owirepdd.c

Microsoft WinCE 6.0 BSP FINAL release source code for use with the i.MX27ADS TO2 WCE600_FINAL_MX27_S

//-----------------------------------------------------------------------------
//
//  Copyright (C) 2004, Motorola Inc. All Rights Reserved
//
//-----------------------------------------------------------------------------
//
/*---------------------------------------------------------------------------
* Copyright (C) 2004,2006, Freescale Semiconductor, Inc. All Rights Reserved.
* THIS SOURCE CODE, AND ITS USE AND DISTRIBUTION, IS SUBJECT TO THE TERMS
* AND CONDITIONS OF THE APPLICABLE LICENSE AGREEMENT 
*--------------------------------------------------------------------------*/


//-----------------------------------------------------------------------------
//
//  File:  owirepdd.c
//
//  Implementation of One-Wire Driver Platform Device Driver
//
//-----------------------------------------------------------------------------
#include <windows.h>
#include <nkintr.h>
#include <ceddk.h>
#include "csp.h"
#include "owire.h"
#include "owire_priv.h"


//-----------------------------------------------------------------------------
// External Functions
extern UINT32 BSPGetDivider();


//-----------------------------------------------------------------------------
// External Variables


//-----------------------------------------------------------------------------
// Defines


//-----------------------------------------------------------------------------
// Types


//-----------------------------------------------------------------------------
// Global Variables


//-----------------------------------------------------------------------------
// Local Variables
static PCSP_OWIRE_REGS g_pOWIRE;
static CRITICAL_SECTION g_hOwireLock;


//------------------------------------------------------------------------------
// Local Functions
BOOL OwireWriteByte(UINT8);
BOOL OwireReadByte(BYTE*);
BOOL OwireWriteBit(UINT8);
BYTE OwireReadBit();


//------------------------------------------------------------------------------
//
// Function: OwireDeinit
//
// Frees up the register space and deletes critical
// section for deinitialization.
//
// Parameters:
//      None
//
// Returns:
//      None
//
//------------------------------------------------------------------------------
void OwireDeinit(void)
{
    OWIRE_FUNCTION_ENTRY();

    // free the virtual space allocated for OWIRE memory map
    if (g_pOWIRE != NULL)
    {
        VirtualFree((void *) g_pOWIRE, 0, MEM_RELEASE);
        g_pOWIRE = NULL;
    }

    // Delete the critical section
    DeleteCriticalSection(&g_hOwireLock);

    OWIRE_FUNCTION_EXIT();
    return;
}

//------------------------------------------------------------------------------
//
// Function: OwireSetDevider
//
// This function sets the time divider register. 
//
// Parameters:
//      None
//
// Returns:
//      None
//
//------------------------------------------------------------------------------

void OwireSetDevider(void)
{
    UINT16 dividerVal;

    dividerVal = BSPGetDivider();

    // set time divider value to get as close as possible to a 1MHz clock
    OUTREG16(&g_pOWIRE->TD, dividerVal);

    DEBUGMSG (ZONE_INFO, (TEXT("OWIRE regs - ctrl: %x  divider: %x  reset: %x\r\n"),
        INREG16(&g_pOWIRE->CR), INREG16(&g_pOWIRE->TD), INREG16(&g_pOWIRE->RST)));

}

//------------------------------------------------------------------------------
//
// Function: OwireInitialize
//
// This function is the initialization routine for the one-wire.  It
// allocates memory for the one-wire registers and sets the
// time divider register.  If there is a failure in any of the
// initialization steps, OwireRelease will be called to clean up.
//
// Parameters:
//      None
//
// Returns:
//      TRUE - If success
//
//      FALSE - If failure
//
//------------------------------------------------------------------------------
BOOL OwireInitialize(void)
{
    PHYSICAL_ADDRESS phyAddr;

    OWIRE_FUNCTION_ENTRY();

    phyAddr.QuadPart = CSP_BASE_REG_PA_OWIRE;

    g_pOWIRE = (PCSP_OWIRE_REGS) MmMapIoSpace(phyAddr, sizeof(CSP_OWIRE_REGS), FALSE);

    // check if Map Virtual Address failed
    if (g_pOWIRE == NULL)
    {
        DEBUGMSG(ZONE_ERROR, (TEXT("OwireInitialize:  MmMapIoSpace failed!\r\n")));
        goto Error;
    }

	OwireSetDevider();

    OWIRE_FUNCTION_EXIT();
    return TRUE;

Error:
    //Cleaning up
    OwireDeinit();
    return FALSE;
}


//------------------------------------------------------------------------------
//
// Function: OwireSoftReset
//
// Software resets the OneWire module.  First set the RESET register
// to 1 and then set it to 0.
//
// Parameters:
//      None.
//
// Returns:
//      None.
//
//------------------------------------------------------------------------------
void OwireSoftReset(void)
{
    OWIRE_FUNCTION_ENTRY();

    EnterCriticalSection(&g_hOwireLock);

    // We must manually assert reset and then deassert.
    OUTREG16(&g_pOWIRE->RST, CSP_BITFVAL(OWIRE_RST_RST, OWIRE_RST_RST_RESET));
    OUTREG16(&g_pOWIRE->RST, CSP_BITFVAL(OWIRE_RST_RST, OWIRE_RST_RST_ENDRESET));

    LeaveCriticalSection(&g_hOwireLock);

    OWIRE_FUNCTION_EXIT();

    return;
}


//------------------------------------------------------------------------------
//
// Function: OwireSetResetPresencePulse
//
// This function is used to detect the presence of DS2502.
// This function should always be called before any
// write or read sequence.
//
// Parameters:
//      None.
//
// Returns:
//      TRUE if Detection sequence failed
//      FALSE if DS2502 exists, presence detected.
//
//------------------------------------------------------------------------------
BOOL OwireSetResetPresencePulse(void)
{
    DWORD startTime = GetTickCount();

    OWIRE_FUNCTION_ENTRY();

    EnterCriticalSection(&g_hOwireLock);

    INSREG16(&g_pOWIRE->CR, CSP_BITFMASK(OWIRE_CR_RPP), 
        CSP_BITFVAL(OWIRE_CR_RPP, OWIRE_CR_RPP_RESET));

    // Need to delay here for 579uSec for onewire
    // module to finish sampling the line and set PST.
    while (!EXTREG16(&g_pOWIRE->CR, CSP_BITFMASK(OWIRE_CR_PST), OWIRE_CR_PST_LSH))
    {
        // If more than one tick count has elapsed, 
        // we have waited longer than 1ms and the 
        // DS2520 must not be present
        if ((GetTickCount() - startTime) > 1)
        {
            DEBUGMSG(ZONE_ERROR, (TEXT("time waited (ms): %x\r\n"), (GetTickCount() - startTime)));
            DEBUGMSG(ZONE_ERROR, (TEXT("PST bit wasn't set!\r\n")));
        }
    }

    // If we are here we have received the presence bit.
    // Now we need to delay here for another 444uSec for
    // onewire module to AutoClear RPP bit.
    // Try to give remaining timeslice to another 
    // thread while waiting.
    while (EXTREG16(&g_pOWIRE->CR, CSP_BITFMASK(OWIRE_CR_RPP), OWIRE_CR_RPP_LSH))
        Sleep(0);

    LeaveCriticalSection(&g_hOwireLock);

    OWIRE_FUNCTION_EXIT();

    return TRUE;
}


//------------------------------------------------------------------------------
//
// Function: OwireWriteData
//
// Write count bytes of data to DS2502.
// This function calls OwireWriteByte to write one byte at
// a time from writeBuf.
//
// Parameters:
//      writeBuf
//          [in] Buffer containing bytes to write to DS2502
//      count
//          [in] Number of bytes to write from writeBuf
//
// Returns:
//      TRUE if write sequence successful
//      FALSE if write sequence failed
//
//------------------------------------------------------------------------------
BOOL OwireWriteData(BYTE* writeBuf, DWORD count)
{
    UINT32 i;

    OWIRE_FUNCTION_ENTRY();

    EnterCriticalSection(&g_hOwireLock);

    // Write one byte at a time to the DS2502
    for (i = 0; i < count; i++) 
    {
        if (!OwireWriteByte(writeBuf[i]))
        {
            return FALSE;