u-boot/board/xilinx/xilinx_iic/xiic_l.c

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/* $Id: xiic_l.c,v 1.2 2002/12/05 19:32:40 meinelte Exp $ */
/******************************************************************************
*
* XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS"
* AS A COURTESY TO YOU, SOLELY FOR USE IN DEVELOPING PROGRAMS AND
* SOLUTIONS FOR XILINX DEVICES. BY PROVIDING THIS DESIGN, CODE,
* OR INFORMATION AS ONE POSSIBLE IMPLEMENTATION OF THIS FEATURE,
* APPLICATION OR STANDARD, XILINX IS MAKING NO REPRESENTATION
* THAT THIS IMPLEMENTATION IS FREE FROM ANY CLAIMS OF INFRINGEMENT,
* AND YOU ARE RESPONSIBLE FOR OBTAINING ANY RIGHTS YOU MAY REQUIRE
* FOR YOUR IMPLEMENTATION. XILINX EXPRESSLY DISCLAIMS ANY
* WARRANTY WHATSOEVER WITH RESPECT TO THE ADEQUACY OF THE
* IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OR
* REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE FROM CLAIMS OF
* INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE.
*
* (c) Copyright 2002 Xilinx Inc.
* All rights reserved.
*
******************************************************************************/
/*****************************************************************************/
/**
*
* @file xiic_l.c
*
* This file contains low-level driver functions that can be used to access the
* device. The user should refer to the hardware device specification for more
* details of the device operation.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver Who Date Changes
* ----- --- ------- -----------------------------------------------
* 1.01b jhl 5/13/02 First release
* 1.01b jhl 10/14/02 Corrected bug in the receive function, the setup of the
* interrupt status mask was not being done in the loop such
* that a read would sometimes fail on the last byte because
* the transmit error which should have been ignored was
* being used. This would leave an extra byte in the FIFO
* and the bus throttled such that the next operation would
* also fail. Also updated the receive function to not
* disable the device after the last byte until after the
* bus transitions to not busy which is more consistent
* with the expected behavior.
* 1.01c ecm 12/05/02 new rev
* </pre>
*
****************************************************************************/
/***************************** Include Files *******************************/
#include "xbasic_types.h"
#include "xio.h"
#include "xipif_v1_23_b.h"
#include "xiic_l.h"
/************************** Constant Definitions ***************************/
/**************************** Type Definitions *****************************/
/***************** Macros (Inline Functions) Definitions *******************/
/******************************************************************************
*
* This macro clears the specified interrupt in the IPIF interrupt status
* register. It is non-destructive in that the register is read and only the
* interrupt specified is cleared. Clearing an interrupt acknowledges it.
*
* @param BaseAddress contains the IPIF registers base address.
*
* @param InterruptMask contains the interrupts to be disabled
*
* @return
*
* None.
*
* @note
*
* Signature: void XIic_mClearIisr(u32 BaseAddress,
* u32 InterruptMask);
*
******************************************************************************/
#define XIic_mClearIisr(BaseAddress, InterruptMask) \
XIIF_V123B_WRITE_IISR((BaseAddress), \
XIIF_V123B_READ_IISR(BaseAddress) & (InterruptMask))
/******************************************************************************
*
* This macro sends the address for a 7 bit address during both read and write
* operations. It takes care of the details to format the address correctly.
* This macro is designed to be called internally to the drivers.
*
* @param SlaveAddress contains the address of the slave to send to.
*
* @param Operation indicates XIIC_READ_OPERATION or XIIC_WRITE_OPERATION
*
* @return
*
* None.
*
* @note
*
* Signature: void XIic_mSend7BitAddr(u16 SlaveAddress, u8 Operation);
*
******************************************************************************/
#define XIic_mSend7BitAddress(BaseAddress, SlaveAddress, Operation) \
{ \
u8 LocalAddr = (u8)(SlaveAddress << 1); \
LocalAddr = (LocalAddr & 0xFE) | (Operation); \
XIo_Out8(BaseAddress + XIIC_DTR_REG_OFFSET, LocalAddr); \
}
/************************** Function Prototypes ****************************/
static unsigned RecvData (u32 BaseAddress, u8 * BufferPtr,
unsigned ByteCount);
static unsigned SendData (u32 BaseAddress, u8 * BufferPtr,
unsigned ByteCount);
/************************** Variable Definitions **************************/
/****************************************************************************/
/**
* Receive data as a master on the IIC bus. This function receives the data
* using polled I/O and blocks until the data has been received. It only
* supports 7 bit addressing and non-repeated start modes of operation. The
* user is responsible for ensuring the bus is not busy if multiple masters
* are present on the bus.
*
* @param BaseAddress contains the base address of the IIC device.
* @param Address contains the 7 bit IIC address of the device to send the
* specified data to.
* @param BufferPtr points to the data to be sent.
* @param ByteCount is the number of bytes to be sent.
*
* @return
*
* The number of bytes received.
*
* @note
*
* None
*
******************************************************************************/
unsigned XIic_Recv (u32 BaseAddress, u8 Address,
u8 * BufferPtr, unsigned ByteCount)
{
u8 CntlReg;
unsigned RemainingByteCount;
/* Tx error is enabled incase the address (7 or 10) has no device to answer
* with Ack. When only one byte of data, must set NO ACK before address goes
* out therefore Tx error must not be enabled as it will go off immediately
* and the Rx full interrupt will be checked. If full, then the one byte
* was received and the Tx error will be disabled without sending an error
* callback msg.
*/
XIic_mClearIisr (BaseAddress,
XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK |
XIIC_INTR_ARB_LOST_MASK);
/* Set receive FIFO occupancy depth for 1 byte (zero based)
*/
XIo_Out8 (BaseAddress + XIIC_RFD_REG_OFFSET, 0);
/* 7 bit slave address, send the address for a read operation
* and set the state to indicate the address has been sent
*/
XIic_mSend7BitAddress (BaseAddress, Address, XIIC_READ_OPERATION);
/* MSMS gets set after putting data in FIFO. Start the master receive
* operation by setting CR Bits MSMS to Master, if the buffer is only one
* byte, then it should not be acknowledged to indicate the end of data
*/
CntlReg = XIIC_CR_MSMS_MASK | XIIC_CR_ENABLE_DEVICE_MASK;
if (ByteCount == 1) {
CntlReg |= XIIC_CR_NO_ACK_MASK;
}
/* Write out the control register to start receiving data and call the
* function to receive each byte into the buffer
*/
XIo_Out8 (BaseAddress + XIIC_CR_REG_OFFSET, CntlReg);
/* Clear the latched interrupt status for the bus not busy bit which must
* be done while the bus is busy
*/
XIic_mClearIisr (BaseAddress, XIIC_INTR_BNB_MASK);
/* Try to receive the data from the IIC bus */
RemainingByteCount = RecvData (BaseAddress, BufferPtr, ByteCount);
/*
* The receive is complete, disable the IIC device and return the number of
* bytes that was received
*/
XIo_Out8 (BaseAddress + XIIC_CR_REG_OFFSET, 0);
/* Return the number of bytes that was received */
return ByteCount - RemainingByteCount;
}
/******************************************************************************
*
* Receive the specified data from the device that has been previously addressed
* on the IIC bus. This function assumes that the 7 bit address has been sent
* and it should wait for the transmit of the address to complete.
*
* @param BaseAddress contains the base address of the IIC device.
* @param BufferPtr points to the buffer to hold the data that is received.
* @param ByteCount is the number of bytes to be received.
*
* @return
*
* The number of bytes remaining to be received.
*
* @note
*
* This function does not take advantage of the receive FIFO because it is
* designed for minimal code space and complexity. It contains loops that
* that could cause the function not to return if the hardware is not working.
*
* This function assumes that the calling function will disable the IIC device
* after this function returns.
*
******************************************************************************/
static unsigned RecvData (u32 BaseAddress, u8 * BufferPtr, unsigned ByteCount)
{
u8 CntlReg;
u32 IntrStatusMask;
u32 IntrStatus;
/* Attempt to receive the specified number of bytes on the IIC bus */
while (ByteCount > 0) {
/* Setup the mask to use for checking errors because when receiving one
* byte OR the last byte of a multibyte message an error naturally
* occurs when the no ack is done to tell the slave the last byte
*/
if (ByteCount == 1) {
IntrStatusMask =
XIIC_INTR_ARB_LOST_MASK | XIIC_INTR_BNB_MASK;
} else {
IntrStatusMask =
XIIC_INTR_ARB_LOST_MASK |
XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_BNB_MASK;
}
/* Wait for the previous transmit and the 1st receive to complete
* by checking the interrupt status register of the IPIF
*/
while (1) {
IntrStatus = XIIF_V123B_READ_IISR (BaseAddress);
if (IntrStatus & XIIC_INTR_RX_FULL_MASK) {
break;
}
/* Check the transmit error after the receive full because when
* sending only one byte transmit error will occur because of the
* no ack to indicate the end of the data
*/
if (IntrStatus & IntrStatusMask) {
return ByteCount;
}
}
CntlReg = XIo_In8 (BaseAddress + XIIC_CR_REG_OFFSET);
/* Special conditions exist for the last two bytes so check for them
* Note that the control register must be setup for these conditions
* before the data byte which was already received is read from the
* receive FIFO (while the bus is throttled
*/
if (ByteCount == 1) {
/* For the last data byte, it has already been read and no ack
* has been done, so clear MSMS while leaving the device enabled
* so it can get off the IIC bus appropriately with a stop.
*/
XIo_Out8 (BaseAddress + XIIC_CR_REG_OFFSET,
XIIC_CR_ENABLE_DEVICE_MASK);
}
/* Before the last byte is received, set NOACK to tell the slave IIC
* device that it is the end, this must be done before reading the byte
* from the FIFO
*/
if (ByteCount == 2) {
/* Write control reg with NO ACK allowing last byte to
* have the No ack set to indicate to slave last byte read.
*/
XIo_Out8 (BaseAddress + XIIC_CR_REG_OFFSET,
CntlReg | XIIC_CR_NO_ACK_MASK);
}
/* Read in data from the FIFO and unthrottle the bus such that the
* next byte is read from the IIC bus
*/
*BufferPtr++ = XIo_In8 (BaseAddress + XIIC_DRR_REG_OFFSET);
/* Clear the latched interrupt status so that it will be updated with
* the new state when it changes, this must be done after the receive
* register is read
*/
XIic_mClearIisr (BaseAddress, XIIC_INTR_RX_FULL_MASK |
XIIC_INTR_TX_ERROR_MASK |
XIIC_INTR_ARB_LOST_MASK);
ByteCount--;
}
/* Wait for the bus to transition to not busy before returning, the IIC
* device cannot be disabled until this occurs. It should transition as
* the MSMS bit of the control register was cleared before the last byte
* was read from the FIFO.
*/
while (1) {
if (XIIF_V123B_READ_IISR (BaseAddress) & XIIC_INTR_BNB_MASK) {
break;
}
}
return ByteCount;
}
/****************************************************************************/
/**
* Send data as a master on the IIC bus. This function sends the data
* using polled I/O and blocks until the data has been sent. It only supports
* 7 bit addressing and non-repeated start modes of operation. The user is
* responsible for ensuring the bus is not busy if multiple masters are present
* on the bus.
*
* @param BaseAddress contains the base address of the IIC device.
* @param Address contains the 7 bit IIC address of the device to send the
* specified data to.
* @param BufferPtr points to the data to be sent.
* @param ByteCount is the number of bytes to be sent.
*
* @return
*
* The number of bytes sent.
*
* @note
*
* None
*
******************************************************************************/
unsigned XIic_Send (u32 BaseAddress, u8 Address,
u8 * BufferPtr, unsigned ByteCount)
{
unsigned RemainingByteCount;
/* Put the address into the FIFO to be sent and indicate that the operation
* to be performed on the bus is a write operation
*/
XIic_mSend7BitAddress (BaseAddress, Address, XIIC_WRITE_OPERATION);
/* Clear the latched interrupt status so that it will be updated with the
* new state when it changes, this must be done after the address is put
* in the FIFO
*/
XIic_mClearIisr (BaseAddress, XIIC_INTR_TX_EMPTY_MASK |
XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_ARB_LOST_MASK);
/* MSMS must be set after putting data into transmit FIFO, indicate the
* direction is transmit, this device is master and enable the IIC device
*/
XIo_Out8 (BaseAddress + XIIC_CR_REG_OFFSET,
XIIC_CR_MSMS_MASK | XIIC_CR_DIR_IS_TX_MASK |
XIIC_CR_ENABLE_DEVICE_MASK);
/* Clear the latched interrupt
* status for the bus not busy bit which must be done while the bus is busy
*/
XIic_mClearIisr (BaseAddress, XIIC_INTR_BNB_MASK);
/* Send the specified data to the device on the IIC bus specified by the
* the address
*/
RemainingByteCount = SendData (BaseAddress, BufferPtr, ByteCount);
/*
* The send is complete, disable the IIC device and return the number of
* bytes that was sent
*/
XIo_Out8 (BaseAddress + XIIC_CR_REG_OFFSET, 0);
return ByteCount - RemainingByteCount;
}
/******************************************************************************
*
* Send the specified buffer to the device that has been previously addressed
* on the IIC bus. This function assumes that the 7 bit address has been sent
* and it should wait for the transmit of the address to complete.
*
* @param BaseAddress contains the base address of the IIC device.
* @param BufferPtr points to the data to be sent.
* @param ByteCount is the number of bytes to be sent.
*
* @return
*
* The number of bytes remaining to be sent.
*
* @note
*
* This function does not take advantage of the transmit FIFO because it is
* designed for minimal code space and complexity. It contains loops that
* that could cause the function not to return if the hardware is not working.
*
******************************************************************************/
static unsigned SendData (u32 BaseAddress, u8 * BufferPtr, unsigned ByteCount)
{
u32 IntrStatus;
/* Send the specified number of bytes in the specified buffer by polling
* the device registers and blocking until complete
*/
while (ByteCount > 0) {
/* Wait for the transmit to be empty before sending any more data
* by polling the interrupt status register
*/
while (1) {
IntrStatus = XIIF_V123B_READ_IISR (BaseAddress);
if (IntrStatus & (XIIC_INTR_TX_ERROR_MASK |
XIIC_INTR_ARB_LOST_MASK |
XIIC_INTR_BNB_MASK)) {
return ByteCount;
}
if (IntrStatus & XIIC_INTR_TX_EMPTY_MASK) {
break;
}
}
/* If there is more than one byte to send then put the next byte to send
* into the transmit FIFO
*/
if (ByteCount > 1) {
XIo_Out8 (BaseAddress + XIIC_DTR_REG_OFFSET,
*BufferPtr++);
} else {
/* Set the stop condition before sending the last byte of data so that
* the stop condition will be generated immediately following the data
* This is done by clearing the MSMS bit in the control register.
*/
XIo_Out8 (BaseAddress + XIIC_CR_REG_OFFSET,
XIIC_CR_ENABLE_DEVICE_MASK |
XIIC_CR_DIR_IS_TX_MASK);
/* Put the last byte to send in the transmit FIFO */
XIo_Out8 (BaseAddress + XIIC_DTR_REG_OFFSET,
*BufferPtr++);
}
/* Clear the latched interrupt status register and this must be done after
* the transmit FIFO has been written to or it won't clear
*/
XIic_mClearIisr (BaseAddress, XIIC_INTR_TX_EMPTY_MASK);
/* Update the byte count to reflect the byte sent and clear the latched
* interrupt status so it will be updated for the new state
*/
ByteCount--;
}
/* Wait for the bus to transition to not busy before returning, the IIC
* device cannot be disabled until this occurs.
* Note that this is different from a receive operation because the stop
* condition causes the bus to go not busy.
*/
while (1) {
if (XIIF_V123B_READ_IISR (BaseAddress) & XIIC_INTR_BNB_MASK) {
break;
}
}
return ByteCount;
}