diff options
Diffstat (limited to 'hw/i2c')
| -rw-r--r-- | hw/i2c/core.c | 31 | ||||
| -rw-r--r-- | hw/i2c/i2c-ddc.c | 4 | ||||
| -rw-r--r-- | hw/i2c/smbus.c | 13 |
3 files changed, 37 insertions, 11 deletions
diff --git a/hw/i2c/core.c b/hw/i2c/core.c index e40781ea3b..2c1234cdff 100644 --- a/hw/i2c/core.c +++ b/hw/i2c/core.c @@ -88,18 +88,26 @@ int i2c_bus_busy(I2CBus *bus) return !QLIST_EMPTY(&bus->current_devs); } +/* TODO: Make this handle multiple masters. */ /* - * Returns non-zero if the address is not valid. If this is called - * again without an intervening i2c_end_transfer(), like in the SMBus - * case where the operation is switched from write to read, this - * function will not rescan the bus and thus cannot fail. + * Start or continue an i2c transaction. When this is called for the + * first time or after an i2c_end_transfer(), if it returns an error + * the bus transaction is terminated (or really never started). If + * this is called after another i2c_start_transfer() without an + * intervening i2c_end_transfer(), and it returns an error, the + * transaction will not be terminated. The caller must do it. + * + * This corresponds with the way real hardware works. The SMBus + * protocol uses a start transfer to switch from write to read mode + * without releasing the bus. If that fails, the bus is still + * in a transaction. */ -/* TODO: Make this handle multiple masters. */ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv) { BusChild *kid; I2CSlaveClass *sc; I2CNode *node; + bool bus_scanned = false; if (address == I2C_BROADCAST) { /* @@ -130,6 +138,7 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv) } } } + bus_scanned = true; } if (QLIST_EMPTY(&bus->current_devs)) { @@ -137,11 +146,21 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv) } QLIST_FOREACH(node, &bus->current_devs, next) { + int rv; + sc = I2C_SLAVE_GET_CLASS(node->elt); /* If the bus is already busy, assume this is a repeated start condition. */ + if (sc->event) { - sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND); + rv = sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND); + if (rv && !bus->broadcast) { + if (bus_scanned) { + /* First call, terminate the transfer. */ + i2c_end_transfer(bus); + } + return rv; + } } } return 0; diff --git a/hw/i2c/i2c-ddc.c b/hw/i2c/i2c-ddc.c index 1227212934..66899d7233 100644 --- a/hw/i2c/i2c-ddc.c +++ b/hw/i2c/i2c-ddc.c @@ -230,13 +230,15 @@ static void i2c_ddc_reset(DeviceState *ds) s->reg = 0; } -static void i2c_ddc_event(I2CSlave *i2c, enum i2c_event event) +static int i2c_ddc_event(I2CSlave *i2c, enum i2c_event event) { I2CDDCState *s = I2CDDC(i2c); if (event == I2C_START_SEND) { s->firstbyte = true; } + + return 0; } static int i2c_ddc_rx(I2CSlave *i2c) diff --git a/hw/i2c/smbus.c b/hw/i2c/smbus.c index 5b4dd3eba4..2d1b79a689 100644 --- a/hw/i2c/smbus.c +++ b/hw/i2c/smbus.c @@ -67,7 +67,7 @@ static void smbus_do_write(SMBusDevice *dev) } } -static void smbus_i2c_event(I2CSlave *s, enum i2c_event event) +static int smbus_i2c_event(I2CSlave *s, enum i2c_event event) { SMBusDevice *dev = SMBUS_DEVICE(s); @@ -148,6 +148,8 @@ static void smbus_i2c_event(I2CSlave *s, enum i2c_event event) break; } } + + return 0; } static int smbus_i2c_recv(I2CSlave *s) @@ -249,7 +251,8 @@ int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command) } i2c_send(bus, command); if (i2c_start_transfer(bus, addr, 1)) { - assert(0); + i2c_end_transfer(bus); + return -1; } data = i2c_recv(bus); i2c_nack(bus); @@ -276,7 +279,8 @@ int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command) } i2c_send(bus, command); if (i2c_start_transfer(bus, addr, 1)) { - assert(0); + i2c_end_transfer(bus); + return -1; } data = i2c_recv(bus); data |= i2c_recv(bus) << 8; @@ -307,7 +311,8 @@ int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data) } i2c_send(bus, command); if (i2c_start_transfer(bus, addr, 1)) { - assert(0); + i2c_end_transfer(bus); + return -1; } len = i2c_recv(bus); if (len > 32) { |