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/*
* This file is part of the libpayload project.
*
* Copyright (C) 2014 Imagination Technologies
*
* This program 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; version 2 of the License.
*
* This program 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.
*/
#include <libpayload.h>
#include <arch/cpu.h>
#include <arch/io.h>
#define PISTACHIO_CLOCK_SWITCH 0xB8144200
#define MIPS_EXTERN_PLL_BYPASS_MASK 0x00000002
/**
* @ingroup arch
* Global variable containing the speed of the processor in KHz.
*/
u32 cpu_khz;
/**
* Calculate the speed of the processor for use in delays.
*
* @return The CPU speed in kHz.
*/
unsigned int get_cpu_speed(void)
{
if (IMG_PLATFORM_ID() != IMG_PLATFORM_ID_SILICON)
cpu_khz = 50000; /* FPGA board */
else {
/* If MIPS PLL external bypass bit is set, it means
* that the MIPS PLL is already set up to work at a
* frequency of 550 MHz; otherwise, the crystal is
* used with a frequency of 52 MHz
*/
if (read32(PISTACHIO_CLOCK_SWITCH) &
MIPS_EXTERN_PLL_BYPASS_MASK)
cpu_khz = 550000;
else
cpu_khz = 52000;
}
return cpu_khz;
}
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