source: rtems/bsps/powerpc/mpc55xxevb/start/bspstart.c @ 762fa62

/**
 * @file
 *
 * @ingroup mpc55xx
 *
 * @brief BSP startup code.
 */

/*
 * Copyright (c) 2008-2013 embedded brains GmbH.  All rights reserved.
 *
 *  embedded brains GmbH
 *  Dornierstr. 4
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.org/license/LICENSE.
 */

#include <mpc55xx/mpc55xx.h>
#include <mpc55xx/regs.h>
#include <mpc55xx/edma.h>
#include <mpc55xx/emios.h>

#include <string.h>

#include <rtems.h>
#include <rtems/config.h>
#include <rtems/counter.h>

#include <libcpu/powerpc-utility.h>
#include <bsp/vectors.h>

#include <bsp.h>
#include <bsp/bootcard.h>
#include <bsp/irq.h>
#include <bsp/irq-generic.h>
#include <bsp/linker-symbols.h>
#include <bsp/start.h>
#include <bsp/mpc55xx-config.h>

/* Symbols defined in linker command file */
LINKER_SYMBOL(mpc55xx_exc_vector_base);

unsigned int bsp_clock_speed = 0;

uint32_t bsp_clicks_per_usec = 0;

static void null_pointer_protection(void)
{
#ifdef MPC55XX_NULL_POINTER_PROTECTION
        struct MMU_tag mmu = { .MAS0 = { .B = { .TLBSEL = 1, .ESEL = 1 } } };

        PPC_SET_SPECIAL_PURPOSE_REGISTER(FSL_EIS_MAS0, mmu.MAS0.R);
        __asm__ volatile ("tlbre");
        mmu.MAS1.R = PPC_SPECIAL_PURPOSE_REGISTER(FSL_EIS_MAS1);
        mmu.MAS1.B.VALID = 0;
        PPC_SET_SPECIAL_PURPOSE_REGISTER(FSL_EIS_MAS1, mmu.MAS1.R);
        __asm__ volatile ("tlbwe");
#endif
}

uint32_t _CPU_Counter_frequency(void)
{
        return bsp_clock_speed;
}

void bsp_start(void)
{
        null_pointer_protection();

        /*
         * Get CPU identification dynamically. Note that the get_ppc_cpu_type()
         * function store the result in global variables so that it can be used
         * latter...
         */
        get_ppc_cpu_type();
        get_ppc_cpu_revision();

        /*
         * determine clock speed
         */
        bsp_clock_speed = mpc55xx_get_system_clock() / MPC55XX_SYSTEM_CLOCK_DIVIDER;

        /* Time reference value */
        bsp_clicks_per_usec = bsp_clock_speed / 1000000;

        /* Initialize exceptions */
        ppc_exc_initialize_with_vector_base(
                (uintptr_t) bsp_section_work_begin,
                rtems_configuration_get_interrupt_stack_size(),
                mpc55xx_exc_vector_base
        );

        /* Initialize interrupts */
        bsp_interrupt_initialize();

        #if MPC55XX_CHIP_FAMILY != 566
                mpc55xx_edma_init();
        #endif

        #ifdef MPC55XX_EMIOS_PRESCALER
                mpc55xx_emios_initialize(MPC55XX_EMIOS_PRESCALER);
        #endif
}