sysspeed.c

WINDRIVER MCP750 BSP

/* sysSpeed.c - Support for determining Bus and DRAM speed */

/* Copyright 1997-2001 Wind River Systems, Inc. */
/* Copyright 1997,1998 Motorola, Inc., All Rights Reserved */
#include "copyright_wrs.h"

/*
modification history
--------------------
01f,25oct01,mil  Moved sysGetBusSpd(), sysGetDramSpd() and sysGetMpuSpd() into
                 sysASpeed.s (SPR 71148).
01e,16sep01,dat  Use of WRS_ASM macro
01d,21jul98,scb  #define name cleanup - removal of board name defines.
01c,13jan98,srr  updated copyright dates to 1998.
01b,16aug97,scb  Add MPC750 (Arthur) support.
01a,09jul97,tb   created.
*/


/*
DESCRIPTION

*/

/* includes */

#include "vxWorks.h"
#include "config.h"

/* defines */

/* typedefs */

/* globals */

#ifdef INCLUDE_I2C
IMPORT	void	i2cgetDIMM (UINT, UCHAR *, UINT);
#endif /* INCLUDE_I2C */

/* locals */

/* forward declarations */

#ifdef INCLUDE_I2C
UINT	getDIMMdramspeed (void);
#endif /* INCLUDE_I2C */


#ifdef INCLUDE_I2C
/******************************************************************************
*
* getDIMMdramspeed - retreive the slowest dram speed for the DIMM
*                    combinations.
*
* This function's purpose is to access the DIMMs via the I2C controller
* and return the slowest speed found.
*
* RETURNS: slowest dram speed
*/

UINT getDIMMdramspeed (void)
    {
    UCHAR DIMM_info[15];
    UINT dspeed;
    UINT ii;

    dspeed = 0;

    /* Check all of the DRAM Serial Presence Detect (SPD) SROMs */

    for (ii = 0; ii <= 6; ii += 2)
	{
	/* Get SPD struct */

	i2cgetDIMM((0xA0 + ii), &(DIMM_info[0]), 14);

	/* Does this DIMM use the slowest DRAM ? */

	if (DIMM_info[9] > dspeed)
		{
		/* Yes! update return value */

		dspeed = DIMM_info[9];
		}
	}

    return (dspeed);
    }

/******************************************************************************
*
* getDIMMrefreshrate - retreive the fastest dram refresh rate required
*                      for the installed DIMMs.
*
* This function's purpose is to access the DIMMs via the I2C controller
* and return the fastest refresh rate required.
*
* RETURNS: refresh_rate
*			0 = Normal refresh rate
*			Non-zero = Fast refresh rate
*/

UINT getDIMMrefreshrate (void)
    {
    UCHAR DIMM_info[15];
    UINT refresh_rate;
    UINT ii;

    /* Default return value to normal refresh rate */

    refresh_rate = 0;
    
    /* Check all of the DRAM Serial Presence Detect (SPD) SROMs */

    for (ii = 0; ii <= 6; ii += 2)
	{
	/* Get SPD struct */

	i2cgetDIMM((0xA0 + ii), &(DIMM_info[0]), 14);

	/* Does this DIMM require a fast refresh rate? */

	if ((DIMM_info[12] == 1) || (DIMM_info[12] == 2))
		{
		/* Yes!  Update return value */

		refresh_rate = DIMM_info[12];
		}
	}

    return (refresh_rate);
    }

#endif /* INCLUDE_I2C */