iic_piix4.c

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 *  'minor',     IN,    minor device number for multi device drivers
 *  'param',     INOUT, variable of type, t_IIC_write_descriptor.
 *
 *  Return values :
 *  ---------------
 *
 *  'OK' = 0x00:              IIC service completed successfully
 *  'ERROR_IIC_COMM_ERROR':   communication error detected
 *
 ************************************************************************/
static INT32 
iic_piix4_write(
    UINT32 major,		/* IN: major device number             */
    UINT32 minor,		/* IN: minor device number             */
    t_IIC_write_descriptor *param )	     /* IN: write buffer       */
{
    UINT8			writecount;
    UINT8			prom_offset;
    UINT8			*bufptr;

    if (param->length <= 1)
    {
        return ERROR_IIC_DATA_ERROR;  
    }

    bufptr = param->buffer;
    prom_offset = *bufptr++;
    writecount = param->length - 1;

    /* Poll for ready and acknowledge SMBus interrupts */
    iic_piix4_poll();

    for (;writecount-- ; prom_offset++, bufptr++)
    {
        /* Setup slave address and write command */
        SMB_WRITE( PIIX4_SMBHSTADD_OFS,
                   (param->IICaddress << PIIX4_SMBHSTADD_ADDR_SHF) &
                   ~PIIX4_SMBHSTADD_READ_BIT );

        /* Setup command (= offset in slave) */
        SMB_WRITE( PIIX4_SMBHSTCMD_OFS, prom_offset );

        /* Setup data to write */
        SMB_WRITE( PIIX4_SMBHSTDAT0_OFS, *bufptr );

        /* Start Byte Data operation */
        SMB_WRITE( PIIX4_SMBHSTCNT_OFS, 
                  (PIIX4_SMBHSTCNT_CP_BDRW << PIIX4_SMBHSTCNT_CP_SHF) |
                   PIIX4_SMBHSTCNT_START_BIT );

        /* Wait for operation */
        sys_wait_ms(5);

        /* Poll for done and acknowledge SMBus interrupts */
        iic_piix4_poll();
    }

    return OK;
}


/************************************************************************
 *
 *                          iic_piix4_ctrl
 *  Description :
 *  -------------
 *  This service comprise following aggregated IIC services:
 *   1) 'write_read' IIC device.
 *   2) 'test'       IIC device.
 *
 *  Parameters :
 *  ------------
 *
 *  'major',     IN,    major device number
 *  'minor',     IN,    minor device number for multi device drivers
 *  'param',   INOUT, variable of type, t_IIC_ctrl_descriptor.
 *
 *  Return values :
 *  ---------------
 *
 *  'OK' = 0x00:              IIC service completed successfully
 *  'ERROR_IIC_COMM_ERROR':   communication error detected
 *
 ************************************************************************/
static INT32 
iic_piix4_ctrl(
    UINT32 major,		/* IN: major device number             */
    UINT32 minor,		/* IN: minor device number             */
    t_IIC_ctrl_descriptor *param )	     /* INOUT: IIC device data */
{
    t_IIC_write_read_descriptor *descr;
    INT32			rcode;
    UINT8			readcount;
    UINT8			prom_offset;
    UINT8			*bufptr;

    rcode = OK;

    switch( param->command )
    {
      case IIC_CTRL_TEST :

        /* TEST command: (TBD not ready) */
	rcode = OK;
	break;

      case IIC_CTRL_WRITE_READ :

        /* WRITE-READ command: */

	descr = (t_IIC_write_read_descriptor *)param->data;

	if( (descr->write_length != 1) ||
	    (descr->read_length  == 0) )
	{
	    rcode = ERROR_IIC_DATA_ERROR;  
            break;
	}

	readcount = descr->read_length;
	prom_offset = descr->write_buffer[0];
	bufptr = descr->read_buffer;

        /* Poll for ready and acknowledge SMBus interrupts */
        iic_piix4_poll();

	for (;readcount-- ; prom_offset++, bufptr++)
	{
            /* Setup slave address and read command */
            SMB_WRITE( PIIX4_SMBHSTADD_OFS,
                       (param->IICaddress << PIIX4_SMBHSTADD_ADDR_SHF) |
                       PIIX4_SMBHSTADD_READ_BIT );

            /* Setup command (= offset in slave) */
            SMB_WRITE( PIIX4_SMBHSTCMD_OFS, prom_offset );

	    /* Start Byte Data operation */
	    SMB_WRITE( PIIX4_SMBHSTCNT_OFS, 
		       (PIIX4_SMBHSTCNT_CP_BDRW << PIIX4_SMBHSTCNT_CP_SHF) |
		       PIIX4_SMBHSTCNT_START_BIT );

            /* Poll for done and acknowledge SMBus interrupts */
            iic_piix4_poll();

            /* read data byte */
            SMB_READ( PIIX4_SMBHSTDAT0_OFS, bufptr );
        }

	break;
	
      default :

        rcode = ERROR_IIC_UNKNOWN_COMMAND;
	break;
    }

    return rcode;
}


/************************************************************************
 *
 *                          iic_piix4_poll
 *  Description :
 *  -------------
 *  This routine polls the SMBus to be not busy
 *    and acknowledges any SMBus interrupt.
 *
 ************************************************************************/
static void 
iic_piix4_poll( void )
{
    volatile UINT8 status;
    for (;;)
    {
        sys_wait_ms(1);
        SMB_READ( PIIX4_SMBHSTSTS_OFS, &status );
        if (status & PIIX4_SMBHSTSTS_BUSY_BIT) continue;
        status &= ( PIIX4_SMBHSTSTS_FAILED_BIT |
                    PIIX4_SMBHSTSTS_COL_BIT    |
                    PIIX4_SMBHSTSTS_DE_BIT     |
                    PIIX4_SMBHSTSTS_INT_BIT );
        if (status == 0) break;
        SMB_WRITE( PIIX4_SMBHSTSTS_OFS, status);
    }
}

/************************************************************************
 *      Implementation : Public functions
 ************************************************************************/


/************************************************************************
 *
 *                          iic_piix4_install
 *  Description :
 *  -------------
 *
 *  Installs the IIC PIIX4 device driver services in 
 *  the IO system at the reserved device slot, found in the
 *  'sysdev.h' file, which defines all major device numbers.
 *
 *  Note:
 *  This service is the only public declared interface function; all
 *  provided device driver services are static declared, but this
 *  function installs the function pointers in the io-system to
 *  enable the provided public driver services.
 *
 *  Parameters :
 *  ------------
 *
 *  None
 *
 *  Return values :
 *  ---------------
 *
 *  'OK'(=0)
 *  'ERROR_IO_ILLEGAL_MAJOR':  Illegal major device number
 *  'ERROR_IO_NO_SPACE':       Device slot already allocated
 *
 ************************************************************************/
INT32 
iic_piix4_install(void)
{
	/* pre-initialize local variables and install device services */
	IO_install(         SYS_MAJOR_IIC,        /* major device number */
             (t_io_service) iic_piix4_init,  	  /* 'init'  service     */
                            NULL,                 /* 'open'  service  na */
                            NULL,                 /* 'close' service  na */
             (t_io_service) iic_piix4_read,	  /* 'read'  service     */
             (t_io_service) iic_piix4_write,	  /* 'write' service     */
             (t_io_service) iic_piix4_ctrl );	  /* 'ctrl'  service     */

	/* call our own 'init' service */
	return IO_init( SYS_MAJOR_IIC, 0, NULL);
}