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author | Cédric Le Goater <clg@kaod.org> | 2017-06-02 11:51:49 +0100 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2017-06-02 11:51:49 +0100 |
commit | 4960f084cfb4d42bb8995dd23ccad168c3e4ad3a (patch) | |
tree | 1be9bb56884e8f3b5d0ce6f56220eb8b8ce7c0ee | |
parent | d0efdc1686405c3873703a8617daba54d3fbb75f (diff) | |
download | qemu-4960f084cfb4d42bb8995dd23ccad168c3e4ad3a.zip qemu-4960f084cfb4d42bb8995dd23ccad168c3e4ad3a.tar.gz qemu-4960f084cfb4d42bb8995dd23ccad168c3e4ad3a.tar.bz2 |
aspeed/i2c: introduce a state machine
The Aspeed I2C controller maintains a state machine in the command
register, which is mostly used for debug.
Let's start adding a few states to handle abnormal STOP
commands. Today, the model uses the busy status of the bus as a
condition to do so but it is not precise enough.
Also remove the ABNORMAL bit for failing TX commands. This is
incorrect with respect to the specs.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1494827476-1487-4-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r-- | hw/i2c/aspeed_i2c.c | 36 |
1 files changed, 33 insertions, 3 deletions
diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c index 67004c6..c762c73 100644 --- a/hw/i2c/aspeed_i2c.c +++ b/hw/i2c/aspeed_i2c.c @@ -169,6 +169,21 @@ 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; @@ -176,6 +191,11 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value) 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; @@ -191,20 +211,26 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value) 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); } if (bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST)) { - int ret = i2c_recv(bus->bus); + 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; @@ -216,16 +242,20 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value) 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) { - if (!i2c_bus_busy(bus->bus)) { + 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); } } |