Subversion Repositories openrisc_me

//==========================================================================

//

//      flash_unlock_block.c

//

//      Flash programming

//

//==========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    gthomas

// Contributors: gthomas

// Date:         2000-09-10

// Purpose:      

// Description:  

//              

//####DESCRIPTIONEND####

//

//==========================================================================

#include "flash.h"

#include <cyg/hal/hal_arch.h>

//

// CAUTION!  This code must be copied to RAM before execution.  Therefore,

// it must not contain any code which might be position dependent!

//

//

// The difficulty with this operation is that the hardware does not support

// unlocking single blocks.  However, the logical layer would like this to

// be the case, so this routine emulates it.  The hardware can clear all of

// the locks in the device at once.  This routine will use that approach and

// then reset the regions which are known to be locked.

//

#define MAX_FLASH_BLOCKS 128

int

flash_unlock_block(volatile unsigned long *block, int block_size, int blocks)

{

    volatile unsigned long *ROM, *bp;

    unsigned long stat;

    int timeout = 5000000;

    unsigned char is_locked[MAX_FLASH_BLOCKS];

    int i;

    FLASH_WRITE_ENABLE();

    block = (volatile unsigned long *)CYGARC_UNCACHED_ADDRESS((unsigned long)block);

    ROM = (volatile unsigned long *)((unsigned long)block & FLASH_BASE_MASK);

    // Clear any error conditions

    ROM[0] = FLASH_Clear_Status;

    // Get current block lock state.  This needs to access each block on

    // the device so currently locked blocks can be re-locked.

    bp = ROM;

    for (i = 0;  i < (blocks/2);  i++) {

        if (bp == block) {

            is_locked[i] = 0;

        } else {

            *bp = FLASH_Read_Query;

            is_locked[i] = bp[2];

        }

        bp += block_size / sizeof(*bp);

    }

    // Clears all lock bits

    block[0] = FLASH_Clear_Locks;

    block[0] = FLASH_Clear_Locks_Confirm;  // Confirmation

    timeout = 5000000;

    while(((stat = ROM[0]) & FLASH_Status_Ready) != FLASH_Status_Ready) {

        if (--timeout == 0) break;

    }

    // Restore the lock state

    bp = ROM;

    for (i = 0;  i < (blocks/2);  i++) {

        if (is_locked[i]) {

            *bp = FLASH_Set_Lock;

            *bp = FLASH_Set_Lock_Confirm;  // Confirmation

            timeout = 5000000;

            while(((stat = ROM[0]) & FLASH_Status_Ready) != FLASH_Status_Ready) {

                if (--timeout == 0) break;

            }

        }

        bp += block_size / sizeof(*bp);

    }

    // Restore ROM to "normal" mode

    ROM[0] = FLASH_Reset;

    FLASH_WRITE_DISABLE();

    return stat;

}