/*
 * Copyright (c) 2010-2012, Freescale Semiconductor, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * o Redistributions of source code must retain the above copyright notice, this list
 *   of conditions and the following disclaimer.
 *
 * o Redistributions in binary form must reproduce the above copyright notice, this
 *   list of conditions and the following disclaimer in the documentation and/or
 *   other materials provided with the distribution.
 *
 * o Neither the name of Freescale Semiconductor, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

void StartPerfCounter(void)
{
    asm("mov r1, #12");         /* divider enable (64 cycles/count), cycle counter reset */
    asm("mcr p15, 0, r1, c9, c12, 0");

    asm("ldr r1,=0x80000000");
    asm("mcr p15, 0, r1, c9, c12, 1");  /*enable C bit of c9,Count Enable Set register */

    asm("mov r1, #9");          /* Counter enable */
    asm("mcr p15, 0, r1, c9, c12, 0");
}

unsigned int StopPerfCounter(void)
{
    unsigned int counter = 0;

    asm volatile ("mrc p15, 0, %0, c9, c13, 0":"=r" (counter):);

    asm("ldr r1,=0x80000000");
    asm("mcr p15, 0, r1, c9, c12, 2 "); /*disable C bit of c9,Count Clear register */

    return counter * 64;
}