + /* No slave found */ + if (!i2c_bus_busy(bus->bus)) { + return; + } + aspeed_i2c_set_state(bus, I2CD_MACTIVE); + } + + if (bus->cmd & I2CD_M_TX_CMD) { + aspeed_i2c_set_state(bus, I2CD_MTXD); if (i2c_send(bus->bus, bus->buf)) { - bus->intr_status |= (I2CD_INTR_TX_NAK | I2CD_INTR_ABNORMAL); + bus->intr_status |= (I2CD_INTR_TX_NAK); i2c_end_transfer(bus->bus); } else { bus->intr_status |= I2CD_INTR_TX_ACK; } + bus->cmd &= ~I2CD_M_TX_CMD; + aspeed_i2c_set_state(bus, I2CD_MACTIVE); + } - } else if (bus->cmd & I2CD_M_RX_CMD) { - int ret = i2c_recv(bus->bus); + if (bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST)) { + int ret; + + aspeed_i2c_set_state(bus, I2CD_MRXD); + ret = i2c_recv(bus->bus); if (ret < 0) { qemu_log_mask(LOG_GUEST_ERROR, "%s: read failed\n", __func__); ret = 0xff; @@ -199,20 +238,25 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value) bus->intr_status |= I2CD_INTR_RX_DONE; } bus->buf = (ret & I2CD_BYTE_BUF_RX_MASK) << I2CD_BYTE_BUF_RX_SHIFT; + if (bus->cmd & I2CD_M_S_RX_CMD_LAST) { + i2c_nack(bus->bus); + } + bus->cmd &= ~(I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST); + aspeed_i2c_set_state(bus, I2CD_MACTIVE); } - if (bus->cmd & (I2CD_M_STOP_CMD | I2CD_M_S_RX_CMD_LAST)) { - if (!i2c_bus_busy(bus->bus)) { + if (bus->cmd & I2CD_M_STOP_CMD) { + if (!(aspeed_i2c_get_state(bus) & I2CD_MACTIVE)) { + qemu_log_mask(LOG_GUEST_ERROR, "%s: abnormal stop\n", __func__); bus->intr_status |= I2CD_INTR_ABNORMAL; } else { + aspeed_i2c_set_state(bus, I2CD_MSTOP); i2c_end_transfer(bus->bus); bus->intr_status |= I2CD_INTR_NORMAL_STOP; } + bus->cmd &= ~I2CD_M_STOP_CMD; + aspeed_i2c_set_state(bus, I2CD_IDLE); } - - /* command is handled, reset it and check for interrupts */ - bus->cmd &= ~0xFFFF; - aspeed_i2c_bus_raise_interrupt(bus); } static void aspeed_i2c_bus_write(void *opaque, hwaddr offset, @@ -262,6 +306,7 @@ static void aspeed_i2c_bus_write(void *opaque, hwaddr offset, } aspeed_i2c_bus_handle_cmd(bus, value); + aspeed_i2c_bus_raise_interrupt(bus); break; default: |