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/******************************************************************************

*

* Copyright (C) 2002 - 2015 Xilinx, Inc.  All rights reserved.

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******************************************************************************/

/*****************************************************************************/

/**

*

* @file xiic_multi_master.c

* @addtogroup iic_v3_1

* @{

*

* Contains multi-master functions for the XIic component. This file is

* necessary if multiple masters are on the IIC bus such that arbitration can

* be lost or the bus can be busy.

*

* <pre>

* MODIFICATION HISTORY:

*

* Ver   Who  Date     Changes

* ----- --- ------- -----------------------------------------------

* 1.01b jhl 3/27/02 Reparitioned the driver

* 1.01c ecm 12/05/02 new rev

* 1.13a wgr 03/22/07 Converted to new coding style.

* 2.00a ktn 10/22/09 Converted all register accesses to 32 bit access.

*                    Updated to use the HAL APIs/macros.

*                    Some of the macros have been renamed to remove _m from

*                    the name and some of the macros have been renamed to be

*                    consistent, see the xiic_i.h and xiic_l.h files for further

*                    information

* </pre>

*

****************************************************************************/

/***************************** Include Files *******************************/

#include "xiic.h"

#include "xiic_i.h"

/************************** Constant Definitions ***************************/

/**************************** Type Definitions *****************************/

/***************** Macros (Inline Functions) Definitions *******************/

/************************** Function Prototypes ****************************/

static void BusNotBusyHandler(XIic *InstancePtr);

static void ArbitrationLostHandler(XIic *InstancePtr);

/************************** Variable Definitions **************************/

/****************************************************************************/

/**

* This function includes multi-master code such that multi-master events are

* handled properly. Multi-master events include a loss of arbitration and

* the bus transitioning from busy to not busy.  This function allows the

* multi-master processing to be optional.  This function must be called prior

* to allowing any multi-master events to occur, such as after the driver is

* initialized.

*

* @param        None.

*

* @return       None.

*

* @note         None.

*

******************************************************************************/

void XIic_MultiMasterInclude()

{

        XIic_ArbLostFuncPtr = ArbitrationLostHandler;

        XIic_BusNotBusyFuncPtr = BusNotBusyHandler;

}

/*****************************************************************************/

/**

*

* The IIC bus busy signals when a master has control of the bus. Until the bus

* is released, i.e. not busy, other devices must wait to use it.

*

* When this interrupt occurs, it signals that the previous master has released

* the bus for another user.

*

* This interrupt is only enabled when the master Tx is waiting for the bus.

*

* This interrupt causes the following tasks:

* - Disable Bus not busy interrupt

* - Enable bus Ack

*        Should the slave receive have disabled acknowledgement, enable to allow

*        acknowledgment of the sending of our address to again be addresed as

*        slave

* - Flush Rx FIFO

*        Should the slave receive have disabled acknowledgement, a few bytes may

*        be in FIFO if Rx full did not occur because of not enough byte in FIFO

*        to have caused an interrupt.

* - Send status to user via status callback with the value:

*       XII_BUS_NOT_BUSY_EVENT

*

* @param        InstancePtr is a pointer to the XIic instance to be worked on.

*

* @return       None.

*

* @note         None.

*

******************************************************************************/

static void BusNotBusyHandler(XIic *InstancePtr)

{

        u32 Status;

        u32 CntlReg;

        /*

         * Should the slave receive have disabled acknowledgement,

         * enable to allow acknowledgment of the sending of our address to

         * again be addresed as slave.

         */

        CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);

        XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,

                 (CntlReg & ~XIIC_CR_NO_ACK_MASK));

        /*

         * Flush Tx FIFO by toggling TxFIFOResetBit. FIFO runs normally at 0

         * Do this incase needed to Tx FIFO with more than expected if what

         * was set to Tx was less than what the Master expected - read more

         * from this slave so FIFO had junk in it.

         */

        XIic_FlushTxFifo(InstancePtr);

        /*

         * Flush Rx FIFO should slave Rx had a problem, sent No ack but

         * still received a few bytes. Should the slave receive have disabled

         * acknowledgement, clear Rx FIFO.

         */

        XIic_FlushRxFifo(InstancePtr);

        /*

         * Send Application messaging status via callbacks. Disable either Tx or

         * Receive interrupt. Which callback depends on messaging direction.

         */

        Status = XIic_ReadIier(InstancePtr->BaseAddress);

        if (InstancePtr->RecvBufferPtr == NULL) {

                /*

                 * Slave was sending data (master was reading), disable

                 * all the transmit interrupts.

                 */

                XIic_WriteIier(InstancePtr->BaseAddress,

                                (Status & ~XIIC_TX_INTERRUPTS));

        }

        else {

                /*

                 * Slave was receiving data (master was writing) disable receive

                 * interrupts.

                 */

                XIic_WriteIier(InstancePtr->BaseAddress,

                                (Status & ~XIIC_INTR_RX_FULL_MASK));

        }

        /*

         * Send Status in StatusHandler callback.

         */

        InstancePtr->StatusHandler(InstancePtr->StatusCallBackRef,

                                   XII_BUS_NOT_BUSY_EVENT);

}

/*****************************************************************************/

/**

*

* When multiple IIC devices attempt to use the bus simultaneously, only

* a single device will be able to keep control as a master. Those devices

* that didn't retain control over the bus are said to have lost arbitration.

* When arbitration is lost, this interrupt occurs sigaling the user that

* the message did not get sent as expected.

*

* This function, at arbitration lost:

*   - Disables Tx empty, � empty and Tx error interrupts

*   - Clears any Tx empty, � empty Rx Full or Tx error interrupts

*   - Clears Arbitration lost interrupt,

*   - Flush Tx FIFO

*   - Call StatusHandler callback with the value: XII_ARB_LOST_EVENT

*

* @param        InstancePtr is a pointer to the XIic instance to be worked on.

*

* @return       None.

*

* @note         None.

*

******************************************************************************/

static void ArbitrationLostHandler(XIic *InstancePtr)

{

        /*

         * Disable Tx empty and � empty and Tx error interrupts before clearing

         * them so they won't occur again.

         */

        XIic_DisableIntr(InstancePtr->BaseAddress, XIIC_TX_INTERRUPTS);

        /*

         * Clear any Tx empty, � empty Rx Full or Tx error interrupts.

         */

        XIic_ClearIntr(InstancePtr->BaseAddress, XIIC_TX_INTERRUPTS);

        XIic_FlushTxFifo(InstancePtr);

        /*

         * Update Status via StatusHandler callback.

         */

        InstancePtr->StatusHandler(InstancePtr->StatusCallBackRef,

                                   XII_ARB_LOST_EVENT);

}

/** @} */