Commit 9cf27d74 authored by Corey Minyard's avatar Corey Minyard
Browse files

i2c:smbus: Simplify write operation 



There were two different write functions and the SMBus code kept
track of the command.

Keeping track of the command wasn't useful, in fact it wasn't quite
correct for the eeprom_smbus code.  And there is no need for two write
functions.  Just have one write function and the first byte in the
buffer is the command.

Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
parent 905cec6d

hw/i2c/smbus_eeprom.c

+16 −31
Original line number Diff line number Diff line
@@ -45,16 +45,6 @@ static void eeprom_quick_cmd(SMBusDevice *dev, uint8_t read) 
#endif

}



static void eeprom_send_byte(SMBusDevice *dev, uint8_t val)

{

    SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *) dev;

#ifdef DEBUG

    printf("eeprom_send_byte: addr=0x%02x val=0x%02x\n",

           dev->i2c.address, val);

#endif

    eeprom->offset = val;

}



static uint8_t eeprom_receive_byte(SMBusDevice *dev)

{

    SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *) dev;
@@ -67,34 +57,30 @@ static uint8_t eeprom_receive_byte(SMBusDevice *dev) 
    return val;

}



static void eeprom_write_data(SMBusDevice *dev, uint8_t cmd, uint8_t *buf, int len)

static int eeprom_write_data(SMBusDevice *dev, uint8_t *buf, uint8_t len)

{

    SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *) dev;

    int n;

    uint8_t *data = eeprom->data;



#ifdef DEBUG

    printf("eeprom_write_byte: addr=0x%02x cmd=0x%02x val=0x%02x\n",

           dev->i2c.address, cmd, buf[0]);

           dev->i2c.address, buf[0], buf[1]);

#endif

    /* A page write operation is not a valid SMBus command.

       It is a block write without a length byte.  Fortunately we

       get the full block anyway.  */

    /* TODO: Should this set the current location?  */

    if (cmd + len > 256)

        n = 256 - cmd;

    else

        n = len;

    memcpy(eeprom->data + cmd, buf, n);

    len -= n;

    if (len)

        memcpy(eeprom->data, buf + n, len);

    /* len is guaranteed to be > 0 */

    eeprom->offset = buf[0];

    buf++;

    len--;



    for (; len > 0; len--) {

        data[eeprom->offset] = *buf++;

        eeprom->offset = (eeprom->offset + 1) % 256;

    }



static uint8_t eeprom_read_data(SMBusDevice *dev, uint8_t cmd, int n)

    return 0;

}



static uint8_t eeprom_read_data(SMBusDevice *dev, int n)

{

    SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *) dev;

    /* If this is the first byte then set the current position.  */

    if (n == 0)

        eeprom->offset = cmd;

    /* As with writes, we implement block reads without the

       SMBus length byte.  */

    return eeprom_receive_byte(dev);
@@ -119,7 +105,6 @@ static void smbus_eeprom_class_initfn(ObjectClass *klass, void *data) 


    dc->realize = smbus_eeprom_realize;

    sc->quick_cmd = eeprom_quick_cmd;

    sc->send_byte = eeprom_send_byte;

    sc->receive_byte = eeprom_receive_byte;

    sc->write_data = eeprom_write_data;

    sc->read_data = eeprom_read_data;

hw/i2c/smbus_slave.c

+5 −20
Original line number Diff line number Diff line
@@ -54,18 +54,9 @@ static void smbus_do_write(SMBusDevice *dev) 
{

    SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);



    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);

    DPRINTF("Command %d len %d\n", dev->data_buf[0], dev->data_len);

    if (sc->write_data) {

            sc->write_data(dev, dev->command, dev->data_buf + 1,

                           dev->data_len - 1);

        }

        sc->write_data(dev, dev->data_buf, dev->data_len);

    }

}
@@ -98,13 +89,7 @@ static int smbus_i2c_event(I2CSlave *s, enum i2c_event event) 
                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;
@@ -177,7 +162,7 @@ static uint8_t smbus_i2c_recv(I2CSlave *s) 
        break;

    case SMBUS_READ_DATA:

        if (sc->read_data) {

            ret = sc->read_data(dev, dev->command, dev->data_len);

            ret = sc->read_data(dev, dev->data_len);

            dev->data_len++;

        } else {

            ret = 0;

include/hw/i2c/smbus_slave.h

+13 −8
Original line number Diff line number Diff line
@@ -46,18 +46,24 @@ typedef struct SMBusDeviceClass 
     * This may be NULL, quick commands are ignore in that case.

     */

    void (*quick_cmd)(SMBusDevice *dev, uint8_t read);

    void (*send_byte)(SMBusDevice *dev, uint8_t val);



    uint8_t (*receive_byte)(SMBusDevice *dev);

    /* We can't distinguish between a word write and a block write with

       length 1, so pass the whole data block including the length byte

       (if present).  The device is responsible figuring out what type of

       command  this is.  */

    void (*write_data)(SMBusDevice *dev, uint8_t cmd, uint8_t *buf, int len);



    /*

     * We can't distinguish between a word write and a block write with

     * length 1, so pass the whole data block including the length byte

     * (if present).  The device is responsible figuring out what type of

     * command this is.

     * This may be NULL if no data is written to the device.  Writes

     * will be ignore in that case.

     */

    int (*write_data)(SMBusDevice *dev, uint8_t *buf, uint8_t len);



    /* Likewise we can't distinguish between different reads, or even know

       the length of the read until the read is complete, so read data a

       byte at a time.  The device is responsible for adding the length

       byte on block reads.  */

    uint8_t (*read_data)(SMBusDevice *dev, uint8_t cmd, int n);

    uint8_t (*read_data)(SMBusDevice *dev, int n);

} SMBusDeviceClass;



struct SMBusDevice {
@@ -68,7 +74,6 @@ struct SMBusDevice { 
    int mode;

    int data_len;

    uint8_t data_buf[34]; /* command + len + 32 bytes of data.  */

    uint8_t command;

};



#endif