bcm1480_utils.c

一个很好的嵌入式linux平台下的bootloader

/*  *********************************************************************
    *  Broadcom Common Firmware Environment (CFE)
    *  
    *  BCM1480-specific functions		File: bcm1480_utils.c
    *  
    *********************************************************************  
    *
    *  Copyright 2000,2001,2002,2003,2004
    *  Broadcom Corporation. All rights reserved.
    *  
    *  This software is furnished under license and may be used and 
    *  copied only in accordance with the following terms and 
    *  conditions.  Subject to these conditions, you may download, 
    *  copy, install, use, modify and distribute modified or unmodified 
    *  copies of this software in source and/or binary form.  No title 
    *  or ownership is transferred hereby.
    *  
    *  1) Any source code used, modified or distributed must reproduce 
    *     and retain this copyright notice and list of conditions 
    *     as they appear in the source file.
    *  
    *  2) No right is granted to use any trade name, trademark, or 
    *     logo of Broadcom Corporation.  The "Broadcom Corporation" 
    *     name may not be used to endorse or promote products derived 
    *     from this software without the prior written permission of 
    *     Broadcom Corporation.
    *  
    *  3) THIS SOFTWARE IS PROVIDED "AS-IS" AND ANY EXPRESS OR
    *     IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, ANY IMPLIED
    *     WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 
    *     PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED. IN NO EVENT 
    *     SHALL BROADCOM BE LIABLE FOR ANY DAMAGES WHATSOEVER, AND IN 
    *     PARTICULAR, BROADCOM SHALL NOT BE LIABLE FOR 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), EVEN IF ADVISED OF 
    *     THE POSSIBILITY OF SUCH DAMAGE.
    ********************************************************************* */

#include "cfe.h"
#include "bcm1480_regs.h"
#include "bcm1480_scd.h"


/*  *********************************************************************
    *  bcm1480_cpu_speed(void)
    *  
    *  Read the PLL divider in the SCD configuration register and
    *  compute the CPU clock frequency.
    *
    *  Input parameters: 
    *  	   none
    *  	   
    *  Return value:
    *  	   CPU clock frequency, in Hz
    ********************************************************************* */

unsigned int bcm1480_cpu_speed(void);

unsigned int bcm1480_cpu_speed(void)
{
    uint64_t syscfg;
    int plldiv;
    unsigned int cpu_speed;

    syscfg = SBREADCSR(A_SCD_SYSTEM_CFG);
    plldiv = G_BCM1480_SYS_PLL_DIV(syscfg);
    if (plldiv == 0) {
	/* default, keep in synch with ui_cpuinfo.c */
	plldiv = 6;
	}

#ifdef _FUNCSIM_
    cpu_speed = 500000;			/* wire func sim at 500KHz */
#else
    cpu_speed = 50000000 * plldiv;	/* use PLL divisor */
#endif

    return cpu_speed;
}