Initial revision

1 files changed, 1228 insertions, 0 deletions

diff --git a/cpu/mpc824x/drivers/i2c/i2c1.c b/cpu/mpc824x/drivers/i2c/i2c1.c
new file mode 100644
index 00000000000..be6ec60a149
--- /dev/null
+++ b/cpu/mpc824x/drivers/i2c/i2c1.c
@@ -0,0 +1,1228 @@
+/*************************************************************
+ *
+ * Copyright @ Motorola, 1999
+ *
+ ************************************************************/
+#include <common.h>
+
+#ifdef CONFIG_HARD_I2C
+#include <i2c.h>
+#include "i2c_export.h"
+#include "i2c.h"
+
+#undef  I2CDBG0
+#undef  DEBUG
+
+/* Define a macro to use an optional application-layer print function, if
+ * one was passed to the I2C library during initialization.  If there was
+ * no function pointer passed, this protects against calling it.  Also define
+ * the global variable that holds the passed pointer.
+ */
+#define TIMEOUT (CFG_HZ/4)
+#define PRINT if ( app_print ) app_print
+static int (*app_print) (char *, ...);
+
+/******************* Internal to I2C Driver *****************/
+static unsigned int ByteToXmit = 0;
+static unsigned int XmitByte = 0;
+static unsigned char *XmitBuf = 0;
+static unsigned int XmitBufEmptyStop = 0;
+static unsigned int ByteToRcv = 0;
+static unsigned int RcvByte = 0;
+static unsigned char *RcvBuf = 0;
+static unsigned int RcvBufFulStop = 0;
+static unsigned int MasterRcvAddress = 0;
+
+/* Set by call to get_eumbbar during I2C_Initialize.
+ * This could be globally available to the I2C library, but there is
+ * an advantage to passing it as a parameter: it is already in a register
+ * and doesn't have to be loaded from memory.  Also, that is the way the
+ * I2C library was already implemented and I don't want to change it without
+ * a more detailed analysis.
+ * It is being set as a global variable in I2C_Initialize to hide it from
+ * the DINK application layer, because it is Kahlua-specific.  I think that
+ * get_eumbbar, load_runtime_reg, and store_runtime_reg should be defined in
+ * a Kahlua-specific library dealing with the embedded utilities memory block.
+ * Right now, get_eumbbar is defined in dink32/kahlua.s.  The other two are
+ * defined in dink32/drivers/i2c/i2c2.s.
+ */
+static unsigned int Global_eumbbar = 0;
+
+extern unsigned int load_runtime_reg (unsigned int eumbbar,
+				      unsigned int reg);
+
+extern unsigned int store_runtime_reg (unsigned int eumbbar,
+				       unsigned int reg, unsigned int val);
+
+/************************** API *****************/
+
+/* Application Program Interface (API) are the calls provided by the I2C
+ * library to upper layer applications (i.e., DINK) to access the Kahlua
+ * I2C bus interface.  The functions and values that are part of this API
+ * are declared in i2c_export.h.
+ */
+
+/*  Initialize I2C unit with the following:
+ *  driver's slave address
+ *  interrupt enabled
+ *  optional pointer to application layer print function
+ *
+ *  These parameters may be added:
+ *  desired clock rate
+ *  digital filter frequency sampling rate
+ *
+ *  This function must be called before I2C unit can be used.
+ */
+I2C_Status I2C_Initialize (unsigned char addr,
+			   I2C_INTERRUPT_MODE en_int,
+			   int (*p) (char *, ...))
+{
+	I2CStatus status;
+
+	/* establish the pointer, if there is one, to the application's "printf" */
+	app_print = p;
+
+	/* If this is the first call, get the embedded utilities memory block
+	 * base address.  I'm not sure what to do about error handling here:
+	 * if a non-zero value is returned, accept it.
+	 */
+	if (Global_eumbbar == 0)
+		Global_eumbbar = get_eumbbar ();
+	if (Global_eumbbar == 0) {
+		PRINT ("I2C_Initialize: can't find EUMBBAR\n");
+		return I2C_ERROR;
+	}
+
+	/* validate the I2C address */
+	if (addr & 0x80) {
+		PRINT ("I2C_Initialize, I2C address invalid:  %d 0x%x\n",
+			   (unsigned int) addr, (unsigned int) addr);
+		return I2C_ERROR;
+	}
+
+	/* Call the internal I2C library function to perform work.
+	 * Accept the default frequency sampling rate (no way to set it currently,
+	 * via I2C_Init) and set the clock frequency to something reasonable.
+	 */
+	status = I2C_Init (Global_eumbbar, (unsigned char) 0x31, addr, en_int);
+	if (status != I2CSUCCESS) {
+		PRINT ("I2C_Initialize: error in initiation\n");
+		return I2C_ERROR;
+	}
+
+	/* all is well */
+	return I2C_SUCCESS;
+}
+
+
+/* Perform the given I2C transaction, only MASTER_XMIT and MASTER_RCV
+ * are implemented.  Both are only in polling mode.
+ *
+ * en_int controls interrupt/polling mode
+ * act is the type of transaction
+ * i2c_addr is the I2C address of the slave device
+ * data_addr is the address of the data on the slave device
+ * len is the length of data to send or receive
+ * buffer is the address of the data buffer
+ * stop = I2C_NO_STOP, don't signal STOP at end of transaction
+ *        I2C_STOP, signal STOP at end of transaction
+ * retry is the timeout retry value, currently ignored
+ * rsta = I2C_NO_RESTART, this is not continuation of existing transaction
+ *        I2C_RESTART, this is a continuation of existing transaction
+ */
+I2C_Status I2C_do_transaction ( I2C_INTERRUPT_MODE en_int,
+				I2C_TRANSACTION_MODE act,
+				unsigned char i2c_addr,
+				unsigned char data_addr,
+				int len,
+				char *buffer,
+				I2C_STOP_MODE stop,
+				int retry, I2C_RESTART_MODE rsta)
+{
+	I2C_Status status;
+	unsigned char data_addr_buffer[1];
+
+#if 1
+/* This is a temporary work-around.  The I2C library breaks the protocol
+ * if it attempts to handle a data transmission in more than one
+ * transaction, so the data address and the actual data bytes are put
+ * into a single buffer before sending it to the library internal functions.
+ * The problem is related to being able to restart a transaction without
+ * sending the I2C device address or repeating the data address.  It may take
+ * a day or two to sort it all out, so I'll have to get back to it later.
+ * Look at I2C_Start to see about using some status flags (I'm not sure that
+ * "stop" and "rsta" are enough to reflect the states, maybe so; but the logic
+ * in the library is insufficient) to control correct handling of the protocol.
+ */
+	unsigned char dummy_buffer[257];
+
+	if (act == I2C_MASTER_XMIT) {
+		int i;
+
+		if (len > 256)
+			return I2C_ERROR;
+		for (i = 1; i <= len; i++)
+			dummy_buffer[i] = buffer[i - 1];
+		dummy_buffer[0] = data_addr;
+		status = I2C_do_buffer (en_int, act, i2c_addr, 1 + len,
+					dummy_buffer, stop, retry, rsta);
+		if (status != I2C_SUCCESS) {
+			PRINT ("I2C_do_transaction: can't perform data transfer\n");
+			return I2C_ERROR;
+		}
+		return I2C_SUCCESS;
+	}
+#endif	/* end of temp work-around */
+
+	/* validate requested transaction type */
+	if ((act != I2C_MASTER_XMIT) && (act != I2C_MASTER_RCV)) {
+		PRINT ("I2C_do_transaction, invalid transaction request:  %d\n",
+			act);
+		return I2C_ERROR;
+	}
+
+	/* range check the I2C address */
+	if (i2c_addr & 0x80) {
+		PRINT ("I2C_do_transaction, I2C address out of range:  %d 0x%x\n",
+			(unsigned int) i2c_addr, (unsigned int) i2c_addr);
+		return I2C_ERROR;
+	} else {
+		data_addr_buffer[0] = data_addr;
+	}
+
+	/*
+         * We first have to contact the slave device and transmit the
+         * data address. Be careful about the STOP and restart stuff.
+         * We don't want to signal STOP after sending the data
+         * address, but this could be a continuation if the
+         * application didn't release the bus after the previous
+         * transaction, by not sending a STOP after it.
+	 */
+	status = I2C_do_buffer (en_int, I2C_MASTER_XMIT, i2c_addr, 1,
+				data_addr_buffer, I2C_NO_STOP, retry, rsta);
+	if (status != I2C_SUCCESS) {
+		PRINT ("I2C_do_transaction: can't send data address for read\n");
+		return I2C_ERROR;
+	}
+
+	/* The data transfer will be a continuation. */
+	rsta = I2C_RESTART;
+
+	/* now handle the user data */
+	status = I2C_do_buffer (en_int, act, i2c_addr, len,
+				buffer, stop, retry, rsta);
+	if (status != I2C_SUCCESS) {
+		PRINT ("I2C_do_transaction: can't perform data transfer\n");
+		return I2C_ERROR;
+	}
+
+	/* all is well */
+	return I2C_SUCCESS;
+}
+
+/* This function performs the work for I2C_do_transaction.  The work is
+ * split into this function to enable I2C_do_transaction to first transmit
+ * the data address to the I2C slave device without putting the data address
+ * into the first byte of the buffer.
+ *
+ * en_int controls interrupt/polling mode
+ * act is the type of transaction
+ * i2c_addr is the I2C address of the slave device
+ * len is the length of data to send or receive
+ * buffer is the address of the data buffer
+ * stop = I2C_NO_STOP, don't signal STOP at end of transaction
+ *        I2C_STOP, signal STOP at end of transaction
+ * retry is the timeout retry value, currently ignored
+ * rsta = I2C_NO_RESTART, this is not continuation of existing transaction
+ *        I2C_RESTART, this is a continuation of existing transaction
+ */
+static I2C_Status I2C_do_buffer (I2C_INTERRUPT_MODE en_int,
+				 I2C_TRANSACTION_MODE act,
+				 unsigned char i2c_addr,
+				 int len,
+				 unsigned char *buffer,
+				 I2C_STOP_MODE stop,
+				 int retry, I2C_RESTART_MODE rsta)
+{
+	I2CStatus rval;
+	unsigned int dev_stat;
+
+	if (act == I2C_MASTER_RCV) {
+		/* set up for master-receive transaction */
+		rval = I2C_get (Global_eumbbar, i2c_addr, buffer, len, stop, rsta);
+	} else {
+		/* set up for master-transmit transaction */
+		rval = I2C_put (Global_eumbbar, i2c_addr, buffer, len, stop, rsta);
+	}
+
+	/* validate the setup */
+	if (rval != I2CSUCCESS) {
+		dev_stat = load_runtime_reg (Global_eumbbar, I2CSR);
+		PRINT ("Error(I2C_do_buffer): control phase, code(0x%08x), status(0x%08x)\n", rval, dev_stat);
+		I2C_Stop (Global_eumbbar);
+		return I2C_ERROR;
+	}
+
+	if (en_int == 1) {
+		/* this should not happen, no interrupt handling yet */
+		return I2C_SUCCESS;
+	}
+
+	/* this performs the polling action, when the transfer is completed,
+	 * the status returned from I2C_Timer_Event will be I2CBUFFFULL or
+	 * I2CBUFFEMPTY (rcv or xmit), I2CSUCCESS or I2CADDRESS indicates the
+	 * transaction is not yet complete, anything else is an error.
+	 */
+	while (rval == I2CSUCCESS || rval == I2CADDRESS) {
+		int timeval = get_timer (0);
+
+		/* poll the device until something happens */
+		do {
+			rval = I2C_Timer_Event (Global_eumbbar, 0);
+		}
+		while (rval == I2CNOEVENT && get_timer (timeval) < TIMEOUT);
+
+		/* check for error condition */
+		if (rval == I2CSUCCESS   ||
+		    rval == I2CBUFFFULL  ||
+		    rval == I2CBUFFEMPTY ||
+		    rval == I2CADDRESS) {
+			;	/* do nothing */
+		} else {
+			/* report the error condition */
+			dev_stat = load_runtime_reg (Global_eumbbar, I2CSR);
+			PRINT ("Error(I2C_do_buffer):  code(0x%08x), status(0x%08x)\n",
+				   rval, dev_stat);
+			return I2C_ERROR;
+		}
+	}
+
+	/* all is well */
+	return I2C_SUCCESS;
+}
+
+/**
+ * Note:
+ *
+ * In all following functions,
+ * the caller shall pass the configured embedded utility memory
+ * block base, EUMBBAR.
+ **/
+
+/***********************************************************
+ * function: I2C_put
+ *
+ * description:
+   Send a buffer of data to the intended rcv_addr.
+ * If stop_flag is set, after the whole buffer
+ * is sent, generate a STOP signal provided that the
+ * receiver doesn't signal the STOP in the middle.
+ * I2C is the master performing transmitting. If
+ * no STOP signal is generated at the end of current
+ * transaction, the master can generate a START signal
+ * to another slave addr.
+ *
+ * note: this is master xmit API
+ *********************************************************/
+static I2CStatus I2C_put (unsigned int eumbbar, unsigned char rcv_addr,	/* receiver's address */
+	  unsigned char *buffer_ptr,	/* pointer of data to be sent */
+	  unsigned int length,	/* number of byte of in the buffer */
+	  unsigned int stop_flag,	/* 1 - signal STOP when buffer is empty
+					 * 0 - no STOP signal when buffer is empty
+					 */
+	  unsigned int is_cnt)
+{					/* 1 - this is a restart, don't check MBB
+					 * 0 - this is a new start, check MBB
+					 */
+	if (buffer_ptr == 0 || length == 0) {
+		return I2CERROR;
+	}
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_put\n", __FILE__, __LINE__);
+#endif
+
+	XmitByte = 0;
+	ByteToXmit = length;
+	XmitBuf = buffer_ptr;
+	XmitBufEmptyStop = stop_flag;
+
+	RcvByte = 0;
+	ByteToRcv = 0;
+	RcvBuf = 0;
+
+	/* we are the master, start transaction */
+	return I2C_Start (eumbbar, rcv_addr, XMIT, is_cnt);
+}
+
+/***********************************************************
+ * function: I2C_get
+ *
+ * description:
+ * Receive a buffer of data from the desired sender_addr
+ * If stop_flag is set, when the buffer is full and the
+ * sender does not signal STOP, generate a STOP signal.
+ * I2C is the master performing receiving. If no STOP signal
+ * is generated, the master can generate a START signal
+ * to another slave addr.
+ *
+ * note: this is master receive API
+ **********************************************************/
+static I2CStatus I2C_get (unsigned int eumbbar, unsigned char rcv_from,	/* sender's address */
+		  unsigned char *buffer_ptr,	/* pointer of receiving buffer */
+		  unsigned int length,	/* length of the receiving buffer */
+		  unsigned int stop_flag,	/* 1 - signal STOP when buffer is full
+						 * 0 - no STOP signal when buffer is full
+						 */
+		  unsigned int is_cnt)
+{						/* 1 - this is a restart, don't check MBB
+						 * 0 - this is a new start, check MBB
+						 */
+	if (buffer_ptr == 0 || length == 0) {
+		return I2CERROR;
+	}
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_get\n", __FILE__, __LINE__);
+#endif
+
+	RcvByte = 0;
+	ByteToRcv = length;
+	RcvBuf = buffer_ptr;
+	RcvBufFulStop = stop_flag;
+
+	XmitByte = 0;
+	ByteToXmit = 0;
+	XmitBuf = 0;
+
+	/* we are the master, start the transaction */
+	return I2C_Start (eumbbar, rcv_from, RCV, is_cnt);
+
+}
+
+#if 0	/* turn off dead code */
+/*********************************************************
+ * function: I2C_write
+ *
+ * description:
+ * Send a buffer of data to the requiring master.
+ * If stop_flag is set, after the whole buffer is sent,
+ * generate a STOP signal provided that the requiring
+ * receiver doesn't signal the STOP in the middle.
+ * I2C is the slave performing transmitting.
+ *
+ * Note: this is slave xmit API.
+ *
+ *       due to the current Kahlua design, slave transmitter
+ *       shall not signal STOP since there is no way
+ *       for master to detect it, causing I2C bus hung.
+ *
+ *       For the above reason, the stop_flag is always
+ *       set, i.e., 0.
+ *
+ *       programmer shall use the timer on Kahlua to
+ *       control the interval of data byte at the
+ *       master side.
+ *******************************************************/
+static I2CStatus I2C_write (unsigned int eumbbar, unsigned char *buffer_ptr,	/* pointer of data to be sent */
+		unsigned int length,	/* number of byte of in the buffer */
+		unsigned int stop_flag)
+{					/* 1 - signal STOP when buffer is empty
+					 * 0 - no STOP signal when buffer is empty
+					 */
+	if (buffer_ptr == 0 || length == 0) {
+		return I2CERROR;
+	}
+
+	XmitByte = 0;
+	ByteToXmit = length;
+	XmitBuf = buffer_ptr;
+	XmitBufEmptyStop = 0;	/* in order to avoid bus hung, ignored the user's stop_flag */
+
+	RcvByte = 0;
+	ByteToRcv = 0;
+	RcvBuf = 0;
+
+	/* we are the slave, just wait for being called, or pull */
+	/* I2C_Timer_Event( eumbbar ); */
+}
+
+/******************************************************
+ * function: I2C_read
+ *
+ * description:
+ * Receive a buffer of data from the sending master.
+ * If stop_flag is set, when the buffer is full and the
+ * sender does not signal STOP, generate a STOP signal.
+ * I2C is the slave performing receiving.
+ *
+ * note: this is slave receive API
+ ****************************************************/
+static I2CStatus I2C_read (unsigned int eumbbar, unsigned char *buffer_ptr,	/* pointer of receiving buffer */
+		   unsigned int length,	/* length of the receiving buffer */
+		   unsigned int stop_flag)
+{					/* 1 - signal STOP when buffer is full
+					 * 0 - no STOP signal when buffer is full
+					 */
+	if (buffer_ptr == 0 || length == 0) {
+		return I2CERROR;
+	}
+
+	RcvByte = 0;
+	ByteToRcv = length;
+	RcvBuf = buffer_ptr;
+	RcvBufFulStop = stop_flag;
+
+	XmitByte = 0;
+	ByteToXmit = 0;
+	XmitBuf = 0;
+
+	/* wait for master to call us, or poll */
+	/* I2C_Timer_Event( eumbbar ); */
+}
+#endif	/* turn off dead code */
+
+/*********************************************************
+ * function: I2c_Timer_Event
+ *
+ * description:
+ * if interrupt is not used, this is the timer event handler.
+ * After each fixed time interval, this function can be called
+ * to check the I2C status and call appropriate function to
+ * handle the status event.
+ ********************************************************/
+static I2CStatus I2C_Timer_Event (unsigned int eumbbar,
+				  I2CStatus (*handler) (unsigned int))
+{
+	I2C_STAT stat;
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_Timer_Event\n", __FILE__, __LINE__);
+#endif
+
+	stat = I2C_Get_Stat (eumbbar);
+
+	if (stat.mif == 1) {
+		if (handler == 0) {
+			return I2C_ISR (eumbbar);
+		} else {
+			return (*handler) (eumbbar);
+		}
+	}
+
+	return I2CNOEVENT;
+}
+
+
+/****************** Device I/O function *****************/
+
+/******************************************************
+ * function: I2C_Start
+ *
+ * description: Generate a START signal in the desired mode.
+ *              I2C is the master.
+ *
+ *              Return I2CSUCCESS if no error.
+ *
+ * note:
+ ****************************************************/
+static I2CStatus I2C_Start (unsigned int eumbbar, unsigned char slave_addr,	/* address of the receiver */
+			I2C_MODE mode,	/* XMIT(1) - put (write)
+					 * RCV(0)  - get (read)
+					 */
+			unsigned int is_cnt)
+{					/* 1 - this is a restart, don't check MBB
+					 * 0 - this is a new start
+					 */
+	unsigned int tmp = 0;
+	I2C_STAT stat;
+	I2C_CTRL ctrl;
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_Start addr 0x%x mode %d cnt %d\n", __FILE__,
+		   __LINE__, slave_addr, mode, is_cnt);
+#endif
+
+	ctrl = I2C_Get_Ctrl (eumbbar);
+
+	/* first make sure I2C has been initialized */
+	if (ctrl.men == 0) {
+		return I2CERROR;
+	}
+
+	/* next make sure bus is idle */
+	stat = I2C_Get_Stat (eumbbar);
+
+	if (is_cnt == 0 && stat.mbb == 1) {
+		/* sorry, we lost */
+		return I2CBUSBUSY;
+	} else if (is_cnt == 1 && stat.mif == 1 && stat.mal == 0) {
+		/* sorry, we lost the bus */
+		return I2CALOSS;
+	}
+
+
+	/* OK, I2C is enabled and we have the bus */
+
+	/* prepare to write the slave address */
+	ctrl.msta = 1;
+	ctrl.mtx = 1;
+	ctrl.txak = 0;
+	ctrl.rsta = is_cnt;		/* set the repeat start bit */
+	I2C_Set_Ctrl (eumbbar, ctrl);
+
+	/* write the slave address and xmit/rcv mode bit */
+	tmp = load_runtime_reg (eumbbar, I2CDR);
+	tmp = (tmp & 0xffffff00) |
+	      ((slave_addr & 0x007f) << 1) |
+	      (mode == XMIT ? 0x0 : 0x1);
+	store_runtime_reg (eumbbar, I2CDR, tmp);
+
+	if (mode == RCV) {
+		MasterRcvAddress = 1;
+	} else {
+		MasterRcvAddress = 0;
+	}
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_Start exit\n", __FILE__, __LINE__);
+#endif
+
+	/* wait for the interrupt or poll  */
+	return I2CSUCCESS;
+}
+
+/***********************************************************
+ * function: I2c_Stop
+ *
+ * description: Generate a STOP signal to terminate the master
+ *              transaction.
+ *              return I2CSUCCESS
+ *
+ **********************************************************/
+static I2CStatus I2C_Stop (unsigned int eumbbar)
+{
+	I2C_CTRL ctrl;
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_Stop enter\n", __FILE__, __LINE__);
+#endif
+
+	ctrl = I2C_Get_Ctrl (eumbbar);
+	ctrl.msta = 0;
+	I2C_Set_Ctrl (eumbbar, ctrl);
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_Stop exit\n", __FILE__, __LINE__);
+#endif
+
+	return I2CSUCCESS;
+}
+
+/****************************************************
+ * function: I2C_Master_Xmit
+ *
+ * description: Master sends one byte of data to
+ *              slave target
+ *
+ *              return I2CSUCCESS if the byte transmitted.
+ *              Otherwise no-zero
+ *
+ * Note: condition must meet when this function is called:
+ *       I2CSR(MIF) == 1 && I2CSR(MCF)  == 1  && I2CSR(RXAK) == 0
+ *       I2CCR(MSTA) == 1  && I2CCR(MTX) == 1
+ *
+ ***************************************************/
+static I2CStatus I2C_Master_Xmit (unsigned int eumbbar)
+{
+	unsigned int val;
+
+	if (ByteToXmit > 0) {
+
+		if (ByteToXmit == XmitByte) {
+			/* all xmitted */
+			ByteToXmit = 0;
+
+			if (XmitBufEmptyStop == 1) {
+				I2C_Stop (eumbbar);
+			}
+
+			return I2CBUFFEMPTY;
+
+		}
+#ifdef I2CDBG0
+		PRINT ("%s(%d): xmit 0x%02x\n", __FILE__, __LINE__,
+			   *(XmitBuf + XmitByte));
+#endif
+
+		val = *(XmitBuf + XmitByte);
+		val &= 0x000000ff;
+		store_runtime_reg (eumbbar, I2CDR, val);
+		XmitByte++;
+
+		return I2CSUCCESS;
+
+	}
+
+	return I2CBUFFEMPTY;
+}
+
+/***********************************************
+ * function: I2C_Master_Rcv
+ *
+ * description: master reads one byte data
+ *              from slave source
+ *
+ *              return I2CSUCCESS if no error
+ *
+ * Note: condition must meet when this function is called:
+ *       I2CSR(MIF) == 1 && I2CSR(MCF) == 1 &&
+ *       I2CCR(MSTA) == 1 && I2CCR(MTX) == 0
+ *
+ ***********************************************/
+static I2CStatus I2C_Master_Rcv (unsigned int eumbbar)
+{
+	I2C_CTRL ctrl;
+	unsigned int val;
+
+	if (ByteToRcv > 0) {
+
+		if (ByteToRcv - RcvByte == 2 && RcvBufFulStop == 1) {
+			/* master requests more than or equal to 2 bytes
+			 * we are reading 2nd to last byte
+			 */
+
+			/* we need to set I2CCR(TXAK) to generate a STOP */
+			ctrl = I2C_Get_Ctrl (eumbbar);
+			ctrl.txak = 1;
+			I2C_Set_Ctrl (eumbbar, ctrl);
+
+			/* Kahlua will automatically generate a STOP
+			 * next time a transaction happens
+			 */
+
+			/* note: the case of master requesting one byte is
+			 *       handled in I2C_ISR
+			 */
+		}
+
+		/* generat a STOP before reading the last byte */
+		if (RcvByte + 1 == ByteToRcv && RcvBufFulStop == 1) {
+			I2C_Stop (eumbbar);
+		}
+
+		val = load_runtime_reg (eumbbar, I2CDR);
+		*(RcvBuf + RcvByte) = val & 0xFF;
+
+#ifdef I2CDBG0
+		PRINT ("%s(%d): rcv 0x%02x\n", __FILE__, __LINE__,
+			   *(RcvBuf + RcvByte));
+#endif
+
+		RcvByte++;
+
+		if (ByteToRcv == RcvByte) {
+			ByteToRcv = 0;
+
+			return I2CBUFFFULL;
+		}
+
+		return I2CSUCCESS;
+	}
+
+	return I2CBUFFFULL;
+
+}
+
+/****************************************************
+ * function: I2C_Slave_Xmit
+ *
+ * description: Slave sends one byte of data to
+ *              requesting destination
+ *
+ *        return SUCCESS if the byte transmitted. Otherwise
+ *        No-zero
+ *
+ * Note: condition must meet when this function is called:
+ *       I2CSR(MIF) == 1 && I2CSR(MCF) == 1 &&  I2CSR(RXAK) = 0
+ *       I2CCR(MSTA) == 0  && I2CCR(MTX) == 1
+ *
+ ***************************************************/
+static I2CStatus I2C_Slave_Xmit (unsigned int eumbbar)
+{
+	unsigned int val;
+
+	if (ByteToXmit > 0) {
+
+		if (ByteToXmit == XmitByte) {
+			/* no more data to send */
+			ByteToXmit = 0;
+
+			/*
+                         * do not toggle I2CCR(MTX). Doing so will
+                         * cause bus-hung since current Kahlua design
+                         * does not give master a way to detect slave
+                         * stop. It is always a good idea for master
+                         * to use timer to prevent the long long
+                         * delays
+			 */
+
+			return I2CBUFFEMPTY;
+		}
+#ifdef I2CDBG
+		PRINT ("%s(%d): xmit 0x%02x\n", __FILE__, __LINE__,
+			   *(XmitBuf + XmitByte));
+#endif
+
+		val = *(XmitBuf + XmitByte);
+		val &= 0x000000ff;
+		store_runtime_reg (eumbbar, I2CDR, val);
+		XmitByte++;
+
+		return I2CSUCCESS;
+	}
+
+	return I2CBUFFEMPTY;
+}
+
+/***********************************************
+ * function: I2C_Slave_Rcv
+ *
+ * description: slave reads one byte data
+ *              from master source
+ *
+ *              return I2CSUCCESS if no error otherwise non-zero
+ *
+ * Note: condition must meet when this function is called:
+ *       I2CSR(MIF) == 1 && I2CSR(MCF) == 1 &&
+ *       I2CCR(MSTA) == 0 && I2CCR(MTX)  = 0
+ *
+ ***********************************************/
+static I2CStatus I2C_Slave_Rcv (unsigned int eumbbar)
+{
+	unsigned int val;
+	I2C_CTRL ctrl;
+
+	if (ByteToRcv > 0) {
+		val = load_runtime_reg (eumbbar, I2CDR);
+		*(RcvBuf + RcvByte) = val & 0xff;
+#ifdef I2CDBG
+		PRINT ("%s(%d): rcv 0x%02x\n", __FILE__, __LINE__,
+			   *(RcvBuf + RcvByte));
+#endif
+		RcvByte++;
+
+		if (ByteToRcv == RcvByte) {
+			if (RcvBufFulStop == 1) {
+				/* all done */
+				ctrl = I2C_Get_Ctrl (eumbbar);
+				ctrl.txak = 1;
+				I2C_Set_Ctrl (eumbbar, ctrl);
+			}
+
+			ByteToRcv = 0;
+			return I2CBUFFFULL;
+		}
+
+		return I2CSUCCESS;
+	}
+
+	return I2CBUFFFULL;
+}
+
+/****************** Device Control Function *************/
+
+/*********************************************************
+ * function: I2C_Init
+ *
+ * description: Initialize I2C unit with desired frequency divider,
+ *              master's listening address, with interrupt enabled
+ *              or disabled.
+ *
+ * note:
+ ********************************************************/
+static I2CStatus I2C_Init (unsigned int eumbbar, unsigned char fdr,	/* frequency divider */
+		   unsigned char slave_addr,	/* driver's address used for receiving */
+		   unsigned int en_int)
+{						/* 1 - enable I2C interrupt
+						 * 0 - disable I2C interrup
+						 */
+	I2C_CTRL ctrl;
+	unsigned int tmp;
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_Init enter\n", __FILE__, __LINE__);
+#endif
+
+	ctrl = I2C_Get_Ctrl (eumbbar);
+	/* disable the I2C module before we change everything */
+	ctrl.men = 0;
+	I2C_Set_Ctrl (eumbbar, ctrl);
+
+	/* set the frequency diver */
+	tmp = load_runtime_reg (eumbbar, I2CFDR);
+	tmp = (tmp & 0xffffffc0) | (fdr & 0x3f);
+	store_runtime_reg (eumbbar, I2CFDR, tmp);
+
+	/* Set our listening (slave) address */
+	tmp = load_runtime_reg (eumbbar, I2CADR);
+	tmp = (tmp & 0xffffff01) | ((slave_addr & 0x7f) << 1);
+	store_runtime_reg (eumbbar, I2CADR, tmp);
+
+	/* enable I2C with desired interrupt setting */
+	ctrl.men = 1;
+	ctrl.mien = en_int & 0x1;
+	I2C_Set_Ctrl (eumbbar, ctrl);
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_Init exit\n", __FILE__, __LINE__);
+#endif
+
+	return I2CSUCCESS;
+
+}
+
+/*****************************************
+ * function I2c_Get_Stat
+ *
+ * description: Query I2C Status, i.e., read I2CSR
+ *
+ ****************************************/
+static I2C_STAT I2C_Get_Stat (unsigned int eumbbar)
+{
+	unsigned int temp;
+	I2C_STAT stat;
+
+	temp = load_runtime_reg (eumbbar, I2CSR);
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): get stat = 0x%08x\n", __FILE__, __LINE__, temp);
+#endif
+
+	stat.rsrv0 = (temp & 0xffffff00) >> 8;
+	stat.mcf   = (temp & 0x00000080) >> 7;
+	stat.maas  = (temp & 0x00000040) >> 6;
+	stat.mbb   = (temp & 0x00000020) >> 5;
+	stat.mal   = (temp & 0x00000010) >> 4;
+	stat.rsrv1 = (temp & 0x00000008) >> 3;
+	stat.srw   = (temp & 0x00000004) >> 2;
+	stat.mif   = (temp & 0x00000002) >> 1;
+	stat.rxak  = (temp & 0x00000001);
+	return stat;
+}
+
+/*********************************************
+ * function: I2c_Set_Ctrl
+ *
+ * description: Change I2C Control bits,
+ *              i.e., write to I2CCR
+ *
+ ********************************************/
+static void I2C_Set_Ctrl (unsigned int eumbbar, I2C_CTRL ctrl)
+{						/* new control value */
+	unsigned int temp = load_runtime_reg (eumbbar, I2CCR);
+
+	temp &= 0xffffff03;
+	temp |= ((ctrl.men  & 0x1) << 7);
+	temp |= ((ctrl.mien & 0x1) << 6);
+	temp |= ((ctrl.msta & 0x1) << 5);
+	temp |= ((ctrl.mtx  & 0x1) << 4);
+	temp |= ((ctrl.txak & 0x1) << 3);
+	temp |= ((ctrl.rsta & 0x1) << 2);
+#ifdef I2CDBG0
+	PRINT ("%s(%d): set ctrl = 0x%08x\n", __FILE__, __LINE__, temp);
+#endif
+	store_runtime_reg (eumbbar, I2CCR, temp);
+
+}
+
+/*****************************************
+ * function: I2C_Get_Ctrl
+ *
+ * description: Query I2C Control bits,
+ *              i.e., read I2CCR
+ *****************************************/
+static I2C_CTRL I2C_Get_Ctrl (unsigned int eumbbar)
+{
+	union {
+		I2C_CTRL ctrl;
+		unsigned int temp;
+	} s;
+
+	s.temp = load_runtime_reg (eumbbar, I2CCR);
+#ifdef I2CDBG0
+	PRINT ("%s(%d): get ctrl = 0x%08x\n", __FILE__, __LINE__, s.temp);
+#endif
+
+	return s.ctrl;
+}
+
+
+/****************************************
+ * function: I2C_Slave_Addr
+ *
+ * description: Process slave address phase.
+ *              return I2CSUCCESS if no error
+ *
+ * note: Precondition for calling this function:
+ *       I2CSR(MIF) == 1 &&
+ *       I2CSR(MAAS) == 1
+ ****************************************/
+static I2CStatus I2C_Slave_Addr (unsigned int eumbbar)
+{
+	I2C_STAT stat = I2C_Get_Stat (eumbbar);
+	I2C_CTRL ctrl = I2C_Get_Ctrl (eumbbar);
+
+	if (stat.srw == 1) {
+		/* we are asked to xmit */
+		ctrl.mtx = 1;
+		I2C_Set_Ctrl (eumbbar, ctrl);	/* set MTX */
+		return I2C_Slave_Xmit (eumbbar);
+	}
+
+	/* we are asked to receive data */
+	ctrl.mtx = 0;
+	I2C_Set_Ctrl (eumbbar, ctrl);
+	(void) load_runtime_reg (eumbbar, I2CDR);	/* do a fake read to start */
+
+	return I2CADDRESS;
+}
+
+/***********************************************
+ * function: I2C_ISR
+ *
+ * description: I2C Interrupt service routine
+ *
+ * note: Precondition:
+ *      I2CSR(MIF) == 1
+ **********************************************/
+static I2CStatus I2C_ISR (unsigned int eumbbar)
+{
+	I2C_STAT stat;
+	I2C_CTRL ctrl;
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): I2C_ISR\n", __FILE__, __LINE__);
+#endif
+
+	stat = I2C_Get_Stat (eumbbar);
+	ctrl = I2C_Get_Ctrl (eumbbar);
+
+	/* clear MIF */
+	stat.mif = 0;
+
+	/* Now let see what kind of event this is */
+	if (stat.mcf == 1) {
+		/* transfer compete */
+
+		/* clear the MIF bit */
+		I2C_Set_Stat (eumbbar, stat);
+
+		if (ctrl.msta == 1) {
+			/* master */
+			if (ctrl.mtx == 1) {
+				/* check if this is the address phase for master receive */
+				if (MasterRcvAddress == 1) {
+					/* Yes, it is the address phase of master receive */
+					ctrl.mtx = 0;
+					/* now check how much we want to receive */
+					if (ByteToRcv == 1 && RcvBufFulStop == 1) {
+						ctrl.txak = 1;
+					}
+
+					I2C_Set_Ctrl (eumbbar, ctrl);
+					(void) load_runtime_reg (eumbbar, I2CDR);	/* fake read first */
+
+					MasterRcvAddress = 0;
+					return I2CADDRESS;
+
+				}
+
+				/* master xmit */
+				if (stat.rxak == 0) {
+					/* slave has acknowledged */
+					return I2C_Master_Xmit (eumbbar);
+				}
+
+				/* slave has not acknowledged yet, generate a STOP */
+				if (XmitBufEmptyStop == 1) {
+					ctrl.msta = 0;
+					I2C_Set_Ctrl (eumbbar, ctrl);
+				}
+
+				return I2CSUCCESS;
+			}
+
+			/* master receive */
+			return I2C_Master_Rcv (eumbbar);
+		}
+
+		/* slave */
+		if (ctrl.mtx == 1) {
+			/* slave xmit */
+			if (stat.rxak == 0) {
+				/* master has acknowledged */
+				return I2C_Slave_Xmit (eumbbar);
+			}
+
+			/* master has not acknowledged, wait for STOP */
+			/* do nothing for preventing bus from hung */
+			return I2CSUCCESS;
+		}
+
+		/* slave rcv */
+		return I2C_Slave_Rcv (eumbbar);
+
+	} else if (stat.maas == 1) {
+		/* received a call from master */
+
+		/* clear the MIF bit */
+		I2C_Set_Stat (eumbbar, stat);
+
+		/* master is calling us, process the address phase */
+		return I2C_Slave_Addr (eumbbar);
+	} else {
+		/* has to be arbitration lost */
+		stat.mal = 0;
+		I2C_Set_Stat (eumbbar, stat);
+
+		ctrl.msta = 0;			/* return to receive mode */
+		I2C_Set_Ctrl (eumbbar, ctrl);
+	}
+
+	return I2CSUCCESS;
+
+}
+
+/******************************************************
+ * function: I2C_Set_Stat
+ *
+ * description: modify the I2CSR
+ *
+ *****************************************************/
+static void I2C_Set_Stat (unsigned int eumbbar, I2C_STAT stat)
+{
+	union {
+		unsigned int val;
+		I2C_STAT stat;
+	} s_tmp;
+	union {
+		unsigned int val;
+		I2C_STAT stat;
+	} s;
+
+	s.val = load_runtime_reg (eumbbar, I2CSR);
+	s.val &= 0xffffff08;
+	s_tmp.stat = stat;
+	s.val |= (s_tmp.val & 0xf7);
+
+#ifdef I2CDBG0
+	PRINT ("%s(%d): set stat = 0x%08x\n", __FILE__, __LINE__, s.val);
+#endif
+
+	store_runtime_reg (eumbbar, I2CSR, s.val);
+
+}
+
+/******************************************************
+ * The following are routines to glue the rest of
+ * U-Boot to the Sandpoint I2C driver.
+ *****************************************************/
+
+void i2c_init (int speed, int slaveadd)
+{
+#ifdef DEBUG
+	I2C_Initialize (0x7f, 0, (void *) printf);
+#else
+	I2C_Initialize (0x7f, 0, 0);
+#endif
+}
+
+int i2c_probe (uchar chip)
+{
+	int tmp;
+
+	/*
+	 * Try to read the first location of the chip.  The underlying
+	 * driver doesn't appear to support sending just the chip address
+	 * and looking for an <ACK> back.
+	 */
+	udelay(10000);
+	return i2c_read (chip, 0, 1, (char *)&tmp, 1);
+}
+
+int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
+{
+	I2CStatus status;
+	uchar xaddr[4];
+
+	if (alen > 0) {
+		xaddr[0] = (addr >> 24) & 0xFF;
+		xaddr[1] = (addr >> 16) & 0xFF;
+		xaddr[2] = (addr >> 8) & 0xFF;
+		xaddr[3] = addr & 0xFF;
+
+		status = I2C_do_buffer (0, I2C_MASTER_XMIT, chip, alen,
+					&xaddr[4 - alen], I2C_NO_STOP, 1,
+					I2C_NO_RESTART);
+		if (status != I2C_SUCCESS) {
+			PRINT ("i2c_read: can't send data address for read\n");
+			return 1;
+		}
+	}
+
+	/* The data transfer will be a continuation. */
+	status = I2C_do_buffer (0, I2C_MASTER_RCV, chip, len,
+				buffer, I2C_STOP, 1, (alen > 0 ? I2C_RESTART :
+				I2C_NO_RESTART));
+
+	if (status != I2C_SUCCESS) {
+		PRINT ("i2c_read: can't perform data transfer\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
+{
+	I2CStatus status;
+	unsigned char dummy_buffer[I2C_RXTX_LEN + 2];
+	int i;
+
+	dummy_buffer[0] = addr & 0xFF;
+	if (alen == 2)
+		dummy_buffer[1] = (addr >> 8) & 0xFF;
+	for (i = 0; i < len; i++)
+		dummy_buffer[i + alen] = buffer[i];
+
+	status = I2C_do_buffer (0, I2C_MASTER_XMIT, chip, alen + len,
+				dummy_buffer, I2C_STOP, 1, I2C_NO_RESTART);
+
+#ifdef CFG_EEPROM_PAGE_WRITE_DELAY_MS
+	udelay(CFG_EEPROM_PAGE_WRITE_DELAY_MS * 1000);
+#endif
+	if (status != I2C_SUCCESS) {
+		PRINT ("i2c_write: can't perform data transfer\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+uchar i2c_reg_read (uchar i2c_addr, uchar reg)
+{
+	char buf[1];
+
+	i2c_init (0, 0);
+
+	i2c_read (i2c_addr, reg, 1, buf, 1);
+
+	return (buf[0]);
+}
+
+void i2c_reg_write (uchar i2c_addr, uchar reg, uchar val)
+{
+	i2c_init (0, 0);
+
+	i2c_write (i2c_addr, reg, 1, &val, 1);
+}
+
+#endif	/* CONFIG_HARD_I2C */